I've been looking for a deal on a m1s90 for a long time and finally came across one this past weekend at a local gun show. H&K sterling, VA is stamped on one side of the receiver and it has a one piece extended tube (maybe 7-round). I want to get it back to the standard length tube. When i bought the gun, I thought i would be able to simply take off the extension but that was not the case. I talked with someone who had a similar issue and when he ordered a standard tube, it was threaded differently at the receiver. This is a duck hunting shotgun and not a showpiece. I will chop that thing off at the threads if it is safe to do so. I would love to hear from someone who may have had similar issues or knows enough about the gun to send me in the right direction. Thanks in advance guys!!!