problem after installing lighter main spring on a uberti 1875

[Dusty Earl]

I installed lighter main springs from VTI in both my uberti 1875's. Took it to the range today. One miss fire every 5 shots in both guns. The adjusting screw didn't seem to help much. The rounds I was using were using winchester primers. I few CCI primed ones that I had seemed to work. You take what you can get with primers where I live. I have my first ever match this saturday. I will have to put the orginal springs back till I can sort this out.

[St8LineLeatherSmith]

did the cartridge primers have a good indention?
if so then the main spring is not the issue you might want to get a lighter trigger spring as well
the smoother and slicker your trigger parts are the smoother the gun will operate
file, clean and polish any rough parts in the trigger group and replace the springs.

[Forty Rod]

Put the original springs back in and write it off to experience.  How much do you think you'll gain with lighter springs anyway?

[St8LineLeatherSmith]

I have the light main spring and piano wire trigger spring gives me a 2 1/2 lb trigger pull I dont remember what the hammer pull was but it is significantly lighter
I couldnt operate the action with my right hand without the spring replacement
not only do my 58's have light springs so do my 75's

[The Swede]

I installed the same main spring from VTI a couple of years ago. Not to make me faster (nothing would help there), but because the stock spring was mighty stiff, and made it a chore to cock the piece. I'm a big guy with strong hands, but man'o man that spring was stiff. I never had issue with misfires.
I would adjust that screw if you haven't already done so. See if that helps? 

Swede

[The Swede]

I installed the same main spring from VTI a couple of years ago. Not to make me faster (nothing would help there), but because the stock spring was mighty stiff, and made it a chore to cock the piece. I'm a big guy with strong hands, but man'o man that spring was stiff. I never had issue with misfires.
I would adjust that screw if you haven't already done so. See if that helps? 

Swede

Please ignore the part about adjusting the screw. Re-read your original post.