Blake

Because the kit uses the front sight block from the donor gun. All the current airsoft SIGs have a front sight. If you want to go sightless, you need to cut the front sight off. Not hard to do since it's pot metal.

A real AR buffer tube will not fit the GWS kit. The layout is the same, but the threading is too small. The G&P 6 position buffer tube will fit, so it's likely all the airsoft replica tubes will fit. The only thing to be aware of is that the replica tubes were not meant to be screwed into anything, so the threaded length may not be long enough for some accessories.

The nameplates with the PC356 and MAC11 indicate they are EBB's.

The trigger, hammer, slide catch and thumb safety are compatible between the hi-capa and 1911. The grip safety needs work, but can be made to fit. Real steel grips are close enough that they will fit snug. I've got Carbon Creation grips on my 1911 and they fit fine.