FTF model 66-8 2.75”

K13 · October 12, 2019, 11:48 PM

New 66-8 S&W 357 has been having several FTF. I recently purchased 1000 rounds of Armscor 124gr 357 and had a FTF almost every cylinder. The worst being only 2/6 firing. Single action had better results. Haven’t tried any other ammo yet. Has anyone had a similar issue? Resolution?

2damnold4this · October 13, 2019, 06:55 AM

Does that revolver have a strain screw? If it does, is it tight or has it been ground down?

K13 · October 13, 2019, 03:52 PM

It was about 2.5 turns loose. I tightened it up after applying blue loctite. While shooting it the cylinder release and rear sight screw backed out. Maybe that was the issue. Everything is loctited in now. Will see if it’s fixed.

2damnold4this · October 13, 2019, 08:21 PM

Good luck and let us know how it goes.

L-2 · October 13, 2019, 10:02 PM

I recall also having some trouble firing Armscor .38 Special ammo.
Besides your strain screw backing out, I suspect Armscor's primer are either hard or not completely seated. The rounds typically fired on a 2nd hit.

Paul105 · October 14, 2019, 08:43 AM

should include making sure all screws are tight.

Paul

Carmady · October 14, 2019, 09:01 AM

"Single action had better results."

That doesn't seem right because DA pulls the hammer further back (with more spring pressure) than SA.

Master Blaster · October 14, 2019, 12:12 PM

Actually the hammer/ firing pin hits harder in single action on all the S&W revolvers I own. Light strikes are more common in DA. A backed out strain screw would definitely cause the issue.

reddog81 · October 14, 2019, 04:42 PM

2.5 turns loose is pretty loose. There's a decent chance that correcting the loose screw issue will fix your problem.

74A95 · October 14, 2019, 05:31 PM

Quote:

Originally Posted by Carmady

"Single action had better results."

That doesn't seem right because DA pulls the hammer further back (with more spring pressure) than SA.

Nope. You have it backwards. The hammer on S&Ws goes back farther on single action than it does on double action.

Carmady · October 14, 2019, 07:26 PM

"Nope. You have it backwards. The hammer on S&Ws goes back farther on single action than it does on double action."

You're right, thanks.

**44 AMP** · October 15, 2019, 11:28 AM

The strain screw on S&Ws should not be "tight". They come from the factory with the screw head flush with the frame, and that's where it belongs.

Various "experts" will tell you how to "adjust" mainspring tension (and trigger pull) using the strain screw, and it will do that, but that isn't what its for.

It's there as an aid to disassemble the gun.

Because its a screw, that will turn in and out, some people just can't keep their hands off of it. And, of course their adjustments are an "improvement", until they get to the point of having misfires...at which point some will blame S&W for having "weak" mainsprings....

October 12, 2019, 11:48 PM	#1
K13 Member Join Date: January 10, 2019 Posts: 19	FTF model 66-8 2.75” New 66-8 S&W 357 has been having several FTF. I recently purchased 1000 rounds of Armscor 124gr 357 and had a FTF almost every cylinder. The worst being only 2/6 firing. Single action had better results. Haven’t tried any other ammo yet. Has anyone had a similar issue? Resolution?

October 13, 2019, 10:02 PM	#5
L-2 Senior Member Join Date: September 8, 2004 Location: Nevada Posts: 523	I recall also having some trouble firing Armscor .38 Special ammo. Besides your strain screw backing out, I suspect Armscor's primer are either hard or not completely seated. The rounds typically fired on a 2nd hit. __________________ (former) Glock Armorer 1911 Armorer LEO (retired)

October 14, 2019, 08:43 AM	#6
Paul105 Senior Member Join Date: March 26, 2007 Location: Montana Posts: 343	Pre Shooting Checklist for New Guns should include making sure all screws are tight. Paul

October 15, 2019, 11:28 AM	#12
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,833	The strain screw on S&Ws should not be "tight". They come from the factory with the screw head flush with the frame, and that's where it belongs. Various "experts" will tell you how to "adjust" mainspring tension (and trigger pull) using the strain screw, and it will do that, but that isn't what its for. It's there as an aid to disassemble the gun. Because its a screw, that will turn in and out, some people just can't keep their hands off of it. And, of course their adjustments are an "improvement", until they get to the point of having misfires...at which point some will blame S&W for having "weak" mainsprings.... __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

October 13, 2019, 06:55 AM	#2
2damnold4this Senior Member Join Date: August 12, 2009 Location: Athens, Georgia Posts: 2,526	Does that revolver have a strain screw? If it does, is it tight or has it been ground down?

October 13, 2019, 03:52 PM	#3
K13 Member Join Date: January 10, 2019 Posts: 19	It was about 2.5 turns loose. I tightened it up after applying blue loctite. While shooting it the cylinder release and rear sight screw backed out. Maybe that was the issue. Everything is loctited in now. Will see if it’s fixed.

October 13, 2019, 08:21 PM	#4
2damnold4this Senior Member Join Date: August 12, 2009 Location: Athens, Georgia Posts: 2,526	Good luck and let us know how it goes.

October 14, 2019, 09:01 AM	#7
Carmady Senior Member Join Date: February 26, 2013 Location: on the lam Posts: 1,735	"Single action had better results." That doesn't seem right because DA pulls the hammer further back (with more spring pressure) than SA.

October 14, 2019, 12:12 PM	#8
Master Blaster Senior Member Join Date: October 11, 1999 Location: One of the original 13 Colonies Posts: 2,281	Actually the hammer/ firing pin hits harder in single action on all the S&W revolvers I own. Light strikes are more common in DA. A backed out strain screw would definitely cause the issue.

October 14, 2019, 04:42 PM	#9
reddog81 Senior Member Join Date: October 16, 2014 Location: Iowa Posts: 1,634	2.5 turns loose is pretty loose. There's a decent chance that correcting the loose screw issue will fix your problem.

October 14, 2019, 07:26 PM	#11
Carmady Senior Member Join Date: February 26, 2013 Location: on the lam Posts: 1,735	"Nope. You have it backwards. The hammer on S&Ws goes back farther on single action than it does on double action." You're right, thanks.