I just wanted to try a few. Does one use Cheddit data? Would they accept Cheddit primers? Thanks yoju.

Short bus, just grab the data from any other straight wall eurotrash hull, so long as you are in the target range of loads under the 10K psi range, and use the same primer hotness of what is called in the load if you are swapping primers.

And, no, they will not hold a Cheddite primer. Unless you wanna get that primer pocket thingy that's supposed to swell the pocket enough to hold a US size primer. Otherwise, you needs a euro size primer.

The primer pocket thingy from Ballistic Products: works good

Replace SWELL with SWAGE and that will be correct. A US shotshell primer is a thousandth's or two smaller diameter than the Euro primers. So, the hull base has to be swaged down just a little to hold a US primer snugly.

And, yes, those Rios will hold a Cheddite primer snugly. Cheddites are French, and that means they are made to fit the European hulls.

good luck, garrisonjoe

See primer diameter measurements and diagram:

https://www.shotgunworld.com/bbs/viewtopic.php?t=440683

They may be made in France, but they have never fit my Rio hulls very well. I always used RIO primers when I could get them. Cheds didn't fall out, but pushed out way too easy for me. YMMV And I ain't gonna mess with that primer pocket conditioner. I'll buy the right primer before doing that.