So I've got another question to ask. Been searching for a few hours but haven't come across a real similar case yet. So anyways, the past two days I've been making a bunch of new test loads for my Magnum Research 1911 in 45acp. So this load is a 230gr Nosler Sporting Handgun truncated cone bullets, with 6.0gr of Unique in Speer brass. I have to set the OAL at 1.173" and crimp at .471" to get this to feed into my barrel and pass a drop test correctly. It ends up being below flush by about .007". I believe that I have a short chamber in my 1911 which paired with the TC bullets made me have to do this, otherwise the bullet hits on the lands before it fully chambers. Do you think that this round can still be test fired with that short of a length? Main concern I have iis about over-pressure, unsure how prone Unique is to it with large varience in the volume of the case. My brain is telling me that it shouldn't be an issue since the 45acp is such a low pressure cartridge and I'm in the middle of the powder range, but I feel better to ask first before I do a test fire. If you guys think that it shouldn't be a big concern, I'll go test them and check out the cases for any signs.
45acp load w/ Nosler Sporting Handgun Bullet
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LiveLife
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Use Walkalong's thread to determine the OAL.Lerk said:
I ran into similar issue when I was barrel drop testing to determine the OAL for HSM 230 gr HP as the bullet base was longer. I ended up using much shorter OAL but when compared to a RN, the bearing surface of the bullet base was at the same location above the case mouth (see comparison picture below with HSM 230 gr HP bullet in the middle)
If you think the bullet base might compress the powder charge, measure the OAL and subtract the length of the case - subtract this number from the length of the bullet to determine how deep the bullet base will seat inside the case neck. If the distance from the case mouth to the top of the powder charge is more than that number, then you are OK. If it is less, then you may have a compressed load and may consider less dense powder that will leave more room for the bullet base to not compressing the powder charge (I was using 5.0 of W231/HP-38 and I had plenty of room but if I was using a bulkier flake powder, I may have compressed the charge).
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For my drop test I use Walkalong's method. Gotta pull a bullet quick to check my powder dimension.
According to my numbers, I'm compressing by about .030", but my judgement says that probably closer to .010"-.015" maybe even less, the bullet bottom and powder top are pretty dang close. I made sure not to shift the powder around too much, didn't want to pack it down or anything, so it was still very loosely packed for the measurement. Here's my numbers if you want to run it yourself:
OAL: 1.164"
COAL: .995"
Bullet Length: .624"
From top of cartridge to top of powder: .425"
From those numbers I determined from the base of the cartridge to the top of the powder is .570" and from the base of the cartridge to the bottom of the bullet was .539".
From observation the powder could be packed down a condsiderable amount yet, but I would guess the .570" would be closer to .550" under normal movement. Even if my guess is incorrect, it still appears to be a small amount of compression according to the numbers. Be wary of a pressure spike with Unique?
I will pull down two more and check again, but I kept a close eye on every cartridge to ensure they were the same, so I am not expecting any large differences.
According to my numbers, I'm compressing by about .030", but my judgement says that probably closer to .010"-.015" maybe even less, the bullet bottom and powder top are pretty dang close. I made sure not to shift the powder around too much, didn't want to pack it down or anything, so it was still very loosely packed for the measurement. Here's my numbers if you want to run it yourself:
OAL: 1.164"
COAL: .995"
Bullet Length: .624"
From top of cartridge to top of powder: .425"
From those numbers I determined from the base of the cartridge to the top of the powder is .570" and from the base of the cartridge to the bottom of the bullet was .539".
From observation the powder could be packed down a condsiderable amount yet, but I would guess the .570" would be closer to .550" under normal movement. Even if my guess is incorrect, it still appears to be a small amount of compression according to the numbers. Be wary of a pressure spike with Unique?
I will pull down two more and check again, but I kept a close eye on every cartridge to ensure they were the same, so I am not expecting any large differences.
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Ok on checks 2 and 3:
OAL: 1.171", 1.173"
COAL: .995", .995"
Bullet Length: .624", .624"
From top of cartridge to top of powder: .452", .459" (I purposely shook and tapped the cartridges to let the powder pack down and settle, I never pushed on the powder with anything though)
Results in bottom to powder top: .543", .536" and bottom to bullet bottom: .547", 549"
So that gives me a space of .004" on Cartridge #2 between the powder and bullet bottom. On #3 come up with a space of .013" between powder and bullet. According to this data I should be alright as I have a tiny gap between them. Cartridge check #1 had the shortest OAL of all 10 of the rounds I made, so it would be the cartridge with powder compression if any of them were going to have it. COAL of all 10 were nearly identical, less then .0005" difference in them.
On the assumption that my powder charges were all the same (I did check every single one of them during loading, so they should be within +/- .1 gr) and that the bullet lengths were all similar, I come to the conclusion that all ten cartridges should have a tiny gap between powder and bullet. Sound like an accurate statement?
OAL: 1.171", 1.173"
COAL: .995", .995"
Bullet Length: .624", .624"
From top of cartridge to top of powder: .452", .459" (I purposely shook and tapped the cartridges to let the powder pack down and settle, I never pushed on the powder with anything though)
Results in bottom to powder top: .543", .536" and bottom to bullet bottom: .547", 549"
So that gives me a space of .004" on Cartridge #2 between the powder and bullet bottom. On #3 come up with a space of .013" between powder and bullet. According to this data I should be alright as I have a tiny gap between them. Cartridge check #1 had the shortest OAL of all 10 of the rounds I made, so it would be the cartridge with powder compression if any of them were going to have it. COAL of all 10 were nearly identical, less then .0005" difference in them.
On the assumption that my powder charges were all the same (I did check every single one of them during loading, so they should be within +/- .1 gr) and that the bullet lengths were all similar, I come to the conclusion that all ten cartridges should have a tiny gap between powder and bullet. Sound like an accurate statement?
LiveLife
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If the bottom of the bullets barely touch the top of the powder charges or have slight air gap, you should be fine.
Bulky large flake powders may tolerate slight powder compression. I use Promo for 9mm/45ACP loads and the flake size is larger than Unique and bulkier. I use 4.0 gr of Promo for 125 gr 9mm LRN/200 gr 45ACP LSWC loads and they do not result in compressed loads - http://www.thehighroad.org/showthread.php?p=7679116#post7679116
When I did load development with Promo and Missouri 9mm 125 gr RN with longer bearing surface than more typical 9mm "stepped" RN that would result in bullet base seating deeper in the case neck, I was concerned with the bullet base compressing the powder charge that filled the case quite full. Actual measurements showed that I would have a slight air gap between the bottom of the bullet and the top of the powder charge.
Bulky large flake powders may tolerate slight powder compression. I use Promo for 9mm/45ACP loads and the flake size is larger than Unique and bulkier. I use 4.0 gr of Promo for 125 gr 9mm LRN/200 gr 45ACP LSWC loads and they do not result in compressed loads - http://www.thehighroad.org/showthread.php?p=7679116#post7679116
When I did load development with Promo and Missouri 9mm 125 gr RN with longer bearing surface than more typical 9mm "stepped" RN that would result in bullet base seating deeper in the case neck, I was concerned with the bullet base compressing the powder charge that filled the case quite full. Actual measurements showed that I would have a slight air gap between the bottom of the bullet and the top of the powder charge.
9mm case with 4.0 gr of Promo
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