20 gauge chamber length

[Scott Chapman]

Dr. Drew: I didn't have a question. Dean asked me for the author of the google document. I had reposted your info from a April 2019 thread in order to provide insight as to the variations in length of fired modern 20 gauge plastic shotshells.

From my keeping up with the discussion on this forum and additional reading, it is my understanding that many learned students of turn of the century fine shotguns believe that 20 gauge guns with 2 3/8" chamber were made to shoot 2 1/2" shells and 2 5/8" chamber guns were made to shoot 2 3/4". However there is variation in the length modern plastic shotshells which can muddy the waters.

Some on this board report to regularly use 2 3/4" shells in guns that are not 2 5/8" chambered, while some will only use 2 1/2". Some argue that it is more about the pressures generated (specifically when talking about composite barrel) and the stress on the old wood.

My take home message is that the more valuable a gun is and perhaps the older (composite barrels +/- oil soaked wood) the more likely the owner is to shoot low pressure RST 2 1/2" shells. I feel that you can't go wrong with this option even with a shooter quality VH or Trojan.

There are some that use standard 2 3/4" ammo in fluid steel barrelled guns (with adequate wall thickness) and never look back. Including heavy pressure waterfowl loads.

It is all what you are comfortable with personally. If you are worried about whether a 2 3/4" shell is going to pattern poorly, produce too much recoil, etc. etc, go out and shoot it on a pattern board and find out. If you don't want to go to the trouble, spend a little extra and buy RST shells and don't worry about anything!