Help with bad Throw-by on a Cobra

[billy82269]

Hello all, I am new here. I recently bought a 1955 colt cobra and plan on using it as a CCW. Before I bought it I checked the timing and everything seemed good. bolt raises fine and falls in the middle 3rd portion of the groove, then locks in just as the hammer goes to full cock. When the trigger is pulled the cylinder is locked solid just as it should. After getting it home and trying it out with double taps from the draw, I am experiencing bad cylinder throw-by. I have to slow down my trigger pull in DA to not get throw-by. I also own an old Police Positive Special and I can not make it experience throw-by no matter how fast I try to pull the trigger. In comparing the 2 I notice that pushing down on the bolt, the Cobra feels as if it takes less force to push the bolt down than the PP. Could the Cobra need a new cylinder bolt spring? Maybe the extra force of a heavier spring might keep the bolt from over riding the notch? If I just wanted this cobra as a range toy I wouldn't care, and would just slow down my trigger pull, but this could be a real problem for carry.

[capstan]

Had the same problem with a DS. The bolt was dropping too late. I bent the bolt so it dropped in middle third of lead/groove and it does NOT throw by anymore.

Never mind - I see that you said it Does drop in the middle - I should read more carefully

[dfariswheel]

A sometime problem with Colt's is an owner reads about lightening the action by clipping a few coils off the bolt spring and bending the mainspring.
Later owners get misfires and deal with the mainspring, but never notice the lighter bolt spring.
When the hammer is slowly cocked, the bolt should smoothly drop into the frame, then pop back up with a sharp "click".

Replace the spring.

[billy82269]

Well... I cracked open the cobra yesterday... The way people talk about how complex they are, I thought it would be a nightmare. To me they are even easier to take apart than the internals of a S&W. It was filthy in there... I removed all internals, cleaned each part and inside frame surfaces, then I stretched out the bolt spring a little. I tried to bend the bolt tail a little but didn't think I did anything however the bolt does seem to drop just a fraction sooner in the groove. All timing still appears good and no more throw-by.

[capstan]

Good Work! Glad it's working well now.