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Feed Issues, Rock-ola James River Armory

This is a discussion on Feed Issues, Rock-ola James River Armory within the Modern M14 forums, part of the M14 M1A Forum category; Try a different firing pin or stone this one...yours may be out of spec. It looks like the cam surface on the tail isn't cut ...


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Old May 21st, 2017, 07:28 PM   #61
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Try a different firing pin or stone this one...yours may be out of spec. It looks like the cam surface on the tail isn't cut deep enough preventing it from properly engaging the cam surface on the safety bridge. This is causing the peening you see on the tail.

I had one that would bind on the safety bridge as yours appears to be doing and a little stoning of the firing pin cam surface remedied it.

The firing pin should move freely in the bolt.

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Old May 22nd, 2017, 02:24 PM   #62
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I found that the firing pin hangs in the bolt, which might be causing the resistance of the bolt to retract. Thoughts?
Yep, seen it many times. Remember I told you to look for shiny spots. They are on your receiver bridge on the pic looking from the rear of the receiver. There is a burr in there on one of two surfaces, or both. The one that is the shiniest and is flat, and the one that is on the left ....at an angle.

It is chewing up your firing pin tail and making more burrs on it, because the receiver is much, much harder than the firing pin is. It only takes a few milliseconds of hanging up time to rob enough gas to short cycle and cause your problem.

Stone or use a fine file sparingly on the firing pin tail and keep it rounded like it was before. Clean it up smooth. You will need a smaller stone to clean up the bridge burrs, and should be good to go then. Keep us posted....Glad you found it. Well done !

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Old May 22nd, 2017, 03:38 PM   #63
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I too have seen this on Bula / Rock-ola receivers. Are you using a Bula bolt or a USGI bolt? In my experience, using a usgi bolt and pin, there was insufficient space between the tail of FP and bridge. Basically, as the pin retracted it was at full throw before it cleared the bridge. In the few examples I have encountered this, switching to a Bula FP helped, and switching to both a Bula bolt and FP helped more and provided a few thousandths clearance. However, if you swap bolts, you MUST check headspace. Measuring the few Bula bolts I have, they are approx .004" longer than GI.

**Edit- to add some measurements, I grabbed a stripped Bula receiver. Using USGI bolt and FP I am getting less than .002" clearance between FP tail and bridge. Swapping to a Bula/Bula combo increased that gap to .008".

This is not a post attempting to bash Bula. Jeff makes a fine product and at a reasonable cost. These are simply my experiences. YMMV.

Rip,

How much clearance should their be between the tail and bridge? I haven't played with enough real M14's to get a good idea, but with an M1 there is usually quite a bit.


Last edited by 4gundrill; May 22nd, 2017 at 03:54 PM. Reason: Added measurements
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Old May 22nd, 2017, 04:51 PM   #64
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I too have seen this on Bula / Rock-ola receivers. Are you using a Bula bolt or a USGI bolt? In my experience, using a usgi bolt and pin, there was insufficient space between the tail of FP and bridge. Basically, as the pin retracted it was at full throw before it cleared the bridge. In the few examples I have encountered this, switching to a Bula FP helped, and switching to both a Bula bolt and FP helped more and provided a few thousandths clearance. However, if you swap bolts, you MUST check headspace. Measuring the few Bula bolts I have, they are approx .004" longer than GI.

**Edit- to add some measurements, I grabbed a stripped Bula receiver. Using USGI bolt and FP I am getting less than .002" clearance between FP tail and bridge. Swapping to a Bula/Bula combo increased that gap to .008".

This is not a post attempting to bash Bula. Jeff makes a fine product and at a reasonable cost. These are simply my experiences. YMMV.

Rip,

How much clearance should their be between the tail and bridge? I haven't played with enough real M14's to get a good idea, but with an M1 there is usually quite a bit.
It's a GI bolt.
I cleaned up the bridge and firing pin. I hope to get to the range tomorrow. I will update this thread with the results.
Thanks for all of the assistance.

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Old May 23rd, 2017, 08:46 AM   #65
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Much better, still short cycling

50 more round, no feed 3 times and failed to stay open on last round. One jam where bolt closed on round halfway in the chamber. Waiting for new firing pin and piston. Could the spring be too strong?

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Old May 23rd, 2017, 11:39 AM   #66
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50 more round, no feed 3 times and failed to stay open on last round. One jam where bolt closed on round halfway in the chamber. Waiting for new firing pin and piston. Could the spring be too strong?
Oh man, I know that sucks. If you cleaned the bridge and pin tail up good, only one thing left, other than a mis-located bridge or cut ....the chamber. Did you ever look at it under a bright light?....Another guy just got a bad chamber too, so maybe there were others went out in a batch that were reamed improperly. His was chrome lined too.

A spring isn't going to be able to be strong enough to cause this issue. I suggest replacing nothing with any more new parts....... and sending it back to the manufacturer. They should pay for shipping both ways if it's something that is their fault.

If they won't fix it for free, send it to me and I will see what I can do for you. If it's the chromed chamber, which is highly suspect at this time, there isn't much you can do except replace it. It could be reamed but eventually it will cause peeling of the chrome later, on up and into the rifling and then rust under that. It would be good for a blaster though, until that happens. It won't affect accuracy either to ream a chrome chamber. I have a carbide reamer for doing it.

So those are your choices as I see it right now. Good luck, we've done all we can do. Let us know.

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Old May 23rd, 2017, 06:46 PM   #67
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I'll contact Jame River and see where that goes.

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Old May 24th, 2017, 05:51 AM   #68
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Do you have pictures of the cleaned up firing pin? I still think the cam surfaces on the FP and safety bridge are not aligning properly. I think the bevel on the FP is insufficient and causing the FP to 'crash' into the safety bridge upon extraction.

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Old May 24th, 2017, 06:00 AM   #69
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I'll contact Jame River and see where that goes.
Good Luck!

Don't let them tell you it needs a welded USGI heel.

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Old May 25th, 2017, 06:27 AM   #70
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Firing Pin comparison & pictures of chamber

I received the new FP from Fulton. I posted pictures of both. I've made notes regarding what mods I made to the original. The new pin sticks slightly in the bolt at the last 32nd at max protrusion. I/m an optimist, and I'm going to test this out at the range. I also attached the best photos I can get of the chamber with a bore camera.

Notice the difference in the shape of the two FP. The new one has less radius and more of a sharp transition. Its also beefier in the inner lo elbow area. Why so different? Is one not GI specs?
I do not know if my "original" FP is actually from JRA.
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Last edited by masspatriot; May 25th, 2017 at 06:57 AM.
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Old May 25th, 2017, 07:50 AM   #71
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Notice any difference in the geometry of the cam surfaces? The old FP cam looks incorrect to me in the photo.

It's that little chamfer that engages the the cam surface on the safety bridge and retracts the FP as the bolt rotates.

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Old May 25th, 2017, 07:55 AM   #72
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Notice any difference in the geometry of the cam surfaces? The old FP cam looks incorrect to me in the photo.

It's that little chamfer that engages the the cam surface on the safety bridge and retracts the FP as the bolt rotates.

It is visible in the first picture. Both were the same until I tried to enhance it.

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Old June 2nd, 2017, 04:27 PM   #73
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Test results

Finally got to the range. New Sadlak piston and new firing pin. fter 11 rounds, failed to pick up next round. Changed op rod spring to new GI and also Sadlak NM op spring guide. 35+ rounds, no short cycle or fail to remain open after last round. I always load 5 rounds in a mag. All rounds through a single hole size of a silver dollar at 25 yards.
Could it have been an extra power spring?
Seems to be resolved. I usually dont change more than one item, but this is getting expensive as far as ammo.
Thanks everyone.

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Old June 2nd, 2017, 04:52 PM   #74
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So called high power op rod springs and cause all sorts of troubles.
Glad the USGI fixed your rifle.
I think you will be amazed how smooth it gets after break in.
Sounds like you have a winner.
Congratulations.

Semper Fi
Art

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Old June 2nd, 2017, 06:46 PM   #75
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For am amateur like me it sounds like the problem is still an unknown; whether it was the firing pin, firing pin bolt combo, or op rod spring. It doesn't seem to answer the question of whether a GI bolt assembly can be used in a Bula receiver, or whether the GI bolt can if the FP is modified. On the flip side, it seems like Bula bolts can be used in non-Bula receivers without issue (?)

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