Problems with misfires

[Randy1911]

I recently bought a used Smith & Wesson Model 14 in 38 Spl. I took it to the range to shoot it and had a few misfires. It was evident the gun had had a trigger job (2-1/4 lb. SA). I took it to my 'smith and he put a new mainspring in it. I thought this would fix the problem, but it didn't. My load is as follows:

38 Spl.
148 gr. DEWC
3.7 grs. W231
CCI 500 SPP

The first thing I thought of was high primers, I checked and the answer was NO. The screw at the front of the trigger guard was also tight. Out of 50 rounds I fired today I had 6 misfires. I tried them in my other 38 and they fired just fine. Any suggestions? I am going back to my 'smith tommorow to see what he thinks. Is there anything I should tell h8m to check?

Thanks in Advance

 

[Jim Watson]

The screw in front of the trigger guard tensions the cylinder stop in older guns. It has no effect on hammer fall. The strain screw near the bottom of the frontstrap is the key player. See that it is all the way in. If it is, examine the tip for signs that it had been filed shorter. Some "trigger jobs" include backing out the strain screw until the gun will just fire Federal primers. Then filing the screw down so that it can be turned all the way in for the same tension.

 

[BBBBill]

Good advice from Jim. While your at it, check firing pin protrusion, cylinder endshake and headspace. Loose headspace and endshake along with a light hammer fall from a short strain screw can result in missfires. Firing pin is least likely source of a problem, but it can sometimes rear its head.
By the way, how does it time up? If you are going to do a tune up, might as well confirm that, too.

 

[Randy1911]

Okay, I did some checking. The firing pin almost hits the cylinder when I pull the trigger and look into the cylinder gap, so I think that is not the problem. The cylinder lock up is tight. There is no end play that I could feel. I put a loaded shell in the cylinder and (cautiously) checked the gap between the shell and frame. I could get a .003" feeler gauge in but not a .004" feeler gauge. Since I am not a gunsmith I will leave the checking the tension screw to my gunsmith. The best I could tell the timing was okay, but I will have my gunsmith also check that. The gun shoots great. I am gettting a 2-1/2" group at 25 yards which is great for my shooting skills. Thanks for the advise.

 

[Randy1911]

Well I just got back from the gunsmith and Jim Watson nailed the problem. The tension screw had been shortened. I have a new screw on order. Thanks for the help.