First precision AR build. Need help

[Baron85]

So I ran across a deal on a 24” lilja 223 barrel today that I couldn’t pass up. I have built multiple AR’s but none specifically as a precision platform so need some help and advice, as well as assembly tips and tricks.

My plan for this rifle is fun at the range shooting groups on paper, shooting steel (local range goes to 1080) and we have monthly tactical matches 300yd and 600yd I would like to play at. Planning on using a spikes billet lower I have had laying around for a while, prs stock, adjustable gas block and trigger tech

My list of questions are

Upper receiver? Is there any real life difference in forged vs billet? How about handguard mounting like the seekins that mounts direct to the receiver vs the barrel but? If there is a difference, what are the recommended uppers for a precision build?

Upper receiver lapping? I read some threads that go back and forth, I’m leaning toward lapping seems to make sense to me unless the hide says that’s a no go. If lapping is where it’s at, what tool for the job?

Fitted bolt head? The barrel doesn’t come with bolt head. Is a fitted bolt anything more than just a bolt that passes the no go headspace? If so, where should I send the barrel/bolt to get fitted? Something any gun Smith can take care of?

Light weight vs standard bolt carrier?

Light/standard/heavy buffer and spring?

recommended adjustable gas block? I have Slr on my other builds, not sure if there is something better?

Should I loctite the barrel into the upper?

I don’t want to spend money just to spend money but want this to be a very nice rifle for my collection and don’t mind spending what it takes for performance. If there is any other advice or tips please do share.

Thanks

 

[bfoosh006]

So I ran across a deal on a 24” lilja 223 barrel today that I couldn’t pass up. I have built multiple AR’s but none specifically as a precision platform so need some help and advice, as well as assembly tips and tricks.

My plan for this rifle is fun at the range shooting groups on paper, shooting steel (local range goes to 1080) and we have monthly tactical matches 300yd and 600yd I would like to play at. Planning on using a spikes billet lower I have had laying around for a while, prs stock, adjustable gas block and trigger tech

My list of questions are

IMHO... and YMMV...

Upper receiver? Is there any real life difference in forged vs billet? How about handguard mounting like the seekins that mounts direct to the receiver vs the barrel but? If there is a difference, what are the recommended uppers for a precision build?

I have used both and am content with either... but I do prefer a snug upper to lower fit, and a snug barrel fit. I am also sure a more ridgid upper is a benefit.

Upper receiver lapping? I read some threads that go back and forth, I’m leaning toward lapping seems to make sense to me unless the hide says that’s a no go. If lapping is where it’s at, what tool for the job?

I lap 'em all... Pacific Tool and Gauge is my choice. I do not like to install the upper into a vise or use a drill press... rather I hold the upper by hand ( upright and on top of the cordless drill ) In my feeble mind... that allows the upper to not be "stressed" or messed with dimensionally if there is some binding... seems to work for me.

Fitted bolt head? The barrel doesn’t come with bolt head. Is a fitted bolt anything more than just a bolt that passes the no go headspace? If so, where should I send the barrel/bolt to get fitted? Something any gun Smith can take care of?

I freely admit, I haven't done this yet.... and suspect that many may not see the benefit inside of "typical" 100yd ranges... but at extreme ranges, I'd bet it is more apparent.

Light weight vs standard bolt carrier?

Standard for me.... typically.
My next build , 14.5" 308 will run a LtWt BCG ( with Adj GB ) and I have a Sonics ERGP 11.5 5.56 coming that I am gonna try a very LtWt BCG and mild recoil spring and low buffer weights... Not Suppressed... Just an experiment with very small gas ports and function results.

Light/standard/heavy buffer and spring?

My Large Frame AR's all run heavy recoil weights and Tubbs Flatwires.... rifle stocks have 9.3oz buffers , carbine 5.4oz buffers. ( both patterns ) and Tubbs Flatwire.

Small frame AR's typically run average buffer weights... and Tubbs Flatwire recoil springs.

recommended adjustable gas block? I have Slr on my other builds, not sure if there is something better?

I installed 1 Adj. GB on a 18" rifle length gas system 5.56... IMHO, it was a waste of money... so this may depend more on your gas system length and gas port size.
ALL my large frames have benefited from Adj GB's .. all SLR, I haven't had any issues. ( A drop of Kroil on the adjustment screw every once and a while. )

Should I loctite the barrel into the upper?

I do... On all of mine , and again YMMV... all of mine have not been heat fit. I now have uppers that will require heating the upper to allow the barrel to fit in.
I will say, IMHO I really have nothing to lose by Lapping and Loctiting ( or SS shimming ) a barrel in place.. so I do it.

I don’t want to spend money just to spend money but want this to be a very nice rifle for my collection and don’t mind spending what it takes for performance. If there is any other advice or tips please do share.

Interiors of buffer tubes can vary greatly in smoothness... polishing them smoother sure makes a difference.

I tend too polish feed ramps, and various other moving parts.. not super perfect, just enough to ease break in, and help positive easy function.

Get a pad for the cheek rest on your PRS stock... that makes it much more comfortable for long days of shooting.

https://www.convergentdesignsolutions.com/store/c16/Cheek_Pads.html .... after adhereing it... lightly wrap an ace bandage around it overnite .... don't wrap it to tight, the ace bandage will pull on the foam, distorting it and its proper adhesion.




Thanks

Expand the quote to see the my thoughts and comments.

 

[WIVigilance]

Following...I’m in same boat

 

[Baron85]

Bfoosh006 thank you for taking the time to answer and give your knowledge. I have done a ton of reading and unfortunately there is rarely a consensus on best practices. This will be my 9th AR to build and I learn something new with each one, and sometimes have to go back and improve the other builds with the new knowledge.

 

[bfoosh006]

Bfoosh006 thank you for taking the time to answer and give your knowledge. I have done a ton of reading and unfortunately there is rarely a consensus on best practices. This will be my 9th AR to build and I learn something new with each one, and sometimes have to go back and improve the other builds with the new knowledge.

And this is always helpful. ( and Thank you for the kind words )

http://bulletin.accurateshooter.com...-to-build-a-truly-accurate-ar-platform-rifle/


Be aware not everyone agrees with some of the modifications... specifically the lapping and Loctite.

My results here https://www.ar15.com/forums/industr...-again-UPDATED-with-Tn-G-results-/301-285762/ helped solidify my trust in lapping and Loctite. Again, as always YMMV.

Not every factory load showed improvement... but many did in a "very noticeable improvement".

 

[ScottPriestley]

I've been right where you are and this is what I came up with:
1. Upper and Lower are just shells - as long as they're milspec they'll hold what I put in them
2. Barrel and trigger are the top 2 keys to accuracy - I like TriggerTech triggers and Lilja is a great barrel.
3. A supported bolt carrier group is a distant 3rd but pricey - think $285-ish
4. Square the receiver face - just do it doesnt cost much to get the tool and only a few minutes to do
5. Loctite/bed the barrel only if it needs it - if it slips in like your favorite cheerleader then yeah, you'll need to bed it.
6. Use an accu-wedge to tighten the mating of upper to lower, or buy a combo set with a setscrew to tighten it up.
7. Tune the gas tube so that it rides center of the gas key when the bolt is forward.
8. Last and maybe not necessary - Loctite/bed the gas block