Bar slide and buffer unknown model

[deerslayer]

Can anyone tell me exactly what ive got here.  What models used this?  The slide has the solid piston and rear setup for the recoil spring into the buffer.  I dont have the connecting rod.  

[deerslayer]

I

[deerslayer]

[Orion]

That's a colt marked slide, it looks like it could be a Colt R75, I don't know if the Monitor had the same setup or not. 

[deerslayer]

I thought about monitor but the gas piston is normal bar length.  Thanks for confirmation thats its colt slide.  

[Junkyardslug]

It's a Colt Commercial setup.   They moved the op spring from the piston to inside the buffer tube.  The idea was to keep the spring away from heat.   There should be a steel rod that connects the back of the side to the divot in the center of the buffer.  The rod just floats in the two divots, it's not attached.   Functionally it's the same setup as an FN-D.   It could also be from the first batch of Swedish BARs (Colt build the first ~10,000) or other overseas contract BARs

When Group Industries made their "Manual Operated Rifle" they didn't mill the hole in the front of the receiver for the op rod to pass through.  They shaved the front of the slide back to fit and used this style buffer/op spring setup to operate the slide/bolt

[deerslayer]

Thank you!