Just purchased an a5 3 shot 16 gauge. I have seen a lot about them shooting the 2-9/16” shell or people machining them to make them accept 2-3/4” shells. I can not find markings on my barrel for either one no size in inches or mm. I know it should say 65 or 70 but the only numbers I see are chamber diameter I think which shows 16.7mm. There are a ton of symbols stamped on there and some that are worn down cans I can’t make out. I have seen that I can shoot the 2-3/4” shells in it with a possible ejection issue. Haven’t tried it yet but what is y’all opinion on this? I have found some 2.5” shells online and they take 4 weeks to receive them. I have 5 boxes of 2-3/4” now to try and see if they eject properly. Gun is not a collector for me it’s a shooter that has all matching part numbers and in very good condition.