Ok.. read up on all this, and have to say: Beautiful stuff, Norm. I plan to evolve into HPA, and it's clear there are no compromises needing consideration. I'm amazed at what you guys have done with these.I want, very much, to make my own breech. If (when?) that fails, it's pretty clear the BNM is the way to go. For a 2240 shorty, it's a bit pricey for me... but, for a higher end gun it seems quite reasonable. If I get one, it can also be used on an Mrod, correct?I don't know anyone with a Marauder I can look over and measure, so I'll order a mag and see where that leads.
I'd say get a bnm breech from Norm unless you want to make a custom breech. He's great to do business with hence I listed him in my sig.