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Discussion Starter · #1 ·
Trying to learn all the visual lessons of reloading for the M1a.
LC brass trimmed to 2.005
cci 200 primer
168 Hornady BTHP
flash holes uniformed
41 grains of IMR 4895
Lee factory crimp
OAL? Didn’t capture that for the post but I’m pretty sure I was right at 2.8

I haven’t had the chrono on these but the ones I loaded at 40 grains of IMR 4895 came in between 2320 and 2380 fps from my 16” barreled rifle.

Simple question though… is this what you consider a flattened primer?
452028
452029
FF6C7153-3675-48C2-9C35-E4C87BE0D062.jpeg
FB219264-56F1-4C84-9B6D-EEA117EBC7DD.jpeg
 

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Discussion Starter · #3 ·
I’m working my way up. Cycles fine in the Scout and the AR.
Thanks
 

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I have been using 41 gn IMR4895 on 168 gn bullets and always cycles fine. It is on the light side but my shoulder is 70 years old.
 
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Daleo,
As others will agree you don't need to crimp especially with bullets that don't have a crimp groove. Been loading for M1A for a long time and never used a crimp and never had a bullet move from the case.

John
 

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Primers look good. Velocity is rather low, best to get some chrono data. You want these moving 2600 FPS or so from a 22" barrel. Usually, somewhere between 40.8 - 41.5 IMR4895 is sweet spot with GI brass. Gotta have chrono data because sweet spot numbers will tighten up. ES and SD will be low when the harmonics for your particular rifle are optimal for a given load.
 
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Trying to learn all the visual lessons of reloading for the M1a.
LC brass trimmed to 2.005
cci 200 primer
168 Hornady BTHP
flash holes uniformed
41 grains of IMR 4895
Lee factory crimp
OAL? Didn’t capture that for the post but I’m pretty sure I was right at 2.8

I haven’t had the chrono on these but the ones I loaded at 40 grains of IMR 4895 came in between 2320 and 2380 fps from my 16” barreled rifle.

Simple question though… is this what you consider a flattened primer? View attachment 452028 View attachment 452029 View attachment 452028 View attachment 452029
Case OAL usually dependent on magazine restrictions. If you reload, you'd probably want to experiment moving bullet closest to lands and grooves, so long as mag dimensions allow it.
 

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The only thing I see is slight cratering but that could just be a little slop in the firing pin hole on your bolt face. Nothing crazy to see there, they look fine. When they really flatten out or pierce is when you should be worried.
 

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And, as all the modern reloading manuals will tell you, visual examination of primers is a notoriously inaccurate method of judging chamber pressure. Sometimes potentially dangerous loads produce 'just fine' looking fired primers.
 

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Discussion Starter · #10 ·
Primers look good. Velocity is rather low, best to get some chrono data. You want these moving 2600 FPS or so from a 22" barrel. Usually, somewhere between 40.8 - 41.5 IMR4895 is sweet spot with GI brass. Gotta have chrono data because sweet spot numbers will tighten up. ES and SD will be low when the harmonics for your particular rifle are optimal for a given load.
Just used my chrono for the first time yesterday,but it was on my 40grain loads
es was57 Sd was18
 

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Discussion Starter · #12 ·
The only thing I see is slight cratering but that could just be a little slop in the firing pin hole on your bolt face. Nothing crazy to see there, they look fine. When they really flatten out or pierce is when you should be worried.
Just changed the pin and extractor maybe 150 rounds ago. No idea about the bolt history though.
 

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Discussion Starter · #13 ·
And, as all the modern reloading manuals will tell you, visual examination of primers is a notoriously inaccurate method of judging chamber pressure. Sometimes potentially dangerous loads produce 'just fine' looking fired primers.
Thats why I threw this out to you guys. Being an ignoriant marony, learning to load through the manuals and reading and being cautious. But I don’t have a real life mentor…
 

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Daleo,
I had the same cratering condition with my AR10, turns out the firing pin hole was to large, bought a JP enterprises bolt and problem gone.

John
 
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