257 Roberts Improved thoughts

[roymunson]

My FIL was a gunsmith and was handing out some of the guns he had made to family over Christmas.
Pretty cool gesture.

So my family ended up with a 257 Roberts Improved. On a Mark V action with a milled barrel. Not sure it'll ever go to the woods, but what can you tell me about it. Didn't come with ammo. But my understanding is its the 28 degree shoulder and not the 40 degree AI version. I can reload, but i cannot even find anything online to buy ammo. Im not deep enough into reloading to reform brass, but would like to at least fire it and see how it works as a tribute to grandpa.

Any input anyone has, direction to go with ammo, etc, would be appreciated.

 

[The Guide]

My FIL was a gunsmith and was handing out some of the guns he had made to family over Christmas.
Pretty cool gesture.

So my family ended up with a 257 Roberts Improved. On a Mark V action with a milled barrel. Not sure it'll ever go to the woods, but what can you tell me about it. Didn't come with ammo. But my understanding is its the 28 degree shoulder and not the 40 degree AI version. I can reload, but i cannot even find anything online to buy ammo. Im not deep enough into reloading to reform brass, but would like to at least fire it and see how it works as a tribute to grandpa.

Any input anyone has, direction to go with ammo, etc, would be appreciated.

If the gun did not come with a set of reloading dies, your in kind of a pickle. You can fire standard 257 Roberts ammo in an Improved chamber and it will be fire formed to the chamber dimensions that you can then measure. Alternatively, you could have a gunsmith "slug" the chamber with lead and get measurements from that.

Jay

 

[pa52855]

If the gun did not come with a set of reloading dies, your in kind of a pickle. You can fire standard 257 Roberts ammo in an Improved chamber and it will be fire formed to the chamber dimensions that you can then measure. Alternatively, you could have a gunsmith "slug" the chamber with lead and get measurements from that.

Jay

Fireforming seems to be the easiest solution

 

[Scoutfan]

Why not ask your fil about it. Sounds like he is the one who built it. Fire forming should also answer your questions. Any reason why you wouldn't ever hunt with it?

 

[Caseknife]

Just buy 257 Roberts ammo and go shoot it. 28 degree shoulder is not as common but dies should be able to be found. Impressive when you insert a factory round and out comes something that looks quite different. I have a Win Mod 70 Fwt in 257AI. It really likes the 90AH at about 3400fps

 

[TaperPin]

In any wildcat or rechambering in the garage it is quite easy to not pay close attention to normal headspace. Factory 257 ammo should fire form just fine if the headspace is checked with 257 gauges, but many rifles have extra long headspace and it was common to either seat bullets out into the lands or neck up and back down to create a false shoulder in the brass when fire forming. Heck, here on Rokslide guys improving chambers with hand turned reamers are sometimes going a little too deep and that’s always been the case. Headspace gauge is $45 on eBay.

257 AI was popular so there are a lot of die sets out there sitting on shelves waiting for an estate sale to bring them to eBay. Right now there are half dozen 257 AI 40 degree sets. I’d just use them to neck size brass until it’s too tight for the chamber and get new brass. Many rifles shoot nothing but neck sized brass just fine.

For $20 or so you could buy a chunk of Cerosafe to make a chamber casting if you like to tinker, or have a gunsmith do it. It melts easily and would show that shoulder angle you have, but says nothing about headspace. You pull the barreled action out of the stock, and the chamber is cleaned and lightly oiled. Then a cleaning rod with tight fitting cotton patch is run in from the muzzle to just in front of the chamber as a stopper for the molten metal. A hair drier preheats the rifle barrel for a smoother cast. The metal is melted in a big metal spoon with a propane torch and poured into the chamber. After a minute the cleaning rod can push out the cast plug. If it doesn’t look good enough, just melt it down and go again.

 

[TaperPin]

I couldn’t help thinking Ackley was never a fan of 28 degree shoulders, but RCBS was. I’m guessing if it does have a 28 degree shoulder it’s the RCBS improved version?

My 6mm-06 is the RCBS improved version and I have been waiting for a couple years for dies to pop up. The barrel will be shot out with neck sized brass before dies come along.

Talking with old timers, they warned me a lot of RCBS improved chambers varied based on which reamer supplier they used and you might have something that doesn’t work with the correct dies. Worst case 25 creed dies could be used to neck size and seat bullets.