Post by Bullshop on May 22, 2020 11:25:00 GMT -7
This is a really quick simple test and is one part of what I hope to test in the future. This test though it didn't prove anything does perhaps reveal some possibly helpful information.
This came about because I wanting a fairly soft batch of bullets to try in a 33 WCF maybe over did the pure lead content of the mix so they came out softer than wanted at BHN-9, proof a scale works better than the bout that much method of measuring. I was hoping for about BHN -11 or so but I got what I got so lets make it work is the positive attitude employed.
Come to think of it says I this is a perfect opportunity to run a test with powder coat to see if that may make the bullets perform as if they were harder. So with that thought we set to coating some of this BHN-9 batch of RCBS 33-200 FN-GC bullets. With a single coating completed measuring some with and without revealed on average of .0025" coating thickness. That seemed about right so I went about sizing, lubing, and gas checking a batch of both coated and non-coated.
That done I set about loading some of each with our standard (for hard bullets) load of 37.5gn of IMR 4895. I had 13 pieces of formed brass on hand so loaded 7 with PC and 6 without. The target shown seems to indicate that the standard load at about 2100 fps was a wee bit over the top for chamber pressure with a BHN-9 alloy weather coated or non coated. The targets were fired at 50 yards with the factory buckhorn sight and to me seems to indicate that we were just slightly over the top in chamber pressure but not by much and that the PC made no difference for the better. Its hard to see but one of the center holes with the PC is a double but remember there were 7 PC holes in that target with only 6 of non-PC
So with the feeling that a slight reduction in chamber pressure might be appropriate with this soft of an alloy I reloaded with a slightly reduced load of 35.7gn IMR 4895. This time I decided to shoot 5 of each so it was maybe less confusing (for me) to mentally grasp the results. This second target pretty much proves the chamber pressure theory because both coated and uncoated shot much better. So in looking at the results of the second target can we draw any definite conclusions as to weather the coated bullets were superior in some way ? I think not because both showed about the same improvement with the chamber pressure adjusted to the alloy hardness. That single target may show an accuracy edge in favor of PC but that is only one target where several may show about an equal average.
An interesting point is the shift in point of impact between the two. Why would that be so ? I guess I will just have to shoot more to find out why and if averages might favor one over the other. Our weather went south with mixed rain and snow so this will have to continue another day.
Another point I hope to explore about PC VS non-PC is with high velocity hard alloy bullets to find out if in that application the PC bullet can raise the top end velocity threshold over a conventionally lubed alone.
Well this was a start of hopefully an educational process.
This came about because I wanting a fairly soft batch of bullets to try in a 33 WCF maybe over did the pure lead content of the mix so they came out softer than wanted at BHN-9, proof a scale works better than the bout that much method of measuring. I was hoping for about BHN -11 or so but I got what I got so lets make it work is the positive attitude employed.
Come to think of it says I this is a perfect opportunity to run a test with powder coat to see if that may make the bullets perform as if they were harder. So with that thought we set to coating some of this BHN-9 batch of RCBS 33-200 FN-GC bullets. With a single coating completed measuring some with and without revealed on average of .0025" coating thickness. That seemed about right so I went about sizing, lubing, and gas checking a batch of both coated and non-coated.
That done I set about loading some of each with our standard (for hard bullets) load of 37.5gn of IMR 4895. I had 13 pieces of formed brass on hand so loaded 7 with PC and 6 without. The target shown seems to indicate that the standard load at about 2100 fps was a wee bit over the top for chamber pressure with a BHN-9 alloy weather coated or non coated. The targets were fired at 50 yards with the factory buckhorn sight and to me seems to indicate that we were just slightly over the top in chamber pressure but not by much and that the PC made no difference for the better. Its hard to see but one of the center holes with the PC is a double but remember there were 7 PC holes in that target with only 6 of non-PC
So with the feeling that a slight reduction in chamber pressure might be appropriate with this soft of an alloy I reloaded with a slightly reduced load of 35.7gn IMR 4895. This time I decided to shoot 5 of each so it was maybe less confusing (for me) to mentally grasp the results. This second target pretty much proves the chamber pressure theory because both coated and uncoated shot much better. So in looking at the results of the second target can we draw any definite conclusions as to weather the coated bullets were superior in some way ? I think not because both showed about the same improvement with the chamber pressure adjusted to the alloy hardness. That single target may show an accuracy edge in favor of PC but that is only one target where several may show about an equal average.
An interesting point is the shift in point of impact between the two. Why would that be so ? I guess I will just have to shoot more to find out why and if averages might favor one over the other. Our weather went south with mixed rain and snow so this will have to continue another day.
Another point I hope to explore about PC VS non-PC is with high velocity hard alloy bullets to find out if in that application the PC bullet can raise the top end velocity threshold over a conventionally lubed alone.
Well this was a start of hopefully an educational process.
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