I read a post on here that mentioned shortening a barrel on a SA shotgun and it was stated that "gas ports had to be opened to have it work 100% due to reduced recoil loads".

I have a 20 GA 1100 skeet gun with a 26-28" barrel (i don't remember exactly) and I'd like to pick up and 18" barrel to swap on. Am I likely to run into issues getting the gun to cycle with the short barrel? I wouldn't even have thought of something like this.

The logic is sound, but I chopped an old 1100 to 18" and it cycles Federal low recoil with no problem. That's the only ammo I care about so it works out. I had problems with it cycling #9 light loads, but #9 is pretty useless anyway...

If you buy a factory 18" barrel (if they even make one in 20ga), it should run OK with heavy loads but may still need the gas ports opened up for light loads. If you cut back a longer barrel, you more likely would have to open up the ports (again, ammo dependent).

how exactly does one go about opening up gas ports? I've never really paid much attention to my shotguns other than to clean them. I'm used to taking apart ARs and things.

Before you start opening up gas ports make sure the gun is otherwise operating correctly with factory ammo. ...replace the gas seal or action spring as necessary, clean and lube, etc.

To open the 1100 gas port (2 ports on standard barrel, 1 port on the magnum barrel) You'll need a set of numbered drill bits*, a small electric hand drill and a way to hold the barrel steady while you drill.

Find the drill bit that will just fit inside the factory port, then drill them out one size larger.

Reassemble and testfire. If the action doesn't fully cycle you need to open the ports to the next size larger. Testfire for function...Repeat as necessary.

You should not need to open the ports more than .005” to .007”,  The pi R square rule comes into play and a little dab will do you.  

* Be sure to use a a set of "1-60 numbered" drill bits, those 1/16" size bits you get a Lowes, Wal~Mart, etc. have way to much increase in diameter from one size to the next.


Here is info on the factory gas ports sizes

Wow, thanks for a thorough answer!

Glad to help.

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