getting first shotgun have ammo questions

[tpuig]

If your shotgun fits you, then just shoot it and have fun. I have short arms, so I had my stock shortened on my first gun (BPS) and it's just sooo nice...
But it costs a bit and I've got too many older shotguns that I don't want to alter.

There are nice shooting shirts with a pad built in that help quite a bit as well.
I have a Browning shooting shirt with removable pad that I love. I use the same pad for a light short sleeved shirt, and a pheasant vest.

The shorter barrel allows the pellets to spread faster. So 18" is not the ideal for trap or skeet. But it's still fun. Keep an eye open for an affordable used Mossberg barrel, they're out there.

As mentioned, a larger number on the shell typically refers to the size of the pellets. So a #8 shell has more smaller pellets than a #4. 7.5, 8 and 9 are pretty close in size and used for small birds (like doves) or clay targets. Larger pellets are used to hunt larger critters. 4-6 for ducks, pheasants, etc. Buckshot for deer, defense, etc.

Then there is the amount of powder. So you'd probably want to find a light load meant for trap with low recoil. Most gun stores would be able to help you. Look for anything that says "reduced recoil" and you should be good to go. (Probably a 1oz or maybe a 3/4oz instead of a 1 1/4 oz)

Lots of good info on the board. Get out there and have some fun. Shotguns are great.

[bsg]

Federal puts out some good reduced recoil buckshot that would be good for HD in a pump shotgun imo; it will say "low recoil" on the side of the box.

check out a Limbsaver recoil pad.

[Revoman]

An 18" barrel might work for skeet, but not well for trap. Will you hit some, probably. Will hit most, probably not.
Skeet is a shorter game, (21 yards) so a shorter barrel is not so detrimental and you want the pattern to open up sooner, which a shorter barrel will do. (Although many pros shoot skeet with a 30"-32" barrel length.)
Trap however, is a long game (From 16 to 27 yards) that in general requires a longer barrel, thus keeping the shot in a tighter group for a longer distance. (Unless you have adjustable chokes.) Even with chokes, trap needs the extra barrel length to allow a little more velocity to help catch up to a bird flying away from you.
Aside from the 'game' part of this is some issues to consider if you are serious about learning to shoot a shotgun.
The lighter the shotgun, the more felt recoil. It's a matter of physics, action, reaction. Even if you use the light recoil shells, the odds are that you will not enjoy the extra recoil that a light gun will give. There is a balance there between too light and too heavy, only you can determine that part.
You NEED to have the stock adjusted to suit you. This will allow for a more comfortable and less traumatic recoil experience, plus you should see the bead better, which will allow you more hits and help with your confidence. A shotgun needs to be comfortable and point where you are looking.
You absolutely must hold your gun tightly into you, meaning that your cheek should be glued to the stock. If you do not, the gun will slap you and you will not wish to continue....it hurts! The same holds true for your shoulder. Hold it away and it will punch you. Either one is no fun and could easily discourage any newb shooter.
This is no slam toward Mossie's, but if you have any aspirations about shooting more clays, then I would opt for an upgrade to your shottie. A Mossie will not stand up to the constant pounding that a higher grade shottie will. (I know I'm gonna get slammed for that part....but it's MY opinion.)
The clay sports are a bunch of fun, but you will learn quickly that equipment is a big part of being really good at it.....if that's your goal.
Recoil pads are varied and most will help. In-the-clothes pads work well too. Most anything that disperses the power will help. Many manufacturer's have turned to making the buttstock wider for this very purpose, to disperse the power over a larger area, thereby creating less felt recoil.
Hope this helps in some way!