05-27-2015, 05:42 AM
I have several Spartan side charging uppers that are similar to the Gibbz. I read some where that both are manufactured by the same people, but that has not been verified. I have one on a 300 Blackout pistol, and a re-upperered a bull barrel upper I had purchased, both had a snug, slight interference fit between the barrels and upper. Few taps of a hammer to seat the barrel. The barrel nut threaded on snug too. I really like the idea of the non-reciprocating side chargers. I just pulled the trigger on a few American Spirit Arms side chargers just because they have an ejection door. I thought that would be a good idea for the Grendel I'm building as a hunting rifle. I'd love to hear how the Gibbz works out for you