S&W Model 10 Modifications

BigJon · October 16, 2008, 10:15 AM

Hi, folks. A few questions on which I hope the revolver pros here can educate me.

I purchased a couple of re-imported Smith Model 10s to keep in push-button safes at either end of my house, and I have converted them to DA-only. I can handle them fine as is, but with the stock springs in the guns and the mainspring tension screw screwed all the way down, the trigger pull is too heavy for ladies to effectively use the weapons.

My questions are about the best way to reduce the hammer and trigger-rebound weights safetly. Specifically, my questions are:

(1) What is the minimum hammer-spring weight I can go down to and still have the pistol reliably ignite .38+P ammo? I know I can figure it out by trial and error at the range, but I'm wondering if there's an accepted standard I can go for before testing at the range.

(2) Am I correct in assuming that I can measure hammer-spring weight by cocking the pistol, attaching a trigger-pull gauge to the hammer, and then pulling the hammer back with the gauge until the hammer lifts off the sear?

(3) On 1911s, for example, I don't cut coils off coil springs such as the mainspring and recoil spring to lighten them. Instead, I buy a lighter springs. With regard to the Model 10's rebound slide spring, though (which is also a coil spring), I see that the spring is pretty long, and I could cut it back a coil or two and still have it be under compression when the rebound slide assembly with spring is installed in the gun. With that being the case, is that a safe way to do it, or is it the better course just to buy a lighter rebound slide spring?

(3B) With regard to the Model 10's mainspring, which is a leaf spring, should I purchase a lighter spring to reduce its weight, or is it safe to back the mainspring tension screw out a few turns, but not so much that the hammer would fall below the safe weight I asked about in number (2), above?

P.S. Am editing to ask another question I forgot to ask:

(4) These are heavy-barrel versions of the Model 10. I believe I'm correct (?) that at one time, Smith made a version of this same gun in .357 - the Model 13 maybe? If that's correct, what would it take to convert these revolvers to .357? Just modifying the cylinder chambers to accept .357 ammo? (These guns have a bit of holster wear, but they were obviously "carried a lot and shot a little" - they are mechanically in excellent condition.)

Thanks, folks.

Best,
Jon

Jim Watson · October 16, 2008, 12:24 PM

I have seen numbers taken as you describe, and they could probably be found someplace but for a home defense weapon, I think actual firing tests with the ammunition to be left loaded is essential.

I have not had a K or L Smith misfire with the lighter mainspring from Wolff. They come with three different rebound springs so there is not much sense in fooling with clipping coils.

I do have one J-Smith, a M38, and an N frame, a M25-2, that demand full power mainsprings, so you must test.

I figure if a defense gun will ignite reloads with CCI primers, it will fire factory loads and have not yet been disappointed.

The next step would be a professional action job with surfaces smoothed and angles corrected so as to reduce friction instead of greatly reducing springs.

M13 magnums have longer cylinders than M10s, with a better heat treat for higher strength. There have been 38s rechambered to .357 without blowing up but I would not want to fool with it. And if those ladies have trouble with a stock DA trigger pull, they will probably be alarmed by the recoil of magnums. Some good stout .38 loads from Buffalo Bore ought to do well enough.

George R · October 16, 2008, 05:33 PM

Factory rebound spring is 18 lbs. Wolff makes a shooters pak of a reduced power hammer spring and three rebound springs (13,14 and 15 lb.) About $15 for the whole thing. Just like your 1911, its always better to get new springs rather than cut down or back off the hammer strain screw. Wonderful guns those 10s.

Bill DeShivs · October 16, 2008, 07:36 PM

Leave the mainspring alone. The trigger return (rebound) spring modification will give the best results. You can also have a "target" trigger fitted.
DON'T back the strain screw off under any circumstances-it will continue loosening itself until the gun will not function.
The .38 Spl. is plenty for home defense.

Slopemeno · October 16, 2008, 10:59 PM

Model 10 heavy barrels are sweet guns as-is.

You don't want to mess around too much with a defensive gun. I'd rather see you spend effort on dry firing the heck out of them so you know them like the back of your hand. Leave the mainspring stock and full strength. If you just HAVE to change something, install a slightly lighter rebound spring.

As far as ammo goes, use the .38 Special 158 +P lead semiwadcutter hollowpoint ammo. It'll shoot really close to point of aim, will be way easier on your ears (compared to .357 anyway) if you ever have to fire it indoors, and has a great track record in actual use. It shoots great in snubs too, by the way.

Practical mods: decent grips. Remove any serrations from the triggers and blend and polish the trigger face so the trigger "rolls" across your finger.

TEDDY · October 20, 2008, 12:24 PM

I have a hb mod 10 and so does my wife.why make them DA only,one might have a need to take a careful shot and single action is best.my gun is as is except for the Bomar rib.it will cut the X ring out at 50 ft.and the trigger is stock.my wifes is "oh my gosh"

October 16, 2008, 10:15 AM	#1
BigJon Member Join Date: May 14, 2000 Location: Montgomery, AL, US Posts: 57	S&W Model 10 Modifications Hi, folks. A few questions on which I hope the revolver pros here can educate me. I purchased a couple of re-imported Smith Model 10s to keep in push-button safes at either end of my house, and I have converted them to DA-only. I can handle them fine as is, but with the stock springs in the guns and the mainspring tension screw screwed all the way down, the trigger pull is too heavy for ladies to effectively use the weapons. My questions are about the best way to reduce the hammer and trigger-rebound weights safetly. Specifically, my questions are: (1) What is the minimum hammer-spring weight I can go down to and still have the pistol reliably ignite .38+P ammo? I know I can figure it out by trial and error at the range, but I'm wondering if there's an accepted standard I can go for before testing at the range. (2) Am I correct in assuming that I can measure hammer-spring weight by cocking the pistol, attaching a trigger-pull gauge to the hammer, and then pulling the hammer back with the gauge until the hammer lifts off the sear? (3) On 1911s, for example, I don't cut coils off coil springs such as the mainspring and recoil spring to lighten them. Instead, I buy a lighter springs. With regard to the Model 10's rebound slide spring, though (which is also a coil spring), I see that the spring is pretty long, and I could cut it back a coil or two and still have it be under compression when the rebound slide assembly with spring is installed in the gun. With that being the case, is that a safe way to do it, or is it the better course just to buy a lighter rebound slide spring? (3B) With regard to the Model 10's mainspring, which is a leaf spring, should I purchase a lighter spring to reduce its weight, or is it safe to back the mainspring tension screw out a few turns, but not so much that the hammer would fall below the safe weight I asked about in number (2), above? P.S. Am editing to ask another question I forgot to ask: (4) These are heavy-barrel versions of the Model 10. I believe I'm correct (?) that at one time, Smith made a version of this same gun in .357 - the Model 13 maybe? If that's correct, what would it take to convert these revolvers to .357? Just modifying the cylinder chambers to accept .357 ammo? (These guns have a bit of holster wear, but they were obviously "carried a lot and shot a little" - they are mechanically in excellent condition.) Thanks, folks. Best, Jon

October 16, 2008, 05:33 PM	#3
George R Senior Member Join Date: December 17, 2004 Location: Boca Raton, FL Posts: 151	Sw 10 Factory rebound spring is 18 lbs. Wolff makes a shooters pak of a reduced power hammer spring and three rebound springs (13,14 and 15 lb.) About $15 for the whole thing. Just like your 1911, its always better to get new springs rather than cut down or back off the hammer strain screw. Wonderful guns those 10s.

October 16, 2008, 07:36 PM	#4
Bill DeShivs Senior Member Join Date: April 7, 2006 Posts: 11,104	Leave the mainspring alone. The trigger return (rebound) spring modification will give the best results. You can also have a "target" trigger fitted. DON'T back the strain screw off under any circumstances-it will continue loosening itself until the gun will not function. The .38 Spl. is plenty for home defense. __________________ Bill DeShivs, Master Cutler www.billdeshivs.com

October 20, 2008, 12:24 PM	#6
TEDDY Junior member Join Date: December 10, 2006 Location: MANNING SC Posts: 837	mod 10 I have a hb mod 10 and so does my wife.why make them DA only,one might have a need to take a careful shot and single action is best.my gun is as is except for the Bomar rib.it will cut the X ring out at 50 ft.and the trigger is stock.my wifes is "oh my gosh"

October 16, 2008, 12:24 PM	#2
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 19,169	I have seen numbers taken as you describe, and they could probably be found someplace but for a home defense weapon, I think actual firing tests with the ammunition to be left loaded is essential. I have not had a K or L Smith misfire with the lighter mainspring from Wolff. They come with three different rebound springs so there is not much sense in fooling with clipping coils. I do have one J-Smith, a M38, and an N frame, a M25-2, that demand full power mainsprings, so you must test. I figure if a defense gun will ignite reloads with CCI primers, it will fire factory loads and have not yet been disappointed. The next step would be a professional action job with surfaces smoothed and angles corrected so as to reduce friction instead of greatly reducing springs. M13 magnums have longer cylinders than M10s, with a better heat treat for higher strength. There have been 38s rechambered to .357 without blowing up but I would not want to fool with it. And if those ladies have trouble with a stock DA trigger pull, they will probably be alarmed by the recoil of magnums. Some good stout .38 loads from Buffalo Bore ought to do well enough.

October 16, 2008, 10:59 PM	#5
Slopemeno Senior Member Join Date: January 19, 2007 Posts: 2,663	Model 10 heavy barrels are sweet guns as-is. You don't want to mess around too much with a defensive gun. I'd rather see you spend effort on dry firing the heck out of them so you know them like the back of your hand. Leave the mainspring stock and full strength. If you just HAVE to change something, install a slightly lighter rebound spring. As far as ammo goes, use the .38 Special 158 +P lead semiwadcutter hollowpoint ammo. It'll shoot really close to point of aim, will be way easier on your ears (compared to .357 anyway) if you ever have to fire it indoors, and has a great track record in actual use. It shoots great in snubs too, by the way. Practical mods: decent grips. Remove any serrations from the triggers and blend and polish the trigger face so the trigger "rolls" across your finger.