Help me isolate cycling issues **UPDATE**

[G38xOC]

I don't load for service rifles, but I found the section about reloading for them in Sierra's manual very complete. Looks like most if not all of it is online here. Thought you might find it useful if you haven't read it already.

ty ,

very useful

[IPSICK]

^
when shooting , the gas block was out about 3 1/2 turns out . I've only turn 7 out after Huckberry recommended that i should turn it all the way out and find load then tune it .

I didnt know 308 gas block were so sensitive , thanks for that information . I will probably stay with 2 loads at the max ( one 150fmj for range , 178grain for hunting down the road) .

as far as observing sign for high pressure and ejection pattern on brass . I did not find has harsh ejection signs . to me it didnt seem overgassed ...

I think Ive found the way though ..
I can do like 2turns out from close for a starting point - put 1 rd test load per shot ( this way i get do two things at once .. load tesing and watching for bolt lock back position ) while adjusting gas block . To me , if bolt locks up back tell me it will extract properly ..

will report back after friday

This is exactly how JP describes it in their instructions for their adjustable gas block that should have come with your upper.

Btw, I'm still not sure if you can find a setting that works well with both a 150gr and 178gr. Good luck.

[G38xOC]

UPDATE

Had a good day at the range today with only two hiccups . this rifle likes varget powder with 150grain FMJ . not so with 178grain A-max . please teach a noob if there are way to bring the loads together to works better on few different type of loads using different weight of the bullets

I still need to bump up little more with TAC . my max test load were that was 42.5 grain and bolt would not lock open still . but had no issues with varget 43gr - 44.5 using 150grain FMJ stuff .

First two pics with Hornady 150gr FMJBT



2nd two shots were with 178gr A-max



so at this point , either I stick with 150grain or use 178grain stuff and rezero ?
how could I make bring these two types together for optimum accuracy ..

[huckberry668]

I assume you shot at 100 yards. Looks like you're getting 3/4 MOA groups with 4 shots of Hornady 150FMJ and 1 MOA with the 3 shots of A-Max. I never had good experience with A-Max. I'd say you found a good load for the 150FMJs.

With your loads I don't think it's the lack of pressure. I'd start looking at something else. One time I added a stock extension to add length of pull and the kit came with a longer stock screw. I didn't replace the longer stock screw after I removed the extension kit and the bolt wouldn't lock open. because the longer screw was preventing the buffer from moving all the way back when cycled.

So if it ejects with authority, I'd suggest checking for:

1. mag spring may not be power enough to push the the follower up to catch the bolt stop.

2. the bolt stop maybe stuck or damaged.

3. buffer maybe too long and not allowing the bolt carrier to move back far enough.

4. buffer spring maybe too long. I know the AR15 rifle length is longer than carbine length and can reduce the bolt carrier travel.

5. maybe the gas block was misaligned with the gas port.