The only other option is to build a milled receiver gun, as your trunions are part of the receiver, and all you will have to do is basically install the barrel, fire control parts, and furniture. Bear in mind that you can buy a complete milled receiver weapon probably as cheap or even cheaper than building one, as the receiver itself is $350 - $400 or so...the things I ran into are that the barrels on these kits are threaded, and my receiver wasn't, so I had to turn the barrel down and press it into the receiver. In order to do this I had to remove the front sight block in order to chuck it in the lathe. This required me making a special jig because of the way the block is installed. I did have to drill one hole, for the barrel pin once I pressed the barrel in. Yeah, I didn't have to deal with installing trunions but I ended up having to do a lot of machine work to complete the gun. I wouldn't do it again; I just happened to get the receiver and parts as a swap for some part time work. Go with a good quality stamped receiver, one that is already hardened like Global Trades or Ohio Ordnance Works, and I prefer to use rivets instead of screws. Buy a parts kit that is completely disassembled, with the old rivets removed. This way whether you use screws or rivets you are ready to go without having to mess with removing the remnants of the old reeiver. Anyway, good luck, and there is plenty of info here if you take the time to scroll around the various threads.