.243 R.S. Magnum No. 3

[jhillas]

That is what it says.

.243 R.S. Magnum No. 3

That is the caliber.

It also says right on the barrel that it was designed by Ramon Somavia and custom made by Larry R Thompson, both of whom are dead.

It was custom made for a brother in law who gave it to me years ago, and we don't know what to feed it.

Mr. Somavia was known for unusual rounds and was the creator of the .257 Condor in the 1940s. He was well known in the Hollister, CA area.

I think it was designed to be a deer rifle and I think it has a .243 caliber barrel, but I think it is paired with a custom larger chamber that uses some other casing that has been necked down.

I had one gun guy look at it and he said "do not try and shoot .243 ammo through that gun."

How do we find out what ammo and how to, I guess, make it?

I am in Northern California but would consider shipping it anywhere for the right expertise.

[DrewN]

Chamber cast would be your first step. Then you'll know where to start. What's the bolt face?

[DrewN]

The .257 Condor is pretty interesting. 160 grain .25 caliber at 2800 FPS. Necked down 7x61 Sharpe and Hart (.532), which was a forerunner of 7mm Rem mag.

[pacrat]

Chamber cast would be your first step. Then you'll know where to start. What's the bolt face?

^^^THIS^^^

To which I'll add,

Slug the Bore.

Those 3 combined steps will tell what it is chambered for with some research.

It MAY be a 243 WSSM. Unless it Pre-dates 2003. https://en.wikipedia.org/wiki/.243_W...r_Short_Magnum

UNLESS ........... It's a One-Off Wildcat.

AFTERTHOUGHT. Does the barrel breech have a recessed ring cut into the opening circumference? If so, parent case is a belted magnum.
And it MAY be a "240 Weatherby Magnum", which utilized a .243 bullet dia.

[DrewN]

Slug the Bore.

Excellent advice. You're probably safe if it's stamped .243, but why take a chance? Lazzeroni is probably the most famous example of a dude who wanted to name things his way, and didn't use conventional nomenclature.

[DrewN]

There's actually a bunch of these obsolete wildcats out there. Dude's could do the math just fine,but the **** bullets of the day didn't perform. A .25 160 grain at 2800 is going to fly flat, penetrate deep and kill some **** dead. If it held together, which it didn't reliably at the time.

[MongooseV8]

Do you know what action/receiver it has?

[jhillas]

Thanks everyone for all of this. I will digest and check, and get back. Will also include some photos.

[flyer898]

I am absolutely sure that when that rifle was built a set of custom dies was also made. I would try and track those down.

[LynnJr]

There is a poster on the accuracy forums who posts under the username Cheechako. His real name is Ray Meketa and he has over 300 wildcat cartridges in 6mm. He is also a cartridge collector.
If he is still around on 6mmbr.com or Benchrest Central send him a PM and he can most likely give you some intel.
Back in the day it was common to shorten and neck down 300H-H brass to make some screaming 6mm wildcats.
Tell him Lynn sent you.

https://www.6mmbr.com/compcartridges.html

[Elgatodeacero]

As mentioned above, using this stuff to make a chamber and throat casting would probably be helpful.

https://www.brownells.com/gunsmith-tools-supplies/barrel-tools/barrel-chamfering-accessories/cerrosafe-chamber-casting-alloy-prod384.aspx

https://www.rockymountaincartridge.com/index_htm_files/Cerrosafe%20Use.pdf

[God Bless America]

Ugh. From an article on the .257 Condor:

"The wild burro, tough and lethargic, is
difficult to convince that he is dead. He is
unprotected in Arizona, so we tested the new
rifle on this noblest varmint of them all. With
a hit in other than a very vital spot, not even
the .357 Magnum would give a quick kill.
Feeling that hits directly on vital spots with
any sizeable caliber would quickly drop an
animal, we concentrated on making poor hits.
Some few deer were hit thru the chest area,
but a majority of all the game was deliber-
ately paunch-shot or struck thru the hips. To
the dismay of the guide, some of the caribou
. were paunched. Regardless of the location of
any solid hit, or the size of the animal, the
reaction was almost invariably the same. It
would stop, appear dazed for an interval of
fifteen or twenty seconds, back up a few
steps, and then collapse."

[pacrat]

Ugh. From an article on the .257 Condor:

"The wild burro, tough and lethargic, is
difficult to convince that he is dead. He is
unprotected in Arizona, so we tested the new
rifle on this noblest varmint of them all. With
a hit in other than a very vital spot, not even
the .357 Magnum would give a quick kill.
Feeling that hits directly on vital spots with
any sizeable caliber would quickly drop an
animal, we concentrated on making poor hits.
Some few deer were hit thru the chest area,
but a majority of all the game was deliber-
ately paunch-shot or struck thru the hips. To
the dismay of the guide, some of the caribou
. were paunched. Regardless of the location of
any solid hit, or the size of the animal, the
reaction was almost invariably the same. It
would stop, appear dazed for an interval of
fifteen or twenty seconds, back up a few
steps, and then collapse."

Ugh for sure. And near the top of the list for UNETHICAL PRACTICES.

[AlexRod85]

Well Thanks For The Informationnn It Really Works!!