.308 build on Mega Arms

[GRIM]

Ok- I've already got a 16" DPMS .308 AR and I'm now going to build a long range semi-auto .308...

I'm going to build on a Mega Arms receiver set and here are the parts that I do know I'll be using.
- 22" Chanlynn barrel (threaded for suppressor)
- David Tubbs CWS to help cut down on the amount of gas blowback (even if only in theory)
- David Tubbs recoil spring


From here I'm leaving it open to suggestions:

Handguard - I like the JP handguard due to it's small diameter. YHM makes a small diameter handguard as well with some picatinny rails machined into the front. I just want to avoid something with full quad rails.

Trigger - I've got a drop-in Timney that I'll probably use.

Buttstock - I want something that is collapsible. Normally I'd go with a PRS but I'm trying to keep this rifle package to as short a overall length as possible. One stock that fits this build is the Magpul UBR but I'm open to anything at this point as long as it's collapisble.

Gas block - Noveske Switchblock for .308 - I can dream can't I? Heck, I'd even volunteer my time to come help work on it! (Yeah, I know... "We're working on it, it's 6 months out" as I've been told for the past THREE years.) Sooooo I guess this leaves me with do I want an adjustable one (JP) or just run a low profile gas block and put up with the huge amount of blowback when running it suppressed. Ideas?


Bolt/carrier - I'd love a DPMS bolt/carrier group that's been EXO coated by FailZero but they don't offer that. Then I'd defer to the JP bolt/carrier but I just read someone's post that said their rifle did NOT like that setup and they went back to a factory DPMS bolt/carrier and it ran just fine.


Ok guys - have at it...

 

[rchman]

Re: .308 build on Mega Arms

Wouldn't a POF with the new hunter rail be closer to what you want?

Regarding the stock, the UBR is nice but very heavy. You may be better off with a VLTOR emod or imod with a tight fitting receiver tube (PWS makes a very tight fitting one).

 

[Howie Feltersnatch]

Re: .308 build on Mega Arms

Grim,
Here are some of my suggestions, and I'm by no means an expert.

Handguard- I'd vote for the Troy TRX. It's a solid rail, tubular design, but enables you to place rail sections at your desire if you do opt to put accessories at the front of your rifle. It's one of the lighter rails on the market. The only grip I have with this rail is it does stay hot for a bit, granted if you're running a lot of ammo through a carbine. In your situation it should serve you well.

Trigger- I've tried the Timney, and it wouldn't be a bad idea since you already have it. However I don't know if you tried a Geisselle High Speed National Match 2 stage, I'd suggest it. It's about 2x as much, but it's a phenomenal trigger. I had one in a carbine I bought, and I took it out because it was the wrong trigger for the rifle, but did mess around with it. I would have kept it but it was for the larger pin colt rifles.

Buttstock- The UBR is a nice choice because it's heavy and will offset the weight of a heavy barrel somewhat. Have you thought about the CTR? Depending how you run your scope mounting solution, you may need a riser and I know there are risers out for the CTR. I'm not so sure about the UBR.

Switchblock- Haven't looked to much at them because I don't have a can, but if you do decide to go with a Lo pro gas block you can go with a gasbuster to help with some blowback.

In all honesty, I'd stick with a DPMS chrome carrier. I had one in a rifle in mine and it functioned perfectly. Never had any problems with it at all, and with it being chrome it was easy to clean.

Another thing I'd look at is a Slash 308 buffer. It should help reliability and functioning with a can.

 

[Redmanss]

Re: .308 build on Mega Arms

A couple questions and a couple suggestions....

With a suppressed 22" barrel, why are you looking for the shortest length coming from the buttstock? You say it's for long range shooting, but are you going to be carrying it in the field? What scope and how high are you going to be mounting it? The reason I ask is for a precision long range platform, you're better off going with a PRS to achieve both proper stock weld and also have a more stable platform.

If you do go with a collapsible, the UBR would not only be solid but would also help balance out that long tube. That being said, I tried a UBR on a MK 12 and still ended up going with a PRS instead for proper stock weld on my high cheek bones. The UBR is getting moved to a 16" .308 later this year.

For the forearm, take a look at the JD Machine sets too, and Big Joe might still have the group buy going for them.

Bolt carrier, Young Manufacturing has a new one out and there was a recent thread on it, but you're probably going to be fine with the DPMS and save yourself a few bucks.

Just a couple more options to look at and food for thought.

 

[GRIM]

Re: .308 build on Mega Arms

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Redmanss</div><div class="ubbcode-body">A couple questions and a couple suggestions....

With a suppressed 22" barrel, why are you looking for the shortest length coming from the buttstock? You say it's for long range shooting, but are you going to be carrying it in the field? What scope and how high are you going to be mounting it? The reason I ask is for a precision long range platform, you're better off going with a PRS to achieve both proper stock weld and also have a more stable platform.

If you do go with a collapsible, the UBR would not only be solid but would also help balance out that long tube. That being said, I tried a UBR on a MK 12 and still ended up going with a PRS instead for proper stock weld on my high cheek bones. The UBR is getting moved to a 16" .308 later this year.

For the forearm, take a look at the JD Machine sets too, and Big Joe might still have the group buy going for them.

Bolt carrier, Young Manufacturing has a new one out and there was a recent thread on it, but you're probably going to be fine with the DPMS and save yourself a few bucks.

Just a couple more options to look at and food for thought. </div></div>

Well - my goal was to be able to reach 1000+ yds with a SMK 175 bullet but I wanted to keep the barrel length as short as possible since I'll hang a can on it occasionally. It will be shot most of the time without the can however I want to be able to use one if need be.

I wanted the overall length to be short as I want to be able to drop it into an Eberlestock backpack and not have it sticking up like a flagpole. That's the reason for the collapsible buttstock.

The scope will be a Zeiss 4-14x44 with the Rapid Z-1000 reticle with low height rings.

 

[rchman]

Re: .308 build on Mega Arms

Careful going too light on the buttstock. A CTR with a 20" barrel will feel really lopsided. An Emod or ACS would be a better choice since they both have a bit more heft to them.

 

[benchmstr]

Re: .308 build on Mega Arms

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rchman</div><div class="ubbcode-body">Wouldn't a POF with the new hunter rail be closer to what you want?

Regarding the stock, the UBR is nice but very heavy. You may be better off with a VLTOR emod or imod with a tight fitting receiver tube (PWS makes a very tight fitting one). </div></div>
pof means you spend over $1800 more, and get less back in this situation

 

[benchmstr]

Re: .308 build on Mega Arms

that jp forearm is a awesome choice...anyone who suggest otherwise simply hasnt used one....those things are epic..