870 Action Arm Tube Identification

[wrfforgotten]

I have Three different action arm tubes. The longest one is the standard size. The smallest one is for the (MCS) Modular Combat Shotgun, measuring at 3.75". The middle one, the tube measures 4.25", does anyone have an idea of what model of 870 it came off of?

Thanks for looking.

[BKinzey]

I think that's for a 20 gauge and maybe a .410. I think they were shorter than the standard.

[CharlotteDup]

I would really like to know these details; that would give me an idea as well.