belted cartridges

Gregg C

Well-Known Member
Nov 15, 2017
Tucson AZ
338-378WBY. Sucks having 1 count em 1 manufacturer of your favorite flavor ! Certainly that is probably never going to happen, but still...


Feb 23, 2020
Have no problems with belted cases. From what been told just have to head space off of belt. I know that full sizing can cause a thinning above belt so I check mine with bent paper clip ,if a ring in side they can separate at least in my experiance


Jun 11, 2013
I have always full length sized my 300wm and there isn't an issue. If I remember right, this was spewed onto the internet as marketing hype for the then NEW belted magnums.
Yep I originally wrote NEW BELTED magnums however meant BELTLESS mags and yes I get it that belted mag cases have been around that long.


Well-Known Member
Mar 30, 2013
Please explain to me what people are talking about when they talk about potential problems with belted cartridges.

I have 7RM and have a 6.5 RM that's shot out....I'd like to be better informed before I build another 6.5 RM,

Yes 6.5 Rem Mag. The barrel is shot.....deep excessive fire cracking in the throat and a deep wide parallel crack in the riffling at the muzzle.
I bought the rifle used and believe the previous owner got it HOT. The rifle was also dropped muzzle down onto something hard. There is a dent in the barrel at the muzzle. The rifling with the crack in it runs right up the the dent.
Pics attached....not the best resolution....but kind of tells the story
Like people are saying, get the tools to measure the shoulder bump distance and stay around .001-.002. You'll have to do a basic die setup, build some rounds and fire them so you can check a fired round, if you cannot get any factory stuff. Sometimes brass will not stretch all the way and take a couple of firings, but I've never personally run into it. Also, Redding has a nice shell holder kit,, that allows you to set you sizing die up once then change out the shell holders to get the right shoulder bump, .002 at a time. Sometimes those belted cases will not resize completely just above the belt and you need a body sizer. These folks have a nice one,, I think there are others. The other thing to not forget is make sure your gunsmith chambers the barrel such that it headspaces off the shoulder not the belt. I think this has become the rule-of-thumb, but it doesn't hurt to mention it. Years ago, the 90s, haha, I did occasionally have separations in cases just above the belt in my 7mm STW. I think I might have been working the brass too much, but it would usually take a number of firings and you can see it form pretty clearly. Good luck with that new burner.

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