I know it's basically a 25 X 308, but how well does it perform and what would it do in a 14" barrel???

Mark,
Any of your 308 based cartridges will do well in a 14 inch barrel. If you are thinking long range deer and elk I would go up to the 260 Remington, 7mm-08, or the 284 Win. They are factory cartridges with the 284 coming out on top if you are talking elk. I would have a hard time choosing between the 7-08 and the 260 if the 284 Win. was not in the running. If I was thinking deer only I would choose the 25 Souper or the 260 Rem. I have never owned a Souper, but it would work great. Of course, a 250 Sav Imp. should be just barely behind the Souper. Decisions, Decisions, Decisions!
Hope this adds to your confusion!
Ernie

My 257 Roberts Improved has been excellent so far! I have a 15 3/4" barrel. I just got the fireforming done last week. It has given excellent results at the short ranges that I'm forced to do at this point. (Range problems with my club.) I'm going to try out some good 257 Robt's loads this weekend. I really want to chronograph a few & see what kind of speeds I'm getting from it.
Rich Jake

Just thought that I would give you another cartridge to consider.

Man that sound like a great project--a 257 AI in a handgun. I bet there aren't many around like that.

sscoyote
I don't know of anyone else yet. So far it has been a lot of fun to shoot. I will do some full power 257 improved loads tomorrow & try to chrono them as well.
Rich Jake

Mark,
Try this link for an article by Rocky Raab on the 25Souper,
http://www.reloadingroom.com/page10.html
think he was using a rifle, but it should work great in a 14-15" handgun.
Mark

Excellent round, but since custom dies are required, you might as well go with the improved version and get the 40 degree shoulder.

If Redding makes .243 Imp bushing dies, these would probably work for the .25x.308 Imp. and solve some die problems.

For the break open guns, use .307 Win brass, but it can readily be set up to use both rimmed and rimless cases interchangeably if you want to use .308 or .243 Win brass.

Mike

Another point, you can shorten .257 Imp. dies to work with the .25x.308 Imp. chamber. .257 Imp. dies are quite available and not too high.

Redding dies are a bit generous with dimensions and would work the best when shortened.... ie, the web diameter produced would be more appropriate than when starting with a .257 Imp. size die that sized pretty small to start with.

Dimensions are dimensions, regardless of what is stamped on the dies.

Mike