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Post by Bullshop on Feb 24, 2022 14:41:34 GMT -7
Until now I have only read excerpts from the book by Dr Franklin Mann, "" the bullets flight from powder to target"" but since I so thoroughly enjoyed Ned Roberts book about muzzle loading rifles I really wanted to read this classic. I just started it but cant put it down and am now about half way through. I wanted to here point out three things that are in stark contrast to current common belief in shooting cast bullets. Rather than wait and possibly forget I want to point out these three things before I continue reading. I am going to summarize to keep it short and simple, FOR NOW.
#1 Of the three methods of loading tested, Pope muzzle/breach loading, fixed ammo, and breach seating or what Mr Mann calls forward loading. Of these three different methods of introducing the bullet into the bore breach seating proved the most consistently accurate even over the Pope system but they were close and fixed ammo coming in last.
#2 Pure lead always out shot alloyed lead
#3 Bore diameter bullets always out shot groove or over groove diameter bullets.
Please note that these were his early tests done from about 1898 to 1905 and all shooting was with black powder. Another point was that smooth bullets without lube grooves predominantly shot better than grooved/lubed bullets.
Now just think about those things in relation to what your current belief may be on this subject. I am also thoroughly enjoying this book and already have in mind several tests I want to do regarding these and a few other points brought up in the book. The only way to describe what I am feeling is """ hog Heaven""!
Later, --- must go read!!!!
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Post by Bullshop on Feb 25, 2022 8:34:34 GMT -7
Something else to ponder, his most accurate bullet shape was a perfect cylinder. It was smooth lacking any lube grooves flat at both ends and of bore not groove diameter. He tried different shaped bases and noses and ogives but the cylinder shot best. So interesting!
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Post by missionary on Feb 25, 2022 11:06:38 GMT -7
So far it is all very interesting ! I know his writings and investigations were highly respected by the big name ballistics men and shooters of that era. 100 yards and less it would not mean a whole lot with a cylinder slug but eventually air resistance / drag would make a horrible rainbow drop. Does this book have any photos / drawings of the massive rifle rests that were used in the test firings? Saw some in a book and I was much impressed what they used to lock a rifle into the recoiling equipment.
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Post by todddoyka on Feb 25, 2022 12:02:24 GMT -7
jeepers creepers!!!!!! give a guy a break on muzzleloaders, will ya? i'm still learning on cast boolits in my rifles.
i have to read Dr Mann says too.
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Post by Bullshop on Feb 25, 2022 18:06:05 GMT -7
He started his 40 year adventure with two goals. One was to achieve best possible accuracy and the other to identify the cause of the off shot in a group. To those ends he dedicated much of his life and recourses. He recorded every test many of which were photographed. The book for the most part is a collection of the tests with evaluation of the results and all photos taken. The standard he set for group shooting was 100 yards. He was only concerned with accuracy to that range and not beyond though they were applying lessons learned to their woodchuck guns a sport that apparently was popular enough at the time that there were clubs and resorts dedicated to the endeavor. His primary goal was to positively identify the cause of the too frequent off shot in a group. In his testing he dispelled may common beliefs that he proved myth. I have prepared some smooth side bore diameter bullets cast in pure lead that I now must try breach seating in my 38-55. My mind is a clutter of ideas to try being guided by his work. We are really cold right now so much that work has been all inside for a few days but Lord willing when it warms I have some shooting to do. Mike you mean what they dubbed " the Gibraltar rest" for its ruggedness. Yes it is well represented in both description and photograph.
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Post by missionary on Feb 26, 2022 5:50:33 GMT -7
That does sound like the rest. I will do a little hunting about. There probably was several similar ones used. I a thinking right now it was what the Springfield Armory used as they were testing the Trapdoor rifles and into the Krag.
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Post by Bullshop on Feb 26, 2022 9:01:36 GMT -7
The trapdoor and Krag were already in existence when the Gibraltar was built. They did use it to test the Krag cartridge and arsenal bullets. Something interesting is the concentric mounting system developed to precisely replace a barrel after it had been removed from the rest. The test barrels were made to fit the rest and each had a short cylindrical chamber that allowed the barrel 360* circular travel in the rest. This allowed testing to determine if the bore was concentric to the barrel. Shooting a group and turning the barrel 1/4 revolution between shots told the story. In this regard Pope barrels were very good even after considering the fact that in comparison he used rather primitive machinery to make them. A barrel that is .010" non concentric will shoot a 20"group at 100 yards in that test just owing to the non concentricity of bore to barrel. We have here a modern production rifle made in Europe that is a copy of the 1885 Winchester chambered in 45-70. It was purchased for conversion to 50-90 but after the purchase it was discovered that the bore is so non concentric to the barrel that on the thin side will not make the minimum required barrel wall thickness of .100" to bore to 50 caliber. The outside diameter is more than adequate but the defect is so acute that it rendered the conversion unsafe. Now considering the stark difference between the tooling and machinery Pope had to work with and what the maker of the afore mentioned 45-70 rifle had to work with the quality of work turned out by Mr. Harry M Pope is quite astonishing.
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Post by missionary on Feb 26, 2022 12:40:13 GMT -7
I may not be remembering right but did not the early barrel makers bore the blank first then turn the outside diameter ? That to me makes far more sense. But then mass production was not their goal as profit drives the methods today.
I have been rebuilding pocket watches 30 years now. The "approved" method today to clean a movement is the ultra-sonic devices. But I have seen the results. Granted the dirt and oil is removed but there is no visual hand time actually viewing the parts for defects and wear. Not sure how many watches I have repaired that were "clean" but terribly defective. So I continue with the old way of cleaning with pig bristle brushes and benzine. That is how I feel about 100 year old firearms. There was a whole different mentality in control of the finished product. Can still be found in small businesses today happily. Henry Rifles somewhat still reflect that.
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Post by Bullshop on Feb 26, 2022 13:00:53 GMT -7
I hope that my work in my business is considered as such.
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Post by missionary on Feb 26, 2022 16:49:33 GMT -7
Why Dan if I ever thought you were not what you are I would ask you if you got hit on the head with something real hard. If you then told me you saw life real different I would stop advising fellers to jab keys your way.... But happily you are one of the good ones who's product is #1 G.I.!!!
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Post by Bullshop on Feb 27, 2022 12:44:35 GMT -7
Now an interesting development. In late 1904 through 1905 it was decided to move from black powder to smokeless powder. The powder used was Sharpshooter an early fast (for rifle) burning powder. The switch from black to smokeless powder changed the pressure dynamics and it was then discovered that pure lead no longer shot best. Through further testing it was proven that alloyed lead now shot better than pure lead which is the reverse of black powder. At about the same time in 1905 they started testing jacketed bullets which also again changed the pressure dynamics. I am impatiently waiting on some warmer weather to try a few things I have prepared for my 38-55 roller. Yesterday I made a breach seater to seat the bullets fully into the barrel ahead of a charged case. I have ready two different bullets one a custom tapered grooved bullet and one a smooth. These are sized to bore diameter accept for the very base band of the grooved bullet being groove diameter. This base band idea is something else extensively tested by Mr. Mann that seemed to consistently give best results. I have bullets cast in pure lead to be tried with black powder as well as alloyed for use with smokeless powder. The smokeless powder I will try is Trail Boss which has already proven accurate with a 300gn tapered spitzer bullet from the same rifle. A number of years ago I won a postal match with that load putting 10 shots into something around .75" at 100 yards with the old roller mounted with an old Weaver T-20 with custom reticle. That more modern scope looks a bit out of place on the roller but it sure works good for testing loads. Once loads are developed I mount an early Parts Unknown long range vernier sight for general target and long range shooting. I doubt if I will shoot jacketed bullets in the 38-55 as I progress with the book but when I get to that point I have a very accurate 308win for that purpose. Interestingly when the switch was made to jacketed bullets he stayed with bore diameter , at least to this point in late 1905.
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Post by Bullshop on Feb 27, 2022 16:16:58 GMT -7
Today no longer able to tolerate being confined to the house I decided to brave the cold and wind to try a few new tricks I learned from Dr. Mann. Its still bitter cold so my hands were freezing and my eyes watering from the wind but I think we have moved forward with our knowledge base. We had to overcome a few other obstacles like the re-mounting of the scope and the change in pressure dynamics between powder charges previously used in fixed ammo and now with forward seating. The powder charged was greatly increased from fixed at 8gn to forward loading at 15gn with the same powder Trail Boss and bullet weight 300gn. In todays shooting 15gn shot best with both bullets but the smooth bore diameter bullet apparently affords so little resistance that at 100% load density chamber pressure need to increase slightly to improve velocity consistency. The problem encountered is that 15gn is a case full and has to be settled by flicking the case before removing from the powder drop or the over heaping powder spills a bit. Flicking a few time settles the powder flush with the case mouth and then topped with a thin card wad. The grooved base band bullet provides enough more resistance that it seemed more consistent grouping but the smooth bore diameter with zero resistance to seating fully into the barrel shows a lot of promise too. I went with the smokeless powder today instead of black because wiping after each shot in such cold becomes difficult so I went with smokeless but stayed with pure lead. Though the results were limited by the weather they none the less show promise and I intend to, Lord willing keep working under the tutelage of Dr. Mann's experience. I took a picture of the target so will get Tina to post it. Interesting is that the large cluster at the bottom is a combination of both bullets while working up the powder charge to 100% density. The first couple tries with smaller charges didn't reach the target accept for the one that bounced. The first shots with 8gn hit the ground well short of the target with very little report and recoil. The final charge of 15 grain was beginning to make a sharp crisp crack to the report. This rifle previously has always been very finicky about loads and took a great amount of time to narrow down what it would shoot well. This simple test in very unfavorable conditions seems to have tamed the beast into a dove. I should have read this book a long time ago! Attachments:
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Post by missionary on Feb 28, 2022 5:36:50 GMT -7
Good Morning The simple joy of applied labor (study also) sure makes a day shine in the heart. The elements will certainly be a hinderence in your pursuit. I remember a 2nd model 1873 in 44 WCF I spent several months gathering parts for some years back. The final Monday I had free before return here was 12 degrees and windy. Did not take long to abandon the 100 yard elevated rifle spot for a slightly less windy 25 yard target space. Some feller built a small "shack" on skids he could move to different distances on his personal range. Just being out of the wind (or wet) is a big help.
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Post by Bullshop on Mar 1, 2022 17:38:12 GMT -7
Think maybe I am honing in on it. Still shooting smokeless powder but not getting good consistent results with the smooth bore diameter or maybe slightly under bore diameter at .3665" My rifle bore dimensions are .368" x .376" The other bullet the tapered grooved bullet is giving very consistent results. Today 3/1/22 I shot the grooved bullet with a charge of 8.5gn Red Dot with just a thin card wad at the mouth of the case. The bullet is fully seated into the barrel about 1/32" ahead of the chamber end. Conditions of the day were much warmer so no freeze ups but very windy. The wind was from about 10:00 and gusting hard enough to blow the cross hairs completely off the target. I tried to shoot between gusts but looking at the angle of dispersion of the group it still seems to have had its effect. No matter though as this trial with pure lead bullets seems to be moving in a positive direction. Let me see if I can get someone to add the picture of todays target, hold on. Attachments:
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Post by todddoyka on Mar 1, 2022 18:44:45 GMT -7
very nice group!!!! even if it was windy!!!
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Post by missionary on Mar 1, 2022 18:47:18 GMT -7
That is looking like good progress. I am guessing that is a 2 inch square so about a one inch group with wind issues from a rifle that was not grouping. Makes me smile from 4500 miles away !
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Post by Bullshop on Mar 16, 2022 16:02:25 GMT -7
Here I am going to ramble on a bit about shooting my 6mm BRM today partly because I want to share what I am learning and partly because the site needs to generate a little chatter. Todays shooting revealed some interesting results and also confirmed some of the conclusions Dr. Mann came to in his extensive testing of bullets tipping in flight and the results it can cause. One thing that stuck with me as I read his book is that he stated that at some point in its trajectory arch that all bullets become tippers. There are different causes of bullet tipping one being inadequate rotational velocity caused by too slow a rifling twist rate for the bullet length being used. Dr. Mann as have I demonstrated that when a bullet is borderline stable or I should say borderline unstable that stability can be improved by increasing the muzzle velocity but obviously there are limits. By shooting through paper screens at 10 foot intervals for 200 yards he also demonstrated that for such a marginally stable bullet that it will print perfect nose forward holes at various ranges and at all ranges inbetween will show signs of tipping, interesting! Todays shooting for some reason broke with protocol and instead of starting at 100 yards started at 60 yards. The reason was that I didnt want to walk all the way out to the shooting bench (100 yards) to test a couple shots to see if the load was worth perusing. For that reason the two shots I had to try I walked the 25 yards to my pick up and shot over the hood. Those looked good so I put a shooting bag on the hood and resting the forend on that I shot a 5 shot .431" group that I was quite pleased with so loaded more for testing at 100 yards. If I had started shooting at 100 yards as usual I likely would have abandoned the load for poor performance and never known how good it shot at 60 yards. I guess I should point out my purpose for wanting to develop a very light load in the 6mm BRM which is to exterminate the gophers that will be appearing soon about my garden plots. The load tested today was with the 100gn RCBS bullet over 4.5gn Red Dot sparked by a CCI large pistol primer. OK so when I got to testing the load at 100 yards I was unpleasantly surprised to find that adding another 40 yards to the range cause a very accurate 60 yard load to fall apart and shoot 1.8" at best for 5 shots. WHAT!!! I thought when I walked to the target expecting to se a group somewhere around .75" What happened? Then I started thinking about DR Mann and what he said about all bullets becoming tippers at some point in their trajectory arch. On close inspection of the target the telltale sign was there of the tipping bullet. What Dr. Mann pointed out is that as a bullet slows its trajectory curve becomes more acute and as the angle of drop increases the bullets angle of flight is changing from it forward motion and so has more frontal area exposed so is battling increased atmospheric drag. The bullets attitude weather up following its original line of fire or down following its center axis and staying point on in its trajectory arch either way is not in line with its forward motion. If the bullets attitude is upward from its forward motion the air resistance is pushing its nose upward and if the bullets nose is following its trajectory curve the air resistance is pushing the bullets nose downward. Either condition at some point causes the bullet to wobble which also increases drag which slows the bullet more rapidly so adds to the drop angle and air resistance. WOW!!! That was hard to explain. Oh yea I should add that the additional 40 yards from 60 to 100 yards caused 9" additional bullet drop from 60 yard zero. Anyway I believe from what I have learned from his book that I can stretch the 60 yard accuracy to 100 yards buy increasing the velocity but that gets a little tricky when using powders that are near a max charge with about half a dozen grains. I think the trick will be something I learned from Harvey Donaldson's book where he pointed out that when a volume charge is found to work good when going to a heavier bullet do not change the volume but just go to a slower burn rate at the same volume. Well I am not going with a heavier bullet but by going to a slightly slower powder may give enough longer push that the velocity might increase enough to get the holes on target to be round at 100 yards. Possibly a combination of slightly slower burn and slightly increased charge weight. What I have found in the past is that when going to a slower burn rate but staying with the same volume the charge weight is increased because the slower burn rate has a higher density. So thats about all that happened today before I got run out by a nasty snow squall that is presently occupying my shooting range. At least I found a super 60 yard load and most shots at garden pests are within that range.
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Post by shootist---Gary on Mar 16, 2022 19:37:49 GMT -7
Daniel, I think that by this time in your life, you have earned a "Master's Degree" in ballistics. You do a very good job of figuring things out, & then are able to explain how you did it. I really enjoy reading your posts, even though a lot of these tests won't benefit me, but will others. Thanks.
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Post by missionary on Mar 17, 2022 8:23:47 GMT -7
Some I re-read 3x and then know I will need to re-think it all.
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Post by missionary on Mar 17, 2022 15:03:00 GMT -7
I sure did enjoy reading Harvey Donaldson's articles in the old Handloader magazines. I do remember that article about same volume loads as it was printed in a old Handloader which I removed and is in one of my binders up north there. I have never tried the practice but may have to one day.
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Post by Bullshop on Mar 17, 2022 15:08:18 GMT -7
Gary you are my friend and because you are may have an inflated image of my abilities. I dont always figure it out but I am always trying. After I read you post I started thinking about transonic turbulence as another possible cause my widening groups at 100 yards. I have been so focused on Dr. Manns experiments that I didnt consider other possibilities. So far at about 3/4 through his book he has not addressed transonic turbulence but he might in the last chapters, we shall see. Anyway as I was shooting I was thinking that the velocity of the load was probably somewhere around the speed of sound at about 1100 fps at my 6000 ft. elevation. The idea that the bullet maybe starting out at a supersonic speed and remaining supersonic out to the 60 yard target but then in the next 40 yards of travel possibly going transonic had not occurred to me until after I read your post. I didnt have the chronograph out because of the bad weather. It may be interesting to chronograph at three points one near the muzzle, one at 50 yards and one at 100 yards. That might tell me something. If it is a possible source of the groups widening a possible cure might be to either keep the velocity subsonic or supersonic for the bullets entire flight and avoid a combination of both.
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Post by Bullshop on Mar 20, 2022 7:35:03 GMT -7
Our weather here on Friday was so nice I decided to take the afternoon off from work and do more shooting with the 6mm BRM to work toward discovery on the grouping issue being very good at 60 yards but badly degrading at 100 yards. I decided to first start out by trying to get the velocity lower instead of higher to where the bullet would start out subsonic. I cant really say why I changed powder from Red Dot to Alcan 101 but I did likely because I got the Alcan powder at a gun show last year for $5.00 a can and it always gives me a good feeling to do good shooting with cheap powder. The two powders have nearly identical burn rate so I just started reducing the charge weight from the 4.5gn I had been using and slowly working down until or if I began to get better accuracy at 100 yards. At a miserly 2.7 gn groups at 100 yards were hovering very close to but not quite at the one inch mark shaving at least half an inch off of what I was getting with the supersonic load. So by going subsonic for the whole 100 yards we got a couple distinct changes in performance. One was better accuracy which is good and was the goal. Just taking a wild guess at velocity I would say between 700 and 800 fps which caused one of the other changes which was trajectory. The drop in between 60 and 100 yards with the original 4.6gn load was nine inches and dropping the velocity to the 2.7gn load added another nine inches making the total change between 60 and 100 yards 18" of drop. The problem that creates is that with even small changes of a few yards distance changes the POI enough to completely mis my intended targets, gophers which are maybe 2" wide by 7" tall. We got the grouping good enough to stay within the 2" wide at 100 yards but now the trajectory is so high in renders the load pretty much useless for anything other than one set range. Another interesting point was that the holes on paper still show signs of tipping but I believe because there was no transonic turbulence the groups were not spreading quite as wide. Thats my story and I'm sticking to it. Now something I always like to look at is cost and a 2.7gn charge yields 2592.5 shots per pound of powder which if I did the math right is 1 1/2 cents per round. With todays component costs that brings a smile but if its unusable its an empty smile. So with pretty much failure in the subsonic direction it appears that my only corrective course is to increase the velocity enough to stay supersonic for the 100 yard flight. Oh yea another point I did really like about the 2.7gn load is the sound level. The supersonic crack is gone and the remaining sound is so low it sounds like a puff of air from an air gun, I like that. With this experience I have to wonder what all the hoopla is about subsonic ammo. Unless you have a range finder and run a computer program its going to be hard to make hits much farther than peeing range. Anyhoo next attempt will be in the direction of higher velocity and I guess a supersonic crack is part of the price I will have to pay.
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Post by missionary on Mar 20, 2022 8:19:10 GMT -7
I tend to also like the frugal approach to solutions. And you sure reached it. Do you not have a "ballistic" cross hair marked scope ? I would think 10 yards from the muzzle there is little noise.
That looks like pellet gun velocity. We have a .25 caliber Hatsun and a .177 Blue Streak that get used for gophers and pests. My idea is if it weights more than 15 pounds the .25 gets the call. So far works out real well to 50 yards. Out to 100 yards we have not tried as our residence for the last 12 years when north only offered 50 yards of needed extermination.
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Post by Bullshop on Mar 20, 2022 14:33:10 GMT -7
That is kind of the problem that either load is a 50 to 60 yard load. With the 2.7gn load it is like shooting a pellet gun only with heavy 100 grain pellets.
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Post by Bullshop on Mar 21, 2022 17:30:04 GMT -7
Today between melting pots of lead I was able to do a little shooting load work toward the gopher load project. I decided to go right about in the middle of the powder burn rate chart and since I have a very comfortable supply went with IMR 4895. Starting at 17gn things looked pretty good but since I could see a little more than normal powder residue in the barrel I kicked it up to 18gn. At 18gn it was shooting very close to 1" at 100 yards. Three 5 shot groups averaged about 1 1/8" to 1 1/4" Not bench rest accuracy but more than adequate for staying inside a 2" wide gopher at 100 yards. This shooting was done with the RCBS bullet that I weighed at 96gn lubed with gas check. A couple days ago I cast more of the RCBS bullets because I was about out and I also ran a few 100 of an LBT spitzer design that runs about 76gn with lube and gas check. Right at the end of my shooting session I decided to substitute the RCBS 96gn bullet with the LBT 76gn bullet but staying with the 18gn IMR 4895 powder charge. I first loaded three rounds of the 5 pieces of brass I had dedicated to this project and shot a tiny cluster that made my heart skip a beat all making a single about 40 caliber hole. That got me motivated so went back inside and loaded the other two pieces of brass and went out and fired them into the same group. The end result of that was that one of the last two went into that same 40 caliber hole and one went about 3/4" from its center. That is what I was really hoping for but didn't dare expect. I will certainly be looking more closely at that load and it comes none too soon either because I spotted the first gophers of spring from the reapers roost today. The down side to this load is its noise level. This rifle an EAB model 97-D has one of his designed breaks that looks like it was scaled down from a tank cannon. It goes a long way in helping to spot my own shots as it does seem to greatly reduce muzzle flip. What it also does is direct the sound right at the shooter so makes the report seem extra loud. With a low noise load I can sometimes get off several shots before they wise up but the big boom gets them running for a hole in one, good in golf but not so in popping pests. Maybe its a good thing having to wait a little longer between shots so the barrel wont heat up in hotter weather if there is such a thing. So that is about where I am at with this right now and I am really liking what I think I am seeing with the LBT bullet. It may not do as well as the heavier RCBS bullet for longer range shooting out to 300 yards or so but this project was all about getting good consistent 100 yard accuracy and I think I may be closing in on that goal.
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Post by missionary on Mar 22, 2022 5:40:37 GMT -7
Does look like any little hole digger within 100 better keep his pesky head way down and be satisfied with using a snorkel.
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Post by Bullshop on Mar 22, 2022 7:06:38 GMT -7
A couple related points I forgot to mention, the rifle has an 8" twist, holes on paper showed no sign of tipping, and though I did not chronograph I estimate the velocity at about 1800 fps with the 96gn RCBS. In assessing the results of shooting the two bullets the RCBS 96gn and the LBT 76gn with the same 18gn charge of 4895 and since the lighter bullet seemed to group a little better might indicate that the 18gn charge is a wee bit over the top for the heavier bullet. To me that means that accuracy with the heavier bullet might be improved by either slightly reducing the powder charge weight for the heavier bullet of go to a slightly slower powder burn rate. This is where the wisdom of Harvey Donaldson comes into play. According to his advice with my powder drop set to throw 18gn of 4895 powder leaving it at that setting and going to a slightly slower powder burn rate should or has great potential to produce the desired results. Using the powder burn rate chart from Hodgdons 2021 annual load guide they assign IMR-4895 with # 96 so going to something with a slightly higher number but close may improve accuracy results. Sometimes consecutive numbers will have identical burn rates so jumping ahead by a few numbers may be practical. Jumping ahead by 5 places puts us at IMR 4064 on the chart so may be something to try if I have some. If not simply staying with the 76gn bullet and 4895 seems like maybe not at all a ban plan.
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Post by Bullshop on Mar 23, 2022 8:43:57 GMT -7
Yesterday was such a gorgeous spring day that I just couldn't stay inside. I got all the casting done to fill all current orders but put off processing and packaging until evening so I could get out the chronograph and do a bit more shooting for this project. The old Ohler model 35-P told a completely different story than I did after the last shooting session. Where I had assumed that the 18gn charge of 4895 was over the top for the 96gn RCBS bullet and where I had assumed from one good target that it was just right for the LBT 76 gn bullets Mr. Ohler told me how wrong I was and that I had much to learn. First off that first target with the 76gn LBT bullet shooting a 40 caliber hole was a fluke and I couldn't get close to that again doing about 2.5" at best. Secondly the velocity uniformity was all over the place with extreme spreads of over 100 fps. With that bit of information and my sometimes not too trustworthy assumption I proceeded to first go to progressively hotter primers as a fix. I had been using LP primers so the progression went like this from LP to LPM the to LR and finally to LRM. The results of the primer shuffle were pathetic but seemed to show that I was best off right where I started with the LP primers. Next attempt at tightening up the velocity spread was to start increasing the powder charge. Where I had again wrongly assumed a velocity of about 1800 fps Mr Ohler again proved me wrong with velocities as high as 2050 fps. That put me in a bit of a bind because I assuming again ( possibly dangerous) that there will be a balance between velocity and max chamber pressure the bullet hardness at about BHN-21 will handle and adding powder until ballistic uniformity improves to an acceptable point may push beyond those limits. Well the home team was having a really bad day because I was wrong again. The affect of adding powder in one grain increments didn't raise the velocity but did increase the uniformity. The first couple grain increase didn't raise velocity but the velocity spread kept getting tighter. At 3 to 4 gran increase the velocity began to climb slightly and the uniformity kept improving. When I hit 23gn or a full 5 gn over where I started at 18gn the velocity had only climbed to 2150 average with an extreme spread of 40. At that all shots were landing in an impressively small hole of what looked like about 50 caliber. I hadn't changed targets for all the shooting so it was pretty shot up but the final several groups in that big raggedy hole had kind of segregated themselves about 2" higher on target than the lesser loads had been centered. I didn't want to take a picture of a shot up target and say see there the ones in the middle because I think that is rather lame because only I see the small group but everyone else just sees a shot up target. Perhaps the load is not yet fully refined and it could improve with still more powder. The session ended right there yesterday but Lord willing I am not done yet. I think that I am getting closer to that balance point I earlier mentioned which may show up at somewhere close to 2400 to 2500. Powder increases are now also starting to show progressive velocity increases so I know we are getting closer to the limit. However if no more progress can be made with this I can live with sub MOA groups and 50 fps velocity spreads if I must. All in all I proved for certain that I am still learning.
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Post by todddoyka on Mar 23, 2022 10:20:26 GMT -7
i don't the 6BRM or how much does it hold, but if it is 60% or less i'd try a tuft of dacron.
when i shot the 444, it was a 300gr fn gc with 24.0gr of 2400 and a tuft of dacron. i forget what case capacity 24.0gr is (is it 30-40% full?). i tried the 20 - 25.0gr of just 2400 and i found +2.5" +/- increase of its accuracy and 100-150fps+/- of extreme spread.
i use dacron in my 35/30-30 too (200gr fn gc with 20gr of 2400/tuft of dacron).
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Post by Bullshop on Apr 2, 2022 14:33:56 GMT -7
I did try a filler with 4895 powder and it did seem to tighten up velocity uniformity but I would just rather avoid it if possible. I decided to drop 4895 because it had moved me too far away from the type of load I was really looking for which is a light recoiling low noise load accurate enough to take gopher to 100 yards. Today I think I found that load. Two things I changed from the Red Dot load that shot so good at 50 yards but not so at 100. The previous load was with the RCBS 96gn bullet with 4.5gn Red Dot. What I changed was the powder burn rate to very slightly slower with IMR-700X and also going to a lighter ( read shorter) bullet. Actually two bullets which are an LBT 76gn spitzer and an NEI 85gn round nose. As the targets show both bullets shot to the same POI and the bottom left target has 6 shots with 3 of each at 50 yards. On the 50 yard target I was simply leaning on a pile of tires but on the 100 yard target I was shooting from my bench with sand bag rest. There was a lot of wobble in the 50 yard shooting. The load was 4.5gn IMR 700X with the CCI # 300 LP primer. The top 50 yard target is with the same sight setting that seemed to zero at 100 yards so that shows a big improvement in trajectory only dropping about 2.5" between 50 and 100 yards a very useful trajectory for shooting gophers out to 100 yards. I am pretty satisfied with this load because it stays well within the width of a gopher out to 100 yards and it is the low intensity low noise type of load I was looking for. Its also nice that I got an 8 pound keg of 700X powder at the last gun show that was at a very good price. Actually I got two kegs of powder for $340.00 which I felt pretty good about. At 4.5gn per shot that a lot of shooting. No chronograph today but I am anxious to do that. With the 2.5" drop between 50 and 100 yards I am guessing somewhere between 14 to 1500 fps, we shall see. Attachments:
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