Question about Sig X5 modularity

This topic can be found at:

November 19, 2020, 11:54 PM
Question about Sig X5 modularity
Hey ya'll - long time no talk.

I had a question about my X5 that I can't find an answer for on Google or youtube.

I have the pre-Legion X5 pistol and I was wanting to move the FCU over to a midsize X frame (not sure if it's called an XCarry or Xcompact). I had a friend who gave me two of the Xcompact/Xcarry frames in black and FDE and a complete slide assembly from a P320 compact.

My question is this -

I pull the X5 FCU out and pop it into the Xcompact/Xcarry frame and it drops in no issue. I take the complete slide and put it onto the frame and it seems as though the guide rod/spring are binding early and thus not allowing the slide to come fully rearward. When I attempt to pull the slide back and flip the takedown lever, I'm not able to and the guide rod is sticking out well beyond the muzzle. Is it possible that the recoil spring/guide rod from the standard P320 compact slide isn't compatible with the X5 FCU? Maybe the takedown lever/pins are different? Can anyone who has both the full sized X5 and a subcompact P320 slide confirm this?

Whats puzzling me is that I can watch multiple youtube videos of people take a Sig P320 compact with the standard p320 curved trigger FCU and dropping the FCU and slide onto the compact X grip module but I can't find out why my X5 FCU wont fit into a compact X grip module with a standard 320 compact slide.

I can add some pictures of what I'm talking about if needed.

Thanks in advance. Glad to see this forum is still here.
November 20, 2020, 08:52 AM

So I put the X5 FCU back into the XCompact grip. Pulled the recoil spring/guide rod out of the 320 compact slide and checked it up against the rails of the FCU and it turns out I had the spring/guide rod installed incorrectly. Its now on correctly and fits perfectly. Man I feel like a dork.
November 20, 2020, 03:42 PM
Don't feel too bad. Learning stuff this way makes you remember a whole lot better for next time.

I found out that the easy way to lock up a 10mm P220 solid was to swap slides (but not the insert) with another 10mm P220. Guess how many times I've tried it since then?

My other Sig is a Steyr...