View Full Version : Round not firing when using bolt release on AR15
Happy New Year. I have a problem with my AR and hope that someone can help. When I use the bolt release to chamber the round and then press the trigger the trigger clicks like normal, but the firing pin doesn't strike the primer, no marks on the primer. If I use the charging handle or during firing when the round is chambered by the rifle everything is fine. Does anyone have an idea of what might be happening? it sounds like the bolt doesn't move all the way in the carrier, so that the firing pin doesn't go out enough, but what would cause this to happen and only when using bolt release? I have a collapsible/carbine stock on this lower.
Thanks,
Alex.
Test it by hitting the forward assist after you release the bolt catch. If it shoots then you know that the bolt isn't going forward all the way after you release the bolt catch. Then you can move on to further investigation of the problem.
Thank you. I'll try, problem is I don't go shooting nearly often enough.
Some brands of AR's (Bushmaster and DPMS come to mind) are kind of notorious for having a relatively tight chamber preventing the bolt from going into battery on occasion. Yours might be one of those. What brand is it?
The upper is centurion arms with NATO chamber and chrome lined mid-weight barrel.
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A few questions:
What ammo are you using? Only one make or different makes?
How many rounds through the gun?
How many since the last cleaning?
Do you keep the Bolt well lubed?
Lastly, what make is the lower? Was it factory assembled?
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Did the rifle just start doing this?
unload the rifle, take the upper off of the lower, remove the bolt from the bolt carrier and slowly slide the carrier into the upper with the upper right side up and upside down.
Do you feel any resistance or hear any noise when the carrier is nearly fully inserted into the upper?
This may sound odd but double check to ensure that you put the firing pin back in after your last cleaning.
If the pin is there remove it and make sure that there is nothing obstructing the area where the pin goes in the carrier.
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How old is the upper and lower? How many rounds? Make sure that you have plenty of lube on the bolt and carrier. Make sure the length of the action spring is a minimum 10 and 1/16 in long.
Thomas M-4
01-01-12, 17:24
The retaining pin is most likely not installed correctly.
If you installed it before you put the firing pin in..
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Didn't the OP post the gun worked fine if he releases with the CH but it just doesn't fire when he releases using the Bolt Release?
If it was assembled wrong, the gun would not function at all.
But maybe it's just me...
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Thomas M-4
01-01-12, 18:24
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Didn't the OP post the gun worked fine if he releases with the CH but it just doesn't fire when he releases using the Bolt Release?
If it was assembled wrong, the gun would not function at all.
But maybe it's just me...
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You are right he did say that.
Assuming it does fire when manipulating the charging handle the OP has a different problem.
This may sound odd but double check to ensure that you put the firing pin back in after your last cleaning.
http://www.primeaffiliate.com/track/images/22.gif
This may sound odd but double check to ensure that you put the firing pin back in after your last cleaning.
As already noted, the rifle wouldn't fire at all if this was the case.
Thanks guys for the suggestions. The firing pin is there. The lower is double star and was assembled by me using Daniel Defense lower parts kit with spike's boron nitrite carrier and bolt and hammer. It only doesn't work when releasing with bolt release/bolt catch. Works fine any other way.
I took the upper off and slid the bolt/carrier by hand and it slides fine, no sounds or obstructions. The upper has around 600 - 700 rounds through it, the lower about 120.
Thanks guys for the suggestions. The firing pin is there. The lower is double star and was assembled by me using Daniel Defense lower parts kit with spike's boron nitrite carrier and bolt and hammer. It only doesn't work when releasing with bolt release/bolt catch. Works fine any other way.
I took the upper off and slid the bolt/carrier by hand and it slides fine, no sounds or obstructions. The upper has around 600 - 700 rounds through it, the lower about 120.
Did you check the recoil buffer spring as mentioned above?
Those damn spikes NiB bcg's again! Must be out of spec due to the application of the NiB and therefore getting hung up!;) just kidding, had to say it, but....you never know.
Something doesn't add up here. There has got to be something happening here.
Is the lower receiver extension screwed in all the way (correctly) to where it just engages the buffer retainer pin?
Was the upper purchased complete from Centurion and dropped onto the DS lower?
Who makes the buffer and the spring? What type of buffer do you have?
Does the bolt slide smoothly in the carrier? What is the free length of the recoil spring? Does the ejector depress smoothly and fully under the bolt face?
TX Rancher
01-02-12, 09:30
It seems like it would have to be something with the spring/buffer/tube. Since the carrier appears to work fine when it's manually worked there doesn't seem to be an obstruction in the way.
What I'm thinking is the difference between using the charging handle and the bolt release is the carrier is probably farther back when using the CH. That would compress the spring a little farther and add some additional energy compared to the bolt release.
I would agree with Iraqgunz and think the place to start would be the buffer/spring/tube area.
The spring is 10 3/4 long. The extension is milspec and buffer is carbine standard. The buffer is moving freely, but I am starting to think that the spring might be weak, even though it is a new spring. The tube seems to be screwed in correctly, far enough.
I don't think you will be able to gage whether or not the spring is weak. The way they are checked for rejection is by measuring and 10.75 is still well within the standard.
If you have an H buffer I would try that. Who makes the carbine buffer?
The spring is 10 3/4 long. The extension is milspec and buffer is carbine standard. The buffer is moving freely, but I am starting to think that the spring might be weak, even though it is a new spring. The tube seems to be screwed in correctly, far enough.
I unfortunately don't know who makes the buffer. Don't know where I bought it either. I don't have an H buffer, do you think one would help in this particular case? Which H buffer would you recommend?
Thanks.
I think it couldn't hurt. As much as I hate internet surgery there is nothing else that even makes sense to me.
Get a BCM H buffer and try it.
I unfortunately don't know who makes the buffer. Don't know where I bought it either. I don't have an H buffer, do you think one would help in this particular case? Which H buffer would you recommend?
Thanks.
Evil Colt 6920
01-02-12, 21:17
Could this be a mag issue? I could be a fool for posting this since I have minimal trouble shooting experience with AR's so feel free to tell me to shut up :) Just seems the mag plays a more important role while using the release as opposed to using the charging handle so the issue could possibly lay there?
Does your rifle have M4 feed ramps? Perhaps you could post a picture of the failure to feed?
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Akaplan,
Just another thought...
Lock the Bolt back using the Bolt Catch like you normally would.
Then slowly pull the Charging Handle back until right when it engages the BCG. Once the CH has engaged the BCG, notice how much the CH moves rearward from engaging the Bolt until it is all the way back.
If you would try this a few times to see how consistent the measurment is and if you would, please reply on how much the CH move rearward until it stops?
Just an idea...
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I considered this, but since it is a Centurion upper I assumed it was correct.
Does your rifle have M4 feed ramps? Perhaps you could post a picture of the failure to feed?
I figured out what buffer it is, it is BCM, but a regular one, I ordered this kit: http://www.bravocompanyusa.com/Stock-Hardware-Mounting-Kit-Mil-Spec-p/stock%20hardware%20kit.htm
Just to clarify something, there is no failure to feed that can be observed from the outside everything looks like it feeds fine, it's just that the firing pin doesn't strike the primer when using bolt release/catch.
Thank you for helping me to figure this out.
Sounds like the bolt carrier is either not going fully into battery or bouncing slightly out of battery.
Try tapping the forward assist after dropping the bolt release to see if there is any extra movement.
there is no failure to feed
right, I'm going back between multiple threads and got confused. It's a failure to lock. If you look closely the front of the bolt carrier won't be as far forward as it is when you release it from the charging handle.
I would try replacing the spring and buffer and see what happens. No need to take off the receiver extension if it’s not the issue. Assuming it is installed correctly it shouldn’t be the problem. BTW what ammo are you using?
If it is indeed failure to lock, It is probably either headspace and/or ammo.
The NIB is .0005" thick per side.
This could reduce headspace by .001" if not compensated for.
Ok, I just caught this. You are using a Centurion upper and a Spike's magical BCG.
1. Did you check the headspace when you did the install?
2. I would also check the firing pin protrusion.
Hmmm. Firing pin protrusion looks fine, but I don't have a tool to check. I was also under impression that AR bolts are interchangeable as long as they are new, is this not the case? Even Monty when I ordered my upper told me that he didn't match bolts to barrels. I don't have a headspace gage, so didn't check the headspace. I haven't seen any problems with the bolt and carrier and this same upper on a different lower with rifle stock, buffer, etc. Wouldn't a headspace problem be constant and not only when releasing with the bolt release?
It sounds like there is a problem with Spike NiB bolt/carrier groups. Is this the case, I bought mine a long time ago and at the time they were considered to be very good.
Thank you guys for all the help.
Alex.
Have you tested it without ammo or magazine? Does the bolt lock?
Hmmm. Firing pin protrusion looks fine, but I don't have a tool to check. I was also under impression that AR bolts are interchangeable as long as they are new, is this not the case? Wouldn't a headspace problem be constant and not only when releasing with the bolt release?
No depth mic or caliper?
Properly made bolts with USGI chambers are interchangeable, for the most part. Most civilian bolts are interchangeable. Headspace would be constant but the little extra added force of charging from the charging handle might overcome the minute extra length. I've seen enough of the uninformed "chamber" NOGO gages in GO chambers, it's easily done.
Also, it sounds like what is happening is when you chamber from the bolt catch the carrier is ending up slightly open and the hammer drives it shut when it falls.
I echo the question above, does the bolt lock from the bolt catch without a round in the chamber?
Yes the bolt locks without round in the chamber. It goes all the way in and pressing on forward assist doesn't produce any movement.
time to find a GO gage after you try a new spring.
quick check, pull the BCG, push the bolt into the locked position and check that the inside arc of the extractor pivots outside the curve of the bolt face. The cartridge feeds straight in from the front and the extractor has to get out of the way.
Yes the bolt locks without round in the chamber. It goes all the way in and pressing on forward assist doesn't produce any movement.
Now try that with live "problem" ammo ( in an appropriate location ) as well as some other "known good" ammo.
If possible, swap BCG and repeat the test, trying to isolate ammo or BCG/head space.
You can force the action closed on a big round/tight headspace, but it takes more force.
It sounds like there is a problem with Spike NiB bolt/carrier groups. Is this the case, I bought mine a long time ago and at the time they were considered to be very good.
The first thing you need to do is step back and take another look before you start spending a lot of money buying stuff you don’t need.
Start with the simplest thing first. Ammo. What ammo are you using? Have you tried any other?
The cheapest fix and quickest is replacing the action spring and buffer. You already have some on its way so before you start trying a bunch of stuff and chasing your tail around, try ammo, spring and buffer first and see what happens.
[QUOTE=akaplan;1186628]
It sounds like there is a problem with Spike NiB bolt/carrier groups. Is this the case, I bought mine a long time ago and at the time they were considered to be good.
First I've ever heard of an issue such as this(if your issue IS actually attributed to the bolt or carrier) with a Spikes NiB bcg or even a spikes standard bcg. I can tell you this though, they(spikes) claims to have a lifetime warranty and though I've never had to cash it in on one of their products (and no I'm not solely a "spikes fanboy") it would be interesting to see what they would be willing to do if your problem is in fact attributed to the bcg and it's components. In any event your talking about "just replacing" something you paid $225 for(cost justified or not) I would contact the manufacture if I thought there was a problem there before shelling out more $ on another bcg.
I ensure head space but I dont offer to do a "matched" set like headspacing to a tighter spec to say have "match" accuracy. This is primarily done at places doing barrel where they have a bolt in hand and cut the chamber to match a bolt that is provided with the barrel. If you add a bolt group to an upper you buy from me I will ensure head space is good. I would first recomend getting a bolt group made to proper mil standards from vendor that specializes in that if you wish I can provide one but my suspicion is that is the root cause of your issue. If you'd like you can send the upper back to me to take a look at.
Thanks
Monty
Hmmm. Firing pin protrusion looks fine, but I don't have a tool to check. I was also under impression that AR bolts are interchangeable as long as they are new, is this not the case? Even Monty when I ordered my upper told me that he didn't match bolts to barrels. I don't have a headspace gage, so didn't check the headspace. I haven't seen any problems with the bolt and carrier and this same upper on a different lower with rifle stock, buffer, etc. Wouldn't a headspace problem be constant and not only when releasing with the bolt release?
It sounds like there is a problem with Spike NiB bolt/carrier groups. Is this the case, I bought mine a long time ago and at the time they were considered to be very good.
Thank you guys for all the help.
Alex.
Thank you Monty,
I"ll send it to you if I can't figure it out. I don't think it is your upper that is at fault, if I did I would contact you first. The upper shoots extremely well and I am happy with it. It shot very well on a different lower. I have a different action spring coming in and I also have one of your bolt and carrier groups, so I will try this next time I go to the range.
Best Regards,
Alex.
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