cracked bolt.

f55

f55

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I received a boydes stock today and some new 5/20 mags, so i decide to try them out, I followed the sticky for testing after putting on a new stock and it failed at first, so removed some of the material from stock where the trigger assembly sits and cycled the 10 time, all clear.

At the range I load up the new mag and shot 17 rounds, the 17th round didn't chamber but just ejected, strange so i put it back in the mag and it fired fine.

I then loaded up the last 3 rounds i had in the 5/20 and fired the first shot with no problems, when i pulled the trigger for the second it fired followed by the third and the bolt cracked, the bottom of the mag blew off, gathered all the brass and all looks normal, no cracks, breaks etc.

I was using reloaded ammo, imr 4895 42gr and cci br2 primers, I weigh each load to make sure its 42gr.

Is this considered a double/slam fire,out of battery firing or something else.

The rest of the rifle seems ok, no idea how this happened and not sure if I trust the m305 any more even if I get a new bolt or replace the rifle.


bolt.JPG

bolt1.JPG
 
I'm sorry that I can't offer any constructive advice other than to say that I'm pleased no one was injured - I am sure that some of the M14 guru's can advise.
 
I recommend this book. It is well worth the money. Chapter 3 (selecting the rifle) and chapter 9 (inspection, tips, and tricks), in particular, will address the various issues that interest you.



Available direct, or from Brownells.

<http://www.scott-duff.com/DuffBooks.htm#m14>
<http://www.brownells.com/.aspx/pid=5806/Product/THE_M14_OWNER_S_GUIDE___MATCH_CONDITIONING_INSTRUCTIONS>

I'll include two isolated quotes here:

"Do not use cast bolts."- pg 51, ch 3

"Most slam fires can be traced back to the loading bench." - pg 108, ch 9
 
Can you post some real good, clear, close up pictures of the bolt and receiver locking lug surfaces??
As well as pictures of the cartridge that was involved with the bolt failure.
 
Stuck firing pin?mabye the Hamer followed the bolt from the material you removed, mabey not enough material was taken out ?? first time firing the rifle?[/
 
BCboy said:
Stuck firing pin?mabye the Hamer followed the bolt from the material you removed, mabey not enough material was taken out ?? first time firing the rifle?[/
Click to expand...

Hi

Rifle has had 600 reloads through it, 800 rounds total.

I racked it 10 times to make sure it passed with the new stock, or should i have done more?
 
Wow, from where I 'm sitting, it's too early to make any judgements. Too many variables that are missing. We would like to know:

* Bullet
* Load (found it in post 1)
* velocity
* powder (found it in post 1)
* Any pistol powders on the reloading bench when you did the load up?
* Which bullet weight was used?
* What make of rifle (Poly, Norc, Armscorp, M1A) ?
* Factory or aftermarket bolt?
* Greased up bolt lugs, bolt raceways
* all cartridges loaded directly from the magazine? I'm assuming so.

Anyways, thankfully you are okay! :cool:

Cheers,
Barney
 
Hungry said:
Wow, from where I 'm sitting, it's too early to make any judgements. Too many variables that are missing. We would like to know:

* Bullet Honady 150gr btfmj
* Load (found it in post 1)
* velocity going by the reloading manual between 2500-2600fps
* powder (found it in post 1)
* Any pistol powders on the reloading bench when you did the load up? nope only load 308, dont own pistols
* Which bullet weight was used? 150gr as above
* What make of rifle (Poly, Norc, Armscorp, M1A) ? Norc
* Factory or aftermarket bolt? Factory
* Greased up bolt lugs, bolt raceways YEP
* all cartridges loaded directly from the magazine? I'm assuming so. YEP

Anyways, thankfully you are okay! :cool:

Cheers,
Barney
Click to expand...

Hi Hungry

If it was something to do with the load, which i don't think it was, what would account for the 2 shots one after other when i pulled the trigger once?
 
I'm more concerned with the cracked bolt lug than possible slam fire per se. Even if there was an issue with aforementioned stuck firing pin or not enough stock material removed during fitting causing hammer-follow, the result would have been unintentional burst fire. The bolt would have still remained intact.

The issue is that because reloads were used, no one can ascertain whether there is a bolt manufacturing issue or an issue with the loads.
 
"...issue is that because reloads were used..." Nope. 42.0 is .6 under minimum. That bolt was damaged already. Nothing to do with the new stock either.
 
Dont get too worried "I have seen lots of broken AR15 bolt and there still great rifles" Stuff breaks some times, no biggy "aslong as your not hurt and the gun is still fine :)
 
Should be able to get a replacement bolt without too much trouble. Lots have been pulled out when USGI ones were retrofitted. Check the rifle carefully, install the replacement, check lug engagement and check headspace.
 
sunray said:
"...issue is that because reloads were used..." Nope. 42.0 is .6 under minimum. That bolt was damaged already. Nothing to do with the new stock either.
Click to expand...

Not sure if it's relevant but the bolt roller has jumped out the guide it sits in 3 times, on first day I fired the rifle, and 2 time in last 4 weeks while racking.
 
Sounds to me like hammer-follow resulting from improper relationship between stock, trigger group, and receiver causing improper disconnector engagement...see the stickies on function check for more info. although the firing pin bridge is supposed to prevent out-of-battery ignition I've seen lots of m1a type rifles where either the bridge was out of spec or the firing pin tang was chipped or out-of-spec.

Anyway...I would replace the bolt, and seriously test the rifle/stock combo for hammer follow. You will also likely have to replace the stock.

Send me a pm...I can hook you up with a new bolt.

Cheers,

Brobee
 
Brobee said:
Sounds to me like hammer-follow resulting from improper relationship between stock, trigger group, and receiver causing improper disconnector engagement...see the stickies on function check for more info. although the firing pin bridge is supposed to prevent out-of-battery ignition I've seen lots of m1a type rifles where either the bridge was out of spec or the firing pin tang was chipped or out-of-spec.

Anyway...I would replace the bolt, and seriously test the rifle/stock combo for hammer follow. You will also likely have to replace the stock.

Send me a pm...I can hook you up with a new bolt.

Cheers,

Brobee
Click to expand...

Hi
I did check the sticky and as said in first post I removed material till it passed the test, or is there something else I missed?
 
sunray said:
"...issue is that because reloads were used..." Nope. 42.0 is .6 under minimum. That bolt was damaged already. Nothing to do with the new stock either.
Click to expand...

Roger. Did not see the original poster's mention of the gr count.

My comment was in the context that if unknown reloads were used for the however many rounds down the pipe, it is a problem to ascertain whether it was a manufacture issue of the bolt or contributed by random reload sold by bubba#2 to the poster of the thread.
 
My 2 cents would be the bolt cracked because it was broken, IYKWIM...

From my research, assuming the OP is a conscientious reloaded (seems the case), and assuming there weren't any mystery-sourced reloads, the OP had a spot of bad luck.

Someone farther up offered a bolt to tide him over; very kind to put that out there, take him up on it, and carry on.

My 2 cents spent. :)
 
Brobee said:
Sounds to me like hammer-follow resulting from improper relationship between stock, trigger group, and receiver causing improper disconnector engagement...see the stickies on function check for more info. although the firing pin bridge is supposed to prevent out-of-battery ignition I've seen lots of m1a type rifles where either the bridge was out of spec or the firing pin tang was chipped or out-of-spec.

Anyway...I would replace the bolt, and seriously test the rifle/stock combo for hammer follow. You will also likely have to replace the stock.
Click to expand...

I've been thinking about this one overnight... Brobee might have the solution. All the other variables do not bring 'red lights' :eek:

Bolts are easy to find (Norc Bolts, I just sold one for $ 50 complete) here on the EE Forum. Also M1A bolts will drop straight in. PM me for more details.

Thankfully you are not hurt... :cool:

Barney
 
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