Forming bra brass with full loads??

[TAJ45]

I still trim to .010 less than actual chamber length. Not sure of any voodoo that may have caused your experience. Clearance is clearance and you either have it or ya don't. Or at least I would think so, when it comes to length. I've just never experienced what you describe. I will say that you can't trust a reamer print to be precise in terms of actual length dimensions.

Lemme offer up this musing re longer throat lengths: Any chance of carbon build up in the clearance area causing some extra pressure?

 

[spclark]

I will say that you can't trust a reamer print to be precise in terms of actual length dimensions.

True enough: the print isn’t the reamer that cut your chamber.

Know your tools!

Like how Sinclair’s chamber length indicators work to gage where your chamber really ends.

Or how to make a chamber cast to get an idea of where (and by how much) your chamber varies dimensionally from the print the reamer used to cut it.

Then you have enough quality information to decide phow far back you want to keep your match cases trimmed.

Any chance of carbon build up in the clearance area causing some extra pressure?

Yes, that can happen. But folks who care typically don’t let it; they use cases of a reasonably consistent length so as to avoid too-long cases that might run foul of a carbon build-up left after shooting shorties.