[greatwhitenorth]

I just bought a Security Six that was pretty rough. It seems to shot really nice out of 4 of the 6 cylinder bores. it will group about 2" with 4 bores and the other two will open it up to about 12". They bore ends on the cylinder all seem to mic out the same and a bullet dropped in to the cylinder bores only requires a light tap for them to fall thru. The timing seems ok. The gun looks like it was but in leather holster and left to rust. I doesn’t look like it was shot a lot? What can I do to make all the bores shoot straight?
The fliers are not consistent either. Bore #1 will throw high or low.

 

[RockDoctor]

a bullet dropped in to the cylinder bores only requires a light tap for them to fall thru.E

This caught my attention. .38 or .357 should drop in easily, unless there is fouling from shooting .38 a lot in the .357 cylinders.

I use to shoot .38 mostly and I would have to use a stainless turbo brush to remove carbon fouling to be able to easily drop in .357 when I carried or for target practice. I also used Shooters Choice to really clean the cylinder.

 

[exlogger]

One possibility is the B/C gap (barrel cylinder). Check all the chambers to see if they are consistent with each other. I have 3 Security Six revolvers and they are all right around .005/.006. Inconsistent gaps will effect velocity.