I have a Browning bt 99 34" for singles and a Browning xt 32" for doubles. I had a SKB under combo that never give me a lick of trouble that I traded for both the Brownings. My thought was 2 guns for the price of one. The one advantage that the combo has over shooting 2 diff. guns is you are shooting 1 gun for both single and doubles. You don't have to worry about making 2 guns fit.
Actually, I'm not sure of the legislative origin or how enforced, but I'm pretty darn sure that it is illegal to have only one trapgun. If it by some chance isn't then we should all write our elected officals and have them pass some worthwhile legislation.
I use my TMX for Singles and Handicap and an MX-3 for Doubles. I don't want a combo gun because I don't want to fiddle with an adjustable comb for a different POI when I shoot Doubles. My Doubles gun shoots flatter than my TMX and I could use it if necessary but I haven't needed a backup gun in 20 years of shooting.
I have right now only one gun. It's a Remington 870 Wingmaster. I plan on having another for backup and an 1100 for backup as well and for doubles and maybe some skeet. The reason I only have one now is because there for many years I didn't have any. I had all of these at one time then I was diagnosed with what is called Myasthenia Gravis or M.G. It's a neuromuscular disease similar to ALS. But, if you do the right things and take your medications as perscribed, eat right, get as much exercise as possible and rest when the body tells ya to, you can make it through life and be somewhat productive. I had to sell all my guns and loading equipment because I could not even lift 5 LBS. I have gotten now to where I can lift 10-20 Lbs. So I am back reloading and shooting somewhat. It takes time to put things back order. I shot the 870 and 110 really well before and am shooting the 870 as good as possible for now. I have to shoot from an Electric Wheel chair and I can say, it's different. there are some new ways of doing things and as of now I feel I do pretty well with it and figure in time it will tell when I get the 1100 if I stay with the 870 or move on to the 1100. Yes the 1100 has less recoil out right. But I can load for the 870 so it has very little recoil. I'll keep everyone updated as to my progress with the two and how things are going with shooting from the wheel chair. But for now the 870 has been smoken em for me. Here is my two cents worth, I believe in having two guns.Both the same in weight and balance and fit the same gage as well. I had the privelege one time of being lucky I had the 870 as backup because I was shooting my Mossberg. I had just purchased the 870 and wasn't able to get it cleaned up and ready to shoot. The Mossy went down on me and I had to push the 870 into action for the rest of that days compitition. This is when I found out the gun shot beautiful and had no problems with it. I did though clean it up and get it ready for the next days compitition. It did very well for me. This ismy two cents worth. Rich. (inPeoria, Az.)