Gp100 357 ftf cci550

[ericuda]

Loaded up some mbc 158 lswc with be86 and cci550 today. Shot over chrono with gp100 twice loaded 5 rounds each time. Both times 5th round had a light primer strike. Tried restrike and nothing.

Restruck with blackhawk and both fired. The blackhawk has a reduced spring, cant remember which. Gp100 is stock.

 

[BBBBill]

Check cylinder end shake, yoke end shake, headspace, and firing pin protrusion. All most be within acceptable limits for proper function. If firing pin protrusion is short check the transfer bar thickness and hammer notch depth. I've had to replace transfer bars and/or adjust hammer notches on a few over the years.

 

[Obturation]

Have you had the gp100 long (did it used to work and now it wont)?
Other primers work ok?

 

[WrongHanded]

Are your fired primers backing out at all? That combined with a little end shake might push the cylinder away from the firing pin far enough, in combination with the (possibly) harder 550 primers, that you get a light strike. CCI primers are apparently quite hard.

Shooting DA or SA? DA often doesn't get quite as hard of a strike because the hammer doesn't travel as far.

 

[ericuda]

I never had an issue until today. As a factory gun I hate to change much more than a spring or 2.