In my opinion the .30 Carbine round makes a better handgun cartridge than a rifle round. My .30 carbine Ruger is more accurate than my WW2 Inland DCM carbine. Two-inch 50 yard groups, fired from sandbags with iron sights firing hand loads are easy, as are 4-5 inch groups off sandbags at 100 yards! The .30 Carbine cartridge is outstanding as a flat-shooting varmint or small game cartridge, fired from the Ruger Blackhawk or T/C Contender.
LC44 Ball Ammo at 100 yards
Accurate 31-100T with 7.4 grains AutoComp at 100 yards.
Firing “full charge” loads is unpleasant without adequate ear protection. Lake City 1944 Ball ammo chronographed 1586 fps from my 7-1/2” Blackhawk, versus 1981 fps from the Inland US Carbine. Cast bullet loads in the Ruger, using the minimum charges which cycle the Carbine, gave 1300-1500 fps. Fired from the M1 carbine they approximate full charge .32-20 loads suitable for the Winchester 1892, giving 1600-1700 fps.
The same powder charges and bullets used successfully in the 7.62x25 Tokarev perform well in the Ruger. A charge of 7.4 grains of Olin Auto Comp, measured with the RCBS Little Dandy Rotor #9 tames muzzle blast to moderate levels, functions the carbine reliably, gives excellent accuracy, and drops the empty brass from the carbine at your feet. Plainbased cast bullets of 14-15 BHN give good accuracy up to 1500 fps in the revolver without leading and 100 yard groups of 3-4 inches with iron sights, versus 5-6 inches for WCC44 and LC44 Ball ammo. My cast bullet loads use Accurate 31-100T cast 15 BHN and sized .310” with Lee Liquid Alox and 7.4 grains of Olin AutoComp, metered with the RCBS Little Dandy Powder Measure Rotor #9. A satisfactory full-charge load with 31-100T is 14 grains of IMR4227, measured with RCBS Little Dandy Rotor #18. This approached the velocity of factory ammunition, shot to the same point of impact as factory loads and didn’t lead, but was not the most accurate load.
Since the 30 Carbine headspaces on the case mouth, case length is critical. Cases which are too short fail to give reliable ignition in the Ruger revolver, because the hammer blow simply drives cases more deeply into the chambers. If cases are too long, their heads bind against the recoil shield and impair cylinder rotation. Failure to pay attention to case length causes problems. Ignition problems in the Ruger are avoided by eliminating cases shorter than 1.28,” or trimming any longer than 1.285.” New Starline brass is held within 1.280- 1.285 inches and I recommend that you do likewise with yours! If your .30 carbine brass is uniform, and of correct near-maximum length, there should be no issues.
Carbide sizing dies eliminate the need for case lube. Any residual oil or greased not removed causes cases to set back upon firing and bind against the revolver recoil shield. Chambers of the Ruger revolver absolutely must be kept free of oil. Most reloading manuals recommend using Small Rifle primers for full-charge loads in the .30 carbine. While this is necessary in maximum loads to prevent pierced primers or cylinder lockup due to primer flow, I prefer to use standard small pistol primers in the Ruger revolver and limit revolver velocity to 1500 fps with 85-100 grain bullets and to 1400 fps with bullets over 100 grains. Using standard small pistol primers gives a reliable visual indicator when pressures exceed about 30,000 psi, which seems to be the point problems at which problems are more likely to occur. With proper bullet fit, moderate loads, and using a taper-crimp die, inertial dislodgement of either jacketed or cast bullets is not a problem. Cast bullets weighing more than about 130 grains are not properly stabilized at realistic revolver velocities in the Ruger’s 20-inch twist of rifling.
Cylinder throats of some Ruger .30 Carbine revolvers may be found as tight as .307-.308” diameter. Cast bullet diameter is limited by chamber and brass dimensions to no more than .310” when using .30 Carbine brass. Some users hone their cylinder throats to .312,” which enables using the same bullets as for the .32 H&R Magnum or .327 Federal. This requires use of Starline .32-20 brass, which is thinner walled to provide adequate neck release clearance for the larger bullet diameter. The New Model Blackhawk .30 Carbine cylinder does not have recessed case heads as did earlier guns. There is adequate head clearance for Starline .32-20 brass and this adaptation works very well for those users.
I find it most appropriate to view the .30 Carbine Ruger as a “rimless .32-20.” I do not use .32-20 brass for assembling full-charge loads in my .30 Ruger. This is because I own several older .32-20 revolvers so I limit all loads in .32-20 brass to standard pressure loads which are safe in the old revolvers. It is absolutely necessary to have a fail-safe method to distinguish “hot Ruger loads” if you also own an older and weaker .32-20 rifle or revolver. Doing so avoids the risk of putting a Hot “Ruger Load” in a nice old gun and either ruining it or injuring yourself.
My Ruger revolver dates from 1977 and came with .310 cylinder throats from the factory. I find this ideal. Cast bullets which “fit” give excellent accuracy. While the .310 cylinder throats are not “optimum” for the .307-.308 jacketed bullets found in factory FMJ or soft point .30 carbine ammunition, my revolver still groups about as well with GI ammunition my WW2 Inland carbine! Best grouping of jacketed bullets is with the .309” diameter Hornady XTP, intended for the 7.62x25 Tokarev or .30 Mauser. The jacket thickness, skiving and cavity geometry of the XTP jacketed bullets enables them to perform well at the full range of velocities obtained from the .30 Carbine Ruger and the M1 carbine.
AutoComp doesn’t give the highest velocity in the M1 carbine, but equals the velocity of full-charge loads, when fired from the Ruger revolver. It does so with less muzzle flash and blast, and better accuracy using less powder. So, what’s not to like? K.I.S.S. Principle!
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Originally Posted by Outpost75
