What choke are you guys using for 870 20 gauge youth and TSS 9's? A buddy's is making some shells with my supplies and he says he's had good luck with the primos tight wad.
It varies a lot between different guns. Some use a Remington Super Full, some get good results with a Carlson 575, others use a Sumtoy 562, and a a lot of folks use Indian Creek either a 562 or 555. I have a youth model 870 and finally settled on the IC 555 and I have shot several different chokes. Shorter barrels may need a tighter choke...although that doesn't hold true all the time.
I've built 10 or so youth 870s with 21" barrels. All have patterned (300+ hits @ 40 yards) very well with the Remington Super Full "Lead Only" chokes with TSS #9 and #9.5s. I did polish all barrels until they were shiny bright without any imperfections I could see with my naked eye and deep cleaned the barrels before I patterned them.
I just finished one up as well. I tried the Turlock, Indian creek, and primos jelly head. I was surprised after all the reading I had done. I got the best pattern out of the jelly head. They were all really close and were all killers, but the Jelly head gave me the most even pattern at twent five and forty yards. Nephew killed with this setup on Saturday afternoon.
Indian Creek .555 or .562 or the Remington Super Full. I never had a primos shoot worth a crap in any of my 870 20's. My daughter shoots a hastings .566 w/ TSS