Need a competent AR-15 gunsmith in Denver

I just completed a Mk12 assembly (Vltor MUR-1A, Centurion Arms MK12 Barrel, BCM Auto BCG, and more) and have encountered what may be a chamber that is right at the minimum spec. I shoot reloads and it appears that the rounds that I have made that fall within the case gauge specs & COAL are to tight in the chamber - ramming the shoulder into the throat causing a little resizing when chambering which in turn requires a 2 handed pull on the charging handle to eject.

I need to find a gunsmith that has actual 5.56 headspace gauges to have a look at it and figure out if I need to have the barrel sent back, or get a bolt matched to it.

I have tried 3 different BCGs (2 BCM auto and 1 PSA premium auto) and the only forgiveness I get is with my PSA BCG with over 4k rounds on it.

I know I probably need to address my sizing die, but at this point it is bottomed out on my shell plate and I can not lower it anymore to push the shoulder back any.

SO - who knows a gunsmith that knows what they are doing - and Gunsmoke is out of the question on principle.

Are you using a full-length sizing die or a neck sizing die? Neck sizing dies are generically used only on bot guns as they do not re-size the case walls, just the neck, which allows the case to be fire formed to a specific chamber. Full length is the way to go in a semi-auto or you will often see exactly what your describing, and some rifles (although rare) will need to use a small base sizing die for 100% functionality.
Were it me, and I am not telling a grown man what to do, but if it were me I would first check my sizing die and if its a neck sizer switch to a full length or small base sizer and see how that works, drop a go/no-go gauge set into the chamber to check and see that its within spec, and if it is, and you are using a full length die, then take it to Bert at BP Tactical and he will fix you up.

What dwalker460 said...to elaborate a little, it sounds like you may just need a finish reamer run through the chamber...no big deal for any competent smith.

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Bert or rob at Bowers

+1 for Bert at bptactical.

Get in touch with Bert (BPTactical). He does awesome work at a very fair price and knows what he is doing. [Awesom]

Here is the link to his website.

http://www.bptacticalservices.com/

And here is a link to his little section of this forum.

http://www.ar-15.co/forums/154-BP-Tactical

Rob at bowers or Bert at BP.

Depending on what side of town you are on. Cant go wrong. Both have done work for me.

My vote and recommendation is for Bert at BPTactical. Berts done a lot of work for me. He does great work, sincerely cares about his work product, and has reasonable prices.

Bert or Myself (Rob) can help you out. It will be fairly easy to determine and correct for either of us. Spent casings will help as well, regardless of which of us you use. Bert is located up north of denver, I am in the tech center. Call Bert for his hours, I am in the shop 10-6, mon-sat. Either one of us will get you up and running fast

Yeap Rob is a good guy as well!

I seriously would check your sizing die though, because I have seen many people try neck sizers and have the same issues you are experiencing.

BPTactical it will be then.

My sizing die is a Dillon RT1200 setup on a Lee LoadMaster - bottomed out on the shellplate. No problems with the first 4k that I have made, it's just this last batch. Might be that I need to have .005 - .010 trimmed off my die base for a little more fluff room.

Last night I went through 500 rounds and culled out 25-30 that were .006 or less above my case gauge max - those were causing a FTF and stuck bolt. Even the ones that are flush with the case gauge max require a fairly stout pull to release the bolt. I need to go through another 300 or so to finish my training class....Yes I am firing this rifle for this class. Not wise? likely, but I want to learn how to run a scoped DMR in a tactical CQ situation. PRS stocks bite back when you have to mortar them.

Best steps to start from scratch on an AR build

Go see Bert @ B&P Tactical. He is the best gunsmith I've dealt with ever.

TD2 went without a hitch, except for having to double handed pull a couple for manual unload/extraction. Might have had a few sneak by that were a tad over max length.

This may turn into a deal with it during lay off. Going to try for next weekend. Will make some calls.