DocMedic Posted May 10, 2017 Share Posted May 10, 2017 Getting a little practice before he-man and I notice my 308 is doing this to my brass. Should I be worried? It does this on every piece of brass Link to comment Share on other sites More sharing options...
kurtm Posted May 10, 2017 Share Posted May 10, 2017 Nice hot load you got there sparky!! Link to comment Share on other sites More sharing options...
M ammo Posted May 10, 2017 Share Posted May 10, 2017 But does it extract ok? I had a 308 that gave me Hell for too long. my re loads would fall in and out of the Gage. but would stick in the gun. Long story, short,, I ground down, the shell holder,, I just held it on a grinder wheel, just a lil bit,, I didn't go nuts on it,, , now when I """""Small Base size"""" it also bumps the shoulder back a lil bit.. 308 ammo works better in all my guns now,, Link to comment Share on other sites More sharing options...
Nugget Posted May 10, 2017 Share Posted May 10, 2017 Let's see the case head. Link to comment Share on other sites More sharing options...
DocMedic Posted May 10, 2017 Author Share Posted May 10, 2017 (edited) Once fired PMC case, a little overflow from the firing pin, but nothing to crazy, no ejector dent. 155 TMK going 2620fps Edited May 10, 2017 by DocMedic Link to comment Share on other sites More sharing options...
caspian guy Posted May 10, 2017 Share Posted May 10, 2017 Maybe early unlock (case trying to extract when chamber pressure is still too high?) What kind of rifle and what powder are you using? Link to comment Share on other sites More sharing options...
DocMedic Posted May 10, 2017 Author Share Posted May 10, 2017 Varget, GAP-10 18inch bartlen barrel Link to comment Share on other sites More sharing options...
Don_B Posted May 10, 2017 Share Posted May 10, 2017 Funny thing but I was also shooting my JP 308 a couple days ago and noticed the same mark. I believe the extractor has a slight undercut that should help with extraction by preventing the extractor from slipping off the rim. I do the same thing with my 1911 extractors. Link to comment Share on other sites More sharing options...
Dan Sierpina Posted May 10, 2017 Share Posted May 10, 2017 (edited) Looks like a little scuffing as the bolt rotated too. The primer is kind of flattened, not that it's uncommon. Edited May 10, 2017 by Dan Sierpina Link to comment Share on other sites More sharing options...
Nugget Posted May 11, 2017 Share Posted May 11, 2017 i was running 168 grain custom comps with varget at 2600 fps out of an 18" barrel. No flattened primers but it was def hot and had some pretty good swipes on the case head until I snapped off my extractor. Little too much gas as it was trying to extract too soon. I replaced the extractor with a Jp and the gas block with an adjustable and turned down the gas a bit. Runs great. Link to comment Share on other sites More sharing options...
DocMedic Posted May 11, 2017 Author Share Posted May 11, 2017 2 hours ago, Don_B said: Funny thing but I was also shooting my JP 308 a couple days ago and noticed the same mark. I believe the extractor has a slight undercut that should help with extraction by preventing the extractor from slipping off the rim. I do the same thing with my 1911 extractors. You know what, I just replaced the bolt with a JP308 bolt just before RM3G Last year. I wonder if it's the extractor the comes with the jp Link to comment Share on other sites More sharing options...
caspian guy Posted May 11, 2017 Share Posted May 11, 2017 Hmmm.... any low mass parts in the gun? Link to comment Share on other sites More sharing options...
DocMedic Posted May 11, 2017 Author Share Posted May 11, 2017 31 minutes ago, caspian guy said: Hmmm.... any low mass parts in the gun? None Link to comment Share on other sites More sharing options...
GetAwayDriva Posted May 11, 2017 Share Posted May 11, 2017 I have a JP bolt in my rifle and my brass looks the same as well. Link to comment Share on other sites More sharing options...
HRider Posted May 12, 2017 Share Posted May 12, 2017 The brass from my 20" AR10 looks the same. It does not have adjustable gas, and I run factory 147 grain ball for the most part (Privi Partizan lately). I use Freedom Munitions 155 Amax for targets past 100 yards. My rifle has a stock, full weight carrier and buffer with a JP spring (rifle length buffer system). It is over gassed, but other than breaking an ejector last year, it has been really reliable. Hurley Link to comment Share on other sites More sharing options...
mic2377 Posted May 12, 2017 Share Posted May 12, 2017 I wouldn't worry about those marks honestly. Perhaps a slighter faster powder would be a bit easier on the brass but otherwise it looks fine. The velocity is in line with reasonable load data as well for that barrel length. Link to comment Share on other sites More sharing options...
72stick Posted May 13, 2017 Share Posted May 13, 2017 Most .308s are severely over gassed. Is the spent brass case mouth or shoulder dented? If not, adjust the gas down till it doesn't cycle and then open it up just a little past where it starts running again and it should be fine. Link to comment Share on other sites More sharing options...
ShootfastRunfaster Posted May 14, 2017 Share Posted May 14, 2017 I have always found PMC brass to be a bit soft in both .308 and .223. I got those marks and nice big ejector swipes when I used to load it. Kuan Link to comment Share on other sites More sharing options...
M1A4ME Posted May 14, 2017 Share Posted May 14, 2017 So far, I've only shot SA FMJ through my GII. Originally it had the factory gas block on it. Then I installed an adjustable gas block on it. I've not seen marks like that on my brass with either set up. I also changed buffers around, early on. No differences seen. Does it leave a mark just from chambering the rounds and then ejecting them by hand? Link to comment Share on other sites More sharing options...
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