Well, if you're going to take a semi-auto, be sure to take two. That way, MAYBE one will be working with scavenged parts when you finish. Benellis and Berettas seem to hold up best at this time I understand.



As far as actual recoil reduction goes, there are only four things you can do:



1) increase gun weight, such as lead or recoil reducers in the stock (I've used Mercury Recoil Reducers and couldn't tell any difference between them and the same wt in lead, not saying there isn't, just my perception).



2) use the best recoil pad you can obtain (not sure of which is top of the heap now, all the good ones contain polysorbathane) along with one of the shirt/shoulder mounted ones IF you can stand the gun mounting problems they create.



3) you can backbore and muzzle brake your barrel. This creates a minimal reduction in felt recoil, especially considering the costs, but every little bit helps.



4) and perhaps the most critical, shoot the very lightest loads you can obtain and be sure to tell your hunt organizer that you want LIGHT 20 ga loads. Most of them do this automatically but it never hurts to reiterate the point.



In order of importance, I'd rank the above 4 items, depending on what gun and recoil pad you are starting with, 2, 4, 1, 3.



In addition, and I don't know how old you are and this may sound ridiculous if you are 30, it won't if you are mid 40s or more, especially if you are not used to physical exercise, but you need to do some simple wt training ahead of time. The wt can be your shotgun, but you need to practice lifting it a few hundred times a day. As you get nearer your hunt, slowly increase gun wt by adding a pound or two of wt. (tape it on). Otherwise, your shoulders could very likely develop tendonitis and I am not kidding. If you have any tendencies toward inflammation, BE CERTAIN to carry some NSAIDS that work for you. Celebrex, viox, etc. Take them in advance.



Finally, toughening your shoulder before you go by as much practice with a shotgun at the local gun club, preferably a 12 (more recoil, more wt to strengthen your muscles), before you go will pay off in both better shooting and a shoulder that is used to recoil. Work up to shooting at least 150 to 200 shots a day just before you leave. There is a big difference in shoulders that are shot off of a lot and the normal virgin ones. Sounds silly, but it is a fact. Believe it.



It is not uncommon for first time visitors to South American (BTW I am referring to Argentina or Uruguay, unfortunately I haven't hunted Bolivia so can't comment about their hunting, but you won't see the volumes of doves in Colombia that you will farther South) dove fields to go "wild" and shoot a couple of thousand shells each day or more. If you are recoil sensitive, try to restrict yourself to NO MORE than 500 in the morning and the same in the evening. Your shoulder will thank you.



Have a great trip, if you like volume bird shooting there is none better.

I too have heard that Benellis hold up well. The newest Benelli has a recoil absorbing gel in the recoil pad.Gatorgordo's comments are very good advice.