View Full Version : New barrel causing bolt to become stuck in battery?
texasmarine022003
04-11-14, 09:38
I recently swapped out my 14.8" WC Match barrel for a 16" Rainier Arms Mountain series barrel. I pick it up from the gunsmith, get home, decide to cycle a 20 round mag through the rifle to make sure everything is working properly. The first two rounds cycle perfectly the on the third round I cannot pull the charging handle back and the bolt is stuck in battery. IT took both hands and quite a bit of force to open and eject the round. Thinking this was a fluke because I have never had any issues with this rifle in the past, so I cycle another two rounds. On the second round it becomes stuck. After getting that one out I decide to cycle the rifle without ammo and after 60 times it never becomes stuck. Curious I begin looking over my rifle in more detail. I look down my hand guard and notice my hand guard has a slight cant to the right. I remove my T.R.I.M. rail and it looks like the barrel nut is not aligned right which is why my hand guard has such a cant in it. Could my barrel extension be off or torqued wrong and be causing the stuck bolt issues? I did run the BCG without the bolt inside the rifle to see if the gas was off center. IT has a slight rub but does not feel too bad.
http://i1167.photobucket.com/albums/q624/texasmarine022003/Mobile%20Uploads/IMG_20140411_093233481_zpsfdh3qlkp.jpg (http://s1167.photobucket.com/user/texasmarine022003/media/Mobile%20Uploads/IMG_20140411_093233481_zpsfdh3qlkp.jpg.html)
http://i1167.photobucket.com/albums/q624/texasmarine022003/Mobile%20Uploads/IMG_20140411_093152824_zpsdo8rwp5v.jpg (http://s1167.photobucket.com/user/texasmarine022003/media/Mobile%20Uploads/IMG_20140411_093152824_zpsdo8rwp5v.jpg.html)
http://i1167.photobucket.com/albums/q624/texasmarine022003/Mobile%20Uploads/IMG_20140411_093044975_zpsqvjk5kxz.jpg (http://s1167.photobucket.com/user/texasmarine022003/media/Mobile%20Uploads/IMG_20140411_093044975_zpsqvjk5kxz.jpg.html)
Tell me you're not doing this with live ammo. :confused:
texasmarine022003
04-11-14, 09:47
Tell me you're not doing this with live ammo. :confused:
Had the rifle pointed down range in my backyard. Before I went to shoot it I wanted to see if it would feed and eject right.
even if using live ammo, who cares. I have loaded and unloaded mine a few thousand times for work and never had any issue. Yes I have even cycled rounds to check mags, new load specs, ect, No difference. Pointed in a safe direction, finger off trigger...
OP, sometimes ammo is not in spec or it gets dinged, dented, ect. This could cause the round to get stuck in the chamber or it could be long and cause the bolt to be tighter. Could be the barrel chamber is 223 and your using 556 rounds. IMO, I would not worry about it and just shoot it. If the bolt and barrel have no issues without ammo, they are fine. It is an Ammo issue is all.
SpankMonkey
04-11-14, 09:54
The barrel is not installed correctly. Expand the first pic and take a very close look at the feed ramps. It should not look like that. You need to take this to a gunsmith before you blow up your gun.
texasmarine022003
04-11-14, 09:56
even if using live ammo, who cares. I have loaded and unloaded mine a few thousand times for work and never had any issue. Yes I have even cycled rounds to check mags, new load specs, ect, No difference. Pointed in a safe direction, finger off trigger...
OP, sometimes ammo is not in spec or it gets dinged, dented, ect. This could cause the round to get stuck in the chamber or it could be long and cause the bolt to be tighter. Could be the barrel chamber is 223 and your using 556 rounds. IMO, I would not worry about it and just shoot it. If the bolt and barrel have no issues without ammo, they are fine. It is an Ammo issue is all.
The barrel is spec is 5.56. I thought about it being an ammo issue as well. The first time it locked up was with Winchester 55gr white box. The 2nd time was with Federal 62gr
texasmarine022003
04-11-14, 09:58
The barrel is not installed correctly. Expand the first pic and take a very close look at the feed ramps. It should not look like that. You need to take this to a gunsmith before you blow up your gun.
Looks like the feed ramp is not flush with the extension on the upper, correct? Just wanted to make sure I'm seeing what you noticed.
SpankMonkey
04-11-14, 10:01
Looks like the feed ramp is not flush with the extension on the upper, correct? Just wanted to make sure I'm seeing what you noticed.
Correct. That looks to be about .040 to .050 over. Reinstall the barrel and check with a gauge to be safe.
texasmarine022003
04-11-14, 10:34
Correct. That looks to be about .040 to .050 over. Reinstall the barrel and check with a gauge to be safe.
Ok I'm taking it to be corrected this afternoon and hopefully that takes care of the problem.
It only does this with a round in the chamber?
Sounds like the barrels headspace is on the shorter end or the ammo is not sized correctly (too long for that specific chamber). I had the same problem with a barrel that had to be replaced under warranty and some rounds I loaded for the previous barrel.
texasmarine022003
04-11-14, 13:42
It only does this with a round in the chamber?
Sounds like the barrels headspace is on the shorter end or the ammo is not sized correctly (too long for that specific chamber). I had the same problem with a barrel that had to be replaced under warranty and some rounds I loaded for the previous barrel.
Went and had the barrel re-installed or attempted to. The gunsmith cracked my barrel nut....FML
A barrel nut shim kit goes along way before you go and over torque the barrel nut....
Went and had the barrel re-installed or attempted to. The gunsmith cracked my barrel nut....FML
A barrel nut shim kit goes along way before you go and over torque the barrel nut....
My apologies, I didn't read the entire thread. Maybe I had a few too many beers last night... As said above, it does look like the barrel is not installed correctly.
But, I did have the same problem with a barrel that was installed correctly and it was due to a shorter headspace. If you are still having the same problem after the barrel is reinstalled, I would look into that before firing.
I'm kinda wondering how you feel about the gunsmith your using ?
texasmarine022003
04-11-14, 20:29
I'm kinda wondering how you feel about the gunsmith your using ?
Lets just say once they order and I receive my new barrel nut I will not be using that shop anymore. The owner talks a good game a seems good to go but the weirdos he calls gunsmiths working in his shop have shown me they either don't know what they are doing or are just lazy.
There's nothing wrong with how that barrel is installed. I have a barrel sitting in one of BCM's new uppers and it looks just like the op's first pic - 0.040" or so from flush. Others have seen this and Grant and BCM have both confirmed it is in spec and acceptable. Variation in how deep a barrel seats in an upper won't affect how the bcg locks up or the reading you'd get with any gage.
That barrel appears to be installed correctly. What obviously isn't correct is the installation of the rail. Whatever is going on I suspect it's due to the shitty install job or maybe the chamber has a burr or something else in it. In any case I would be seeking someone out who is competent and can look this over.
texasmarine022003
04-12-14, 14:26
After measuring the lipped part of the barrel extension on the WC barrel vs. Rainier Mountain Series barrel, the Rainier barrel's looks to be 0.03 wider than the WC barrel. This is why the barrel not would not time correctly. I have since ordered the shim kit for it. Could the gas tube be slightly off centered to where I would notice it much by looking at it, and perhaps be the cause of the bolt getting stuck every so often?
Alaska3006
04-12-14, 23:30
I see a gap on your M4 feed ramps......my need to set your barrel back.
I suggest get a gauge go/no go
Exactly what do you mean by "time correctly"? You need to let someone competent with the correct tools look at this.
After measuring the lipped part of the barrel extension on the WC barrel vs. Rainier Mountain Series barrel, the Rainier barrel's looks to be 0.03 wider than the WC barrel. This is why the barrel not would not time correctly. I have since ordered the shim kit for it. Could the gas tube be slightly off centered to where I would notice it much by looking at it, and perhaps be the cause of the bolt getting stuck every so often?
constructor
04-13-14, 13:03
I see a gap on your M4 feed ramps......my need to set your barrel back.
I suggest get a gauge go/no go
Don't do this. You can not set your barrel back.
Head space is determined by the depth of the chamber in the barrel, the distance from the front of the barrel extension to the front of the lugs and the distance from the back of the bolt lugs and face of the recess in the bolt.
I agree with everyone else the handguard install was jacked. Other than that you need to find a bolt that headspaces correctly with the barrel.
The feed ramps aren't a big deal but you can blend them in a little better if it bugs you.
even if using live ammo, who cares. I have loaded and unloaded mine a few thousand times for work and never had any issue. Yes I have even cycled rounds to check mags, new load specs, ect, No difference. Pointed in a safe direction, finger off trigger...
OP, sometimes ammo is not in spec or it gets dinged, dented, ect. This could cause the round to get stuck in the chamber or it could be long and cause the bolt to be tighter. Could be the barrel chamber is 223 and your using 556 rounds. IMO, I would not worry about it and just shoot it. If the bolt and barrel have no issues without ammo, they are fine. It is an Ammo issue is all.
Finger off the trigger and the gun pointed is a safe direction,, sounds like we should use it as a safety rule :cool:
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