Possible .257 wildcat

[nhenry]

Reposting this from the Hammer board.

I have an idea for what I think would be a swell pronghorn-muley cartridge, but I don’t know if it’s been done before.

My idea is to take the 6.5x55 Swede case, neck it down to .257, and give it a blown out case and either 35° or 40° shoulder (like an Ackley case). It would get either a 7 or 8 twist barrel

Anyone know if this has been done? I fully realize there is such a thing as 257 roberts (and the AI), but 7x57 does not have Lapua brass like 6.5x55 does.

It’d be in a Tikka action so it can be seated out as far as I need to. Thinking about 3.1-3.2 COAL depending on the bullet. I should be able to reach a hypothetical 3200 fps or more with a 100gr class bullet.

What says the Peanut Gallery?

 

[cloverleaf]

Any .25 is a good .25- If I recall, you are sniffing around the 257 Roberts AI terrtiory. Nothing wrong with that! I could be wrong on the numbers.... Brass is a key. Was just reading today that at one point the 6.5x257 Roberts was a popular wildcat. (Kinda the reverse of what you are proposing.) Apparently, there was a massive influx of 6.5 Arisaka rifles post WWII but no brass. So - enterprising gunsmiths rechambered them for a 257 Roberts case necked up to the 6.5 mm. (According to the Speer #7 manual circa 1966). As I said, go for it, could be fun! CL

 

[JD338]

Interesting. Custom dies might be very expensive.
You looking at a short action or long action? If long action, a 25-284 would be a good one as it's already established. Of course you could also go with a 25-06 AI, it's a flat liner. Another one might be the 6.5 Weatherby RPM necked down to .257 cal.

JD338

 

[remingtonman_25_06]

Sounds like a lot of work and money to reinvent the wheel to shoot a 100g bullet at 3200fps when a 25/06 will easily get 33-3400fps as is.

But, if it's a short action, why not a 25 creedmoor or 25-284? Plenty of good brass and same if not higher velocities.

Then again, I know exactly what you mean by wanting something different. If you want it, do it! That's a good enough reason as it is

 

[gerry]

In a Tikka action a 25-6.5x55AI would be a perfect fit if you want something a bit different. Like was mentioned a 25-284 or 25 Creedmoor would be an easier option. The 257 bore is getting some good new bullets and is getting more popular so no wrong choices in those 3 mentioned.

 

[RL338]

With a 7 or 8 twist barrel I rather have a little more horsepower and run the 130’s that are out there. For 100gr bullets there are multiple choices without so much added work.

 

[xphunter]

7T barrel (Maybe a 7.5T) would be my choice.
25-284 would be the easy button, to save all of the the time and money with expensive dies.
If, you wanted a tad more performance with the 284 Winchester family of cartridges, you could, "Shehane" it, but I would just neck down Lapua 6.5-284 brass and be done with it. You may need to do a little outside neck turning, depending on the reamer the gunsmith uses.

 

[nhenry]

For once, I’m not looking for velocity on this. I just want something that’s mine and something my kids can grow up shooting comfortably, I suppose. If this hasn’t been done, then I’d like to be the first. I have nothing but love and adoration for the other quarter bores mentioned.

I get great satisfaction by hunting with a rifle that I built, using ammo that I loaded and tested up. This is one step further.

For what it’s worth, I’m an engineer so my mind’s already a little screwy and can’t leave well enough alone

 

[xphunter]

Nothing wrong with unique.
Pick an odd shoulder angle and body taper to make it more completely your own.
If you improve it (Reducing neck length and increasing body length) choose some oddness there to better ensure it's uniqueness.
Making the neck part of the reamer, where you are required to do some neck turning, ensure some more uniqueness.