Shot my new SSX today out of a 11-87 with a 21" tube. The results were pretty good. I fired four rounds of Hevi 13 7's with patch ran down the barrel between shots. She turned 137, 150, 117, 134.
I'd be happy with that
Thats pretty decent. My 870 digs the SSX sporting a 155 average with the Hevi 13 7s. Has put up a high in the 170 range. That choke shoots the Hevi's more consistant than Feds.
I like those 130 to 140 patterns. Deadly in 10 but some margin of error in the 20.
I got similar results with a Jellyhead .570. Over all it looks like the SSX average is higher, but I will still need to do a little more shooting to prove it. I get the feeling that 130 - 140 is going to be the best that gun does no matter what I screw in the end of it. Unless I maybe try different ammo. I think the shorter tube is holding the ammo back some. I'm not going to spend too much time or money trying to get a 150+ average, with a 21" barrel.
Try the Feds. Mine also liked the Feds. The feds were a low 140 average out of the SSX. That choke was more finicky with the Feds though. It did not like shooting them dirty. With the Hevis it didnt matter. It was gonna put up big numbers for me. It gets a little better with more rounds going through it.
At 40 yards those four patterns are great. Tight, but not to tight. You got plenty at forty, plus some margin of error. good luck next season.
I let my son run a box of lead thru it after we patterned it.
My son has the same choke in his 21' 870 and averages mid to high 160 every shot with the feds and has sevral patterns in the 180's he shot a ton of lead through it, I mean dove loads, squirrel loads, turkey loads and every other 20 guage load I had in the house, it seems like it helped the choke shoot consistently to me.
the ssx is it 550 and are the feds the heaveyweights and i asume these are #7 not 6
The SSX is .550 the numbers mentioned above are from Hevi 13 7's.