Thinking about building a 22LR trainer now that Manners is offering the MCS-T4 for the Mark II E-Receiver guns.

Nobody local to me seems to have these in stock so I'll probably buy from Bud's; the -SR is $82 more than the plain jane FV.

So, help me make the decision: the longer barreled FV and buy $82 worth of ammo, or the -SR for the shorter, fluted, threaded barrel and oversized bolt knob?