What is the name of this cartridge?

[cumminsnut76]

So awhile back I posted trying to find a cartridge setup for a lightweight walk about rifle round. Like the idea of the 30 badger but wanted a little more power. Decided on running a piece of 357 mag brass through a 300 blackout die. What would you call this little booger? Obviously a rimmed 300 blackout but just wondering if there is a name specifically for this setup. Also what twist would you use? Not looking for suppressed. 110-170grain is the plan

[Recycled bullet]

I was just thinking about that my goodness!

So I've got this big bucket of 38 Special brass, then my eyes diverted to the 300 Blackout resizing die and then I started rubbing my two brain cells together... I wonder how well that would work with 225 grain Spire point bullets

[cumminsnut76]

The 30 badger is wonderful with the 38 special. I don’t know how it would work with the 300 blackout die. Interesting thought. I used magnum brass on thisnone

[challenger_i]

300 BO is based on the 221 Fireball/223 Remington case dimensions, and the base diameter is smaller than 38/357.
The 300BO sizing die supplied by Lee has been reported to be over-size (lots of chatter on the 300 BO threads about cases formed in Lee dies not fitting the chamber). I took a Lee 300 BO die and "dressed" the area of the die below the shoulder so that it would fit a 357 case. Was easy: split the end of a dowel that was slightly smaller than the die, inserted emery cloth and chucked this in a cordless drill, set on low speed. The task of opening up the die body took about 5 minutes of careful honing. One can do a finish polishing with a linen swatch in place of the emery cloth and jeweler's rouge.
This die makes a really pretty case. I use it for making 38 sp shot shells, using 357 Max cases. However, If I EVER get another Martini Cadet, I am contemplating doing what the OP has in mind: a 30/357.

[challenger_i]

A tad bit of research came up with something similar: 30 Bobcat.

[barrabruce]

Been around since the 50’s in various forms.
30 picra is the latest
30 aet

[243winxb]

30 Bobcat.

[john.k]

If Bertram will sell 222rimmed cases not necked down ,then you can easily have a rimmed 30 blackout.........the chamber easily made by lathe turning a rim recess to suit.

[rockrat]

Run a 357 max. into a 300 BO die backed off a bit. Kind of like a short 30 Apache (1.610 vs 1.76 inches long)

[M-Tecs]

30 Paxton, 30-357 Paxton or 30 Bobcat is what I have heard it called in the past. More recently I have heard it called 300 Blackout Rimmed or 300AAC Rimmed.

[JDHasty]

I don’t remember, but Hornady used to sell brass.

[marlinman93]

The .30-357 has been around for a long time now. It was once a very popular silhouette cartridge, and does quite well on steel, especially with heavier .357 bullets.

[cumminsnut76]

What twist rate would you use on a 16in barrel 125-170grains?

[firefly1957]

I did some measurements when I ran .223 brass into a 256 Winchester magnum die because the rimless round has a higher base I measured a 5% lower case capacity . Probably get a slight increase going to your rimmed round from rimless .

I would like to see someone come out with a .25 caliber pistol round based on the rimless case using .350 legend solves the slight .002" case difference at the base . I do not want the new round I would just like some effective bullets for my 10" Contender .256 WM !

[BobT]

Very Similar to the .30 Reece cartridge also. The Reece is based on a slightly shortened .357 magnum case.

[barrabruce]

What twist rate would you use on a 16in barrel 125-170grains?

1:10
1:12 inch twist would handle subs and high velocity my 30-30 does
1:14 pre loved match barrel might be nice

If you put a truck axle on it and a perch belly stock. A half a Hubble telescope you could use it for pb cast bullet match shooting. They use a 30-20 case or 32miller short which is similar as far as I can tell.