Looking at a very nice Walter Abe pre-64 in .257 Imp, do not care for this calibre, barrel is nicely marked and worth saving. Is there any cartridge based on the '06 head size that will clean up the chamber on a rebore without setting back the barrel? The .257 Imp has very little body taper. .280 maybe?

25-06? 25-284? 7x57 AI?

To clean up a 257 AI chamber and stay with an 06 case head you will probably have to go with an AI of some type. I didn't take the time to plot it up so just guessing at the moment. While the 284 case is larger in dia I don't know if it will clean up the shoulder it will be real close.

Should have specified a factory cartridge .... I have to confess I stopped handloading decades ago.

All of the standard '06 based cartridges will have too much taper in the case to clean up the AI chamber. I can't think a anything short of a new barrel that'll work.

What wrong with the 257AI? Most folks, me included, think it works very well.

quote:

Should have specified a factory cartridge

Well for the most part I would call you pretty much SOL. Quickest would be to open it up to a magnum case. I for one would love the 257AI.

A rough look indicated that the various Howell chambering would be close to cleaning up your chamber. They sell ammo http://www.hunting-rifles.com/Ammo/ammunition.htm.
Other option is to get ammo from someone like Quality. http://www.qual-cart.com/ they load for a number of the AI versions. Say a 7x57AI 280AI etc.
As a last note Quality loads for the 257Roberts AI as well. Even if don't hand load you can get a lot of custom ammo and shooting for the cost of a rebore since you are really looking at custom anyway you go except a magnum case.

looks like the 284 win will do it.





Thanks Steve!!!

keep in mind that a rebore and rechamber is generally no cheaper than a rebarrel.

My guess is he has a 40 deg AI not the RCBS. I drew it up. If my math is right the 284 will clean the case/shoulder corner with a whole .004" to spare. Since you are going to shoot factory ammo even if the corner didn't completely clear you would have proper headsapce and worst case you might end up with a slight ridge on the neck of your fired brass.

The black line is a 257R AI and the blue is a 284.

Thanks gents. Looks like .284 is it. Leads to another question, does anything have to be done to magazine lips in receiver or to magazine box of pre-64 to get fat .284 to feed properly? Truth to tell I hate to waste full length action on short cartridge, rebarrel might be better but then I lose the nicely engraved Walter Abe address on the barrel. Barrel is only 22" so rebore and rechamber to a .300 Winchester Mag or .338 is not such a bright idea either. Might have to relearn handloading again and keep the .257 Imp !!!!

I had a 22" 338 Wnag and it worked fine.

Quality Cartridge

.257 Roberts Improved (Ackley)

Prices Shown are for Retail Customers, Dealers Please Call for your price OR use Dealer Price Sheet.

Bullet Wt. Price (Bx 20)
Empty Brass 29.97*
75gr Barnes-X 49.97
75gr HP 39.97
75gr V-Max 42.97
85gr Ballistic Tp 42.97
85gr Barnes-X 49.97
90gr Barnes-XBT 49.97
100gr Ballistic Tip 42.97
100gr Barnes-XBT 49.97
100gr Partition 45.97
100gr SPT 39.97
115gr Ballistic Tip 42.97
115gr Barnes-X 49.97
115gr Partition 45.97
117gr BTSP 39.97

quote:

Originally posted by vigillinus:
Thanks gents. Looks like .284 is it. Leads to another question, does anything have to be done to magazine lips in receiver or to magazine box of pre-64 to get fat .284 to feed properly? Truth to tell I hate to waste full length action on short cartridge, rebarrel might be better but then I lose the nicely engraved Walter Abe address on the barrel. Barrel is only 22" so rebore and rechamber to a .300 Winchester Mag or .338 is not such a bright idea either. Might have to relearn handloading again and keep the .257 Imp !!!!

What good is the name on the barrel if it's not the bore, caliber, etc.. that it originally was to start with? Kind of like having a mint 55 Thunderbird with a Chevy engine in it, if you know what I mean. Notthing wrong with the caliber it is.

Helps ID the stock ....