Thread: Crimping 7mag brass

G'day all i'm just wondering how many of you boys/gals with 7mm rem mag crimp their brass when loading and if so how do you find it affects accuracy ( good or bad ) there's so many different opinions out there its hard to decide whether its worth while I tried a couple of crimped ones and thought they shot more accurate than no crimp so I suppose its to crimp or not to crimp then if its crimp how much cheers

i load 7mm rm but never crimped it.

Unless you actually need a crimp to stop the projectile falling out or moving under recoil, then I just consider it another variable that you can experiment with.
When im working up loads ill often test different powder charge in a crimped and non-crimped version. Sometimes the crimped ones shoot better, sometimes not.

Thanks fellas for the info and mimms2 no I don't neck turn never even thought about it maybe I should look into it a bit further I annealed my first lot of 7mm brass today and they come up good I found that when I loaded them there was no tight spots during projectile seating like previously with non annealed brass in short I found them easier to deal with annealed you'll have to forgive me as i'm still finding my way around the 7mm rem mag I've used it for awhile but never fiddled with it as I am now so thanks again cheers

I reckon the benefits of crimping shows when your loading well used cases and not annealing.

Thanks Dicko that sounds like a fair statement as crimping would put a fairly even tension on brass with uneven tensions by several firings sounds good thanks mate I do intend to anneal from now on when the brass needs it I've had a couple of cases get very minute cracks form on the very tip of the neck which is a sign of slight hardness

I never crimp any centre fire rifle cartridge- if you’re not getting decent neck tension then you need to anneal the necks, or perhaps your neck die set up needs looking at. You can really feel the difference when seating the pill between annealed and not annealed cartridges even after one or two firings

Yes chainsaw that's what i noticed to i have never annealed any brass prior to now and when i done a few i loaded them and found that the tension was more consistent than the unannealed ones which had the odd tight couple i might even look at annealing the 22-250 brass and see how it differs from the unannealed i might get a chance to try the annealed 7mm mag loads today it'll be interesting to see if there is any change in accuracy

Originally Posted by mimms2

And this is a thing that needs to be tested in your rifle with your loads.

I personally dont crimp (anything) But i don't load for levers and I'm single stage so it's an uneccessary extra step for me.

"A couple" isn't a great indicator. Load 50 and shoot them under all weather conditions you're likely to need acuracy in. That will give you an answer.

Are you neck turning? That'd be my step 1 to consistent neck tension.

What mimms2 said.

Neck turning and bushing dies gives great consistency and repeatable neck tension. As others have said, annealing is important too otherwise necks will harden.

I have never crimped anything, but some say they do well with that approach.

Crimp cases/projectiles are an "almost" a must on then semi-auto rifles because the recoil and movements of the system (it is only MY knowledge). "Normally" if you loosing neck tension and or accuracy maybe your brass has harden for the times it has been fired (magnums will harden faster than non magnums with 308 case capacities average equivalents) annealing will bring the brass back to good tension if proper annealed, not enough or too much only will create more variance, a consistent neck tension is what will give you consistent accuracy and velocity (keep low extreme speed (ES) and standard deviation (SD)).

My experience with 7 Rem Mag is as i have had 2 at one point and hunt and target shoot with them, still reload and do load development to many different rifles brands and all of them have different "likes".

I hope it is of some help, let "us" know if any more info needed, i will do my best to help where i can.

Mac