(Another long-winded one, guys--sorry.)
Uh--Art--Gotta call TILT on your reply--
I've chron'd several factory .30 USC loads, and none went as much as 2,000 out of my old Inland carbine. I understand that in different barrels, your mileage may vary, etc.
Just checked the Speer #12 manual, and they don't show any loads at all with the 110 gr. bullets which reach 2,000. Their MAX is with 15 gr. of 296 powder, magnum primer, your choice of the 110 FMJ, SP or HP, for 1981 fps. They say their values are from an 18 inch bbl. I thought the military carbines were 16 inch, but could be wrong. I'm too lazy to dig mine out of the safe and measure it. NOPE! Small Arms of the World shows 18 inch as standard. Sorry.
The factory loads I chronographed included Win 110 HP, some Hornady--I think SP but it may have been HP-- and some Lake Cities 52 military. I note that I've read lately that there was a HUGE amount of "LC52" ammo loaded during the 1960s for US aid to S. Vietnam. I don't know if this was some kind of tactical/strategic/black ops ruse, or if there was just a lot of empty Korean War-era brass left in storage. Doesn't matter anyway.
The velocities quoted makes the .30 USC a less-than-sporting proposition for deer-size game, in my opinion. But, the question had to do with the carbine as a defensive weapon.
In that light, it is not bad--In the late 60s, a lot of cops were convinced that the 110 gr. .357 mag load, at about 1400 (published velocities--pretty overrated, actually) with the first reliably expanding factory bullets, was considered pretty hot stuff.
And a few deer were killed with it. Most nowadays figure this set of ballistics is WAY too light for deer.
Now, think--The .32-20 was long thought to be an adequate defensive cartridge. And it is still a heap more load than the .32 H&R mag. It was a lot lighter than .30 USC. At close range--real defensive distances--the ability to precisely place the little 110 grain pill would probably do quite well.
Most of the above replies included some personal anecdote, so here's mine, second hand though it is--
When I was a teenager, our Methodist preacher told a little of his war experiences, prior to getting The Call. He was a young company commander and went ashore at Omaha Beach on D-Day, armed with a .45 pistol and a M1 carbine. He said they weren't very far off the beach before the inadequate power of the carbine was proven to his (dis)satisfaction. He picked up an M1 RIFLE and sighted it in. He knew about shooting, and felt that the open country of Normandy seemed to demand power and accuracy more than light weight and handiness.
ETB-- If you have a .30 Carbine, it should serve close range defensive purposes well. Ammo's not cheap, but costs a lot less than most centerfire long gun fodder. Keep it clean, practice, etc. I'd a lot rather be missed by a .44 mag than hit with a .30 USC.
Best regards--
RR
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