Pressure = Velocity

 Over the years I've owned, and still own, 2 handguns that produce higher velocities than the reloading manuals predict. The first was a Ruger Security Six, and the other a Kimber 1911 45acp. Higher velocity means higher pressure. I usually do all my reload testing for accuracy (consistency) then measure velocity just for the record. This time that bit me in the ass.

Using Sierra bullets and Sierra loading manual I found a load for the AR15 Grendel that met my expectations. Recently I loaded a box for confirmation without measuring velocity. That was a mistake. I was ignoring possible pressure issues. After about 15 rounds into the box, the rifle locked up. I couldn't clear it, so it's at the local gunsmith.