I won't say it's FX's fault as each ammo would like a different twist rate, I am grateful that FX has multiple twist rates available so we can find a good ammo/liner combo. From what I saw on youtube the slug liner works well with NSA and hybrids due to slightly faster twist rate. As each slug's length are different so does the twist rate that is optimum for that particular ammo, longer the slug the faster the twist rate. It's a complicated combination of speed, twist rate and projectile stabilization requirements to achieve desirable results.
Here is my speculation on liner use case for .25 slugs:
STX liner = 1/27 = pellets(920FPS FX tune), hybrids(950FPS or more)
STX superior = 1/23 = pellets(920FPS FX tune), hybrids & medium/shorter weight slugs(32G and lower @ 900+FPS)
Slug liners = 1/21 = heavy pellets like JBS MK2(880FPS FX tune), heavier/longer slugs (900+ FPS)
Now, i'm not going to buy all 3 and try all 3 types of ammo to try them out since I'm not a youtuber but my theory is just my theory.
My planed use cases are below and I'm sticking with my slug liner:
Backyard tune: 680FPS .25 Hades, at much lower speed the pellet can use a little faster twist rate for stabilization and it is VERY accurate!
Hunting 1: JSB .25 heavy MK2 @ 850-900FPS, it can use faster twist rate due to less diablo shape or slightly more slug shape, hence the much higher BC
Hunting 2: H&B .25 31G slugs @ ~950FPS, it's a slug so it likes faster twist rate and higher speed, once I run out of these I'll probably stick with NSA since they come in bigger boxes and lighter 26 grain size
Hunting 3: NSA .25 26G slugs @ ~950FPS, can't hunt anything bigger than rabbits here in CA, some of the youtubers and Utah air guys used this combo to good success
I spent a good amount of time testing Hades(3 tins), JSB King(4 tins) and JSB heavy(1 tin) and they are all VERY accurate at lower speed through slug liners. My yard is relatively small so I'm sticking to Hades once I blow through the JSB 25G pellets. I really like the JSB Heavy MK2 and they are VERY accurate out of slug liner between 650-850FPS speeds I've tested, it made no difference at all in that range. When it comes to slugs I simply didn't have enough time on them so really say but the limited testing I've done so far the H&N is pretty good, not JSB heavy good but I haven't really tuned for it. Once I finally get to hunt in the windy plains with it I will thoroughly tune my gun and test them, that might be a while.
I may not happy that I didn't get the superior liner which would of saved me the trouble of buying slug liner but I'm not entirely pissed off due to the fact that I can fine tune and match ammo to liner for that ultimate accuracy.....if I want to spend more money. Either way I'm currently very happy with the slug liner due to my use cases are quite polar opposites and different from what the superior liners are made for, slug liner's faster twist rate actually match my use cases slightly more perfectly. So in the end you won't see me running out buying the superior liner.
