Building a Precision Rig

[UWone77]

Most of my carbines are general use oriented. 14.5 - 16" guns that are used for training, plinking, loaning, ect. I've never really built a 5.56 gun with strictly precision in mind. In fact when I think about it, my .308 builds are not really precision oriented either.

Anyhow, when I received my Rainier Arms Mod2 Billet Set, I set out to start building an accurate 18" blaster. So far here's the upper:

Rainier Arms Mod2 Billet Upper
Rainier Arms Ultramatch 18" SPR Barrel (Rifle Gas)
Rainier Arms Match NiB BCG
Rainier Arms Gen2 FORCE Rail 15"
Rainier Arms Raptor
Geissele Super Gas Block Pinned







Played around with the muzzle devices between the RAC and Epsilon. I think I want to go with a brake on a 18" possibly a suppressor mount. We'll see.

More to come as this progresses.

[Ride4frnt]

Trade ya my 15" gen1 force!

Looks good. Are you sticking with the epsilon or the RAC?

[WHSmithIV]

I've been thinking of what would make a good precision build. Something I could shoot a mile with reliably. I figure 6.5 Grendel is likely the best for that since it's still supersonic passing 500 yards and passes a .308 bullet at that distance. It's designed to be accurate to 800 yards. So, I've been toying around with starting a build for that.

[UWone77]

I've been thinking of what would make a good precision build. Something I could shoot a mile with reliably. I figure 6.5 Grendel is likely the best for that since it's still supersonic passing 500 yards and passes a .308 bullet at that distance. It's designed to be accurate to 800 yards. So, I've been toying around with starting a build for that.

I had a 16" 6.5 barrel earlier this year I was thinking about using, but ended up giving it to a buddy who really wanted it more than I did, and reloads.

If I do a 6.5 down the road, I think it's going to be a Creedmore.

[WHSmithIV]

I have to research it more for the Grendel vs. the Creedmore. I'll also have to set up for reloading due to the cost of the ammo. So, it's a project for down the road.

[Computalotapus]

I am starting a .308 build here soon as well. Will be insteresting to see how your build comes out. Doing an 18" SPR barrel as well.

[JoshAston]

Creedmore is based on .308, so you'd need a .308 sized platform for it. Grendel is based on 7.62x39, I think, maybe .220 Russian. It fits in an AR15. Obviously the Creedmore outperforms the Grendel by a decent margin, launching heavier bullets at higher velocities. My personal favorite is .243 out of a 1/8" twist barrel. It will outperform anything in its class quite handily.

[UWone77]

Creedmore is based on .308, so you'd need a .308 sized platform for it. Grendel is based on 7.62x39, I think, maybe .220 Russian. It fits in an AR15. Obviously the Creedmore outperforms the Grendel by a decent margin, launching heavier bullets at higher velocities. My personal favorite is .243 out of a 1/8" twist barrel. It will outperform anything in its class quite handily.

Exactly, which is why I'd want a Creedmore build if I went with 6.5. I have enough AR15 receivers so, if I wanted to venture out into a different caliber, 6.5 Creedmore is where I'd want to drift towards... and the other reason I dumped my Grendel Barrel. Although I was impressed with the ballistics.

[mustangfreek]

Nice build as always Poobah...(wtf...lol)..... everywhere i look guys have this killer receiver set...uhhhh

Anyways, good looking stuff there, decided on optics ?


The debate for creedmoor,grendel,260 etc is for another thread..There are plus and minuses to them all, and not an expert but have been looking at al lthe numbers for them for a while.

[alamo5000]

First a question... what will be your choice of optic for this?

My current build has 'precision' component in mind as well... hopefully you will see pics of the completed rifle within a week.

I have just some random comments though based not around AR, but around shooting in general...what is the twist rate of your barrel?

I am the last one to be doling out advice but I will just make random comments. Matching the round down to the grain weight makes a huge difference in shooting precision. The type of barrel is probably one of the most important parts. I would also say trigger is probably a close second most important for precision. What kind of trigger are you considering?

What distance are you talking 'precision' at and what would you define as satisfactory when using the term 'precision'? And at what distances?

I have had all these questions rolling around in my head for quite some time (like a year or two) contemplating my build... and it's pretty much coming to fruition. We have the same goals here... I got to my conclusions by asking a lot of questions from a lot of people, but I am asking how you have thought through your build...so please do share as I am quite curious.

[GaSwamper]

Outstanding upper you're putting together there UW. Too bad we're on separate coasts, I may would have to let the 18'' Wolverine upper challenge you're 18'' 5.56. As far as a larger platform to build on for the big boy cals I'm eager to see ARPerformance's NexGen scheduled to be ready next year. ARP says it will offer .308 and .260 to start with more to follow in a 7.5lb platform.

[Pyzik]

That's gonna be a nice rifle.

After my pistol k am wanting to do a precision build. Wanting to go billet for it as well.

Looking forward to following this build.

[Ride4frnt]

That's gonna be a nice rifle.

After my pistol k am wanting to do a precision build. Wanting to go billet for it as well.

Looking forward to following this build.

Boy you won't regret that. The 18" gun I just built is so fun.

[UWone77]

Trade ya my 15" gen1 force!

Looks good. Are you sticking with the epsilon or the RAC?

Good question, at this point, I don't know.

Nothing wrong with the Gen1 Force you know, this is the same rail, just slanted. Do you really need that?

First a question... what will be your choice of optic for this?

My current build has 'precision' component in mind as well... hopefully you will see pics of the completed rifle within a week.

I have just some random comments though based not around AR, but around shooting in general...what is the twist rate of your barrel?

I am the last one to be doling out advice but I will just make random comments. Matching the round down to the grain weight makes a huge difference in shooting precision. The type of barrel is probably one of the most important parts. I would also say trigger is probably a close second most important for precision. What kind of trigger are you considering?

What distance are you talking 'precision' at and what would you define as satisfactory when using the term 'precision'? And at what distances?

I have had all these questions rolling around in my head for quite some time (like a year or two) contemplating my build... and it's pretty much coming to fruition. We have the same goals here... I got to my conclusions by asking a lot of questions from a lot of people, but I am asking how you have thought through your build...so please do share as I am quite curious.

This is a Rainier Arms Ultramatch, so it has a 1:8 twist.

This should ring steel all day with no problems at 600 yards, which is the max range I can find in my area. The last 16" Select Barrel I tested was about 1.1 MOA (for my level of shooting at 300) so this should do better with the ratchet rifling and additional velocity with the extra length.

Trigger will be a Geissele National Match DMR. Also have a SSA-E in my bin, but that's probably going on the SBR.

As for the optic. No idea yet. We'll see how it develops.

[alamo5000]

This should ring steel all day with no problems at 600 yards, which is the max range I can find in my area. The last 16" Select Barrel I tested was about 1.1 MOA (for my level of shooting at 300) so this should do better with the ratchet rifling and additional velocity with the extra length.

1.1 MOA at 300 is pretty darn good.

Around where I live in East Texas it's heavily forested so getting the long shots is not all that common. 200 -300 yards is pretty much what you're going to get around here. That said right up the road there is a formal range (15-20 minutes) that is at least 600 yards, and another 10 more minutes after that a friend has a private 1,400 yard range that I can use for free...That said on my AR build the sweet spot I am aiming for is 200 yards inward.