Question for folks that have been in a simialr situation - My son is 11 5' 93lbs and is getting into wing shooting. We borrowed a Rem 21" 20 gauge semi auto from a friend and he was able to knock down his first duck two weeks ago. He was able to handle the gun just fine, but it looked like he could handle a longer barrel. Researching youth and compact guns, they are either really small (21") which I think he might already have outgrown or models such as the A300 which can get LOP down to 13" but only come in 28" barrels. My question is this - What is the shortest barrel you would use for duck hunting? There are 24" and 26" options out there as well. I am leaning towards a Browning Silver Hunter Micro 20 gauge in 26". My thought process is the following - he has a little sister that is chomping at the bit to start hunting (she is still too young by a couple of years), once he grows into a 12 gauge she can take over that gun, he can get my AL391 and I can get a new one. I can also get a larger stock to have it fit me or him if my younger one decides its not for her. I would like to stick with a gas operated gun as I am familiar with them.

Get a 28 gauge 26 lenght

You will probably ending up using the gun more than him, since its just a sweet caliber

26" 20 gauge is a good idea. I personally think its best to learn with a pump as it helps to slow the kid down some, usually results are better shots

My son is pretty close to yours is size, age, and weight. We have great success shooting the youth model Remington 1187.

20ga

Since you seam to like Beretta, try the A-400 I have a xplor in 20 that I took teal hunting and it was great 26" barrel