Need help with a Prime P228 Custom GBB

[stealth_ferret]

I bought a Prime Sig Sauer P228 nearly two years ago and I am just now getting around to giving it some TLC.

 

One of the issues (at least I think it is an issue) is that the inner barrel seems to not fit the shorter outer barrel correctly.

 

For those not aware the Prime P228 conversion kit is used to modify a Marui P226. It includes a metal frame and slide, shorter recoil guide and shorter outer metal barrel. You are required to then cut down various parts including the inner barrel and recoil spring amongst others. However as I bought it used I don't have details of how short the inner barrel should be.

 

There is a lip at the end of the outer barrel and the inner barrel fits neatly inside it when placed manually but as soon as it's installed/cycled the barrel moves and drops short of the lip. Then obviously the lip prevents it going back again.

 

This doesn't seem right but at the same time I am not sure how much longer the inner barrel could be without protruding from the end?

 

I know that an aftermarket UAC blowback housing was used (as it's broken and I had to drill out stripped screws to replace it) so the hop chamber could be aftermarket too?

 

So does anyone have any experience with either the Prime P228 Kit or the Marui P226 who can advise whether this is wrong and if so what the issue might be?

 

Pics below...