Post by tinkerpearce on Dec 14, 2022 1:54:01 GMT -5
Recently someone posted a S&W Custom Shop Model 625 with a 2" barrel on a gun page I frequent and people there lost their minds, calling it stupid and saying it would get 400 fps velocities and all kinds of crap. It was similar to this one, only fancier.
I suspected it was maybe not so stupid. I had a Brazilian-Contract M1917 languishing in the safe and got to thinking. After checking that a replacement barrel was available to me I decided to do a little science.
I have 200gr. JHP defensive loads for my Detonics Combat Master which has a 3-1/2" barrel and a year or two back I tested it. I got a velocity of 848fps, and when fired into Clear Ballistics Gel through four layers of denim the bullet's average expansion was .640" with 14" of penetration. Good baseline.
I cut the barrel of the 1917 at 2" and chronographed it with the same load. I got an average velocity of *drumroll...*
...841 fps.
This might seem weird but it really isn't. BBTI.com tested the loss of velocity from a revolver's cylinder gap and found out it was a lot less than people thought it was. Auto pistol barrels are measured from the muzzle to the breech. If you measure the modified M1917's barrel from the muzzle to the breech it's just over 3-1/2". My particular M1917 has an extremely small cylinder gap (less than .0015".) Given the separation of the tests in time and conditions (temp, humidity etc.) and other variables I can't say the load performs any differently between these two guns. In other words it will work just fine from a '2" barrel.'
I liked the look of the M1917 with the 2" barrel and decided to keep it that way. I bobbed the hammer and cut 40 LPI checkering on the top so it is still easy to thumb-cock if desired, polished the serrations off of the trigger, new front sight and some antler grips and an American Holly grip adapter. I also did a mild trigger job; it's now super smooth but not super-light, maybe 8-1/2-9 lbs.
Recoil is definitely a thing, but it's manageable and the gun shoots quite well.
I suspected it was maybe not so stupid. I had a Brazilian-Contract M1917 languishing in the safe and got to thinking. After checking that a replacement barrel was available to me I decided to do a little science.
I have 200gr. JHP defensive loads for my Detonics Combat Master which has a 3-1/2" barrel and a year or two back I tested it. I got a velocity of 848fps, and when fired into Clear Ballistics Gel through four layers of denim the bullet's average expansion was .640" with 14" of penetration. Good baseline.
I cut the barrel of the 1917 at 2" and chronographed it with the same load. I got an average velocity of *drumroll...*
...841 fps.
This might seem weird but it really isn't. BBTI.com tested the loss of velocity from a revolver's cylinder gap and found out it was a lot less than people thought it was. Auto pistol barrels are measured from the muzzle to the breech. If you measure the modified M1917's barrel from the muzzle to the breech it's just over 3-1/2". My particular M1917 has an extremely small cylinder gap (less than .0015".) Given the separation of the tests in time and conditions (temp, humidity etc.) and other variables I can't say the load performs any differently between these two guns. In other words it will work just fine from a '2" barrel.'
I liked the look of the M1917 with the 2" barrel and decided to keep it that way. I bobbed the hammer and cut 40 LPI checkering on the top so it is still easy to thumb-cock if desired, polished the serrations off of the trigger, new front sight and some antler grips and an American Holly grip adapter. I also did a mild trigger job; it's now super smooth but not super-light, maybe 8-1/2-9 lbs.
Recoil is definitely a thing, but it's manageable and the gun shoots quite well.
