Main spring adjustment

[Will Lynchem]

Last year I bought a Uberti model 73 short rifle.  I took it down to Jim Bowie at the Cowboy & Indian store. He installed a 5th generation short stroke kit and did a full action job on it. The rifle has worked flawlessly up till about 2 months ago. The last three matches I have shot, at least a half a dozen rounds have not fired because the primer has failed to ignite.  I can then put the same round in one of my Vaqueros and it fires just fine. It's like the firing pin does not have enough umph! to set off the primers. These are the same primers, brass, powder and bullets I have used since day 1.  My question is, is there a way to adjust the main spring tension or do I need to take it back to the Cowboy & Indian store?
Really not looking forward to a 3 hour one way drive through LA to get there   Thanks in advance,  W. L.   

[Blackfoot]

On the lower tang, in front of the lever latch there are 2 screws, one large and one small.  Tighten the small one a bit to put more tension on the spring.

Blackfoot

[Will Lynchem]

Thanks Blackfoot, I have a Wild Bunch match in about three hours from now. I'll give it a try. W. L.

[Will Lynchem]

Hey Blackfoot,  Worked like a charm! Tightened the screw 3/4 turn and did not have a single misfire in 6 stages of Wild Bunch shooting.
Thanks again, W. L.       

[Cliff Fendley]

Screw may have backed off or spring got weaker, gun got dirtier, who knows. Just keep an eye on where it is and if it moves you can always add a little loctite to it.