Post by Bullshop on Aug 10, 2017 12:24:40 GMT -7
While attending the gun show at Wisdom MT two weeks ago I had a fella approach me with a proposition about a couple Husqvarna rolling blocks he had chambered for the 8x58 rimmed Danish cartridge. He was offering to trade me one of the rollers a Husqvarna made sporter for some bullets and some information. What he proposed was a $400.00 trade value for my bullets at my regular bullet cost. That was half of the trade as he wanted me to develop load data for the cartridge as well as find what the barrel bore-groove dimensions are. He also wanted to know how he might go about loading ammo without the correct loading dies as well as what could be used for brass casings other than original 8x58 R brass. This kind o thing is always a delightful challenge for me so I accepted his offer and am now the owner of yet another old roller chambered for an interesting old cartridge the 8x58 RD.
The rifle metal is in very good condition with good bore condition. The barrel bluing is still good over all and there is still much visible case color to the receiver, very nice ! The finish on the wood is terrible but the wood itself looks good and should re finish nicely. The front sight is a ramp with insert but the insert slides in from the front not the side so maybe not so easy to find. The rear sight is a simple dove tail drift for windage but fixed for elevation. The fixed elevation became an issue as POI was quite low to the sights so the only way to correct elevation for now is to hold high. I figured out that by holding the very bottom of the front sight ramp level with the top o the rear sight and centering the front bead on target put me on at 100 yards. This is good for 100 yard hunting but lacks something in precision for target shooting. Anyway we are on paper!
In researching what to use for brass I found some people using 7.62x54 Russian and claiming good results. I didn't have any on hand but found the 45-70 rim dimensions are a near perfect fit in both diameter and thickness so I set about forming some cases from 45-70.
The procedure I used to form cases was to first anneal some brass by setting the heads in a shallow pan of water then heating the neck shoulder area with a propane torch. This seems to have worked well as all cases formed nicely without any loss. After annealing I first tried to form the cases in a 7.62x54 Russian die but found the 45-7- case head diameter too large to fully enter the Russian die. Next I went with a form die to convert 45-70 to 33 Win and this worked well to set the shoulder back and form a neck. Next the necks went into a 357 mag die for diameter reduction and then final neck reduction was in a 32-20 die. The 32-20 die sizes the case necks perfectly to have a firm hold on the .328" diameter bullets I am using.
All the research I have done says this barrel should have a .323" groove but slugging it revealed the bore groove dimensions to be .319" x .326" diameter. Factory bullet weight seems to have been196gn with a jacketed round nose bullet. I wanted to try a bullet diameter at about .002" over my groove diameter and long enough to seat out far enough to come close to the riling in the looooog throated chamber. I have a few molds that will drop that large in diameter but only one that is long enough for that long throat which is the custom group but design we did on that other site called the 8mm max. Mine come out at about .3285" and 250gn with gas check.
A little internet search revealed some pressure testing of some original Norma ammo from the 50's and 60's. The 50's ammo was marked for rolling block but by the 60's they were making no distinction between ammo for rollers or Krag Jorgenson rifles. Some pressure trace data I found is as follows,
#1 Norma designated for rolling block --196gn RN jacketed FMJ @ 20,467 PSI @ 1764 ps
#2 Norma no special designation -- 196gn soft nose @23,350 PSI @ 2058 fps
#3 Norma marked for Danish Krag 196gn SP @ 25,374 PSI @ 2143 fps
The author mentions a slow even rise in pressure from the pressure trace indicating a fairly slow powder burn rate. I decided to play it safe and start with a burn rate that could not produce excessive pressure even with a case full that burn rate being one of the 870 ball powders, H-870, AA-8700 or WC-870. I had all on hand but went with the WC-870 for no other reason that that is what I spotted first. This very slow powder led to my first problem the discovery that I formed cases from Lever Mag brass with small primer pockets. For this reason I used CCI small rifle magnum primers but even the SRM primers were having trouble lighting that very slow dense powder giving hang fires and wide velocity spreads.
Next was to speed up the burn rate a bit and go with extruded powder instead of ball to hopefully improve ignition. I also wanted a fairly bulky powder to fill the case without developing too much pressure. What I decided on is IMR 7383 an extruded powder with the same burn rate as IMR 4831 but with a greater bulk to more completely fill the case. Starting at about 70% load density with this powder was still giving erratic ignition and inconsistent velocity so I slowly increased the powder charge until ignition improved but velocity was similar to the factory Norma ammo. My bullet is heavier that the Norma ammo but they used jacketed bullets which in my own experience yields a higher pressure at equal velocity to that of a cast lubricated bullet. At roughly 1900 ps with my 250gn cast bullet I felt I was about max to stay in the pressure range of the Norma ammo but still not getting the velocity uniformity I wanted. Not wanting to add more powder I decided to try some filler in the form o styro packing popcorn. As it has in other similar situations the PP filler tightened up the chrono numbers and the final 4 shot test string went 1901, 1909, 1912, and 1902 fps. inal adjusted powder charge for this load was 42.5gn IMR 7383. I think the small primers are part of the ignition problem and the next time I form cases I will be sure to use brass with large primer pockets.
The 45-70 re formed cases come up quite a bit short but usable. Ideally I think 45-90 brass should be just right and may require a slight trim to get correct case length. I had very few 45-90 cases available so thought I would start this learning curve with the 45-70 brass then when I perfect a process go with the 45-90 brass.
Well that is where I am so far with this project not finished but well under way. When I get the sight thingy figured out I will try to post some targets to show average accuracy with this rifle load combination. With a 250gn bullet at 1900 fps and for the ranges an iron sighted rifle is good for this rifle will handle any task I could ask of it here in Montana territory. I see now why The three Scandinavian countries decided to make these old rollers available to hunters in sporting configured rifles. Its plenty of cartridge in a very light weight hunting rile and in sporter is equipped with a euro style sling swivel on the barrel and butt stock.
In conclusion, I LIKE IT !!! but then like old Will Rogers " I never met a roller I didn't like"
The rifle metal is in very good condition with good bore condition. The barrel bluing is still good over all and there is still much visible case color to the receiver, very nice ! The finish on the wood is terrible but the wood itself looks good and should re finish nicely. The front sight is a ramp with insert but the insert slides in from the front not the side so maybe not so easy to find. The rear sight is a simple dove tail drift for windage but fixed for elevation. The fixed elevation became an issue as POI was quite low to the sights so the only way to correct elevation for now is to hold high. I figured out that by holding the very bottom of the front sight ramp level with the top o the rear sight and centering the front bead on target put me on at 100 yards. This is good for 100 yard hunting but lacks something in precision for target shooting. Anyway we are on paper!
In researching what to use for brass I found some people using 7.62x54 Russian and claiming good results. I didn't have any on hand but found the 45-70 rim dimensions are a near perfect fit in both diameter and thickness so I set about forming some cases from 45-70.
The procedure I used to form cases was to first anneal some brass by setting the heads in a shallow pan of water then heating the neck shoulder area with a propane torch. This seems to have worked well as all cases formed nicely without any loss. After annealing I first tried to form the cases in a 7.62x54 Russian die but found the 45-7- case head diameter too large to fully enter the Russian die. Next I went with a form die to convert 45-70 to 33 Win and this worked well to set the shoulder back and form a neck. Next the necks went into a 357 mag die for diameter reduction and then final neck reduction was in a 32-20 die. The 32-20 die sizes the case necks perfectly to have a firm hold on the .328" diameter bullets I am using.
All the research I have done says this barrel should have a .323" groove but slugging it revealed the bore groove dimensions to be .319" x .326" diameter. Factory bullet weight seems to have been196gn with a jacketed round nose bullet. I wanted to try a bullet diameter at about .002" over my groove diameter and long enough to seat out far enough to come close to the riling in the looooog throated chamber. I have a few molds that will drop that large in diameter but only one that is long enough for that long throat which is the custom group but design we did on that other site called the 8mm max. Mine come out at about .3285" and 250gn with gas check.
A little internet search revealed some pressure testing of some original Norma ammo from the 50's and 60's. The 50's ammo was marked for rolling block but by the 60's they were making no distinction between ammo for rollers or Krag Jorgenson rifles. Some pressure trace data I found is as follows,
#1 Norma designated for rolling block --196gn RN jacketed FMJ @ 20,467 PSI @ 1764 ps
#2 Norma no special designation -- 196gn soft nose @23,350 PSI @ 2058 fps
#3 Norma marked for Danish Krag 196gn SP @ 25,374 PSI @ 2143 fps
The author mentions a slow even rise in pressure from the pressure trace indicating a fairly slow powder burn rate. I decided to play it safe and start with a burn rate that could not produce excessive pressure even with a case full that burn rate being one of the 870 ball powders, H-870, AA-8700 or WC-870. I had all on hand but went with the WC-870 for no other reason that that is what I spotted first. This very slow powder led to my first problem the discovery that I formed cases from Lever Mag brass with small primer pockets. For this reason I used CCI small rifle magnum primers but even the SRM primers were having trouble lighting that very slow dense powder giving hang fires and wide velocity spreads.
Next was to speed up the burn rate a bit and go with extruded powder instead of ball to hopefully improve ignition. I also wanted a fairly bulky powder to fill the case without developing too much pressure. What I decided on is IMR 7383 an extruded powder with the same burn rate as IMR 4831 but with a greater bulk to more completely fill the case. Starting at about 70% load density with this powder was still giving erratic ignition and inconsistent velocity so I slowly increased the powder charge until ignition improved but velocity was similar to the factory Norma ammo. My bullet is heavier that the Norma ammo but they used jacketed bullets which in my own experience yields a higher pressure at equal velocity to that of a cast lubricated bullet. At roughly 1900 ps with my 250gn cast bullet I felt I was about max to stay in the pressure range of the Norma ammo but still not getting the velocity uniformity I wanted. Not wanting to add more powder I decided to try some filler in the form o styro packing popcorn. As it has in other similar situations the PP filler tightened up the chrono numbers and the final 4 shot test string went 1901, 1909, 1912, and 1902 fps. inal adjusted powder charge for this load was 42.5gn IMR 7383. I think the small primers are part of the ignition problem and the next time I form cases I will be sure to use brass with large primer pockets.
The 45-70 re formed cases come up quite a bit short but usable. Ideally I think 45-90 brass should be just right and may require a slight trim to get correct case length. I had very few 45-90 cases available so thought I would start this learning curve with the 45-70 brass then when I perfect a process go with the 45-90 brass.
Well that is where I am so far with this project not finished but well under way. When I get the sight thingy figured out I will try to post some targets to show average accuracy with this rifle load combination. With a 250gn bullet at 1900 fps and for the ranges an iron sighted rifle is good for this rifle will handle any task I could ask of it here in Montana territory. I see now why The three Scandinavian countries decided to make these old rollers available to hunters in sporting configured rifles. Its plenty of cartridge in a very light weight hunting rile and in sporter is equipped with a euro style sling swivel on the barrel and butt stock.
In conclusion, I LIKE IT !!! but then like old Will Rogers " I never met a roller I didn't like"
