6mm Max in a Six8 receiver set? Yes.

[vmpglenn]

Brownells finally got some SOLGW 14.5" 6mm Max barrels in, so I picked one up with one of their coupon codes.

I paired the barrel with a Riflespeed adjustable gas block, which IMHO are simply the best for tuning unsuppressed/suppressed shooting on the fly.

I initially shot a few dozen rounds of the factory 90gr ELD-X using .350 Legend 20rd mags. Function was flawless and the barrel stacked rounds in basically one ragged hole. Recoil was minimal, and the POI shift with my legacy Surefire can was only a quarter mil straight down - probably due to the barrel being very stout. I didn't chrono the loads, but they should ballpark around 2600fps.

I've handloaded the once fired brass with 100gr Speer BTSP and definitely will chrono these.

On a whim, I decided to see if 6Max rounds would work with my Six8 receiver set and Magpul PMAGs... Yes, yes they do.

Rounds stack a bit wonky, but they fit and feed just fine. The rounds slide out of the polymer mags like butter. The Six8 PMAGs have *just* enough inside length to allow the spec'd 2.3" COAL.

Pretty dang cool. The Six8 20 rounders fit 22 6Max rounds and the 30 rounders fit 33 or so. Love it.

 

[TonyTheTiger]

I've always thought those receivers would be cool to stuff all kinds of wildcat rounds in. Are they still regularly available? Or do you have to buy the whole gun?

 

[vmpglenn]

You can get just the receiver set; they come in and out of stock pretty regularly. I got mine at GrabAGun last year.

 

[Ernest 5.56]

I'd love to see the groups

 

[TheOE800]

The tragedy of the Six8 is those mags. The Saudis paid enough to get 6.8SPC in a polymer mag, then all design of that platform ended. A thinner-walled metal magazine with increased COAL would have been great.

 

[vmpglenn]

The tragedy of the Six8 is those mags. The Saudis paid enough to get 6.8SPC in a polymer mag, then all design of that platform ended. A thinner-walled metal magazine with increased COAL would have been great.

I'm happy the 6mm Max rounds fit well in the available Magpul polymer mags. It's a pretty compelling combination.

 

[LRRPF52]

I was wondering about the same thing, since I have an empty New Frontier Armory receiver set and some Six8 PMAGs.

I was going to bore the Six8 mags out for Grendel though of course. Has been done successfully.

Regarding the 6mm Max, since it’s a smaller case diameter than 6.8, I figured it would rattle around and the stack might not align properly.

Downside with 6mm Max is likely an inefficient propellant burn due to a longer powder column. That usually messes with SD if you don’t get full conversion inside the chamber area.

Would have made a much better SCHV cartridge in 1957 than the 222 Rem Special (aka 5.56x45mm).