In anticipation of the next installment in the Winchester WSM line, I let my gunsmith talk me into converting a SS Winchester short action into a 25-300 WSM. Now I am worried that Winchester might make that 25 caliber change on the super short magnum line. I have been necking down 270WSM brass and waiting for 25 WSM to come around as a factory load. Well it hasn't and I'm stuck with no loading data. Should I use 257 WBY starting loads or top loads for 25-06.Any help would be nice so I don't blow the thing up with an overload or an underload!
lb404

I don't think you made a mistake. If something goes commercial I think it will be WSM no WSSM. A Super Short would have nothing to offer over a 25-06 except action length. Either way you still may have an orphan, but a good cartridge anyway. I would start with the 25-06 loads and work up from there, better too little than too much.

By the way, me , personally, I'm waiting for the 6.5 WSM or 6.5 RSUM, either will do.

I would start with 25-06 max loads and work up carefully. - Dan

Thanks.
lb404

You can instrument the rifle fairly cheaply, without changing its appearance, and get your own pressure data.

Go to www.fabriquescientific.com. For about $150, you can get everything you need. The strain gauge is an electrical resistor, about 1/4" x 1/2", and paper thin. You just epoxy it to the barrel, halfway down the chamber, under the forestock, where it can't be seen.

The meter unit gives answers in "microstrains" which are easily converted to PSI just from a couple of dimensions off your rifle.

So, with that, you can start with any powder you can find, and work up loads that you have pressure tested.

Steve Faber (fabrique scientific) has sold the last of his strain meters and will be making no more.

He is in the concept stage of a new device, but it is still a ways off.

A decent internal ballistics program can get you awfully close. Even Homer Powley's calculator will get you within a few percent on a good day. Look for "winload" on Google, it's a free download. FWIW, Dutch.

If you subscribe to the "money is no object" train of thought then you might look into a Kolbe P-max. I couldnt say how accurate they are but it looks interesting. Considering the cost of most electronics it would appear that this product is in need of some competition.

http://www.border-barrels.com/