interchangeability of 870 parts

[dghboy315]

i'm getting a few used 870s. i want to create one 18" HD gun w. surefire light and youth stock, one 20" 3gun gun w/ mag extension, and one 28" hunting/sporting gun.

my question: are 870 parts such as barrels and stocks totally interchangeable? even btwn old and new models? btwn express 3" and magnum 3 1/2"? btwn sythetic and wood models?

also, how do you remove the stock?

finally, what size mag extension will fit on a 20" barrel? i'm looking at Choate extension. What's the max mag i can get?


thanks

 

[Dave McCracken]

Remington claims that all parts are interchangeable within gauge. IIRC, Kuhnhausen says that trigger groups are not quite universal, that there are several sizes in any model differing by a few thousandths.

Dunno about that, there's been some swapping around here without any size glitches.

+3 extension fits under a 20" barrel, or may stick out just a little. I'll show you mine next time we get together.

Also, I see little need for both an 18" HD tool and a 20" gamer gun, lots of overlap there. But, far be it from me to discourage multiple 870s....

 

[dghboy315]

you have a point and i'm still thinking abou it.

basically my reasoning is that i don't want the surefire light on my 3gun gun. i don't want to light to get beat up if it doesn't need to. plus i want a gun always ready to fight. my 3gun gun will be in different states of cleaning and transportation.

i'm still not sure.

 

[dghboy315]

so, i'm still trying to decide btwn 3 870s or 2.

please tell me if my facts are right:
a std 870 hold 4 shots in the mag tube + 1 in the chamber (5 total)
the max mag extension for an 18.5" bbl would make the capacity 6+1 (7 total)
the max mag extension for a 20" bbl would be 7+1 (8 total)
is all this correct?

it hardley seems worth it to buy a whole new 870 for only 1 extra round, right?