Re: How Stupid is this idea for fire forming?
He described a headspace issue.
The case heads are not reaching the boltface without a stretch just forward of the webs, because the case is expanding and grabbing the chamber walls beforehand. With this, the primers slam back to the boltface, nearly leaving their pockets.
Normally the caseheads are within a few thou of the boltface. The reach is small enough that little to no thinning occurs near the webs, and headspace is even better reduced.
He wishes to jam the bullets to force the caseheads back to the boltface before firing.
If you don't have the same issue, then it's likely your ammo is different, or your chamber, or your chamber is loaded up with oil(a dangerous condition).