Home Forums Hunting & Shooting Custom Rifles & Wildcats .25/7mm Rem mag

New to this wildcat arena but shot one mentioned above and really liked the rifle, its handling and its performance. Any info on the history of it, the proper wildcat name for it, loads for it, anything, would be appreciated.

The one I shot was formerly a Weatherby ultra-lt. wt. in Rem 7mm mag and rebarreled, of course & w/muzzle break. The gent that has it had only recently aquired it along w/beau coup gear and equipment, no books or load data so info on it was sparse at best.

I have the same rifle in Rem 7mm mag and the itch struck me.

Thanks in advance for whatever you guys can lend on it.

I couldn't find any loads for the .25-7RM but the old .25 Ackley Magnum is darn close in size being about .050 shorter than the parent 7RM case.
LoadData.com has 60 loads for the .25 Ackley Magnum which should prove good in your proposed wildcat. Given the slightly larger case capacity of your wildcat you may be able to work up loads that end up a bit larger than those for the .25 Ackley.

If you want the data PM me and I'll send you all 60 loads.

i've often wondered about this, but I always thought that it was pretty much just a .257 Weatherby? i'm also interested in this cartridge. I'll definitely keep an eye on this thread.

Sorry I can't, be any help to you but im glad someone else is thinking about this cartridge.

Brett (Mac)

The .25 Ackley case is reported to hold 81.16 grains of water.
The .257 Weatherby 85.63 grains.
The .264 Win Mag 81.51 grains.
And the 7mmRM 83.19 grains.

All according to the "Handloaders Manual of Cartridge Conversion"

I would just chamber it to the great .257 Weatherby and save money on standard dies and have better performance to boot.

I too have thought about this cartridge. But when you start to think about the cost of dies or trying to find a smith with that reamer, I always remind myself that the .257 Weatherby is already there with everything available. The only thing that may be difficult to obtain would be the brass but even it could be made from readily available .264 Win or 7mm RM brass.

Unless you want the "unique/cool" factor, there are a lot of positives to just do the Weatherby.

I have had two custom 257 Roys with zero freebore and eight or so Rem 700 7 Mags.

With Reloader #22 and a 120g, CCI-250 primer, velocity of the 7 mag is 3500-3600 fps, and very tiny three shot groups were the bullets over lap.

If you already have a 7 Mag, you may want to spend the bucks on the above components to see what your rifle shoots before you dump $1200 in a new wild cat. The 7 Mag with the 120's at 3600 with a muzzle break is a fantastic round.

In my custom 257 Weatherby's with zero freebore, I made brass out of NEW 7 mag brass, Winchester brand is the only brand to use. I necked down the 7 Mag brass, sent it to PTG and had Dave Kiff make a 257 Weatherby reamer off the brass with it's slightly shorter neck, .003+ over loaded dia neck, zero freebore, .2575 throat, 1 1/2* leade angle. This is probably a very cheap way to go for a guy that is wanting to make a 25 caliber hot rod off of a 7 Mag case due to the expense of dies. I got the perfectly formed double radius of the Weatherby case on the first pass in my full length Bonanza sizers, using Imperial sizing wax. Once and twice fired 7 Mag had all kinds of problems with necks and shoulders collapsing due to work hardening.

Having said this, the 7 Mag would be an ideal platform to make a 25 Caliber wild cat, and with shortened freebore, velocities would be in the 3800+ fps with a 26" barrel and 3600 fps with the 115's. Special dies, reamer, headspace gage would have to be purchased for the gunsmith, but they would be yours for life.

For those of you considering the 25/7RM, give some thought to the idea of necking down new Winchester brass to 257 Roy and having a reamer ground to fit the neck that is about .040(max) shorter than std 257 Weatherby brass.

Winchester brass is about 12% tougher than Weatherby brass, at least on the lot# that I had Rockwell tested.

+1



I guess I've always considered the 257 WM to have that... I mean, aside from this forum, I know no one who has one.

I'm not a mag guy at all and if I were going to something with that much case capacity I personally would choose something with higher-BC projectiles available like the 6.5 or 7mm, but in my opinion the 257 WM has a high cool factor. And I do like wildcats, too, so I can understand the additional "cool" of the 25-7RM.

Interesting-sounding project. Good luck; I'm interested to hear about results.

One thing about case capacities is, they're measured to the casemouth. Cartridge neck length can vary quite a bit.

Keith's chamber makes the .257Wby come alive.

The case capacities given in "The Handloaders Manual of Cartridge Conversion" are indeed measured to the case mouth.

That said, the comparison of relative case capacities is still valid since they are all measured in the same fashion.

I however much prefer the method Ken Waters uses to measure capacities. He measures to the base of the neck.

keith,

How do your freebore-free .257 Wby's shoot?

There's a gunsmith in Wharton,Texas that builds a 25STW.He runs a guide service in Mexico called 3J or JJJ outfitters,best I can remember his 1st name is James.

I thought about it and did some research. I found data for the 25/264 Win mag...basically what you are looking for. IT&D has reamers for the 257STW and 25/264 so it wouldn't be too hard to go either route. IT&D does good work too.

In the end, I went with the 257 Roy. It was just easier.

RH

It may be named 257 Baker magnum. I know of one and the owner calls it by this name.

8mmwapiti

It's called the 25-06 with a 26 inch barrel.........




Casey

Mule Deer, first trip to the range with R#22, Fed 215', 100g Nosler Ballistic tips and 100g Nosler partitions was really a day I'll never forget.

The 100g Ballistic tips were shooting in the 3's and the 100g Partitions were shooting .400-.500, three shot groups fireforming new brass, I do load at the rifle range.

I can't claim the idea, I copied a gunsmith that had chambered quite a few of these...he's long gone to the happy hunting ground.

This cartridge is 200-250 fps faster than a custom 25/06 with a 26" barrel, been there-done that.

Gents, one and all, many thanks for the replies. The wealth of knowledge and the willingness to share it here never ceases to amaze me.

I've gotta admit that I may have been a bit overcome by the cool factor mentioned here (so true) and the fact that zapping that 400 yd. iron plate javelina at will was a blast. Weren't too bad for the ego, either! That rifle just plain fits and I have one!

All said and done, I'm leaning very strongly toward just rebarreling what I have to a .257 Roy, much to the advice given here.

Again, many thanks.

I recently rechambered a Pre'64 Model 70 SG from 25 Ackley Mag(originally a 257 Rbts) to 257 Weatherby to avoid the long search for dies and brass forming duty....

I can also answer that. They perform better than a chamber with std. dimensions.

I have 2 rifles done with that reamer. The first one is a trued single shot Savage with shouldered 12twist/29" Hart and 4" long brake. Load testing with RL22 and 3 different 100gr Sierras produced mid .2"s at 3982 and 4010. Another 1/2gr powder and groups opened way up, I found out later that the brake had loosened. The Sierra 1625 explodes a rockchuck.

The #2 gun is a Savage repeater with 10twist 26" Douglas heavy sporter, barrel nut. I've only fooled with it a little and so far seems to prefer 100BalTips. This gun handles much easier.