"Truing" an AR's receiver face?

[BrigandTwoFour]

Hey guys, had a thought.

I've seen some people before talk about truing up the front of the receiver extension to make a perfectly level and squared up contact between the barrel extension and the receiver as a method to really tighten up the accuracy of the gun.

I never thought much about it because I wasn't interested in squeezing every last bit of accuracy out of my guns....yet.

I've come across a few companies that now do it as a service package for accurizing an AR.

Do you think there is merit to this process? Would there be any appreciable gain? Or is this all just pixie dust and unicorn jizz?

The gun I have in mind is a precision .308 project that is currently at a stand still due to the panic, but will ultimately turn into a no-expenses-spared kind of thing (well...not literally...I'm not that rich).

[mkmckinley]

Best bet would be to just buy one that's true in the first place. Something like the Rainier Arms Ultramatch or Vltor MUR will be machined precisely and ensure everything is lines up straight. I'm not sure what truing could be performed on an AR upper after it's machined but I can't imagine it would exceed what high end manufacturers are accomplishing with strict QC and CNC machines. Besides that I think the main thing that matters is having the flat top perfectly in line with the bore/receiver face and built as much rigidity into the design as possible. I'd also wantthe barrel extension to have minimum clearance in the receiver i.e. a slip fit.

[BrigandTwoFour]

I would be all over that Rainier receiver if they made it in .308 (I'm already using the Ultramatch .308 barrel, though).

There doesn't seem to be a whole lot of options out there regarding .308 upper receivers like there are with the smaller AR-15 platform. I have seen 'smiths polish the mating surface, which is why I'm asking.



I'm just wondering if anyone thinks its actually worth the expense.

[ICANHITHIMMAN]

I wish I could quote a source but I believe this it total BS! Even if a bolt action rifle receiver is trued it will gain nothing if the barrel used is not cut to the same standards.

[VooDoo6Actual]

Interesting thread.

I tend to agree w/ posts above regarding in-spec / out-o-spec. Of course it's true regarding barrel etc.
I always check specs for QC. If you examine the interface where receiver links up with barrel nut or rail interface on an OBR / LMT / KAC / Barrett (which are all sub MOA capable) you'll notice how each manufacture addresses (w/ their proprietary methods, patents etc.) this important accuracy issue.

A Bullet (missile) doesn't give a Rat's Ass which breech & tube it's launched from.

I also agree about .308 L/R availability & know what you are referring to. While DPMS seems to be the prevailing pattern there are non-compatability issues w/ certain components. Proprietary specs are respected for the most part.

FWIW, I've been working w/ Seekins & SI Defense stuff lately that is pretty dead nuts on typically. NEMO Arms has some good stuff I've been working with that might be worth a look at.

I know Young's MFG. .308 BCG's production are already spoken for so that's going to be like finding Unicorn Jizz for sure.

[caelumatra]

They sell the tool at Brownells.
http://www.brownells.com/gunsmith-to...prod20220.aspx



But that's for an AR15 not an AR308 so once I actually read your OP I realize my link is useless for you lol

[BrigandTwoFour]

Thanks for all the input, guys.

I did contact a company local to me who performs this service on AR-15s and asked about doing it on a .308. They said it can be done, but there would be an extra cost to set up for it since they don't currently have the tools.

That said, I don't think there will be a need for it. I'd rather get the gun assembled and shooting to see where I'm at. If I feel like there is room to squeeze more out of it, and there aren't any other things that can be done, then I'll consider doing this. From what I've read about the manufacturer of the upper receiver, I don't suspect there will be any issues with the spec. I'm probably not a good enough shooter at this point anyway to really notice a difference.

Voodoo, I was planning on getting a Young MFG whenever I can find one. Who is sucking them up?

[TehLlama]

The outfit I work at regularly does stuff at ~.0002" precision, but frankly no projectile is going to give half a crap about that - it's like trying to figure out how much better a lighter kid's see-saw will do at flinging things when there's an elephant at the other end, it's going to be completely lost in that process.

This does have me thinking about how reasonable it would be to start making the .308 uppers though...

[C4IGrant]

While i think the discussion is interesting, I don't think it matters (enough). For me, if you want improved accuracy, fit the bolt to the barrel, use the lowest ACCEPTABLE torque value on the barrel nut and use spacers to time the flash suppressor/MB.



C4

[chakup]

While i think the discussion is interesting, I don't think it matters (enough). For me, if you want improved accuracy, fit the bolt to the barrel, use the lowest ACCEPTABLE torque value on the barrel nut and use spacers to time the flash suppressor/MB.



C4

Wait lowest torque? I'm no sniper, but it seems whenever these sort of topics come up (generall talking bolt guns) I've always seen higher torque numbers. Can you explain/help me understand here?