New LR-308 Build

[Fairchild670]

I’m wanting to be sure I’m not missing anything as far as parts in assembling a LR-308.

Currently, I’ve acquired a:
lower receiver
Lower parts kit with grip
Trigger assy
Assembled upper receiver with forward assist and port door
4-12x42 scope

Left to acquire is:
Bolt assy
Charging handle
Barrel
Barrel shroud
Gas block
Gas tube
Stock
Magazine


Caliber is to be .308.

 

[FatBoy]

receiver extention
buffer
buffer spring

By barrel shroud, do you mean handguard?

 

[Fairchild670]

By barrel shroud, do you mean handguard?

Yes, I do. Thanks!

Buffer spring and buffer tube, missed those. Again thanks!

Hadn’t come across receiver extension yet, got some more reading to do!

 

[FatBoy]

receiver extention is the buffer tube.

 

[6ShotsOr5?]

Maybe your upper already has a muzzle device such as a flash suppressor or a muzzle brake. If not, you might want one of those. Usually a 308 barrel would have 5/8x24 threads. If you are adding a muzzle device, usually you either need a crush washer, a peel washer, or some shims. The manufacturer of your particular device will tell you which one, and sometimes they are included with the muzzle device.

LR308 can be a bit finicky about the buffer and buffer spring, and the ones you need won’t be the same as for a .223 Rem / 5.56 NATO rifle. I recommend contacting Clint at Heavy Buffers for those items.

I haven’t seen many scopes that size with a built in mount so you probably need a scope mount. For an LR308 with that size scope you will probably need a cantilever mount that lets you shift the scope forward a bit to get the proper eye relief. Larue Tactical and Spuhr mounts are a few companies that I have used for these, but there are lots of other companies that make these.

You may need to buy some tools also, or a friend that can help. I suggest you watch a video on Brownells or YouTube to learn what you need and how to do it. Assembling a lower is easy but there are a few tools that make it a lot easier, and a few tips that will help you avoid having small springs or pins fly out and get lost on the floor somewhere. If you have assembled an AR15 lower it’s basically the same as that.

 

[Fairchild670]

So now a handguard question... The receiver is an Aero Precision M5, not the new enhanced version. And I’m seeing most free float handguard assemblies seem to be advertised as DPMS GII.
Does any of this matter when picking a free float handguard?
Barrel nut, all the same? Free float handguards attach to the nut and I know it comes with the assembly.

Am I to assume that if a part says “... LR-308...” it’s good to use?

 

[Twdmar]

Get an adjustable gas block. Many lr308 barrels are overgassed. Also because of the overgassing, the extractor and ejector springs are too strong.

 

[Fairchild670]

Twdmar... thanks for the tip; was just mentally debating that.

For those who may stumble across this in their own attempt at a first time AR build if it’s a dpms pattern receiver the key phrase to google the proper Handguard is “high profile Handguard” or “low profile Handguard”. This got me pointed in the right direction and I’m potentially side stepping the mistake of spending $$ on the wrong parts!

 

[tobnpr]

Brownell's had a good component checklist online last time I looked.