Newbie with BCG question

[mkdonald]

I am totally new at this, but I am very mechanical. I have assembled watches and car engines from scratch. I really enjoy building mechanical things. I decided to build an AR 15 and have thoroughly enjoyed the process. I am nearly complete, but I have a question. I have the Brownells assembly video and the instructor puts the BCG in the upper and locks it forward. Then he demonstrates sliding the bolt carrier back and forth by sticking his finger in the back end and sliding it out and then forward with relative ease. Mine is way tighter than that! I have a Larue stealth upper, Daniel Defense 16" M4 barrell, Spikes Nickel Boron BCG. I did function test it according to the video and it does lock and eject the dummies properly, but it has to really slam forward to lock in place. When I take the BCG out and push the bolt back and forward, it is not as easy as it looks in the video....seems tighter. Should I be worried?

[bkb0000]

have you fired it? properly lubricated? do you have another BCG (preferably regular phosphate) you can try?

the billet receivers can be on the tighter side of tolerances, and your treated BCG might be on the wider side of tolerances. from the way you describe, i'd probably go ahead and put a good 500 rounds through it and see how it performs. if you have problems, i'd try a different carrier.. and if you still have problems, i'd call larue.

[mkdonald]

Haven't fired it yet. I ordered a headspace guage just to be sure it is good. I also still need handguards. I have tested it everyway you can with the dummy rounds and it seems right. Just very tight. I saw another thread that talked about tightness and they recommended the same as you. Just wanted to doublecheck becuase of the coating on the BCG. It appers to slide well in the receiver and fits well into the gas tube. The bolt just seems stiff as it goes into the barrel extension to lock. When I pull the ch back (more force required than it seems on the video) it slams forward and locks properly. I moved the bolt back and forth while out of the receiver and it is definitely not as loose as others I have handled. Maybe just needs a break in? Anyway...thanks for the advice!!!

[M76F]

It will loosen up the more you use it. New BCGs always feel "stiff" to me, but they break in fast.

[markm]

I've never had a carrier group that wouldn't manually cycle as you describe. :confused:

[tylerw02]

Are you sure your gas block is indexed properly? Your gas tube could be canted; creating friction on your gas key causing excessive resistance when you attempt to manually cycle your BCG.