AR Sponsor
Posted: 6/30/2013 3:39:29 PM EDT
|
I was just taking a look at my 11.5 inch upper and noticed that the bolt doesn't lock up tight, all my other uppers it doesn't move this one with the upper off and bcg is in there you can push down on it and moves around about a 32nd of an inch.
Now I haven't had a chance to shoot it yet but never had an upper like this, I tried other bcg and it's the same. |
|
Quoted:
I was just taking a look at my 11.5 inch upper and noticed that the bolt doesn't lock up tight, all my other uppers it doesn't move this one with the upper off and bcg is in there you can push down on it and moves around about a 32nd of an inch. Now I haven't had a chance to shoot it yet but never had an upper like this, I tried other bcg and it's the same. Are you saying when you drop the BCG in it doesn't seat flat, and you have to push it in another 32nd of an inch? |
|
If I understand you right, take your bolt carrier group back out and make sure your bolt is all the forward before sliding it back in. It kind of sounds like your cam pin is getting in the way because the bolt isn't all the way forward.
I was taught in the Army to hold the bolt carrier in your hand and slap it downwards to make the bolt extend as far as it can. Try this and let us know. |
| It sits flat, best way I can describe it is with the upper off and bcg in, if you push on it from the bottom closeest to the barrel it has some play (about a 32nd of an inch) none of my other uppers do this. Not sure how this would effect function but it would seem to me accuracy would be greatly effected. Is this something I should contact BCM about? |
| Totally normal. Bolt carrier fit to upper receiver diameter is not a tight tolerance. There needs to be some space to account for any debris that accumulates during firing. AR15s are modeled after combat rifles and are designed around absolute reliability. Tight tolerances in the BCG to upper fit would be detrimental to that reliability requirement. |
|
Just seemed like to much excess, much more than my others, or well I'll see how it shoots and go from there. I'm gonna be running a can on this in the near future so will see if this causes more problems (shorter lock up time ?)
If it is a problem I'll send it to BCM, I never had to do that for those who have are they easy to deal with? |
AR Sponsor