I recently installed a Choate 5 round extension on my wife's 870 Express 20 gauge. My feelings are mixed on the subject and I have since removed it, replacing the original follower, spring, cap, etc, etc...
While I am happy with the ease of installation and the overall function of the extension, I am not satisfied with how the end of the extension is deflected from the centerline of the magazine when the sling clamp is installed. Please see the pics below.
The distance from extension to barrel at the connection point to the original magazine is approximately 1/4 inch.
The distance at the muzzle is approximately 3/8 inch.
When I remove the clamp, the extension returns to the centerline and remains 1/4 down the entire length.
While the feed is not hindered by the deflection nor does the shot hit the extension - we put 100 rounds through it this weekend - I am concerened with the weld on the end of the extension cracking from the stress of the deflection and merely thumping an intruder in the forehead with the extension and getting sued.
I purchased the extension from MidwayUSA. I was trying to find a 2 or 3 round extension - all of which were out of stock - and snapped this one up without a second thought. Then I started to read the reviews of the Choate extensions. Some good review, some bad reviews. I think if I could get a sling clamp which does not deflect the extension, I would reinstall it and be very happy, even though it stretches out five full inches from the muzzle.
I have sent a request for help to Choate and expect a reply in the coming week.
I will let you know what they say.