I don’t have much to offer about the competitions, but the 500 is a solid platform, in general.

 

The Mossberg 500 barrel attaches at the front of the mag tube…
A standard barrel cannot be mounted to the eight shot mag tube.

 

I hadn't thought of that. Thanks for the heads-up.

 

I have a 24" aftermarket Hastings barrel for my Remington 1100. It replaced the original 28" fixed choke factory barrel. I needed the invector choke system for hunting. The shorter barrel is easier to handle in tight spaces and still knocks the birds down. No experience with pumps or Mossberg.

 

Keep in mind if you cut four inches off that 28” barrel you’re cutting off the choke.

 

24" barrels might be available for 500.
24's are definitely available for the Mossberg 835. They call them "turkey" barrels, but you can screw in screw in mod or open chokes in them so I'm not sure what makes it a "turkey" barrel. Nothing really, other than the fact that you wouldn't want a short barrel for duck or goose.

 

I'm guessing GB means Great Britain. Yeah, I just noticed HM ARMED FORCES where, guessing again, HM means 'Her Majesty'. I'll try to come back because I'm not understanding the part where 24" might be unwieldy.

 

Maybe 24" would be unwieldy compared to a more easily wielded 20" ? Depends on the type of competition I suppose.

 

That's what I mean. I'm not getting the situation or type of competition.

 

All I know is I recently bought a 1988 Mossy 500A from a guy here on GT. It has 3 barrels,a wood forearm and stock,which you don't see anymore, and is pump action. Can't wait to shoot it !

 

Mossberg 500s are great guns, especially from that era. For "practical" shotgunning, consider the 24-inch slug barrel (smooth bore). I wouldn't bother with mag tube extensions. Just learn to reload on the go (tactical reload) as necessary. I would change out the OEM thumb safety (plastic) as they're prone to breaking and replace with a larger, metal one.

Knocking over steel plates? Consider the low recoil versions of slugs and buckshot.

As part of the competition, have your club consider a stage where you transition from long gun to handgun. Have fun.

 

I would try the present " as is" configuration.

If the 28" barrel is not to your liking, then purchase a 24" barrel with screw in choke tubes.

I would not cut the 28" barrel down to 24".

 

Wouldn’t everyone be subject to the same length restrictions? 24 might seem unwieldy but it is probably more “wieldy” than a 28.

 

Have a 1973 Mossy with 28 and 18 inch barrels. Works 100% of the time. Also have a circa 1980 Mossy think it was called the Cruiser with 8 rd magazine and 20 inch barrel Both guns are MORE useful with the shorter barrel. Since you are limited to 24 inch, I would see if Mossberg has a 24 inch. Personally would not cut down current barrel