870 express magnum question

[awwhite1012]

I just purchased a 7 shot extention from trac star after dremeling out the dimples in my tube I was able to install it no problem. My question is I have the newer model that uses the plastic cap instead of the old spring retainer should i place that plastic cap into the extention or just leave it out? Also I know it is supposed to be a 7 shot extention adding two shells to my tube but mine only orginally held 4 is this normal? And lastly the side of my 870 says Express Magnum but on remingtons site they are all listed as super mags is there a reason behind this?
Thanks

 

[VARifleman]

Leave the plastic piece out, make sure you use a BARREL CLAMP so that you don't pop the extension out brushing it up against something, the capacity is normal, if they say 7 shot extension, they probably mean 6+1, but you'll find out if you can put 7+1 in.

As for 870, 870 Mag, and 870 Super Mag, it means 2 3/4", 3", and 3 1/2" chamberings max for the receiver (barrels need to be chambered appropriately too) respectively.

 

[awwhite1012]

Thanks for the info and I do have a barrel clamp on but on that note is there a right or wrong way on placement?

 

[dfariswheel]

As above, leave the plastic out.
In the tube you should have ONLY the magazine follower and the magazine spring.

There is no "right way" to install most clamps.
Simply install it on the barrel, with the clamp "about" 2 to 3 inches back from the muzzle.
If the clamp tends to slide under recoil, put some black electric tape on the clamp where it touches the barrel.

Don't over tighten the clamp screw, the screw can strip.

The Remington 870 18" barrel with an extension holds 6 shells in the tube, and one in the chamber.