Stuck Trigger Spring Screw

[Coyote Roper]

I have a Pietta 1858 NMA, the screw under the trigger guards that holds down the trigger spring will not budge.  I have a pair of these pistols and the other one came loose with no trouble.

I am using a proper fitting screwdriver and have managed to bugger the screw head a little along the way.

I have tried saturating screw with penetrating oil but it still won't budge.

Any tricks or suggestions I can use to break this screw loose?

CR

[Gun Butcher]

  CR, I have had good luck with placing a proper fitting srcewdriver in the slot and tapping on it rather hard. This will sometimes stretch the threads just slightly and allow the screw to break loose. Don't get to crazy with the tapping but do give it a few good licks. Just make sure you have the gun in a vise of somekind that will hold it steady and not slip which could hurt the finish.

[Pettifogger]

If you work on Italian guns buy one of these.  Best investment you will ever make.  It's a miniature impact wrench, about as big as a cigar.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93481

[stepnmud]

I have a impact driver simular to Pettifogger's ref., and works surprisingly well.

[Coyote Roper]

Thanks for the input.

I will try to find one of those on Tuesday.

CR

[Pettifogger]

One thing to remember.  The drive is a 1/4" drive and will accept Brownells and other makers' gun screwdriver tips.  Don't use the bits that come with the impact wrench unless you hollow grind them to fit your screw perfectly.

[44caliberkid]

Try some heat too.   A butane lighter or propane torch.