257 Roberts +P Question

B

Bitman

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What is the difference between 257 Roberts and the 257 +P brass? Is the +P case thicker?

If your going to be fire forming cases for a 257 Ackley Improved, which brass should you use? The +P or the regular 257 brass? Does it really matter, as long as you use all the same cases?


Also, what is the best replacement trigger to use on the older Ruger M-77 with the tang safety?
 
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Good question. I only use the +P 257 brass, and don't know the difference between it and other 257 brass. I'd like to hear what others say in answer to your question. All of my loads were developed with the +P brass.
As for what brass works best for fireforming, I've never had a problem with either Rem or Win brass. I think Win brass is a little harder than Rem's, at least in 223 when I'm fire forming 223AI loads.
 

I use the parent 7x57 Mauser [Remington] brass to form my three Ackley's 244,257,7x57. I have also experimented with both Rem & Win 30-06 brass cut and formed to 244 AI with excellent results.
I doubt the standard or + P brass will matter that much when fire forming for the AI. Going with Ackley’s intention to continue the use of factory ammo in the improved chamber.

B…
 
It's my understanding that the +P brass is thicker.
If this is true, wouldn't you have less internal volume for powder?
 
I can tell you this. I bought Win +P brass. Set the sizing die according to mfgrs. instructions. Could barely get the bolt closed. Took me a bit to figure out because the guy I bought the gun from also had a scope base screw sticking into the action. Long story short, I had the screw the die down a good amount to even get a round to chamber smoothly, so the brass must be thicker, and though I did not check (because I wasn't really interested) I'd bet the powder capacity is less.
 
PS:The best trigger for your older M77 tang safety is a Canjar set trigger. Good luck finding one as they are not made anymore. I do see them on occasion. I've used a number of aftermarket triggers in other guns and they all pale in comparison to the Canjar; the sucker has a trigger shoe as wide as a bulldozer blade but boy it is sweet. My M77 tang safety in .257 Roberts came with a Canjar. My gunsmith said the trigger is worth more than the gun!
 
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