I'm not a tactical shotgun expert...so to some extent you're asking the wrong guy ..../ but yes, I agree that the bulk of aftermarket stuff - that guys like to add on to tactical shotguns ..are more for the mossberg or remington mfg'd guns...
http://www.browning.com/products/ca...ontent=bps-all-weather-high-capacity-firearms
I can only go based on what Browning says on the gun ( but it looks like the capacity is 5 rounds / and I suspect its 5 rounds of 2 3/4" shells - not 3" shells ) where it might only be 4 rounds of 3" shells. But if you need more data - I'd suggest you call Browning or go see the gun at a local retailer.
With a fixed open cyclinder choke - yes, it ought to be able to fire any type of tactical ammo you want to shoot ( in 12ga of course ) - up to the max of the 3" chamber / so you can't shoot any 3 1/2" shells .. Remember shotshells are measured after they're fired - not before.
As a leftie - I still thing a BPS is probably a smart choice for you.
Another company you probably want to check out is Wilson Combat - along with their high end handguns / they specialize in a line of tactical shotguns ...and they'll either customize your gun / or you can buy 4 or 5 models from them ( I think all on the Rem 870 platform ) but they might have others. They're good folks - especially on the handgun side ( I've dealt with them a lot ) ...and I have buddies that have some of their tactical shotguns and they're very happy with them.
Benelli also makes a nice tactical semi-auto ---the M-4 / which I think is a pretty nice gun / I've fired them a little at my local range. One of my boys was a Marine - and he spoke highly of the military version...
but I think you have a lot of options out there these days if you want a tactical shotgun...depending on your budget ( some of these options will get up around $2,000 ) but its better to look at everything / and shoot as many as you can - before you buy.
Everybody should buy and shoot what they want ...but I do think there is a difference between a "Tactical or Fighting Shotgun" vs a "defensive shotgun". A pump gun with a 26" or 28" barrel is not the optimum for "Tactical Fighting" ...but it can sure be a "defensive" gun. And only as an observation ...a bunch of my sons buddies - all in their 30's --- went out and bought versions of the Mossberg and Rem's 18" or 20" or whatever ...fixed cyclinder chokes ...and they all shot them a little ( like 100 shells ) ...and now, for the most part --- none of them have fired them in at least 2 yrs ...but they're all looking for semi-autos or O/U shotguns to come out and shoot some sporting clays with ....and almost all of them - said they think the tactical shotguns are cool ...but they were a waste of money ...and have turned instead to a variety of handguns as "primary defensive" weapons. So just think this thing thru ...
I have 50 or more guns in my safe ....and no "tactical" shotguns ...but I don't feel like I've left something out ....or "black rifles" either.../ they can be cool ...and if you want one /buy one. But I don't feel like my collection is incomplete without them .../ that's why I say I don't need em / don't want em ...I'm very happy with a well made Wilson Combat 1911 in .45 acp as my primary defensive weapon. I have well over 20,000 rds thru that Wilson ...and its never once let me down ...and it still looks good / and shoots great !
