Random idea. What if players who purchased all 3 rifles were allowed to purchase a 4th, the Custom variant, that would allow barrel and stock and other integrated parts switching?
For example, let's say I'm working on the Mk 16.
I take the CQC barrel, attach a full stock from the SV variant, and I get a Short Mk 16 with higher accuracy than a standard CQC but a bit lower handling. Or if I put the sling plug on the mid-size for a better handling, lower accuracy rifle?
Or, let's say we we want an MP5K with the A2 stock. We can create that.
If we want a stock on a CQC LMG, we can do that, and the stats will trade off.
Etc., etc., etc.
Basically, a reason to own the full set = more customization beyond the stock custom.
The variant would simply be called: