Benjamin Maximus multi-shot breech?

Thanks guys for the replies

Here's a direct copy & paste from the CustomAIr webpage (My bold font)

To use Crosman standard barrel you must cut it right after air transfer port (because now air transfer port is already in barrel bushing which is needed for Marauder Magazine) also you need to make pellet entrance (just make a little cone in barrel)
Also barrel hole in breech is 10.98mm but Standard Crosman barrels are 11mm and the diameter varies. So you must machine your barrel 5cm length to 10.96mm


IMO that's like buying a carburetor for my old Chevy and finding that the mounting bolt pattern needs to be re-drilled, the manifold ported , and a scoop installed so it all fits under the hood.

That's why I'm wondering if the same is true with the GMAC



Ed