[fivesidedpolygon]

Hey guys. First, I apologize; I know this has maybe been covered a thousand times, but it takes such a long time to sift through old posts covering stuff like this...I tried, but couldn't find one. And it could be that I have a unique problem (although that seems unlikely.)

I have a new (500 rounds through it) SA m1a standard. Now after 500 rounds, same as when it was new, the bolt will hang up while hand cycling about one time out of ten. It just catches and doesn't come forward - it can be annoying at best, dangerous to the fingers at worst.

Here's what I can tell. It runs flawlessly while firing (now that I fixed my out-of-spec op rod situation. I had the same problem as this guy: http://m14forum.com/modern-m14/79184-m1a-bolt-stuck-back-help-3.html ) My bolt hangs up just slightly forward of the bolt catch, but it is not making contact with the bolt catch. It happens with or without magazine, with or without trigger group, and has never happened while live fire cycling. Interestingly, I can't get it to happen when upside down, so I think gravity has something to do with it.

As far as I can tell, it *seems* like the bolt is catching somewhere inside the receiver and is happening as a result of the inconsistent pressure inherent to hand cycling. I don't have a special spring guide, but I can't see that it would have an affect on what's happening. The problem is that I can't see exactly WHERE it's hanging up, because it won't happen when the works are upside down (and I don't have a good enough shop set up to clamp it right-side up and see underneath the receiver.)

I'm hoping just a lug needs to be polished or something. Any experience or suggestions welcome! Thanks buds.

 

[aloreman]

nothing wrong with your gun. let the action do the work

 

[MUKAK]

funny u posted it this, my scout also does this, the bolt tilts and dont wanna go forward when the bolt is all the way back during hand cycling, looks like it catches the bridge area, i have to pull the charge handle back more to free it

 

[garandguy10]

You may have a out of spec bolt or receiver. Probably best to contact SAI and ask them to look at it for you under warranty.

 

[nf1e]

My guess is that the extractor tail is slightly long and catching on the receiver bridge. Easy fix would be to shorten the tail so it does not protrude past the bottom of the bolt.

 

[fivesidedpolygon]

funny u posted it this, my scout also does this, the bolt tilts and dont wanna go forward when the bolt is all the way back during hand cycling, looks like it catches the bridge area, i have to pull the charge handle back more to free it

Yep, same here!

It's definitely not a big deal for semi-auto fire. I guess the reason I finally want to address it is that I bought a .30 cal suppressor and will eventually try to set this rifle up to run suppressed subsonic, in which case I'll be hand cycling for each round fired and I don't want this to be happening while chambering live rounds. Thanks for the feedback guys.

 

[KurtC]

As far as I can tell, it *seems* like the bolt is catching somewhere inside the receiver and is happening as a result of the inconsistent pressure inherent to hand cycling. I don't have a special spring guide, but I can't see that it would have an affect on what's happening. The problem is that I can't see exactly WHERE it's hanging up, because it won't happen when the works are upside down (and I don't have a good enough shop set up to clamp it right-side up and see underneath the receiver.)

I'm hoping just a lug needs to be polished or something. Any experience or suggestions welcome! Thanks buds.

You're not riding the bolt forward, are you? You hand cycle by pulling the oprod handle all the way to the rear and letting go.

 

[subscriber]

You're not riding the bolt forward, are you? You hand cycle by pulling the oprod handle all the way to the rear and letting go.

I think he means riding the bolt home "dry"; as in, without stripping a round from the magazine. The "without magazine" part would seem to indicate this.

It is against my religion to drop the bolt or slide on an empty chamber, full force, with any firearm. Some of you don't mind doing this, and cite it as standard practice in the US military; so how can it be bad. It depends on who paid for the rifle and who pays for spares...

It is ideal for a semi-auto to cycle at crawling speed, but if the bolt or slide hangs up somewhere in its travel, it is probably of no consequence - things happen much faster during live fire.

My 1911 will feed live ammo, even if you follow the slide down at glacial speed, without sticking anywhere; but this should not be the expectation. My new Scout seems to have only just enough force in the recoil spring to strip the top round from a full mag and make it all the way into battery, when the charging handle is pulled all the way back and released. It goes "Ka.....chunk"; rather than sounding like a single event. I am not aware of any bolt "slowness" when shooting it.

 

[Dave P]

"You hand cycle by pulling the oprod handle all the way to the rear and letting go."

Kurt is right - you never ride the bolt home. Treat the oprod like a slingshot: pull it all the way back and let the spring slam it home.

Be safe and point down-range while doing this with live ammo.

 

[KurtC]

The M14 and M1 do not function like an M16, where a tubular bolt carrier slides effortlessly in a tubular receiver. Nor does it work like a bolt action, where each lug has a smoothly polished raceway.

The M14 bolt rattles around the receiver, being dragged back and forth by one lug loosely contacting the operating rod. It is supported only by the bridge in the rear and an oversized raceway on the left. The underside is concave, so it only contacts the receiver bridge when either the front or rear is resting on it. It has to tilt down in the rear in order to set the hammer, then come up level again as it moves forward.

They function rough when new, but usually smoothen up a bit as the parkerizing is polished smooth on the bolt and receiver contact areas.

 

[JayKosta]

...
My bolt hangs up just slightly forward of the bolt catch, but it is not making contact with the bolt catch. It happens with or without magazine, with or without trigger group, and has never happened while live fire cycling. Interestingly, I can't get it to happen when upside down, so I think gravity has something to do with it.
...

----------------------------------------
I think you're saying this happens when you are just carefully release the bolt and slowly allow it to move forward - NOT attempting to close the bolt on a round in the chamber.

If that's the case, then maybe you are moving the oprod 'handle' up/down/out and not allowing it to go straight forward. Try again several times to make sure that's not the cause.

If that doesn't solve it, start investigating by removing the bolt and giving it and the inside of the receiver a good 'looking over' for and dings or scuff marks that look out of place. I'd especially look at:
- raised area at rear of bolt
- the little nub of a lug near the rear of the bolt
- receiver safety bridge and firing pin tang
- the bolt roller and the interior of the cam in the oprod

Jay Kosta
Endwell NY USA

 

[Flyboy56]

You got your answer from the first responder aloreman and was expanded on by KurtC.
You have no problem. They all exhibit this trait to a greater or lesser degree. Strange but true.

 

[MUKAK]

makes sense