Sometimes you're better off shooting under less...formal...conditions than at a 'real' range, as long as it's acceptable to be shooting where you are, you have proper permission to be there, you are absolutely safe in your activities and you clean up after yourself when you are done. Unfortunately in today's world, that sort of place is harder and harder to find. But it is worth the effort to do so. Access to a farm field for informal hand or Trius type trap thrown clays, or to a gravel or sand pit for other practice, can often still be had if you ask around carefully. And some help/teaching/mentoring from a more experienced shotgunner can be a big plus as well.
Note that it may take joining a club or other organization which has access to some sort of facility for shooting, and it may cost money to do so. If you find one you can get along with, that's well worth doing- I have held memberships in a half dozen clubs over the years as I have moved around from job to job, all of them have been well worth the money and time (some clubs require you to put in 'work days' as a condition of membership). Ask at your local gun shops and see what options you have in your area.
Look for and take advantage of training opportunities near you. There are hunter safety classes available almost everywhere, for example. Many NRA- certified instructors are offering various classes all over the country- just go to
http://www.nrahq.org/education/training/basictraining.asp and check. And please don't whine to yourself (if you are subject to doing such things) that 'oh, I don't need to do any of that kid stuff, I know all that already, that isn't what I want to do.' IT'S TRAINING. IT'S AVAILABLE, AND IT IS INEXPENSIVE. Take advantage of it.
You can easily go off and pay $500 for a weekend shotgun class with a nationally known instructor or school (plus another $500- $1000 for lodging and meals and gear and ammo and travel), and you are going to get hammered with the same FUNDAMENTALS. Learn the fundamentals right, and learn them first, and never ever worry about having to listen to them again from another source. Every time I have gone anywhere for training I have gotten a safety lecture, and a refresher on fundamentals. It's part of the program. It is why you are there, TO LEARN.
No one has a corner on the shotgun game, _anyone_ worth their salt can teach you something if you are willing to learn from them. I have seen literally some of the best instructors in the world- as students. They sit back, shut up and look for worthwhile new things to learn. That is why they are so good- they are always willing to learn new angles, new details, new approaches. You should be too.
Check with any avilable gun clubs in your area. See if they offer basic instruction in any of the clay games, or if there are members willing to help new shooters get started. You may have to put a longer barrel on your 870 to use it at the club but it is worth having a field/hunting/clay games barrel to fit the gun anyway, and they don't cost a lot relatively speaking. But use YOUR gun, even if you do have to get another barrel for it. You learn by spending trigger time, and it is best to spend it on your gun, even if it's with a different barrel. That won't affect basic stock fit and mounting.
Look around you for a club that runs 3-gun matches. Find out what it would take for you to participate, find out if there are ever shotgun- only side matches, see if you can get started with them. One word of warning- don't fall head over heels into the 'game' mentality, use it as a hardware manipulation training venue, NOT a place to learn/practice tactics and strategy. Shooting under pressure, shooting moving targets, reloading under pressure etc are all good aspects of the shooting game, becoming a gear god gamer isn't.
It can be a chore to find a place to shoot, and to find good people to shoot with. But it is part of the whole picture. And it is definitely worth doing.
Cheap ammo is pretty much what EVERYONE practices with. No need to practice all the time with your 'for real' fodder. But at the same time, you should look to finding real-world ammo that your gun feeds reliably, and that performs well for you, and that doesn't cost an arm and a leg. Basic buckshot and slug loads will work fine for any real-world defensive application, you don't have to (and shouldn't IMO) spend $5 a round for stuff like flechette loads, strung buck etc. that some people tout as the gotta-have defensive ammo. They are gimicks and are not necessary, not even adviseable IMO.
Good luck, have fun, and STAY SAFE,
lpl/nc
