I put 20 rounds of 220 grain WFN through her and there is significant lead in the barrel. Took me 30 minutes to clean it all out. Anyone else have this issue? KKM order on its way for an aftermarket drop in.

Ps ammo was Buffalo Bore. Awesome ammo just won't work in my stock barrel it had significant deposits.

Chances are no commercial lead bullet is going to work well in your Glock.  My G29 slugs at .402, and others who have taken this check have found similar oversize values.  Commercial lead bullets are sized to work in a .400 bore and are too hard to "size up" from pressure.  Without fitting or being deformed to fit on firing they will lead larger bores.

Your KMM barrel should be closer to .399-.400 and work fine with most commercial lead bullets.  Alternately, casting your own that are .403" would yield fine results.