FX I give up on this STX barrel and slugs

[Squirrelmageddon]

I have a .25 700 STX Superior with a 1:24 twist that shoots JSB 33g pellets exceptionally. It can't shoot a NSA .249 26.8gr slug with any accuracy. 25 yard group sizes are over an inch. I've shot them from 900FPS all the way to 1023 FPS in 10 FPS increments and they won't group well at any speed. Each FPS increment test I shot at least a full mag starting with my hammer spring tension at 4.5 and lowering it until I saw the FPS start dropping. I shot down to 2.5 HS tension is many runs to make sure I wasn't destabilizing the slug from turbulent air behind the slug. Nothing was really making dramatic improvements. Pretty much it would shoot 1 to 3 flyers on a 5 shot group.

I was thinking, #%$, did one of my kids knock my gun off the table when I was inside and put it back with a busted up scope or what? So I put it back on the pellet port and pellet tune and shot 100 rounds of pellet perfection. WTF is wrong with this barrel?

NOTE: The moderator was removed to rule out clipping. I was frustrated and not giving a dam what the neighbors were thinking LMFAO. Every screw was just checked with a torque driver. Nothing could have been moving around.

 

[MiG-77]

Superior liners with 1:24 twist are ”pellet liners”. My liner dont shoot any slug as good as JSB/FX pellets (some slugs are just horrible ie ZAN). FX hybrids are closest to those.

 

[Squirrelmageddon]

Superior liners with 1:24 twist are ”pellet liners”. My liner dont shoot any slug as good as JSB/FX pellets (some slugs are just horrible ie ZAN). FX hybrids are closest to those.

Dam, I've always heard the STX heavy liners with their tighter twists were only needed for heavier slugs. So what twist rate should I be looking for?

 

[shaman]

You have no choise - the heavy liners in .25 are with 1:18 twist rate
There are "slug liners" - 700mm in .25 with 1:16 but most of suppliers do not make difference between both

 

[MiG-77]

Dam, I've always heard the STX heavy liners with their tighter twists were only needed for heavier slugs. So what twist rate should I be looking for?

You can find (light) slug that will work in Superior aswell. You just need to test many brands. For me FX hybrids were best, JSB knockouts second best. None were as accurate that JSB/FX pellets but FX Hybrid came close. FX hybrids are just too expensive for me to shoot regurally.

 

[Vetmx]

I have never found a slug that will outshoot the proper pellet out of my 500 or 600mm .22 or .25 superior liners. Those damn things can really shoot a pellet. I do have a .22 superior that with a few mods does really well with slugs. It will match a pellet when the gun and I are in sync. A .25? Forget it. I do believe slugs are harder to shoot than pellets. But that’s another topic for another day.

 

[MiG-77]

I have never found a slug that will outshoot the proper pellet out of my 500 or 600mm .22 or .25 superior liners. Those damn things can really shoot a pellet. I do have a .22 superior that with a few mods does really well with slugs. It will match a pellet when the gun and I are in sync. A .25? Forget it. I do believe slugs are harder to shoot than pellets. But that’s another topic for another day.

Agreed on .25. I can shoot under MOA groups with good pellets but even with good slugs it is about 1-1.5 MOA.

I have not tested how much it will improve with heavy liner and slugs.

 

[HogKiller]

You have no choise - the heavy liners in .25 are with 1:18 twist rate
There are "slug liners" - 700mm in .25 with 1:16 but most of suppliers do not make difference between both

THAT is because FX in their infinite wisdom, or lack there of, uses the SAME part number for the barrels. Suppliers would actually have to look at the barrels to find the twist rate. Just like they change o-ring specs but don't update their drawings.

 

[cmatera]

Even if the twist rate is etched on the barrels like the new ones (the old ones had a sticker that always fell off the oily barrel), the only way to be sure of the twist is to check it yourself. Sad that we can't trust the manufacturers and dealers, but that's the way it is.

 

[srtmat]

Slugs can be a real headache to dial in. Those 26.8gr are pretty short slugs. I would suggest trying something a little heavier. I think you can run slugs all the way into the mid 30grs though a regular superior Liner. I’ve had decent results with 29.5 and 33.5 NSA slugs in superior liners. Sometimes “your” barrel and “that” slug just aren’t going to jive no matter what you do. I’ve sent more than my fair share of slugs down range with what I would consider fairly limited success. Thankfully most of my shooting is inside of 100yds and 34gr JSB’s are a fantastic pellet.
Good luck

 

[qball]

What’s your reg pressure?

 

[qball]

You have no choise - the heavy liners in .25 are with 1:18 twist rate
There are "slug liners" - 700mm in .25 with 1:16 but most of suppliers do not make difference between both

Easy way is to call them and ask them to look at the laser engraving on the liner to confirm.

 

[Squirrelmageddon]

Easy way is to call them and ask them to look at the laser engraving on the liner to confirm.

It's definitely a 1:24. I really need this gun to shoot slugs. I need a projectile with a better BC and better energy retention for 100+ yard pesting. I'll give it one try and order a heavy liner and some heavier gr slugs. I'll try some JSB, Zan, and NSA slugs. If I can't get a good 100 yard group outta one of them I'll turn that liner into the most expensive fireplace poker ever and send FX a pic of it LMAO.

 

[Ranchibi]

Also....slug diameter will play a major part in slug accuracy. Slugs need to be spin stabilized and the superior liners have a mild choke the slugs need to grab the lands there. Pick a lighter slug in the same weight but in a few different diameters, accuracy will be evident right away and you will know what diameter your liner prefers, then tune the speed from there for pin point accuracy.

 

[MiG-77]

It's definitely a 1:24. I really need this gun to shoot slugs. I need a projectile with a better BC and better energy retention for 100+ yard pesting. I'll give it one try and order a heavy liner and some heavier gr slugs. I'll try some JSB, Zan, and NSA slugs. If I can't get a good 100 yard group outta one of them I'll turn that liner into the most expensive fireplace poker ever and send FX a pic of it LMAO.
View attachment 420691

With that liner I would try FX hybrids (in USA you can order directly from manufactor RMR and much cheaper prise. In their site they are called SLAP) and JSB 33.49gr Knockouts (for me 0.251 fitted better). Also heavier NSA could be good (I dont have access to those in here Europe). Basically everything up to that ~34gr in slugs is viable. Heavier than that "Superior heavy" liner is better option.

 

[Mooseyard Airgunner]

With that liner I would try FX hybrids (in USA you can order directly from manufactor RMR and much cheaper prise. In their site they are called SLAP) and JSB 33.49gr Knockouts (for me 0.251 fitted better). Also heavier NSA could be good (I dont have access to those in here Europe). Basically everything up to that ~34gr in slugs is viable. Heavier than that "Superior heavy" liner is better option.

Fireplace poker .HaHA. I have a bunch of FX liners I could do that with.

 

[Peashooter]

The 600 mm barrel that came with my Maverick was cursed, it would only shoot 1 pellet at the more normal speeds of 800 - 900 FPS
Anything else had to be sub 600 FPS. but granted then some of the pellets was also laser like, but i did not get a high power FAC airgun to have a glorified blowpipe.

Changing to a 700 mm fixed that, and that barrel also shoot 13 gr slugs just about as good as the heavy liner i also have, which i absolutely CAN NOT get to shoot heavy ( 16 - 20 gr slugs ) particular well.
But in .177 i also feel the heavy liner is a rip off as it have the same twist rate as the pellet liner.

 

[HogKiller]

It's definitely a 1:24. I really need this gun to shoot slugs. I need a projectile with a better BC and better energy retention for 100+ yard pesting. I'll give it one try and order a heavy liner and some heavier gr slugs. I'll try some JSB, Zan, and NSA slugs. If I can't get a good 100 yard group outta one of them I'll turn that liner into the most expensive fireplace poker ever and send FX a pic of it LMAO.
View attachment 420691

Or you can turn it into a 600mm, by getting rid of that pesky choke.. 1 each slug barrel. I've found, after watching hours of videos, that Matt Gruber(sic??) had it right, too much air and you can kiss off hitting something with a slug. You need to find that absolutely PERFECT setting, just enough air and not one CC more at the muzzle.