Changing 257 Roberts to a 257 AI

[Bitman]

I'm not much of a rifle guy, so I thought I'd ask the experts.
What is involved in changing a rifle chambered for 257 Roberts, to a 257 Ackley Improved?
About how much would it cost?
Any recommendations on Gunsmiths to do it?
Thanks, Dave

[Rick in Oregon]

It's a very basic simple matter of just running in the improved reamer into your chamber on the lathe. Cost varies by region and smith, but figure about $150 for the job. Just make sure the smith uses a piloted reamer and it's new or almost new.

By coincidence, P.O. Ackley thought the .257 Improved was the best improved cartridge of his entire lot. It was his personal favorite. I helped a buddy rechamber his M77 to 257AI, and it's now his favorite rifle & caliber for our mule deer and antelope here. He also uses it for rock chucks with stellar results.

That is an excellent rechambering option, and one that you'll be glad you did.

[Bitman]

Thanks Rick,

Hey, one more question.
Would the 257AI still have an advantage over the 257 Roberts, loaded with the +P cases?

[Wrangler John]

I use both Winchester +P and standard Winchester and Remington cases. Seems to me the Winchester +P cases are just the same as regular cases but head stamped for hotter loads to keep them segregated from stuff made for older rifles. You don't need the +P cases, the AI will give about 200 fps more average velocity. I use the Hornady 75 grain V-Max and Barnes 80 grain TTSX with H-380 powder for varmint - whoa, is it good! Talk about a Klingon Disruptor!