Official FX STX Barrel Liner Twist Rates

There has been a lot of questions lately from shooters wanting to know the twist rate of their barrel. Here is an official list of twist rates for the current offering of FX STX barrel liners.

Note: Some shooters have speculated that FX has changes twist rates on some of these liners (particularly the slug liners). This is not accurate. Some choking techniques have been perfected, but twist rates have remained the same.

(Measuring twist rates can be a little tricky and it's understandable why one person thinks they have measured the twist differently than another)

For those who don't know, the .22 cal Pellet Liner B are liners designed to shoot heavier .22 pellets like the JSB .22 cal redesigned Monster pellets. The .25 Pellet Liner B are liners designed for the heavier JSB King Heavy (MK1 & MK2).


Also for those experimenting with slugs, lubricating your slugs a little goes a long way in aiding accuracy.





1555520480_1921005845cb75be07238b5.40178374_Twist-Rates.jpg


 
So now, with that info dunno what I have

I have measure 1:18 for a supposedly slug liner 600mm sent to me in february 2019 (terrible btw with slugs) I am measuring wrong?

Here is the measure of my "Slug Liner"



Or what has been sent to me is not a Slug Liner?


Assuming this is a .22 caliber correct. It could be the case that things were mixed up either on our side or the retailer. That would explain the horrible results with slugs. I'll have our customer service guy (or gal) reach out to you and see about getting that swapped out. We're out of that length of .22 slug liner currently but expecting some in a couple of weeks.
 
  • Like
Reactions: .20calguy
ok I have a brand new never shot ..whats stock in an impact x..25 cal?

I struggle seeing the gage..so I just shoot my crown..and struggle there as well

thank you

From the chart, 1:27 for pellet liner A.

Good information to have! 

I’ve heard lots of ideas of the best pellet lube. What do you at FX recommend to lube the slugs?

Kevin,

Here's what I use. Though I haven't had problems, the lube certainly hasn't hurt anything. Also, check Matt's video that just got released today.....he talks about lube/silicone spray.

1555528704_54079755cb77c00e70490.69755365_Screenshot_20190417-151456.png





 
So now, with that info dunno what I have

I have measure 1:18 for a supposedly slug liner 600mm sent to me in february 2019 (terrible btw with slugs) I am measuring wrong?

Here is the measure of my "Slug Liner"



Or what has been sent to me is not a Slug Liner?


Assuming this is a .22 caliber correct. It could be the case that things were mixed up either on our side or the retailer. That would explain the horrible results with slugs. I'll have our customer service guy (or gal) reach out to you and see about getting that swapped out. We're out of that length of .22 slug liner currently but expecting some in a couple of weeks.

Also of note moving forward all slug liners FX Sweden creates will come with a heat shrunk label onto the liner listing the caliber and type. This is to help avoid mix-ups from happening on any level.

Yes 0.22

That was my thought also. That is why I was wondering for a while now about Twist Rates on liners. The retailer I bought from made several mistakes with my order and by the time I receive my third liner (and I only bought one...so now I have 3 liners for drink Coca Cola! :) ) it was the liner in the picture, with no marks whatsoever indicating that was a slug liner. So with your new info on liners twist rate, now we can identify the liners easy when they have no marks on it. I got tired asking for a solution to the retailer, in words they say they will fix it, but in actions nothing, now they do not even answer my emails. Is all good tho, I bought another liner from another retailer and got it right, with a label on it this time and shoots pretty good, and I bought the Mk2 from the same retailer and next week I will have it y my hands. ( that is the good thing I love in USA, you can actually choose! where your needs are fulfilled better)

I appreciate FX USA take the time to help shooters, as you might know I am a big fan of FX and I always thought that the problem should be fixed by the retailer (I am a retailer and importer my self , not AG related, so I know a few things about customer service), anyway BIG THANKS! Just read the PM. 
 
Thanks for the information. FX-USA is the best thing that's ever happened to FX :)

I am curious if there's some special way to measure this officially. I have an early 600mm .22 slug liner, and it's 1:18 (not 1:16) according to my notes. I have a new 700mm .22 slug liner that measures 1:16-1/8" rather than 1:15 as indicated. Both of these are far enough off that it doesn't seem like it could be a measurement error, unless there's some non-intuitive way to measure that I'm not aware of. 

Thanks,

Rusty