.30 Carbine-Do you trim your brass or not?

[ShooterAZ]

I have noticed that after a few firings that my 30 Carbine brass is not stretching much, if at all. These are fired in an M1 Carbine BTW. I'm just wondering what you guys are doing? Do you trim your Carbine brass, or treat it like other auto pistol brass (which I don't trim). Obviously a time saving step for me if not needed. What say you?

[leadhead]

You bet I trim it....I've read where you can have very serious problems if you don't trim.
The carbine head spaces on the mouth of the brass and if it gets to long, you could have
a premature discharge out of battery. I trim mine every time just to be sure.
Denny

[Outpost75]

I trim to 1.280" using the Lee Quick Trim in the loading press.

I load for both an Inland M1 Carbine and a Ruger revolver. It is important for the Ruger revolver that cases not be too short.

In the M1 Carbine max case length is 1.285" and the usual trim-to length is -0.005" from that, so 1.280", which works well in both guns.

I use Federal 200 or Remington 6-1/2 primers and RCBS Little Dandy Powder Measure rotor #18 which meters either 13.5 grains of IMR4198, which I use with Accurate 31-100T plainbased cast bullet, accurate in the revolver and also cycles the carbine, or the same #18 rotor meters 14 grains of IMR4227 which is a full-charge load with Accurate 31-120TG, which is the same bullet profile with a gascheck heel added to the base.

Attachment 199544Attachment 199545

The 14 grain charge of 4227 also works well with any 90-110 grain jacketed bullet and cycles reliably. K.I.S.S. principle.

[Larry Gibson]

With new, milsurp or range pick up 30 Carbine brass I check the case length after sizing with a home made case gauge. If any need trimmed they get trimmed on a Forster trimmer with electric screw driver attachment. After that I don't trim as the case length hasn't increased. Some of my cases have been loaded who knows how many times the last 50 years. Actually on firing I find the cases shrink and when sized they return to spec oal.

Larry Gibson

[williamwaco]

In a word. No. I never trim them. Never found them to be stretching.

[ShooterAZ]

Thanks guys, that's kind of what what I figured but I thought I'd ask. They're just not stretching any appreciable amount.

[mozeppa]

i don't have the carbine .....but i do have the revolver.
and it also head spaces on the case mouth.
so yes , i trim.

if you don't trim for the revolver and they get too long you'll lock up the cylinder.

[308Jeff]

I have my Giraud set for 1.285" and I trim after every resizing. For me, they seem to grow .04-.05" with every firing.

[KenT7021]

I have never had to trim .30 Carbine brass.I use it in the carbine and a Blackhawk.

[Poygan]

In a rifle, I didn't have to trim. In a Blackhawk, trimming was necessary to avoid binding.

[308Jeff]

For those who don't trim, is that because your brass stays within spec? Or does it just keep functioning okay for you?

[jimb16]

I check them every time. Some cases stretch and some don't. If they do, they get trimmed. If they don't them why bother? Head space IS important, so watch them. Trim when it is needed.

[Larry Gibson]

For those who don't trim, is that because your brass stays within spec? Or does it just keep functioning okay for you?

Both.

Larry Gibson

[ShooterAZ]

For those who don't trim, is that because your brass stays within spec? Or does it just keep functioning okay for you?

I have been loading mine in LC72 cases, trimmed after the initial firing (factory) and subsequently loaded numerous times after that. If they did stretch, it is barely measurable. It's not a big deal to check them and I have been. I agree with jimb16's advise, trim when needed. It just hasn't been needed (yet). My experience pretty much mirrors Larry Gibson's. The same goes for auto pistol brass, though I never trim those. They shrink, not stretch.

Edit to add that I do lightly lube the cases before sizing, even though using carbide dies.

[308Jeff]

Interesting. First 30 Carbine brass I ever bought was LC72. Pulls from Jeff Bartlett.

I should probably add that I've had to trim nearly every piece of once fired 30 Carbine I've ever bought (and the never fired LC72), except one headstamp that I don't recall which was actually short of 1.280".

I have so dang much 30 Carbine brass that I've never messed with my twice fired stuff.

The reasoning behind my question of about "just functioning" is, I've ofter wondered if the "30 Carbine Trim Length Is Critical" is founded, or just another internet perpetuated myth.

[Larry Gibson]

"I've ofter wondered if the "30 Carbine Trim Length Is Critical" is founded, or just another internet perpetuated myth."

In my experience as previously posted you've answered your question.

Larry Gibson

[dale2242]

My carbine has a minimum length chamber.
I , like Larry Gibson, check them the first time and trim any over maximum length.
I haven`t had to trim them since....dale

[Outpost75]

My Ruger Blackhawk works best with cases trimmed to 1.280". Once trimmed they usually only need to be checked to be sure they are a thou' or so under the maximum 1.285"

The Inland GI carbine is less fussy and eats everything if cases are properly sized and not excessively crimped. I use just enough taper crimp to remove all mouth flare, and generally a compressed, case full of powder to support the bullet base in the same manner as using black powder in the .44-40, so that "telescoping" of loaded rounds isn't a problem.

My Ruger revolver has .310" cylinder throats, and the ogive of the bullet north of the crimp groove drops as-cast to fit, whereas I size driving bands to .311", so inertial dislodgement of revolver bullets isn't a problem either.

As a general rule, with a few exceptions, I use commercial Starline, Winchester or Remington brass in the Ruger, and military LC, WRA and WCC in the Inland M1 Carbine. Most often the plainbased Accurate 31-100T in the Ruger and the gaschecked 31-120TG in the Inland, so brass type is helpful to distinguish loads.

I load plainbased bullets with 14 grains of IMR4198.
Gaschecked or jacketed bullets with 14.0-14.5 of IMR4227.

The two types of ammo are functionally interchangible for use in either gun.

[Texas by God]

Good stuff guys. I'm fixing to dive into .30 Carbine reloading for my wife's Howa Sporter. And your input is well timed.
Best, Thomas.

[mac1911]

I have my trimmer set to 1.28? For 30 carbine. If I shoot the same brass in one rifle it does not seem to need trimming for several reloads.
I use a home made case length gauge. Plop it in and see if it goes beyond the gauge. My gauge is probably a bit on the longer side 1.285+ all I,know is its less than 1.290 both my carbines will pass a commercial no go gauge.