Virginian:

Try cutting out a coil at a time from the firing pin spring.

I am not familiar with the Rossi, but if it has a movable block that rises to transfer impact to the firing pin, you might want to check that for burrs before messing with the firing pin spring.

The only other thing that may be causing you problems is headspace due to an improperly reamed chamber. That is a warranty item and actually a safety item that will probably be replaced for free.

If you haven't jacked up your Humvee with it yet, give the management a chance to fix your problem.

Rossi is a subsidary of Taurus firearms of Brazil, and their reputation for customer service is great.

Good luck!

Bountyhunter