Oh dear, another one of those posts...

[dafish]

Hello!

Living here in Illinois, I've decided I'd best build a few AR-10/AR-308’s whilst I can.  As you can guess, I’m hoping for a few tips. 

🙂

Purpose:   Genera -  Everything from a rare deer hunting trip to pool cue chalk shooting at 100 yards.   I shoot a 7005R that is better than I am (by far) but for these I’d still like to build something that’s sub moa.  When I’m killing paper that will be typically be at 300 yards, but I occasionally get access to a 500 yard range.  I suppose a coke can at 300 yards is the minimal accuracy goal. 

 

Budget:  It will be what it will be.  However, this is a price/performance build, not a high end “damn the cost” nor a “how cheap can I build it” exercise.   Money will go as needed to places that need it, less so to other areas.   I'll handle trigger and optics later, so I've deferred 50% of the cost already.

I’ve already ordered three stripped Aero Procession M5 lower and upper sets, Magpul PRS for the stock, JP’s bolt, and a Criterion 18.5" SS barrel.   However, I've still a few questions.  If you don’t mind sharing, here goes:

 

Q1:  I’ve read some disparaging remarks about the Aero LBK.   Which I have to admit had been my plan.   Is there better fitting, more complete, and and correct LPK ya’ll would recommend?

 

Q2:  My time behind my 700-5r tells me recoil management affect accuracy.  I was thinking about using the Armaspec Stealth recoil spring.  Any advice or comments?

Q3:   I'm going to use rifle length gas.  Is there any magic to selecting a gas tube, or is this one of those "just pick any rifle length tube and move on" moments?

Q4:   Headspacing:  How is this adjusted?   Can the bolt be tuned?  You can't hardly ream a chamber to be tighter.  Is this something even an average (and that's all I'll have here) gunsmith can get right?  Are there different sized bolts?  How... Why.. huh?

Here's the build list in case in matters..

Thanks in advance!

d

 

 

[sketch]

most likely that will all work.. you said the trigger is later but its included in the lpk. ? 

the upper parts ok.

gas tube should match the mfg. barrel gas length.

* seekins adj gas block,  are you going to supress? 

then the guru @98Z5V will tell you about the reciever specks.. 

[98Z5V]

WTF.

That first post is full of all kinds of stuff, but I'm not going to get into it tonight.  In the meantime @dafish, go post an intro and tell us more about yourself.

This one right here:

Q4:   Headspacing:  How is this adjusted?   Can the bolt be tuned? 

How many rifles do you own, and how accurate are you with them?  Is this your first semi-auto AR platform?

This isn't a slam - these are serious questions, and not something to "be inferred" as "being attacked."  If somehow, I've hurt your feelings, and you feel that way, and you're offended - then get over those hurt feelings. We need to be men and deal with life, as it presents us.

Please hit the intro section and tell us about yourself, and please answer my questions honestly.  That's the only way to go forward from here.

[dafish]

Howdy all!

Sketch:

  Yes sir.  I should have said "a better trigger is later".  Yep, I know the LPK comes with a FCG.  Thanks though, for I might not have right?  I suppose I should also fess up I've got at least one scope sitting around unused, a few red-dots, and etc.  It's not like I won't be able to shoot the thing. enough to debug it.

   Gas:  Yea, I don't know diddly, but I think I've picked up a recommendation to use rifle length whenever possible and certainly at 18" or more.   I meant to state I knew rifle length for the tube, but maybe I forgot.  The question is "What brand/style" for the receiver tube..   I've just not seen that talked about much.

  Suppress:  Nope.  I know you can read anything on the internet, but it looks like the three most common build problems are (in order even) 1) Mismatched parts, 2)  Big expectations/little budget, and 3)  Gas problems.  I've seen enough suggestions from those with experience that I'm going to build (I'm actually building three of these) the first one with adjustable gas (Heck the seekins isn't expensive) and then look at it again for the next two.

98Z5V:

Nope, not butt hurt.  Been a problem I take it?   None the less, I know when I'm the Noob, so....

I shoot a lot more handgun that rifle, but for rifles I shoot a Rem 700 5r in .308, a RR AR-15 in 5.56, and a Ruger 10/22 for screwing around. 

I really only shoot 200 and 300 yards (don't have access to a longer range more than 2 times a year), and I'm not consistent enough on the bolt gun.  It's probably a 1" or so gun at 300 and I'm more like 6".  Heck, I shoot  much tighter groups on the AR-15.  I suppose I'm MOA on it.   In my mind I'm not managing the recoil well .  Specifically not keeping the barrel on target.  You'll notice a muzzle break for the AR-10.   Sure, things get tighter when I shoot FGGM, but I know where the loose screw is on the bolt gun.  Mind you when I get access to a range again (i don't at this moment) I'm going to try a brake on the 5r.

BTW, the 5r is part of my confusion.  I recall a discussion (it was last year) talking about tightening groups with tighter headspace.   Since I'm the problem with accuracy at this moment I sort of mentally flushed it.   And naturally it's come up again and I'm not smart enough (yet) to know how one addresses the whole thing.

Moving on, please consider this:  I'm not building to how I shoot today, I'm building this as a one and done investment..  Times be changing and I don't trust Illinois politicians crooks. 

Building experience:

Well, we'll see right?  I'm OK taking the AR-15 apart, but I've got a pretty good armorer book and taken a basic armorers course, so...   I take my handguns apart more, but then I shoot them all the time.  Rifle is more an occasional summer hobby.

All:

I read a fair bit, here included, so I've read a lot of the commonly published answers.  But I certainly don't know any tricks, and my sense is there are tricks outside of "send it back if you get a no-go" as regards headspace.  In truth I'm going to ask Fulton and Criterion of they'll sell me a JP bolt that's already headspaced, but then we're back to "what they heck are they doing?"   So far I can't see anybody doing anything to adjust them.

Yep, I'll go do an intro.

 

Thanks to all!

D

 

 

 

 

[jtallen83]

6 hours ago, dafish said:

Q1:  I’ve read some disparaging remarks about the Aero LBK.   Which I have to admit had been my plan.   Is there better fitting, more complete, and and correct LPK ya’ll would recommend?

Used a couple, without trigger, in the 308 platform and never had an issue. I do swap the bolt catch for a Sig 716 catch but that is a preference and not a needed swap.

6 hours ago, dafish said:

Armaspec Stealth recoil spring.  Any advice or comments?

Never heard of it. If you want trouble free then buy an Armalite buffer kit and be done.

6 hours ago, dafish said:

Is there any magic to selecting a gas tube,

Get one that fits, there is AR-15 rifle size and Armalite AR-10 size, depends on what the barrel maker uses for specs.

6 hours ago, dafish said:

Headspacing:

Find out what your barrel/bolt maker uses and buy a set of gauges like them. It can be adjusted, hell man went to the moon, not sure I would want to do either.

[Sisco]

Just 2 cents; You have probably already read that the LaRue trigger is currently the best deal on a trigger. At under $100, it is not a deal breaker to get it early. Armalite has the buffer system down pat. You can put it in and forget about it.

[98Z5V]

You cannot adjust headspace on an AR platform - it is set by the person that builds the barrel, which is a multi-step process.

You can change headspace on an AR barrel, if there's not enough headspace to begin with, and that requires a chamber reamer, and reaming the chamber deeper in order to meet minimum headspace (which the barrel builder obviously did not do properly). 

You should check headspace on every single Big AR build that you do. 

[dafish]

On 6/19/2019 at 6:13 AM, Sisco said:

Just 2 cents; You have probably already read that the LaRue trigger is currently the best deal on a trigger. At under $100, it is not a deal breaker to get it early. Armalite has the buffer system down pat. You can put it in and forget about it.

Yep.  But thank you anyway!  Hey, if you buy two the cost per trigger is down to $83.50.  ( did I just sound like my wife at a shoe sale?  uh-oh...)

I keep bumping into the Armalite buffer is just plane dialed in.  I might yet, but we shall see.  I may try one of the Armaspec SRS, and one of the JP's and see what I think. 

Thanks again!!

d

[dafish]

19 hours ago, 98Z5V said:

You cannot adjust headspace on an AR platform - it is set by the person that builds the barrel, which is a multi-step process.

You can change headspace on an AR barrel, if there's not enough headspace to begin with, and that requires a chamber reamer, and reaming the chamber deeper in order to meet minimum headspace (which the barrel builder obviously did not do properly). 

You should check headspace on every single Big AR build that you do. 

10-4.   Seemed like something can be milled on a bolt gun to bring the headspace down.  But I've gone looking in the interim and I can't find anything credible to support any accuracy benefit in any condition.  It all seems to come down to safety.  

Thanks!

D

 

[mrraley]

Well, since I know you don't live far from me now, it would be easy to have a get together and build this thing.

I have a complete, brand new in a sealed package, ArmaLite lower parts kit for an AR-10B (bolt catch is different) that could be used in the lower receiver.

As for putting this thing together... that's easy. I've read a few armorers manuals myself also.

[SimonSays]

Dafish, if I had an opportunity to spend the day with mrraley putting together a rifle....a bus load of Nymphomaniac’s couldn’t keep me away. (Well, I guess I’d share with him as payment for his time.). 

Seriously, take him up on it. You’ll learn more in that afternoon than you ever will from books. 

[98Z5V]

14 hours ago, mrraley said:

Well, since I know you don't live far from me now, it would be easy to have a get together and build this thing.

I have a complete, brand new in a sealed package, ArmaLite lower parts kit for an AR-10B (bolt catch is different) that could be used in the lower receiver.

As for putting this thing together... that's easy. I've read a few armorers manuals myself also.

  Having this guy offer to put your Big AR together is like Carroll Shelby offering to come over to help you work on your car...  

This is fucking epic, right here...      Way to go, Pat, bigtime, man...  

[jtallen83]

@dafish jump on this opportunity, a one on one build class with @mrraley is a bucket list item. 

[dafish]

That is a FANTASIC offer.  Mrraley, it's going to be a bit while I build funds, but I'll most certainly take you up on that offer!!

Thanks to all for the tips and suggestions!

D

 

[dafish]

Wait a darn moment!!

Did I just read this:

Mrraley was the Chief Armorer at Armalite at the time of his post, and he's talking about Armalite parts, specifically, in this thread.  He's not talking about any DMPS-based parts in the least.

Yikes!  OK then.  I get it!  You may color me deeply impressed.  And out of the QC to boot.  Huh.  You know, I sorta thought they built cannon's there, but that is home to the Rock Island Arsenal.  Then you have Rock River arms in the area, as is LMT Defense.  And as I recall Les Bauer was out of Lee Claire.

Yes, I need to get back to the QC more often....