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Wow..you've owned several of these rifles ehh...must be nice...to have owned several exceedingly rare rifles...Were these actually Newton rifles..or ones just chambered so...?
Yes...the 8x68s brass is very strong and is the best canidate for making the brass...and as I said case dimensions do vary...but if one does the math ..one will see that a 53,000 PSI load in a 30 Newton is not going to produce more back thrust than a full house SAMMI rated 500 S&W cartridge...which happens to be rated at 60,000 PSI..nor is the back thrust anymore than that already being put on the receiver by a 65,000 PSI 270 load...so as to the strenght of the action...NEF doesn't see a problem doing it......so I can't see it being one either...While the NEF Handi certainly isn't as strong as a good bolt action...it isn't as weak as some have advocated either.
If a person was going to load for a case like this in a Handi..he should do so cautiously...as one should anytime reloading...and they should slowly work up the loads in small increments..This cartridge
could be loaded obstinsivly hotter than any chambered in the Handi...just as many other wildcats or otherwise obsolete cartridge could be...but it doesn't have to be...to work...and the original loadings for this bears this out...It's up to the individual loading for it to set the parameters for it to function...As you know...one can't run down to Walley world to buy ammo for it...and that really isn't figuring into this topic...since the original poster asked what
could a 308 Handi be rechambered to...There is data available for this cartridge...and that is a good starting point for load development...one could get crazy with it...and try to push it to the max...but I don't see that happening here...and it was never conveyed as the posters intent...
Mac