Tolerances from gun to gun

[roymunson]

Reloading for my new 300 WSM.
The old one was a Winchester Model 70 w/ a BACO barrel.
New one is a CA Ridgeline w/ a carbon barrel.

I'm finding the same charges that worked in the model 70 are causing pressure issues in the CA. Is that abnormal? I'm self taught in some of the reloading, and the fit and finish in the CA are much tighter than the Model 70.

My last gun liked H4831sc on a 200 grain bullet, this one seems to prefer the H4831SC on a 180 grainer. Suggested charges in H4350 seem to be messing with pressure and leaving my brass in rough shape.

I'm getting in just under 3000 fps with the H4831SC and it's accurate as well.

Am I doing something wrong that I'm getting such different pressure results from gun to gun, or is that simply a product of the CA being built better than the Winchester. That's what was suggested to me by a guy at the gun counter.

 

[JF_Idaho]

Not abnormal. Even 2 Ridgelines would be different.

 

[Harvey_NW]

First off, never trust the guys at the gun counter, because 99% of them don't have a frickin clue what they're talking about.

Secondly, more info is needed.

What is the barrel length?
What is the charge weight?
What is book max?
Did you work up to pressure?
Are you loading to SAAMI length or .XX" off the lands?
Did you measure the case head at the .200" of fired cases?
Are you using new or fireformed brass?

All of that matters, and depending upon the answers it could be perfectly normal or you may have an issue of something like an under spec chamber.

 

[TaperPin]

Chambers will vary a lot - SAAMI spec chambers can vary by .002” all over in most cartridges and be within the spec, but it’s a voluntary standard and self policed so it doesn’t surprise me if a rifle comes along with a giant chamber. Smallish chambers often shoot more accurately, but larger chambers have fewer customer service complains due to pressures or fouling from no cleaning.

Barrel inside diameter also varies from brand to brand, by a number of tenths. Bullets also vary a few tenths between brands.

I’ve had a rifle that never shot faster than 150 fps under published max velocities, and another that was that much over a normal max.

 

[Lawnboi]

CA tends to cut a shit chamber. Probably the root of your issues.

 

[Peterf225]

Every rifle is going to be different. I have had very little luck with multiple rifles shooting the same reload the same. Even two exact rifles with consecutive serial numbers can/will shoot different.

 

[Castle Rock]

Not abnormal. Even 2 Ridgelines would be different.

Buy a European rifle, all of a sudden those differences disappear