Bumping your post hoping you get some knowledgeable answers.

Frank

 

Is the chamber peened? (have a little divot where the firing pin hits, displacing metal into the chamber area) That could cause the shell to incompletely enter the chamber and the bolt closing/firing fin falling pushes it the rest of the way, leading to a light strike. Or perhaps the recoil spring is worn enough that it isn't pushing the shell all the way in to the chamber for the pin to strike against and ignite?

 

Thank you Jeff, I will look at these areas over the next few days when I have a chance to get back to my bench. It just seemed strange that these two tubular magazine models have the same problem with light strike indentions on the rim. I have a couple other clip feed versions and have never had a problem with them. These two problem rifles I bought over the last 3 or so years and had never shot them until last weekend. I'll try swapping out parts from the 4 rifles to see if I can identify what might be the problem.

 

I had the same issue with an older Italian magazine feed XXII. For me, it seems the casing wasn’t seating all the way in the chamber due to a carbon ring. I used some carbon dissolver and a lot of elbow grease to remove it. Fires reliably now, esp. with CCI SV. I do still get the occasional stove pipe.

 

I have 2 Weatherby Mark XXII tube feed rifles. Both marked Japan, serial numbers T16332 and T04673. I have had them for a few years and took them to a friends range yesterday to do some shooting. I was using new CCI Standard Velocity for ammo. They both are not firing reliably, maybe 3 out of 10 rounds discharge. Both rifles are leaving a very light mark on the rim of the cartridge. I have swapped firing pins from other of this models I own as well as the firing pin spring. Still no joy. Both guns are clean as can be, the one blond stock on s/n T16332 was so clean in the bolt/trigger group, I don't think it was ever fired, I mean MINT condition CLEAN! So why are they both not striking the rim hard enough to discharge the round? I am hoping someone on here has dealt with this before and can advise me. Or if anyone knows of a top notch gunsmith who is known to be good working on these models, could you please share their names and contact information. Thank you for whatever information that might help. Oh, and I did try other types of ammo, no joy.

I also have two Mark XXII, Japan, tube-fed (T-08457 and T-00819) that came to me used but pretty much new--not fired much, if at all. T-08457 was, I'm pretty sure, new, just 45 years old. It had light strikes, misfires on about 1 in three (that varied depending upon ammunition--it really choked on Winchester bulk and didn't do too badly on CCI Standard Velocity). I changed the hammer spring (Numrich at gunpartscorp.com has them). The new one was 3/16" longer than the one I removed. Afterwards, it fired flawlessly, even the Winchester bulk ammo. The change is not a trivial task, but doable if you're patient and have some mechanical skills. I suspect the gun sat in someone's cabinet for it's entire life cocked, and the spring eventually took a set at a permanent shorter length. Personal opinion, it's better to park a hammer in the uncocked position. Another problem I had was that T-00819 would have frequent failure-to-eject jams, not too often with CCI Standard Velocity but worse with the 1200-fps ammo like Federal AutoMatch and CCI Mini-Mag. The ejection port, where the bolt handle sticks out, is different. On T-00819, it was narrow, on T-08457 much wider (taller). Almost like the factory made some changes along the way. I finally took a file and enlarged the port on T-00819 to match the port on T-08457, and the problem disappeared. It's an aluminum receiver, painted black. A little masking tape and a light coat and good as, or better than, new.

 

I also have two Mark XXII, Japan, tube-fed (T-08457 and T-00819) that came to me used but pretty much new--not fired much, if at all. T-08457 was, I'm pretty sure, new, just 45 years old. It had light strikes, misfires on about 1 in three (that varied depending upon ammunition--it really choked on Winchester bulk and didn't do too badly on CCI Standard Velocity). I changed the hammer spring (Numrich at gunpartscorp.com has them). The new one was 3/16" longer than the one I removed. Afterwards, it fired flawlessly, even the Winchester bulk ammo. The change is not a trivial task, but doable if you're patient and have some mechanical skills. I suspect the gun sat in someone's cabinet for its entire life cocked, and the spring eventually took a set at a permanent shorter length. Personal opinion, it's better to park a hammer in the uncocked position. Another problem I had was that T-00819 would have frequent failure-to-eject jams, not too often with CCI Standard Velocity but worse with the 1200-fps ammo like Federal AutoMatch and CCI Mini-Mag. The ejection port, where the bolt handle sticks out, is different. On T-00819, it was narrow, on T-08457 much wider (taller). Almost like the factory made some changes along the way. I finally took a file and enlarged the port on T-00819 to match the port on T-08457, and the problem disappeared. It's an aluminum receiver, painted black. A little masking tape and a light coat and good as, or better than, new.

Thank you John for sharing your experiences with these fine Weatherby Mark VII's. I still have not had them back on the bench to work on. I will, and will post what transpires.