The Firing Line Forums - View Single Post - What ammo should I use for my S&W .357 Model 19-4?

BillCA · November 25, 2008, 07:11 AM

Painter, welcome to the forum!

Regards to your Model 19... you know you practically got a "steal" on that gun at the price you paid, right? Nice job. Now, as to ammo...

Short history
The Model 19 was one of S&W's premier police revolvers and was carried in huge numbers by police between the 1950's and 1980's. For most of it's lifetime, S.O.P. was to practice with .38 Wadcutters or .38 RNL ammo and use the .357 Magnum on duty. Instructors believed it was sufficient to use low-powered loads to develop good shooting habits and techniques that would carry over under stress, even with the much more powerful .357 Magnum loads.

In the late 70's, police training adopted the "train like you fight" doctrine which required a lot of .357 Magnum ammo for training and qualification. Most officers used a 125g JHP (Remington or Winchester) duty load so that's what most agencies used for training. Police armorers soon found many Model 19's failing. Heavy erosion of the forcing cone, top strap and cracking of the frame along the "flat" beneath the barrel.

According to several different sources, the shorter 125g (and 110g) bullets have two problems. First is that they exit the cartridge case much sooner than the longer 140g+ projectiles. This means there is more time for hot propellant gasses to act on the topstrap and forcing cone. the standard 158g bullet builds up more pressure and (apparently) moves much slower from cylinder to the rifling, which burns more propellant inside the case & cylinder. The lighter bullets also tend to impact the forcing cone harder because of their speed from cylinder to rifling. This tends to "hammer" the metal more than the heavier bullet. Bullets of 140 grains or more have sufficiently long bodies to reduce the gas cutting and are less prone to impact damage to the barrel.

Part of the problem is that the .357 Magnum barrel has to have a flat spot cut at the bottom to allow the cylinder yoke to close. This sets up a stress point that seems to transfer the impact forces to the frame under the barrel.

Recommendations
Note that this problem occurs with .357 Magnum ammo, not lightweight .38 Special ammo.

In response to your question, when using .357 Magnum ammo, I would use 140g or heavier bullets in a K-Frame .357 like your Model 19. If you use .38 Special, you can use any bullet weight desired as the forces are much lower.

There is conjecture as to whether the damage is accumulative or a combination of factors (age of the gun, total rounds fired, cleanliness of the gun, it's temperature, how fast shots are fired, etc). I lean towards the accumulative theory -- that the more "lightweight" rounds are fired, the more likely the damage.

Come home safely, Thomas!

November 25, 2008, 07:11 AM	#4
BillCA Senior Member Join Date: November 28, 2004 Location: Silicon Valley, Ca Posts: 7,117	Painter, welcome to the forum! Regards to your Model 19... you know you practically got a "steal" on that gun at the price you paid, right? Nice job. Now, as to ammo... Short history The Model 19 was one of S&W's premier police revolvers and was carried in huge numbers by police between the 1950's and 1980's. For most of it's lifetime, S.O.P. was to practice with .38 Wadcutters or .38 RNL ammo and use the .357 Magnum on duty. Instructors believed it was sufficient to use low-powered loads to develop good shooting habits and techniques that would carry over under stress, even with the much more powerful .357 Magnum loads. In the late 70's, police training adopted the "train like you fight" doctrine which required a lot of .357 Magnum ammo for training and qualification. Most officers used a 125g JHP (Remington or Winchester) duty load so that's what most agencies used for training. Police armorers soon found many Model 19's failing. Heavy erosion of the forcing cone, top strap and cracking of the frame along the "flat" beneath the barrel. According to several different sources, the shorter 125g (and 110g) bullets have two problems. First is that they exit the cartridge case much sooner than the longer 140g+ projectiles. This means there is more time for hot propellant gasses to act on the topstrap and forcing cone. the standard 158g bullet builds up more pressure and (apparently) moves much slower from cylinder to the rifling, which burns more propellant inside the case & cylinder. The lighter bullets also tend to impact the forcing cone harder because of their speed from cylinder to rifling. This tends to "hammer" the metal more than the heavier bullet. Bullets of 140 grains or more have sufficiently long bodies to reduce the gas cutting and are less prone to impact damage to the barrel. Part of the problem is that the .357 Magnum barrel has to have a flat spot cut at the bottom to allow the cylinder yoke to close. This sets up a stress point that seems to transfer the impact forces to the frame under the barrel. Recommendations Note that this problem occurs with .357 Magnum ammo, not lightweight .38 Special ammo. In response to your question, when using .357 Magnum ammo, I would use 140g or heavier bullets in a K-Frame .357 like your Model 19. If you use .38 Special, you can use any bullet weight desired as the forces are much lower. There is conjecture as to whether the damage is accumulative or a combination of factors (age of the gun, total rounds fired, cleanliness of the gun, it's temperature, how fast shots are fired, etc). I lean towards the accumulative theory -- that the more "lightweight" rounds are fired, the more likely the damage. Come home safely, Thomas! __________________ BillCA in CA (Unfortunately)