Thread: Rechambering 7mm blaser

With the brass situation atm wondering if it's possible rechamber a carbon barrel to 7mm lrm or 7mm prc.
Once iv gone through the brass I have atm.

I’m no gunsmith but looking at respective brass dimensions I doubt rechambering is going to work. Especially not for 7mmPRC or 7LRM. I’ve drawn up a chart myself from published dimensions available via Google search.

One of the critical areas where 7BM differs is “E” in chart attached- this is case diameter just in front of rebate rim. 7BM is stated as 0.545 (Unfired brass I have on hand measures 0.542 with my calipers). Most of the other 375RCM derivatives are significantly smaller at 0.532). Given you can’t make your chamber smaller then seems unlikely a change would be viable? The likes of SAUM & 28Nosler are bigger at “E” being 0.550. This might be an option but are quite different calibres to 7BM.
I hear that Blaser are working hard on getting someone else to make their brass after Norma dropped it. There are some other options coming. See other threads on here. So I’d not rush into doing anything drastic at this stage.

Cheers good info there..
Surly someone should been keen to manufacture brass form them,must be plenty of rifles out there.

I’ve heard RWS might be taking on the brass, let’s hope so.

Originally Posted by rod

Cheers good info there..
Surly someone should been keen to manufacture brass form them,must be plenty of rifles out there.

Unfortunately quite difficult to rechamber the 7BM

I will be making some 7BM brass in the coming weeks