Thread: 7mm wsm to 270wsm sizing

Originally Posted by Micky Duck

ok so I just have to ask....what happens if/when you chamber one of the upsized cases and close bolt????
will it do so easily??? that SHOULD tell if chamber has been large on previous rifle....also if your chamber is on generous size to begin with it may not actually be such a big issue...maybe???

Greetings Micky and dannyb,
I almost suggested this but there may be a fly in the ointment. The resized cases will be around .007" or 0.18mm larger in neck dia than a .270WSM case. The chamber is likely large eough to accept this but maybe not. The difference between a loded round and a fired case in my 7mm SAUM is less than that so assuming the same tolerances the reformed cases may not chamber at least not easily. My recent fiddling with a comparitor and competition shell holders suggests that most chambers are batween .002" or 0.05mm and .008" or 0.2mm longer than sizing dies. This is well short of the 0.038" or 0.96mm difference between the .270 amd 7mmWSM nominal chambers.
Regards Grandpamac.