I have 2 1100s and five 1100 barrels of different lengths, chokes, etc. 4 of the barrels are completely interchangeable with no problems. The fifth barrel when installed on either of the two receivers, apparently causes the gun to malfunction, specifically, the spent shell is not ejected. The gun fires normally and the bolt slides back but, for whatever reason, the spent shell is not ejcted and the bolt closes normally. My question is where on the barrel extension do I start looking for the problem? The barrel is a very tight fit on one receiver but fits normally on the other one. I have had 1100s for 25 - 30 years but have never experienced this before. I have had similar situations but it was always a malfunction in the receiver so am not used to a problem that appears to be cntered in the barrle, not the receiver.