The two pictures above show the two module types. The first pic shows the standard full-sized modules (which are like those made by other manufacturers) and the second pic shows the small (209 sized) modules (which are similar to the Variflame). You’d have to have a different plug configuration (and a deeper sealing shoulder to use the large modules. You can use the 209 type modules with no special modifications. I was just talking with Mark about this specifically a day or two ago.
The barrels he’s currently making are bored (for the plug sealing shoulder) a little deeper so that there is room for the larger module. If you have an older barrel like I do, it likely isn’t compatible with the large modules.
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