I took a close look at my 870 to see what may be causing problems with loading the extra two rounds that it should take with the Remington 2 round factory extension on an 18.5" barrel. Your mileage may differ, especially with a different gun or brand extension.
Some noted potential causes are (first three all involve a gap):
(1) a loose extension (just backed off a hair creating a gap for the edge of the follower to catch in if it is even slightly angled), this is unlikely to happen if you extension has a barrel clamp,
(2) failure to tighten the extension down all the way during assembly abd cause the gap,
(3) catching of the follower spring in between the extension and the
magazine collar during assembly (the spring may release during loading and leave the dreaded gap,
(4) a dent in the leading edge of the extension (mine has one that JD at AIP Tactical thought may be a problem. It is ever so slight but the edge protrudes inwards and could be catching on the follower, and/or
(5) a bad follower. (My OEM follower is made of teflon like material. It has minute rough spots in the end pointing towards the muzzle that may have been caused by catching on something. Possible a harder materail wouldn't catch. A fix may be to cut a bevel in the lip so the folloer tends to over ride anything it may catch upon. As designed, it is beveled just the opposite apparently so the sping doesn't catch on the lip of the follower. All references to the follower are to the open end inside of which the spring rests.) I thing I will just get a Wolf follower.
If I am wrong, tell me. I can see why Remington went to a solid extended tube for tactical models. If you want a dedicated tactical gun, say you are a LEO, that is the way to go. I like to be able to use it with either a field or security barrel.
Last edited by TheKlawMan; November 25, 2012 at 05:00 PM.