Is 6.5 Grendel SAAMI 52,000 PSI spec out of date?

[LRRPF52]

I’ve had this conversation with Bill many times, and there were many considerations that went into specifying the Maximum Average Pressure.

He could have engineered a rifle that would shoot the 6.5 Grendel cartridge at much higher pressures like a .260 Rem or 6.5x47 Lapua, but then you’re back into the recoil/blast problem from a lightweight AR-15 chassis.

This was something meant to be easy to shoot by hunters and target-shooters alike, where you don’t come off target so violently like with .308-based cartridges.

Engineering the action to take higher pressure would have required longer barrel extension lugs, longer bolt lugs, and a resultant longer-travelling bolt carrier in the action.

This would require a longer action and then you’re into an AR-10 at that point, which defeats the benefits of the lightweight, compact AR-15.

You could use exotic alloys for the bolt and extension if you wanted to toss all the recoil and muzzle blast penalties aside as acceptable compromises, but bolts and barrels would then cost significantly more. Figure a doubling of the cost for each bolt and extension into the equation. Bill’s forecast for the market was that the high pressure approach would reduce acceptance as to make 6.5 Grendel a very limited, low-exposure proposition and not worth the effort.

He also wanted an affordable drop-in upper receiver for those with existing rifles to capitalize on the AR-15’s modularity.