Mark,
Please tell use what modern day rifles you know for a fact that has come apart or had damage because of monometal bullets, for that matter I'd like that info from anyone here. I don't recommend them in any pre-war rifle. It has been my experience over the years that the only rifles that have come into my shop with blown or split barrels have been the pre-war rifles. The strength and quality of steel today compared to the old English steel is light years ahead. I had a Lancaster in the shop last year that was split length wise from the mid point to the muzzle, and the bullet used was a Woodleigh. The point I'm makeing is that no matter the quality of the older rifles the steel wasn't that good. And handloading for them should be done with exacting precision.