A different headspace question.

[RustyShackle]

As far as "grossly undersized" being dangerous, how much would that be given the jump from SAAMI spec to Ackley Improved is relatively larger for fireforming the AI cases?

Per my post above, FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin, so anything more than 0.014 is a recipe for disaster IMHO.

My thought was if he swapped bolts back and had grossly undersized reloads for his 'new' headspace. Without having measures on both setups and dimensions of his reloads it sounds like really unnecessary risks. Hopefully OP takes a moment to get things all sorted out before proceeding.

[Texas10]

I guess you guy's didn't read where the OP swapped the bolts from his two rifles. That is the problem,not his head space. If he will use the correct bolt with each rifle,the problem is solved!

Oh, I think everybody got that, but it was still an opportunity to pass along good information, Txhillbilly.

[RC20]

While I do not advocate it, my Mode of 1917 rifles are way out on the ragged edge of field reject. Just about fail.

No issues (so far) as long as the brass stays with that chamber.

It is going to fire form out a lot and stretch as it does that and may lower case life. I don't shoot huge amounts though so don't know for sure.

Definitely more better not to stretch them any more than the minimum needed.

[RC20]

I guess you guy's didn't read where the OP swapped the bolts from his two rifles. That is the problem,not his head space. If he will use the correct bolt with each rifle,the problem is solved!

You are right, my brain finally caught up with that but it was too late!

Still a lot of good discussions and info.