double action misfire

Cimarron Slim · February 20, 2005, 12:02 AM

I am the proud new owner of a Western Auto Model 99 nine-shot .22 RF double action revolver. Actually it's a High Standard Sentinel snub nose. The gun appears to be in very good condition and works fine when shooting single action. However, when shootng double action, 2-3 rounds will misfire for each full cylinder. It does not appear to be the same chambers each time, and if struck again the rounds will fire. I've tried 4 different brands of ammo, both std and high velocity with the same result. I disassembled the gun and found it to be very clean with little to no internal wear. The tip of the firing pin doesn't appear damaged, and I cleaned the gun thoroughly with no improvement in function. While disassembled, I worked the action and noticed the hammer falls further when the gun is fired single action than when it does when fired single action. Could it be that the distance the hammer is falling from single action is adequate to always fire the cartridge while the slightly shorter double action hammer fall is only good 80% of the time.

I only paid $50 for this gun, and don't plan on using it for personal protection, just as a plinker and "woods" gun. But I would like it to work correctly. It is a high standard, albiet a low cost one. Am I asking to much of a $50 dollar used gun?

Any ideas on could be the problem?

dakotashooter2 · February 20, 2005, 02:48 AM

Is your cylinder locking up during firing? I had a very similar experience with a taurus (centerfire). I found that the cylinder stop was hanging up and when fired double action the cylinder would over rotate and my firing pin was hitting the edge of the primer or the rim of the case. A little polishing of the stop and its slot solved the problem. It was difficult to figure out because often just the little movement of the cylinder caused by turning the gun would cause the stop to pop up. Might be worth checking out.

CaptainRazor · February 20, 2005, 03:56 AM

Just a thought here, but how about a weak/broken hammer mainspring?

Dave Sample · February 21, 2005, 12:07 PM

I think it needs new springs. The hammer does not go back as far on DA as it does on SA mode. That is the nature of the beast. Get some new stuff and install it. It should be worth a Spring Kit From Wolff.

Cimarron Slim · February 21, 2005, 09:41 PM

Thanks for the replies. Dakotashooter2, I checked the lock up and also how the hammer was striking the cartridge rim. It seems to be hitting where it should so I don't think lockup is the problem.

I agree that a weak hammer spring might be the problem. The longer hammer throw seems to be OK in SA mode, but not quite enough to be consistly strong enough in the shooter DA throw. Sounds logical anyway. I'm going to check if wolf has the springs, or maybe I can modify the existing spring.

Tim R · February 21, 2005, 09:52 PM

As a quick fix you might also try diffferent ammo. I've got a Erma LA 22 (looks like a Luger) that won't shot some .22's worth a darn. It's still fun to shoot.

James K · February 25, 2005, 12:14 AM

Some folks don't believe it, but it takes a harder blow to set off a .22 cartridge than it does a center-fire round. The reason is that the .22 case has to contain all the pressure and so has to be quite hard, where a center-fire primer need only contain a small fraction of the pressure and can be fairly soft.

I think a new mainspring will correct the problem.

Jim

February 20, 2005, 12:02 AM	#1
Cimarron Slim Junior Member Join Date: February 19, 2005 Posts: 2	double action misfire I am the proud new owner of a Western Auto Model 99 nine-shot .22 RF double action revolver. Actually it's a High Standard Sentinel snub nose. The gun appears to be in very good condition and works fine when shooting single action. However, when shootng double action, 2-3 rounds will misfire for each full cylinder. It does not appear to be the same chambers each time, and if struck again the rounds will fire. I've tried 4 different brands of ammo, both std and high velocity with the same result. I disassembled the gun and found it to be very clean with little to no internal wear. The tip of the firing pin doesn't appear damaged, and I cleaned the gun thoroughly with no improvement in function. While disassembled, I worked the action and noticed the hammer falls further when the gun is fired single action than when it does when fired single action. Could it be that the distance the hammer is falling from single action is adequate to always fire the cartridge while the slightly shorter double action hammer fall is only good 80% of the time. I only paid $50 for this gun, and don't plan on using it for personal protection, just as a plinker and "woods" gun. But I would like it to work correctly. It is a high standard, albiet a low cost one. Am I asking to much of a $50 dollar used gun? Any ideas on could be the problem?

February 21, 2005, 09:52 PM	#6
Tim R Senior Member Join Date: November 30, 2004 Location: God's side of Washington State Posts: 1,601	As a quick fix you might also try diffferent ammo. I've got a Erma LA 22 (looks like a Luger) that won't shot some .22's worth a darn. It's still fun to shoot. __________________ God Bless our Troops especially our Snipers.

February 20, 2005, 02:48 AM	#2
dakotashooter2 Senior Member Join Date: January 13, 2005 Posts: 498	Is your cylinder locking up during firing? I had a very similar experience with a taurus (centerfire). I found that the cylinder stop was hanging up and when fired double action the cylinder would over rotate and my firing pin was hitting the edge of the primer or the rim of the case. A little polishing of the stop and its slot solved the problem. It was difficult to figure out because often just the little movement of the cylinder caused by turning the gun would cause the stop to pop up. Might be worth checking out.

February 20, 2005, 03:56 AM	#3
CaptainRazor Senior Member Join Date: February 16, 2005 Location: Charleston, WV Posts: 302	Just a thought here, but how about a weak/broken hammer mainspring?

February 21, 2005, 12:07 PM	#4
Dave Sample Junior member Join Date: December 10, 2004 Location: Prescott, AZ Posts: 1,002	I think it needs new springs. The hammer does not go back as far on DA as it does on SA mode. That is the nature of the beast. Get some new stuff and install it. It should be worth a Spring Kit From Wolff.

February 21, 2005, 09:41 PM	#5
Cimarron Slim Junior Member Join Date: February 19, 2005 Posts: 2	Thanks for the replies. Dakotashooter2, I checked the lock up and also how the hammer was striking the cartridge rim. It seems to be hitting where it should so I don't think lockup is the problem. I agree that a weak hammer spring might be the problem. The longer hammer throw seems to be OK in SA mode, but not quite enough to be consistly strong enough in the shooter DA throw. Sounds logical anyway. I'm going to check if wolf has the springs, or maybe I can modify the existing spring.

February 25, 2005, 12:14 AM	#7
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Some folks don't believe it, but it takes a harder blow to set off a .22 cartridge than it does a center-fire round. The reason is that the .22 case has to contain all the pressure and so has to be quite hard, where a center-fire primer need only contain a small fraction of the pressure and can be fairly soft. I think a new mainspring will correct the problem. Jim