What to expect for 20" 260 AR platform

[coltm4]

I'm at a crossroad for my large format AR build. I'm seriously considering a 260 Rem because I've always wanted the ballistics of the 260/ 6.5mm projectiles. But the back of my head keeps nagging me that 260 is and should be a bolt gun project and not an AR. That said, I'm considering a 20" Lilja barrel in 260. How hard is the AR platform on 260 brass and what kind of performance (velocity, range, per type of bullet) should I expect? I plan on adjustable gas with selector for "on, suppressed, off". Help please. I reload and I'm pretty agnostic about the issue.

 

[Pat M]

I run a DPMS .260 bull barrel, i run a mellow 142gr Sierra at 2700, (123's can run a lot faster)
an adjustable gas block is the way to go for nice non hammering on the brass, i suggest going with a more tuneable gas block (as apposed to full/half/off)

Mine throws the brass 3 1/2 feet at 2:00, same with my suppressor on (brass dose get dirtier with can on) but no plugs needed

 

[LRRPF52]

I think .260 Rem and the AR10 go hand-in-hand, with some caveats.

The firing pin hole size can be more of a limiting factor than anything else as far as hand loads go. Armalite BCG's, or a bushed DPMS style BCG will deal with that better.

Other than that, you're off to the right start by looking at the Lilja barrel option. I have a Bartlein on mine that GA Precision did, and it's a shooter, printing consistent .4" to .6" 5-round groups at 100yds, and well under MOA out to 1000yds. I'm very pleased with it.



From a 20" barrel, you can expect to shoot 123gr at around 2800fps. 130gr will be in the mid-2700's.

 

[Vandon16]

I'm racking my brain over a .260 AR build myself. Hmmm...

 

[coltm4]

Since I only know enough to be dangerous... Don't I want the higher BC projectiles in the 130+gr at 2800 and above? Is this doable without killing brass. And by killing brass, I mean I get 6 reloads before scrap bin. I don't have high hopes as compared to bolt guns, but I think 6x isn't too unreasonable. Thanks for the replies so far. I'm really wanting to learn. Thoughts on JP BCG and bolt?

 

[LRRPF52]

That's where I'm at with the 130gr VLD, 2820fps avg with H4350. I get several loads on my 7mm-08 brass before pockets are loose, maybe 4-5 loads, but that was when I was using N540, which was too hot for my tastes in the long run.

My Lapua brass is holding up well. I can push the 142gr SMK to 2700fps with RL17, but I really like the 130gr for a 22" barrel gasser. Very nice balance of speed, retained energy, wind drift, and low recoil compared to .308 Winchester.

 

[MarkCO]

Any chance you can get behind one and shoot a few rounds? For me, I just could never get used to the multiple recoil impulses when shooting "precision". If I think about it, I feel 4 distinct pulses, if I am thinking about groups, I still feel three. I really enjoy my ARs, and I might again try a large pattern in the DPMS G2, but I just never felt comfortable with my .260 AR pattern rifle.

 

[Newtrick]

I have DPMS AR in .260. Love it. Very accurate, reliable also. You're on the right track. Mine is a 24" bull, my next will be a 20". Go for it.

It beats the brass some, but I'm sure I'll get numerous loads per casing. I use Lapua brass for my bolt .260. and Southwest ammo for my AR. I shoot out the ammo, and then reload the brass.

 

[Thebelly]

I have the 20" .260 barrel on my LMT MWS. It pushes the 123 Scenars about 2825 fps out of it with H4350.