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STX TWIST RATES
- Thread starter huntjunky
- Start date
Ok, it's official...For my gun, .25 Impact STX 700 mm: 1:28 twist rate Coincidentally or intentionally, this happens to be 1 full twist for the entire length of the barrel liner, 700 mm (27.56"). Interpolating the information for the .22 700 mm, I kinda expect the .25 slug liner to be around 1:22 or tighter. Generally speaking, the slugs require a faster twist rate for proper long range stability and faster yet, the heavier the slug selection. I'm surprised at how mild the twist rate is for the pellet liner. My Lothar Walter barrels are 1:16 & 1:18 for pellets. If anyone hears/knows the proposed .25 twist rate, let us know. Perhaps it is still in R&D...Frederick, Matt, Roelf you out there? I expect an answer by the time I get back from partying, tonight. 
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I would bet that once the 22 slug testing is done, the 25 slug testing will ramp up.
Though FX has shipped some 25 slug liners.....I just don't know who has them.
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Both my liners have the same twist rate. The only difference is that the slug liner is not choked.
I know I got one of the first slug liners and when I measured the Twist rate it was exactly the same as the regular "X" liner.
I contacted UA and they confirmed that both liners have the same twist the only difference they said was the choke.
I know I got one of the first slug liners and when I measured the Twist rate it was exactly the same as the regular "X" liner.
I contacted UA and they confirmed that both liners have the same twist the only difference they said was the choke.
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I'm banking on the information given to me by Matt and the Air Hunters. They've never steered me wrong.
I will confirm when my liner gets here, as I need to enter this information into Strelok.
I will confirm when my liner gets here, as I need to enter this information into Strelok.
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I would bet that once the 22 slug testing is done, the 25 slug testing will ramp up.
Though FX has shipped some 25 slug liners.....I just don't know who has them.
I know I don't have mine yet.
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I checked my Email and confirmed that both liners I have are 1:18 twist. The the only difference is the slug liner isn't choked.
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I have been checking Bullet stability calculator. Both 21 and 19 will work good with 1:18 twist in the 600mm. So, will a 23 in a 1:16 twist in a 700 shot a little slower. Check it out.
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I sure wish FX would publish this sort of info. I debated the barrel length heavily between 600 and 700, and my goal was to shoot the heavier slugs. I never imagined the twist rate was different. Had I known, I would have ordered the 700mm. There was always a statement about the 500mm barrel and lighter slugs that no one could explain, and I bet it was based on a slower twist rate.Â
If I had the money to waste, I'd buy a 700mm barrel liner, and cut it off to 600. It would be interesting to try the higher twist rate, and no choke. I wonder what the twist rate on the 700mm pellet liner is? There are probably some of those laying around collecting dust when people get the slug liner.
Rusty
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I'm in complete agreement. The PR isn't so great right now, they should at a minimum provide better, detailed descriptions for the SKUs that their vendors use in product listings (Don't take that as a shot at the vendors, it's not what I'm saying).
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The Smooth Twist X pellet liners have much slower twist rates. 1:25 or in that range depending on caliber. Pellets are drag stabilized and kept in the right position on the barrel with the head and skirt touching in two areas. That makes them very forgiving in any barrel or twist rate. Slugs requires a specific twist rate acourding to their weight and caliber to stabilize. They also need a very specific choke acourding to their weigh and caliber to make sure they exit the barrel correctly. It makes them very unforgiving and that is why the tolerances in the slug liners took so long to perfect, but they are fine tuned now and shipping out. Matt just shot a sub MOA group at 202 meters (221 yards) using 28gr NSA slugs out of the 700mm slug liner today. Crazy stuff.
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I have the 600mm pellet A, and slug A liners. In the past, I did quick measurements of the twist, and believed they were the same at somewhere between 18 and 19. Yesterday I mad a more careful measurement, and it does appear there is a slight difference in twist. My pellet liner appears to be 1:19, and the slug liner is 1:18. This makes better sense than both being the same as I previously believed.Â
I still don't understand why there isn't a chart that shows all the twist rates for the various barrels and sleeves.Â
Rusty
I still don't understand why there isn't a chart that shows all the twist rates for the various barrels and sleeves.Â
Rusty
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