28" barrel short stroking-

[Drifter]

Varget is too slow.

It's burn rate isn't too slow, but perhaps you're referring to the velocities it produces in the Grendel cartridge. It's a shame more can't be squeezed in the case.

For the OP, a supposedly temp stable powder that produces decent velocities and seems to be a little slower burning versus 8208, you might consider trying AR-Comp. It's burn rate should be comparable to Varget, but with higher resulting velocities. My setups will sometimes short-stroke with 8208, but never with AR-Comp.