Hello all...Half the articles I read tell me that the 1895 marlin 45/70 must be re-threaded to go 450 alaskan. Some say its tough enough the way it is. What I need is first hand knowledge. NOT links to a business,but someone whos done it or personally knows someone who's done it....Cause if a fella's rethreading everything and shortening thats a whole different can of worms than just rechamber...I've talked to marlin,they say these things are proofed to 60,000 psi, so I dont see why .018" per side reamed out and ran at under 40,000 psi would be a big deal even with the square top thread they come with. Like I said,any first hand knowledge PLEASE.PS,As they come is this square thread a deep cut good contact square in both barrel and receiver, or square on barrel and vee'd on receiver...Thankyou all