Thanks man. I've tried that. It won't let me add the M40 1/2-28 or the L40 barrel to cart. Just says "You need to choose options for your item." and reloads the page. That website has been trash for a few years now, always glitchy and offers options they won't sell you. I called in last year and was told they weren't selling them anymore. Was hoping someone had another source.
I bought an extended M40 barrel from someone from this site years ago and had it threaded in the .45 pitch by TRoS. I suspect you could do the same if you can get your hands on an L40 barrel. I would ask your threader if an extra .5” is enough to do the thread pitch you want, BEFORE buying the barrel.
I’d be surprised if SteyrUSA didn’t have some L40 barrels around. I wouldn’t be surprised if they had no threaded .40 barrels.
I was planning on threading it 9/16-24, so .5" would give me 11-12 threads of engagement. That would be fine with my comp design (I'd be doing the threading on my lathe). Guess I'm going to have to track down an L40 factory barrel. I was hoping that someone made a match grade aftermarket barrel.