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Discussion Starter · #1 ·
OK - so I have a 1919a4 that Troy converted to 54r for me. Has run well for 8-10 thousand rounds, and today after shooting 500 rounds, the bolt broke. It appears (even from the fuzzy pic) that the face of the bolt that holds the rim of the round has ripped off in the shape of the rim. So.... question. Why did that happen? How can I keep it from happening again? Is that just one of those unavoidable things?

All input welcome.
 

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It is the weakest area of a bolt. Consider how many thousands of rounds that bolt saw before the 54R mod. I would consider it just a normal breakage from use. Sucks but it is what it is.
 

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My guess is, unless you have been having problems with extracting cases previously, it was either caused by some bad spec ammo or just fatigue in the bolt face metal.....neither of which is fixable. These 1919 parts are somewhat old and subject to breakage. At 10K+ rounds through it I'd just chalk it off to time for a new bolt.........unfortunate, but the price of too much fun. :)
 

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Discussion Starter · #4 ·
Well it's good to hear that at least I didn't do anything to facilitate the problem. I've already e-mailed Troy about getting another couple of bolts converted for 54R. Does anyone have a few spare 7.62 bolts?

Thanks
 

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PhD in Over-Engineering
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If you need a couple of bolts, I can help you out at $50 each plus shipping. Just let me know.

That aside, I am curious as to the maker of that bolt. I've only seen one Saginaw bolt break there, but it is more commonly the RIA ones, as they tend to be heat treated to a much harder level.
 

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Discussion Starter · #6 ·
If you need a couple of bolts, I can help you out at $50 each plus shipping. Just let me know.

That aside, I am curious as to the maker of that bolt. I've only seen one Saginaw bolt break there, but it is more commonly the RIA ones, as they tend to be heat treated to a much harder level.
How would I know who made the bolt. What do I look for?
 

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PhD in Over-Engineering
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How would I know who made the bolt. What do I look for?
There will be a drawing number marking and a two or three letter code, which designates the maker. It can be underneath, on the left side or on top, depending on which maker. Potential codes are SG, BA, RIA and BCI. The other possibility is if you have a WWI bolt, which is before drawing numbers were used. If that's the case, it would have a W in a circle underneath one of the rear lugs by the sear slot, or an R in a triangle on the rear face, right side.
 

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How would I know who made the bolt. What do I look for?
Get anything except an RIA bolt. They are over hardened and the t-slots are prone to breakage.

I've repaired bolt faces that chipped.

Were you shooting the same lot of ammo you started with?

Reason I ask, sometimes if you change ammo lots/manufacture the rds may go into the chamber farther by as much as 0.010". This caused you to crank in the barrel until it bottoms out on the bolt face (-1click). That causes the rd to float in the t-slot. When it fires the case flows back to the bolt face then extraction starts and the few thou gap it created is enough to hammer and fatigue the t-slot and eventually cause a fracture like you experienced. The ammo test is it must stick out of the back of the barrel at least 0.120" min and 0.130" max.
 

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Discussion Starter · #9 ·
Get anything except an RIA bolt. They are over hardened and the t-slots are prone to breakage.

I've repaired bolt faces that chipped.

Were you shooting the same lot of ammo you started with?

Reason I ask, sometimes if you change ammo lots/manufacture the rds may go into the chamber farther by as much as 0.010". This caused you to crank in the barrel until it bottoms out on the bolt face (-1click). That causes the rd to float in the t-slot. When it fires the case flows back to the bolt face then extraction starts and the few thou gap it created is enough to hammer and fatigue the t-slot and eventually cause a fracture like you experienced. The ammo test is it must stick out of the back of the barrel at least 0.120" min and 0.130" max.
I will have to check to see which bolt I had. As for the ammo - lord knows. After 8K rounds..... they are from all over the place. All Russian surplus. All 148 lt ball. Check you e-mail or PM please.
 
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