AR .308 build questions

[ARAK]

Gents,

I am about to start my FIRST build of a .308 AR platform and I need some information.

1.) Is there a separate LPK required for the .308?
2.) My lower is a machined 80% lower. That is already done and looks good. Rather than using trial and error, is there any way I can tell what upper is going to fit, DPMS/ RRA/ ??? Same question concerning magazines.
3.) Any suggestions on barrels? I'm looking at a 20" as all I plan on doing for now is shooting paper?
4.) Any suggestions on optics and bipods for down the road?

I have assembled 4-5 5.56 lowers and have the basic equipment. I just want to know what I am getting into before I start dropping more dinero than just going out an buying a factory-built.

Thanks is advance for your help!

 

[7.62x39]

There are two basic platforms DPMS and Armalite. 90% of the AR308 stuff you see available online is for the DPMS platform.

What company mfg the lower?

 

[Mountain]

Assuming DPMS pattern, any AR15 trigger will work. Most everything else like the grip is the same except the front pivot pin is longer and the bolt catch pin screws in rather than being a roll pin. They do make AR-308 specific triggers with heavier springs and heavier hammer. If punching paper, I suggest a standard AR15 trigger for a lighter pull. If you are shooting old milsurp you might get the occasional light strike but paper targets don't shoot back.

Check out Ballistic Advantage Premium Series barrels. I have their 20" stainless barrel in 6.5 Creedmoor. Averaging 0.6 MOA at 100 yards with factory ammo, with a $300 barrel. That's a steal for such accuracy. I have a thread on this but have to leave now...

edit-

https://www.northeastshooters.com/vbulletin/threads/312406-Done!-Aero-M5-in-6-5-Creedmoor?highlight=6.5+creedmoor+build

Link to my build on a DPMS pattern lower. Since you are in free country, you can ignore the weld job for the thread protector. You can run with a brake, but accuracy might be better with a simple thread protector. I'm extremely pleased with the Ballistic Advantage barrel. On a platform such as this, a great barrel and matching or at least well fitting bolt plus a quality trigger are the critical components for accuracy. Everything else is for show, assuming the other components are of decent quality.

I highly recommend Harris bipods. USA made, top quality, good price, and they have a number of models to suit your needs. Look at the 6-9" models for your AR.

Optics recommendation would depend upon your budget.

 

[ARAK]

There are two basic platforms DPMS and Armalite. 90% of the AR308 stuff you see available online is for the DPMS platform.

What company mfg the lower?

Tactical Machining in Florida did the 80% lower.

 

[ARAK]

Assuming DPMS pattern, any AR15 trigger will work. Most everything else like the grip is the same except the front pivot pin is longer and the bolt catch pin screws in rather than being a roll pin. They do make AR-308 specific triggers with heavier springs and heavier hammer. If punching paper, I suggest a standard AR15 trigger for a lighter pull. If you are shooting old milsurp you might get the occasional light strike but paper targets don't shoot back.

Check out Ballistic Advantage Premium Series barrels. I have their 20" stainless barrel in 6.5 Creedmoor. Averaging 0.6 MOA at 100 yards with factory ammo, with a $300 barrel. That's a steal for such accuracy. I have a thread on this but have to leave now...

edit-

https://www.northeastshooters.com/vbulletin/threads/312406-Done!-Aero-M5-in-6-5-Creedmoor?highlight=6.5+creedmoor+build

Link to my build on a DPMS pattern lower. Since you are in free country, you can ignore the weld job for the thread protector. You can run with a brake, but accuracy might be better with a simple thread protector. I'm extremely pleased with the Ballistic Advantage barrel. On a platform such as this, a great barrel and matching or at least well fitting bolt plus a quality trigger are the critical components for accuracy. Everything else is for show, assuming the other components are of decent quality.

I highly recommend Harris bipods. USA made, top quality, good price, and they have a number of models to suit your needs. Look at the 6-9" models for your AR.

Optics recommendation would depend upon your budget.

Much appreciate the information, Mountain. Optics budget ~$500-700.

 

[7.62x39]

2.) My lower is a machined 80% lower. That is already done and looks good. Rather than using trial and error, is there any way I can tell what upper is going to fit, DPMS/ RRA/ ???..

Tactical Machining in Florida did the 80% lower.

TM only sells DPMS platform 308 lowers

 

[Mountain]

Much appreciate the information, Mountain. Optics budget ~$500-700.

There are probably others who can give much better optics recommendations than I. Mostly I shoot irons. For a bit less than $500, I have had good luck with my Millet LRS-1. Magnification up to 25X and a very large objective. So far so good- it's held up well and holds zero. In your range, for the best quality I suggest looking at whatever Leupolds are available and suit your needs. Your going to want decent glass so that you can stretch those 308 legs.

 

[ARAK]

TM only sells DPMS platform 308 lowers

Thanks!

- - - Updated - - -

There are probably others who can give much better optics recommendations than I. Mostly I shoot irons. For a bit less than $500, I have had good luck with my Millet LRS-1. Magnification up to 25X and a very large objective. So far so good- it's held up well and holds zero. In your range, for the best quality I suggest looking at whatever Leupolds are available and suit your needs. Your going to want decent glass so that you can stretch those 308 legs.

Much appreciated, Mountain. I'm partial to Leupolds anyway.

 

[spt_1955]

A couple of things I learned from my AR308 build.

TALK to the manufacturer to find out what parts your lower/upper takes. They can answer questions like :

1. My 308 lower was advertised as an Armalite-A LPK (as opposed to an Armalite-B) and everything on the Armalite-A LPK fit except the bolt release catch pin turned out to be a threaded pin (DPMS) as opposed to a roll pin (Armalite). I called the manufacturer and they looked and said "oops.. sorry the engineers changed the CNC program and did not tell us". LOL.

2. DPMS uppers have a different barrel nut thread pattern than DPMS and I think some manufacturers have their own proprietary configurations (RRA, LMT?) You need to know what pattern your upper is.

3. DPMS uppers have both a High and Low configuration for the rail height. YOu need to know what height yours in order for your rail to line u if you want a monolithic rail system.