This one is standard size for all gauges. 14.5" length of pull, which is about right for most "average" men of 5-10, 18- lbs.
I am 6-4, 300+ lbs so every off the shelf stock is too small for me. LOL
Except for custom made stocks, all of my fitted shotguns look like this at the butt end of the stock:
A properly fitted gun makes a HUGE difference in results. Shooting a shotgun that doesn't fit you is like trying to run in shoes that are too small or too big. It's possible but it adds a degree of difficulty and uncertainty that hinders performance. I had no idea how important it was until I ponied up the money and had my first gun fitted.
FWIW, I have an 1100 in 28 gauge that has a cut off stock. It's even shorter and feels like a toy to me but it's perfect for young kids. Unfortunately, I didn't know these little kids were coming to the ranch until I had already left home or I would have brought that one and even the younger kid probably could have shot it.
Top to bottom: my fitted O/U sporting clays gun with fitted stock, Beretta A400 28 ga with standard stock, Remington 1100 28 ga with cut off stock.