Unable to retract bolt with round in chamber.

[andyo5]

This has happened to me several times. At the range, I have a round chambered and everybody wants to go 'cold' to check targets, etc. I remove the magazine and attempt to pull the bolt handle to eject the round from the chamber.
No go. I cannot pull the handle back. The only way to get the round out of the chamber is to fire it. The case then ejects normally. The chamber is not fouled. I clean it regularly.

Does anybody understand why this happens?
Can you suggest a solution?
Thanks.

 

[k22fan]

First, I've never touched an M&P 15 and have limited experience with AR-15 derivatives. The cause of loaded rounds sticking in chambers usually is they were not resized enough. They can become stuck by a bolt action's cams pressing them in tight or a simi-automatic's recoil spring hammering them in. Simi-autos do not have the typical bolt action's leverage while removing cartridges manually.

This is not limited to reloads. Often rifles that are sold as match grade or target rifles have chambers that were cut to minimum tolerance. It is common to encounter factory cartridges that are a press fit in them.

Occasionally standard production rifles also wind up with minimum chambers. I've had to return a few full length resizing dies for dies that would make brass small enough for standard production rifles. Lyman and RCBS both asked for sample fired cases returned along with the dies. For free they sent back dies made or selected for my chambers.

 

[agksimon]

Is this factory ammo or reloaded? If factory, what brand?
If they are reloaded, not sizing the case all the way down or not using small base dies, can cause rounds to stick in the chamber.

 

[s&wchad]

What bullet weight are you shooting? Heavier bullets are longer.

I've seen heavier bullets (over 62gr) engage the rifling when the bolt closes, which effectively locks the charging handle. We had one shooter at our range trying to shoot 75gr Russian ammo in his AR-15 and the gun wouldn't fire, because the bolt wouldn't close enough. We finally had to pound the charging handle back with a piece of wood. The bullet had obvious rifling marks near the ogive.

 

[agksimon]

What bullet weight are you shooting? Heavier bullets are longer.

I've seen heavier bullets (over 62gr) engage the rifling when the bolt closes, which effectively locks the charging handle. We had one shooter at our range trying to shoot 75gr Russian ammo in his AR-15 and the gun wouldn't fire, because the bolt wouldn't close enough. We finally had to pound the charging handle back with a piece of wood. The bullet had obvious rifling marks near the ogive.

Oooh, not good. Maybe cause overpressure?

 

[H47]

This sounds like you may be using steel cased Russian ammunition. This stuff has a lacquer coating on the case to lubricate it during function. If a round is placed into a hot or warm chamber and allowed to sit while things cool off (doesn't take very long) the lacquer melts and then solidifies, gluing the round into the chamber. The sudden and intense heat of subsequently firing the round melts the lacquer, releasing the case.
Does any of this sound familiar?

 

[rwsmith]

I've had the bullet in the rifling problem....

Not with a AR but a bolt rifle. It was jammed so tight I had to pull the bullet in the process of extraction. I think a more sophisticated way would be to use a brass rod in the muzzle to push the bullet slightly back into the case.

I'm an experimenter and use a LOT of different bullets in different guns and I'm constantly running into probs like that.

 

[Fishinfool]

^^^^^^^ Pretty much all of the above is a possibility. A very good reason to do a "plunk" test prior to using a new brand / type of ammo or reload.

Larry

 

[lrrifleman]

Andyo5,

I would say that the most likely culprit is your ammo, but it could be the chamber.
1. If the ammo is factory, check the C.O.L.
2. If the ammo is reloaded, are you using a neck sizing die or a full length sizing die?
3. If the ammo is reloaded, how many times has it been reloaded since the brass has been trimmed? [If the brass hasn't been trimmed it is wedged into the throat, and locking up the action.]

If the problem occurs with only reloads, figure that the cases need to be trimmed. If it occurs with both reloads and factory ammo, chances are that some of the cases (even factory) are out of spec. However, it is possible (but not all that likely, that your rifle has a short chamber.

 

[Ray1970]

All excellent replies so far. I will add that the headspace could be tight from the factory. If you aren't using new, brass cased ammunition from a major manufacturer you might try a box or two and see if that works. If the problem persists then maybe you can find someone to check the headspace for you.

 

[andyo5]

Ammo is my reloads, using Federal military cases. Hornaday 55g bullets. OAL as recommended by Hornaday. There is a cannelure, and I am using it.
I am loading with Varget below maximum recommended charge weight.
Overpressure not likely the issue, since the round that would not extract had not yet been fired.
Sizing/reloading dies are Dillon. I am full length resizing.
Has also happened with Federal factory ammo.

 

[vonn]

Small base dies are recommended for semi auto use,but if Federal factory gives a problem you may have a tight chamber? Not an expert but my friend had the same problem and the dies cured it.

 

[k22fan]

Call Dillion, say you'll return the FL sizer with fired brass, and ask if they will replace the FL sizer for free. Telling them RCBS and Lyman happily do that might encourage them to be as good as the competition. In my experience, all the manufacturers of reloading tools act like they know we are a small segment of the population that will be customers for life. Aside from that, Dillion's reputation for customer service is second to no one.

By the way, while a small base sizer would have been a good idea to start with, I had to return one of those so buying one would be spending money unnecessarily on a gamble.

Good luck.

 

[MichiganScott]

Ammo is my reloads, using Federal military cases.

Likely your problem is you didn't resize the case enough. I've never used a small base die in any military semi-auto from Garands through M1As and ARs. I suggest that you may not be pushing the shoulder back far enough.

Personally, I'd just mortar the gun to get the shell unstuck, but that will get you kicked off a public range.

 

[k22fan]

25 years ago an RCBS customer service rep explained it this way. In order for reloading tools and rifles to be affordable shell holders, FL dies and rifle chambers have to be allowed to vary within tolerances. If the FL die dimension range was set small enough that all FL dies will make cases freely enter minimum chambers then a customer who by luck gets a minimum dimension shell holder and FL die combined with a maximum dimension chamber then he would create dangerous excess headspace by resizing with his FL die set to contact his shell holder. To prevent that the FL die minimum and maximum dimensions are little larger and the occasional customer who winds up with a FL sizer that will not make brass small enough for his tight chamber is handled individually.

The world is not perfect but on the bright side the die that is returned to you will be a custom match to your chamber. It would cost a fortune to do that for everyone.

 

[otisrush]

If it has happened with factory ammo I highly doubt it's the reloads.

I'd make sure the gun is all copacetic. I agree the chamber might be tight.

Although - given I said it's not likely the reloads - maybe load up a dummy round or two (no primer or powder) and see if they get stuck as well? You can also use a Sharpie to paint the pullet before chambering. Then if it is getting caught on something marks will be left. (The bullet can also be "smoked" - using a match or candle to cover the bullet in black soot prior to chambering it.)

OR

 

[WR Moore]

Ammo is my reloads, using Federal military cases. Hornaday 55g bullets. OAL as recommended by Hornaday. There is a cannelure, and I am using it.
I am loading with Varget below maximum recommended charge weight.
Overpressure not likely the issue, since the round that would not extract had not yet been fired.
Sizing/reloading dies are Dillon. I am full length resizing.
Has also happened with Federal factory ammo.

I note you mention it happens with factory ammo, I'd suggest calling S&W about a return for inspection.

That said, you've got Dillon dies, did you also get a case gauge to properly set the sizing die? They aren't screw 'em down till they hit the shell holder. You need the case gauge to properly set the sizing die.

Do you trim your brass? I had issues with this long ago, it's called a learning experience.

Finally, the use of small base dies in auto rifles is, in my experience, not necessary. Slightly out of spec cartridges will be chambered without issue by the force of the bolt going forward. Extraction generally isn't an issue. Most modern die suppliers note that small base dies are only necessary for rifle with chambers smaller than SAAMI specification. This pretty much eliminates the vast majority of semi-auto rifles. BTW, the Dillon dies sort of split the difference between standard and small base dies. Small base dies will reduce the shoulder and the area just in front of the case web more than standard dies.

Note: I've got a bolt gun with a dead minimum SAAMI .223 chamber and it handles the product of my Dillon dies without issue.

 

[andyo5]

- maybe load up a dummy round or two (no primer or powder) and see if they get stuck as well? You can also use a Sharpie to paint the pullet before chambering. Then if it is getting caught on something marks will be left. (The bullet can also be "smoked" - using a match or candle to cover the bullet in black soot prior to chambering it.)

OR

Good idea. I already have a dummy round and will try this.

 

[andyo5]

Do you trim your brass? I had issues with this long ago, it's called a learning experience.

No, I haven't been trimming. I figured that since the cases are all once fired military, they were all within spec to begin with. Maybe that is a mistake?

 

[old&slow]

Usually once fired are OK and won't need to be trimmed..
But two or three firing will probably need trimmed..

Good ideas and reasons already posted.. I would suggest maybe getting a Wilson / Dillon case gage to check your ammo.
They are not that expensive and easier to use than a 'plunk test'.

I was going to suggest making sure your sizing dies are fully sizing / bumping the shoulders back a .001 or .002. But if factory ammo is doing the same thing , probably that's not the problem..

Have you used a chamber brush on the chamber ,, any chance that may be gummed up ??