Ruger SP101 .22 Long Rifle Annoyance (Help/Advise Please)

[cslinger]

I have a Ruger SP101 in .22 Long Rifle that is exhibeting some strange behaviour.

After about 40 rounds or so it starts to occasionally spit, almost like being out of time, yet it doesn't happen with every shot. I have eyeballed the timing using the full lockup, look down the barrel etc. technique and it does not appear to be out of time on any cylinder.

The spitting is worse, more frequent, it seems with high velocity ammo, CCI Mini Mags for example. It was almost non-existent with Eley match ammo. The Mini Mags also seem more likely to leave quite a bit of lead residue in the chambers.

For about the first 180-200 rounds accuracy is excellent, tack driver like. After that it seems to go to pot. Course it could just be my finger getting tired but I really feel that mechanical accuracy goes down hill at this point.

There seems to be quite a lot of leading that develops very quickly right above the forcing cone. Right in the area between the top of the forcing cone and the top strap.

The cylinder gap is very tight and I have no problems with the cylinder turning even after many many rounds.

There is no end shake and the side to side play is no worse then any other revolver I have ever handled.

So with those symptoms hit me with you best diagnosis.

Thanks
Chris

 

[Majic]

Lead and lube build-up at the forcing cone. Try brushing the forcing cone clean every 50 rounds or so.

 

[22hipower]

dirty gun
clean it

 

[farscott]

One other possibility: I have a four-inch Ruger SP-101 that did the same thing. I could not figure it out until I measured the diameter of the charge holes with a set of pin gages. Turns out that one charge hole was several thousands larger than the rest. It must have been large enough to allow a bullet to enter the forcing cone and barrel offset from parallel.

To make a long story short, I sent it to Ruger, and it came back with a new cylinder assembly. Never a problem since then.