Absolutely. 6.5g is a 1k yard round

Biggest question I am unsure about, is whether to go 18 or 20" bbl. This will require a rifle length gas system then, correct?
Guess I need to start browsing and putting together some more parts.

Our mods happen to have any of those 20% off at ALG from SHOT again this year?

Go 18. Spend a little extra and go with white oak, criterion, rainier ultra match ect. Rifle gas yeah

I went with the PRI Mk12 Mod 0 "clone" upper and built my own lower. I say clone as now PRI offers a more true to spec version and then a more "off the shelf" parts one. When i bought they were much cheaper and only had one option. But its a douglas 18" with rifle legnth gas. PRI sights, and the AEM collar.

For the lower just went with a standard lower, geissele SSA-E trigger, and an A2 stock.

For glass i went with the Leupold mark4 2.3-8x36 which was the "correct" scope for the mk12 mod 0. it is a nice scope but looking now at their cost not sure I would recommend it vs what it cost a few years ago.

I did otp it off with a AEM5 suppressor though.

This is an interesting article where they tested muzzle velocity vs barrel length in 5.56 ammo https://rifleshooter.com/2015/12/223-re ... -6-inches/

I’d go 18” personally, but just because I think 20” with a muzzle device looks too long.

Hot damn I bet that's a sweet rig. What MOA can you pull off with match grade?

OP, 18" over 20". It'll be that much lighter and handier. Yes that'll be rifle length gas. With nicer barrels you can get a gas block with it that'll be drilled for pinning in addition to the set screws. Very solid that way.

There seems to be a growing consensus that the traditional scope type for an SPR, is a little outdated, in that while higher magnification excels out at extreme range, a really good 1-8 or better yet 1-10 LPVO makes the gun more versatile overall.

At least that was the intent with mine, the collapsible stock and short rail are there so it can perform well up close, as a primary rifle.

I ran mine for a while with a 2.5-9, and I get alot better use out of it with the 1-6, and the illuminated reticle makes it awesome up close, AND at night.

We did have a few, but they are long gone.

I havent shot it with "match" ammo. With just my regular 55gr reloads it will still shoot 1 moa though.

And yeah the scope choice really just depends what itll be used for. Ive fine with the 2-8 and it works just for for the ranges I'd really use the 556 in. I wouldnt buy Mark4 for the price point they go for new now. To many other options I feel are better at that price point.

I havent shot it with "match" ammo. With just my regular 55gr reloads it will still shoot 1 moa though.

And yeah the scope choice really just depends what itll be used for. Ive fine with the 2-8 and it works just for for the ranges I'd really use the 556 in. I wouldnt buy Mark4 for the price point they go for new now. To many other options I feel are better at that price point.

For optic I think I will swap my PA 1-6 with ACSS reticle from a carbine, to the SPR, and replace the Carbine optic. Would be nice to upgrade, but that will cone down the road.

I thought the Mark IV was discontinued?

I think technically they arent available commercially anymore. Was back in like 2014ish (thats around when i built mine) i want to say they discontinued them. Then the Marines came along and wanted to order them so they seem to come and go in limited supply for sale as special buys. But i dont really know anymore as i dont really follow leupold or the mk12 clone groups

Velillen, I'm guessing your 55gr load is something that you purposefully worked up, like the rest of us do. To me, in that respect, it qualifies as match grade.

That sounds like great performance, I'm guessing that if your barrel is 1/7 or 1/8, it'll like 62 and 75gr even more, like mine does. Outstanding!

For factory, Hornady 75gr BTHP is awesome, as is Federal 77gr SMK gold medal.

My load of 62gr Hornady FMJ over 24.4 gr H335 is my most accurate 5.56 load to date.

A little bump.

Parts come in today to start this build. A year ain't bad, right? So far:
Aero M4E1 Upper/Lower set
Aero LPK minus fcg/grip
Aero UPK
Aero BCG Phosphate (also have a RA Nickel Boron I could swap)

Looking to go with a 16" BLK LBL bipod integrated forearm. Leaning towards Damage Industries Enhanced buffer system. All other parts are still up in the air.

Between RRA 2 stage or a Geissele.