Trying again to post my test and see if it gets garbled up again...
Our fantasy was a modern, RIMMED .40 cal. cartridge which could use either .40 S&W or 10mm jacketed or .38-40 cast bullets.
Our objectives were for it to serve the medium game “packing pistol” role, approximating full charge .38-40 black powder ballistics with smokeless, in a smaller, sturdy case, formed from common brass, avoiding the excess free airspace and fragile nature of .38-40 brass.
A case full of black powder or Trail Boss should be adequate for Cowboy Action, plinking. or small game at 700 fps with either round ball or bullet.
The .44 Russian case has just the right case capacity to launch a ½ ounce of lead, to about 700 fps with 20-21 grains of 3Fg or 3.5-4.0 grains of Trail Boss, matching the .41 Long Colt from a 5-inch revolver. In a strong, modern gun, such as the Ruger Blackhawk, its case capacity 10% greater than the 10mm Auto produces a powerful hunting load.
Our initial objective to achieve 1000 fps with 182-grain or 950 fps with 220-grain cast bullets was met with 5 grains of Bullseye in either .40 S&W or 10x25mm Rimmed cases. Slower powders like Auto Comp or 4227 enable even higher magnum velocities in the Ruger revolver.
Dave Manson made the reamer, identified as “.40/.44 Special Short 1-Inch.” John Taylor rebarrelled our Rugers using a Green Mountain “gunsmith special” 10mm barrel with 16” twist, rechambering one cylinder for each gun to .40 S&W, and the other to 10x25mm.
Source brass is Starline .44 Russian, which we neck down and use as is, resulting in a 0.970-0.975” case. The shoulder angle is 6 degrees, 48 minutes Basic, the same as the .38-40 Winchester. Case body diameter is .454" at the shoulder, the same as the .38-40 and .457" at the base, and the same as the .44 Special.
Doug Phillips aka “DougGuy” in North Carolina made our loading dies by cutting down and honing out .38-40 dies on his Sunnen hone. His price to modify a set of .38-40 dies to 10x25mmR is $150. The die alteration process is as follows:
- FL sizer and seater are both cut off by 0.4" and a new thread relief is turned.
- Neck portion of the sizer die is honed inside up to .420" diameter to produce a tight and correct fit for loading .400” jacketed bullets, without expanding, but flaring only.
- Neck portion of the seater die is honed inside to .429" diameter and the ball seat of the seater die is honed up to .402", because if it is tighter, then it really needs to be.
- Once you have fire-formed brass, it is possible to neck-size only by using a 0.525” spacer with your .40 S&W Auto dies.
We are now using necked down Starline .44 Russian brass as-is. MUCH easier than cutting off .44 Specials. The shorter .975 case doesn't cause any problems, but the chamber will accept a full 1 inch case of you want to do that. Cylinder throats on our revolvers are .4015.” Anyone ordering the reamer from Dave Madson should specify .40/.44 Special Short 1" Rev1 6-18.
First range trials were conducted firing the converted Blackhawk with its .40 S&W cylinder. Firing 180-grain FMJ Winchester White Box the Ruger was zeroed at 25 yards with its rear sight bottomed out. I then fired .40 S&W hand loads assembled with Accurate 40-182H bullet and 5 grains of Bullseye. Winchester .40 S&W 180 FMJs clocked 1043 fps and the cast Accurate 40-182H with 5 grains of Bullseye 1079 fps from the 5-inch barrel.
Hand held off sandbags, running over the chronograph, six-shot 25-yard groups were 2”. Next range trip I fired 10x25mm loads in Starline .44 Russian brass with 180 Hornady FMJ, Accurate 40-182H and 40-220H, all with 5 grains of Bullseye. The 180-grain Hornady FMJ with 5 grains of Bullseye give 932 fps with a standard deviation of 15 fps over a six-shot string. Accurate 40-182H with the same 5 grains of Bullseye in the 10x25 gave 1009 fps, an Sd of 10 fps and shot to the sights at 25 yards, just like it did in the .40 S&W. The 40-220H gave 949 fps with a standard deviation of 10 fps and grouped at the top edge of the black on a B15 25-yard timed and rapid-fire pistol target. Indeed, about right for a 100-yard zero. Both groups very slightly left, maybe one click to center them up.
The 10x25R case holds 20 grains of Goex 3Fg or 4.0 grains of Trail Boss filling gently to the shoulder without compression. Max BP is 24 grains using a drop tube or compression die. A charge of 4.5 grains of Trail Boss is a good loading maximum with 4.8 grains being the “absolute full stop not to be exceeded.”
Some interesting historical footnotes put our wildcat into proper perspective:
The .44 Richards-Mason conversion for the 1860 Army Colt used 20 grains of black powder with a ½-ounce bullet (218 grains) for 700 fps, dating from 1871.
The 1890s era, third-generation .41 long Colt with its 1.00" case and 200 grain, .401" diameter bullet was propelled by 21 grains of Black Powder.
The British .44 Webley of 1868 used 19 grains Black Powder and a 200 grain bullet for 700 fps from the Royal Irish Constabulary revolver.
All of the above three cartridges transitioned to smokeless powder from black powder before their production ceased between the World Wars.
Yes, we are reinventing the wheel.
A single-shot rook rifle for this round is also planned. Maybe a levergun too if I can find a project Marlin cheap.
