I'm with Steve on this one. Nine thou is a bit high, but not egregiously so. If those tubes are indeed 44-thousandths then those shells will never come close to causing this gun a problem (barring a stuck wad, but that's any gun). Moreover, if felt recoil isn't bad then I'd not be too-concerned about the head of the stock either.
The felt recoil of the Herter was definitely less than the felt recoil of the RST 1oz. loads. That's part of the reason I was surprised to see the 9000 PSI figure... if that's correct.
Herter's offers a 1 oz. Field & Target @ 1290 fps, a Select Field Dove & Quail 1 oz. at 1250 fps, and the Target LR 1 oz. @ 1060 fps.
B&P Competition One 1 oz. at 1160 fps is 6530 psi.
I suspect the 9000 psi is the Field & Target.
If the chambers have been lengthened, the wall thickness at the end of the chamber and forcing cone is critical.
I wondered if that was the case. 9000psi seemed really high for the low recoil load. I'll have a the barrel walls rechecked.
So with a measured .044" wall thickness you guys are worried at 9K? I would not be. What is CIP for a Brit 2&1/2" shell? Very close to 9K. You have very thick walls if measured correctly.....proceed and have fun.
These are the wall thickness as told to me from the individual I bought the gun from. I'll have them re-measured to confirm. And I re-weighed the gun.... it's actually 7 3/4 lbs.