Perry;
I once had a list of all the hull lengths available in the various gauges from UMC back around the turn of the last century. On nearly all of them you could get from 2" to 3" in 1/8" steps with 3" being available in at least the 12 & 10 gauges & 2 9/16" thrown in for the 14 & 16 gauges. There may be some other lengths in there I am forgetting, but unfortunately I misplaced that list somewhere over the years.
Stevens had a very early pump gun in 3" 20ga, in fact may have been their very first pump. Operating from memory here, but may have been a model 20. It had a very short breech bolt with correspondingly short receiver. I have a post 1907 Lefever Arms Co 16ga H grade double with 3" chambers. This gun appears to have had very little use & as the 3" hulls would have been available at the time it was built, but never really became a standard, I highly suspect it was ordered this way. There would seem to have been little incentive to have had it rechambered later. I seem to recall having read of an "Old" Parker 20ga with original 3" chambers but don't recall the circumstances now.
