I've shot a couple different ported chokes and haven't noticed a recoil difference. Ofcourse I was shooting 3.5" mag loads so even a 20% drop in recoil is still going to feel like I'm being kicked by a horse... But one ported choke I have for my 870 claims 40% reduction and I know it didn't do that...
As far as patterning, the choke that really interests me is the pattern master. It's ported but it also has little knobs that grab the wad to keep it from slaming into the shot column after leaving the barrel. I've heard and read many reports from people getting very tight patterns with more open chokes. The pattern master "sales literature" is very interesting also on how their design works.
However, like all shotguns, one choke / load by work great in one gun and not in another.
For best overall results I'd say take whatever choke you get and pattern multiple loads through it. I have friends that buy one choke and one load, spend tons of money on the choke, then complain about the pattern and sell the choke, or don't care about the pattern and assume since they spent $$$ that it's the best it can be based on the sales literature.
For this upcoming season I'm going to try making my 870 supermag back into a long range shooter again with hevishot this time instead of copper plated lead. I'll use it for sitting along fields where long shots are the rule and not the exception. For brush busting, hunting during the rain, etc, I'll be using my mod choked nef pardner and #4 3" mag hevishot.
For the 870 I plan to mount my Remington cantiliver rib scope mount (I'm not sure if Remington still makes the scope mount or not, blamps to any remington rib) and mount a millet sp1 reddot. Next I'll start with 3" mag hevishot through my new remington full "lead/steel" gold colored choke, .691" in restriction. Remingtons extra full choke is .687, .004" tighter..., so I won't be testing it... Remingtons next tighter choke is the superfull at .665", I'll be testing this choke, and then finally the ported "ventilator" choke at .655". The "hevishot" choke from Remington is .675", just .010" more open than the "super full" and .016" tighter than the "full". I have the full, super full and ventilator so I'm going to try to do it without buying the "hevi tube" by varying the shot size.
I currently use the "full" choke shooting #2 hevi at coyotes so I'll start with patterning that choke with #4 hevishot. Then I'll pattern #4 hevi with the .665" super full choke and note the difference. It's possible the .665" choke over chokes the large #4 pellets. As a rule the larger the pellet the tighter the pattern through the same choke unless it overchokes the load. My .665" superfull choke might pattern hevi #6's great, very very tight, but may put hevi #4's into a pattern like a mod but with holes in it, that is a "blown pattern" because of too much choke. I'll probably use whichever is tighter for #4 shot, the full or the super full. If the full is tighter, the superfull is blown, but the full isn't tight enough, and finances allow, I'll get a box of #5 hevishot and try that through the superfull. If the #5's pattern tighter in the tighter choke than the #4's in the more open choke than I'll use them. if not, I'll save my penny's and buy a box of #4 3.5" mags and see if that is better or worse.
But I imagine I'll end up using the .665 super full choke with either #4 or #5 shot, if I were to bet it would be #5 shot as the #4 would be over choked, but we'll see. I imagine the #4 and the full choke will be very good, just not as tight as the super full and #5 shot. Since this will be LOOOONG range rig w/scope, I'll probably try and stretch it as far as I can.
And like in the past, ventilator choke, win supreme #4, 3.5" mag, and a deadly 60 yard pattern, a tom will sneak in around from my side and I'll miss a 10 yard shot to my weak side.... :wink: and I'll be cursing the day I decided to spend the $$$ on building the long range rig when my nef single shot, fixed mod choked barrel shooting #4 hevi would have made easy work of him...
later,
scruffy