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Gentlemen and Ladies,
Yesterday I was shooting my M39 Finn Mosin Nagant rifle with PPU brass. After firing, and before sizing, I checked the shoulder with a Hornady Headspace guage with my calipers. To my surprise, the brass is stretching .025" after firing. Is this normal for a rimmed case? Thanks.https://uploads.tapatalk-cdn.com/201...2c926e9d02.jpg
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Rimmed cases stretch upon firing, just like rimless and belted cases. When you fire it, the brass stretches to fill the chamber, thus the term “ fire forming”. If your rifle has a very sloppy oversized chamber you will get more stretch, or if the headspace is off, you will get excessive stretching.
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Should I just size the shoulder back a few thousandths by backing my sizing die off? I'm probably overworking my brass by full length resizing. Using Lee pacesetter dies.Quote:
Originally Posted by JeffreyDeGraff
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That is what I would do.Quote:
Originally Posted by Garand46
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Thanks
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Nice fire formed brass now . Neck size and bump a couple thousandths
I don't have a neck sizing die yet. It's on my list to get. I bumped the shoulder back .002 to .003" and it chambers fine. Need some bullets and powder and I'm ready to load some ammo.Quote:
Originally Posted by PhantomF4E
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Keep us posted. I’m working over an old m38 for my son for his first deer rifle. Waiting for the last of the pieces and parts to come in.
JTD
Will do. I need to see if my barrel is .308" or bigger. A 308 muzzle guage won't even start in the muzzle.
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Loading up 15 test loads for my Finn M39. 150 gr Hornady fmjbt boolits from Wes, some IMR 4895 powder, and WLR primers in PPU cases. https://uploads.tapatalk-cdn.com/201...1a4bebe529.jpg
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Looking good. Need a range report after you get to shoot them.
JTD
Sorry for the looong delayed range report. It didn't go as planned. The shots were all over. PPU match 182gr outperformed my handloads. I need to slug the barrel. I believe the tighter groups were my .243 loads. https://uploads.tapatalk-cdn.com/201...d891f27e0e.jpghttps://uploads.tapatalk-cdn.com/201...84f9db588c.jpghttps://uploads.tapatalk-cdn.com/201...c8c836f064.jpg
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Definitely slug your bore, some m39 were .308 bore, others were .312. I’ve just been messing with an m38 that I put together for my son. It has a larger bore. I’ve been using reduced loads of H4895 and have had decent results. .308 125gr sst are shooting about 3” groups at 50yds. .310 123gr gold dots shoot 12” group @50 ( I think the bullet is too short to stabilize properly). The 150gr Speer and hornady soft points will do an inch @50. There is definitely a huge difference between the different diameter bullets.
JTD
I finally slugged my bore today. After buying some .311" lead roundballs today, the first one went in too easily. I flattened the second one and started it with an aluminum rod, then pushed it the rest of the way with a 1/4" wooden dowel rod. I lubed the barrel with gun oil and it pushed out the breech easily. With my calipers, I'm reading .311". On the hunt for some .311" bullets now.https://uploads.tapatalk-cdn.com/202...78bc2f90a2.jpghttps://uploads.tapatalk-cdn.com/202...cba621b326.jpgQuote:
Originally Posted by JeffreyDeGraff
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Wes carries Speer .311 150gr SP and 180gr RN on the website.Quote:
Originally Posted by Garand46
JTD
Ordered the 150gr hot cor SP .311s and some spare brass and it arrived yesterday. Looking for Speer load data now.https://uploads.tapatalk-cdn.com/202...27230b1be5.jpgQuote:
Originally Posted by JeffreyDeGraff
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Speer doesn’t have anything for 7.62x54R. Hornady, Lyman and Sierra will be your best resources.Quote:
Originally Posted by Garand46
JTD
Thanks! Waiting on a .311" expander ball/decap pin now.
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What dies do you have?
JTD
Lee Pacesetter 3 die set.
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I use an RCBS 2die set with Lee factory crimp die. The rcbs comes with a smaller (for .308) and larger ( for .311-.312) expander balls. I recently did a test loading .311 bullets in brass sized for 308 and brass sized for .311. Same powder charges and seating depth, long story short, they both shot the same. Same point of impact same group size. My rifle does shoot better with a light crimp though.
JTD
Interesting info. I will keep it in mind when I'm ready to load up some new ladder loads. My expanders won't arrive until Monday. I will experiment with crimping as well.Quote:
Originally Posted by JeffreyDeGraff
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A few weeks ago, I loaded up some Speer .311" 150gr sp spitzer flat base bullets (#2217) that I got from Wes a while back. I seated them at 2.840" col, going off of Hornady data. H4895 at 40, 41, 42, 43, and 44.0 grains. These cases were sized previously with a .308 expander in Lee Pacesetter dies, by bumping the shoulder back a few thousandths. As the photos show, the lighter charges seemed to be more accurate and closer to elevation zero on the M39 as well. Heavier powder charges put the poi 6 to 8 inches below the poa. Not wanting to replace or modify my front sight, I will probably play around between 40 and 41 grains. A charge of 39.7gr can propel a Hornady bullet at 2,400 fps, plenty enough for a whitetail deer. I don't need velocity as most shots are below 120 yards. The 2" orange target circles weren't easy to see at 100 yards today. https://uploads.tapatalk-cdn.com/202...1c6bfe9910.jpgAttachment 1631Attachment 1632Attachment 1633Attachment 1634Attachment 1635
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That 40.0gr load has perfect elevation, and shoots well too. I seat that bullet at 2.900”. Did you crimp these test loads? Ive got some good groups with H4895, I’m trying out IMR4320 next. Sorry for all the jumbled random thoughts.
JTD
Thoughts are good! I may try 2.900" next time around. I didn't crimp these. May try a light crimp next time as well. Minus the 1 flyer, it's a 1.5" group, good enough for deer hunting.
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My rifle shoots better with a light crimp, that why I was asking. 1.5” is plenty good enough. Keep me updated with any progress.
JTD
Will do. I just seated these to spec today and was running out of daylight to try a crimp. Thanks for all your help!
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