How to keep bolt closed longer

D

dan158

New member
I am still getting burrs on the rims of my brass like the shell is being ripped out before it cools down enough..
I have a jp adjustable gas block that is set up correct but still getting the burrs.. Would a stiffer spring work to help this or not really because of the gas block.. I had acouple pieces of brass not fit in the shell holder also.. Thanks. Dan
 
Not much to say other than what I said above along with the shells are being ejected about 5 o clock.
Also how does one tell if bolt is locking up correctly.. The gun is shooting great just got those burrs and wouldn't fit in shell holder couple of times.. This has happened since first fired ammo thru it.. Factory also.. I have pics posted on here showing the brass..
 
You might smooth the horns on the extractor. At times they dig in no matter how long it is closed.

To keep it closed longer you could go to an M16 BCG that is heavier. Heavier buffers can also be used. Personally I have the heavier carriers in all my builds and run adjustable blocks on most of them. The adjustable set up is the easiest and most straight forward way to deal with the pressure.

Greg
 
Originally Posted By: AdamT"Perfect" ejection is between 3 o'clock and 4:30



Ok mine is right about the 430 mark not the 5 sorry about that.. If I turn the gas down it wont lock the bolt back but throws the brass out at 3..
 
Another thing I didn't mention is that after about 10 rounds after I clean the BCG the bolt gets harder to push into the locking lugs.. When I take the BCG out, the bolt is really tight pushing into the carriage.. Really tight until I clean and lube again.. I will post pics of the bolt face and the brass and post..
 
Originally Posted By: GLShooterYou might smooth the horns on the extractor. At times they dig in no matter how long it is closed.

To keep it closed longer you could go to an M16 BCG that is heavier. Heavier buffers can also be used. Personally I have the heavier carriers in all my builds and run adjustable blocks on most of them. The adjustable set up is the easiest and most straight forward way to deal with the pressure.

Greg

Side charge upper...
 
Originally Posted By: dan158Originally Posted By: GLShooterYou might smooth the horns on the extractor. At times they dig in no matter how long it is closed.

To keep it closed longer you could go to an M16 BCG that is heavier. Heavier buffers can also be used. Personally I have the heavier carriers in all my builds and run adjustable blocks on most of them. The adjustable set up is the easiest and most straight forward way to deal with the pressure.

Greg

Side charge upper...

They don't all weigh the same. I've even seen converted M16 carriers to side charge.

Greg
 
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whats your recipie for those loads?


your primers are showing cratering, which is usually a sign of a relatively hot load - which will cause both the extractor swipes and the ejector marks as well.
 
Headspace combined with over gassed? Dehorn extractor. Is it stiff pulling expander ball out? If it is maybe it's pulling the shoulder.
 
Split neck.. This is happening with with reloads of 4rth or 5th. And the marks I am getting on my brass is from factory ammo and 26.5 and up H4895.. I haven't loaded up below that..

This is a JP barrel and JP bolt that came with the barrel.. This is the first year I have shot it and I built it back in 2014 I believe it was.. Have to check posts..
I hate to change up anything.. I had couple good 3 shoot groups at 3800+ fps
And to get that speed I am loaded at 27.6 of H4895... Almost at max for the 40s.

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Now you're giving some good info...

Those speeds are really high compared to what Hodgdon says, indicating higher pressure. I use a lot of R-P brass also but it is soft and will show ejector marks, etc faster than most. I would back it down to 3550 or 3600 fps and see what your brass looks like. Smoothing up the corners of the extractor as was mentioned above won't hurt either.
 
with a 40gr vmax in hornady brass, hornady's 9th lists max load at 26.7grains H4895 at 2.245" COAL.

as mentioned above... bring your charge down a bit and you'll not only get your brass to last longer, but you should be able to find a good accuracy node. Running charges that hot is not only hard on your brass, but its also hard on your rifle long term. You're not doing yourself favors running them that hard.

my 204 is most accurate at right around 3700 fps - with 32 grain vmax. it'll almost bughole them at that speed & the brass is beautiful when i'm done with it.


and the critters wont be able to tell the difference.
 
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