Can anyone recommend a full choke tube for and 870? Gifted to my son my 870 express this year and it only has the modified choke that I used for ducks. Would like something a little tighter.

Go to Carlson's https://www.choketube.com/

I'd like to hear from anyone as well that has used any of these expensive after market chokes to see if they are any better in the field.

I have used several, including the RemChoke Full and Improved Modified rated for steel. I find the ImpMod patterned the tightest with #2 and larger shot sizes, up to B.

Your modified choke for the Express is a good shooting choke in my opinion. I haven't patterned mine in years but the modified choke is effectively a full choke with steel and a modified choke with lead. When I measured the id of aftermarket steel shot full chokes years ago, most had an id very close to the factory Rem Choke modified. I have killed 1000's of ducks and geese in the last 30 some years, after switching to steel shot, with a Rem Choke Improved Cylinder choke and a Modified choke. There are also Full Rem Chokes for lead or steel. I would pattern your modified tube before buying another choke.

If you want or think you need something tighter then go get a Full Rem-choke rated for Steel or Lead or purchase an aftermarket choke like Carlson's. Probably be a good idea to pattern what you have first to see how your choke/load combo is performing at the distance of your shots.

Why do you want something tighter than the Mod choke? A Mod choke (~.018-.020" constriction) is a pretty good all around waterfowl choke.

Are the aftermarket chokes any "better" than factory chokes? That would depend on your definition of "better." Choke tube sellers make all kinds of claims mixed with slick marketing to convice you that you need one or several of their chokes. If they could "prove" improved performance in some way or the other, don't you think they would gladly put forward some empirical data to support their claims? And as side note, one photo of a pattern or an artists rendition of a pattern isn't empirical data!!!

Here is some food for thought on these topics.

Some pros and cons of extended choke tubes include:

1) extended tubes are usually easier/faster to change (usually no wrench needed),

2) most extended tubes have the choke/constriction printed on the exposed portion (visible when installed) while some flush tubes don’t have notches to indicate choke constrictions when installed,

3) extended tubes provide muzzle protection from possible muzzle damage (dint) that could make choke removal or instillation difficult,

4) extended tubes provide additional length which allows for the possibility of different choke geometry and design (ramp angle and length, choke angle and length, parallel section length, porting and endless marketing gimmicks) which may or may not provide improved performance,

5) extended tubes usually weigh more than flush tubes which may or may not be a good thing for your gun’s balance,

6) some shooters think the extended tubes look cool and some like the traditional uncluttered look of flush tubes, and

7) extended tubes are generally more expensive (the choke makers like that).

None of this means extended choke tubes work/perform "better" (whatever that means) than flush chokes. It really depends on the kind of performance you need/want from your chokes and loads for your type of hunting/shooting. However, if you aren't going to take the time to pattern them properly (with the ammo you use) to find out how they really perform then it doesn't really matter, just use what you like.

Here are the true constrictions (from a bore gauge) of my factory flush Rem-chokes and some Carlson's extended waterfowl chokes for your comparison.

12 GAUGE
REMINGTON CHOKES
FACTORY FLUSH REM-CHOKES
SK / -.010" constriction
IC / .009" constriction
M / .018" constriction
F / .037" constriction
F (Steel/Lead) / .037" constriction
Turkey Super-Full (HEAVY SHOT) / .053" constriction
Turkey Super-Full (LEAD) / .063" constriction

12 GAUGE
CARLSON’S EXTENDED REM-CHOKES
IC (CLOSE RANGE) / .007" constriction
M (MID RANGE) / .017" constriction
F (LONG RANGE) / .027" constriction

Hope this helps, good luck.