Got it put together, now time to troubleshoot (7.62x39 AR)

[rOmiLaYu]

Both are issues present. When being fired, it was picked up 4/5 times, just not enough pressure to fully cycle the bolt. I have no idea why that changed when manually cycling?

I feel like we are saying different things. When you manually cycled the bolt, did the rifle remove the rounds from the chamber every time?


Granted the velocity and forces involved under recoil are different but if the rifle isn't grabbing the rounds under manual cycling, it won't under recoil, either...and vice versa.

 

[freedom]

This is useless without pics.

 

[lftd&pwrstrok'n]

I feel like we are saying different things. When you manually cycled the bolt, did the rifle remove the rounds from the chamber every time?


Granted the velocity and forces involved under recoil are different but if the rifle isn't grabbing the rounds under manual cycling, it won't under recoil, either...and vice versa.

When manually cycling, it never grabbed the round. No attempt at all to extract. When shooting the rifle, it did attempt to extract all but 2 times. The first round was a stove pipe the next 3 or 4 were partial extractions, w/ the spent casing left in the chamber and the next round out of magazine partially "loaded". At no time was a round extracted and a fresh round loaded.

 

[rOmiLaYu]

When manually cycling, it never grabbed the round. No attempt at all to extract. When shooting the rifle, it did attempt to extract all but 2 times. The first round was a stove pipe the next 3 or 4 were partial extractions, w/ the spent casing left in the chamber and the next round out of magazine partially "loaded". At no time was a round extracted and a fresh round loaded.

Then 100% it is an extractor issue. Even if you remove the extractor from the bolt, the case will still leave the chamber due to gas pressure. Think gas blow back operated weapons that don't have an extractor. The round still leaves the chamber even though it isn't "extracted." The problem in a closed system like the AR is that the case is not in a controlled rearward path as held in place by the extractor so instead of being in a controlled rearward motion and contacting positively with the ejector sending the case out the starboard side window, the case is caroming all over the upper receiver, never hitting the ejector and the bolt is slamming back home, wedging the non-ejected shell.

The recoil on a 7.62x39 is more than a standard 5.56 and as such, the extractor spring may not be able to hold on under the more violent recoil....or at all, given your manual cycling. I'd first check to see if there even is an extractor spring (you never know), and if there is one, either replace it with a stronger one or use the old o-ring trick.

 

[lftd&pwrstrok'n]

Then 100% it is an extractor issue. Even if you remove the extractor from the bolt, the case will still leave the chamber due to gas pressure. Think gas blow back operated weapons that don't have an extractor. The round still leaves the chamber even though it isn't "extracted." The problem in a closed system like the AR is that the case is not in a controlled rearward path as held in place by the extractor so instead of being in a controlled rearward motion and contacting positively with the ejector sending the case out the starboard side window, the case is caroming all over the upper receiver, never hitting the ejector and the bolt is slamming back home, wedging the non-ejected shell.

The recoil on a 7.62x39 is more than a standard 5.56 and as such, the extractor spring may not be able to hold on under the more violent recoil....or at all, given your manual cycling. I'd first check to see if there even is an extractor spring (you never know), and if there is one, either replace it with a stronger one or use the old o-ring trick.

I will go ahead and order a stronger spring either way. Fairly certain that I won't be able to find one locally!!

ETA: Atl Range and Ordnance happens to have them in stock and I will go by there on my way to work this afternoon. Incidentally, I don't know why that "other" local "AR" place is even in business? This is about the 3rd or 4th time I have called or gone by there and they never have parts in stock. But, I guess they do not claim to be the parts leader, just " Atlanta's leader in customized AR-15's".

 

[rOmiLaYu]

I will go ahead and order a stronger spring either way. Fairly certain that I won't be able to find one locally!!

ETA: Atl Range and Ordnance happens to have them in stock and I will go by there on my way to work this afternoon.

Incidentally, I don't know why that "other" local "AR" place is even in business? This is about the 3rd or 4th time I have called or gone by there and they never have parts in stock. But, I guess they do not claim to be the parts leader, just " Atlanta's leader in customized AR-15's".

I've always felt like they cater more to the Mall Ningey Brigade. They will sell you a super-"custom" AR but don't want guys that know what they are doing knocking around the store...afraid they might educate their customer base. Of course that's just my unsolicited and poorly informed opinion.

 

[Allsmiles]

I've always felt like they cater more to the Mall Ningey Brigade. They will sell you a super-"custom" AR but don't want guys that know what they are doing knocking around the store...afraid they might educate their customer base. Of course that's just my unsolicited and poorly informed opinion.

That is why their prices are still at last panic pricing. They are outrageous on small parts also.
The offer still stands if you need to try out a different BCG/upper that has several cases of spent steel case ammo under its firing pin. I do miss the $40/500 battle packs.

 

[mtdawg169]

So, you spent $200 on a barrel and bolt carrier group and you're surprised that you're having issues?

 

[lftd&pwrstrok'n]

So, you spent $200 on a barrel and bolt carrier group and you're surprised that you're having issues?

Where was your "constructive criticism" during my thread seeking help in doing this build? I read and researched, these parts had good reviews. What else can I say?

 

[mtdawg169]

Where was your "constructive criticism" during my thread seeking help in doing this build? I read and researched, these parts had good reviews. What else can I say?

I'm sorry man, that was uncalled for. But there is some truth in it. I haven't been on here much lately and didn't see the original thread. I'm at a zoning meeting now, but when I get home later tonight I'll re-read the thread and offer up some more helpful thoughts.