AR Build

[dmharvey]

Put this together for just under $1,000.00 with a Timney trigger and the Primary Arms scope. Shoots great, 1" groups at 100 yards all day using M193 ammo.

[MarcSpaz]

Looks good! Did you end up using that poly lower?

[dmharvey]

I bought a couple of those poly lowers a while back. This one is the last of them and I plan to hang onto it. I took the rifle out to the range today and it shot 1-2" groups at 100 yards with 55 grain ball ammo. Heading back out tomorrow to try some 62 grain ball ammo I have and then I need to start experimenting to see what it likes best.

[MarcSpaz]

I have heard nightmares about poly lowers for AR's. Buddy of mine had one of his break the very first time he fired it... and it had a 22LR upper. Wasn't even a 5.56. If you have some that worked out for you... you should hold on to them forever.

Mind if I ask the brand? I am guessing they are better quality than others. If I ever do a poly lower, I'd at least like to stack the odds in my favor. LOL

Compared to a 55, a 62 grain should give you some really solid groups at long range (500-650 meters) depending on your twist rate. I don't know if you will see much difference at 100 or even 200 meters. Assuming a 16" barrel... a 1 in 10 is good for 55-62, a 1 in 9 gets up to a 75, and a 1 in 7 is great for 62 - 77, but over spins a 55 just a bit. Not to the point I would say don't use 55 grain... but enough that you might see rounds fail to yaw... which is likely not a problem for civilians poking holes in paper. LOL

[dmharvey]

I've heard some of the earlier poly lowers had issues with them being weak around the front take-down pin. The ones I've messed around with (by New Frontier) seem sturdy enough that I bought several after tearing one down and inspecting it closely. Short of using a rifle as a sledgehammer I don't see any reason why one of these lowers would fail. In the case of the gun posted above, I went with the poly lower because I really like the way it shifted the overall balance a little. When I do my AR build in 7.62 NATO I'll probably go with a billet lower since the thing will be a tank anyways.

I'm running a 16" barrel with a 1:9 twist on the gun above. Any suggestions for commercial rounds in the 70-75 grain range? I'd like to try some out just to see how they do.

[MarcSpaz]

Assuming you want over the counter and ready to fire... Black Hills has some re-man 77 grain. They are dirty as hell, but very inexpensive to buy. I would only use them outdoors on a windy day because of the smoke. LOL

The best over the counter I have run is the Hornady 75 grain HP's. Its a clean, top dollar round and very well put together. Its "match grade", so at a little over $1.40 a round, just make sure the sticker shock hasn't kicked in before you pay for them. There will be plenty of time in the car on the way home to question your buying decision.

After that, you drop into the .223... Remington and Winchester both have nice rounds between 69 and 77 at about $1.15 each and the price goes up from there, regardless of brand.

If you reload... Nosler.

[dmharvey]

Thanks, I don't reload (plan to at some point) but my dad does a lot of reloading and I might see if he'd be willing to work up a couple of loads...maybe buy enough to do 100 rounds of each one and give him half of them since he has an AR too (M4-style Stag Arms with 1:9 barrel).

Below are the two loads I'm considering. Any others you suggest as a good starting point?

==================================

Bullet:
Nosler, Custom Competition, 69 gr. HPBT

Powder:
A-2230, 23.5 gr.

Primer:
WSR

==================================

Bullet:
Nosler, Custom Competition, 77 gr. HPBT

Powder:
RL15, 23 gr.

Primer:
WSR

==================================