FX Lock this thread please- Discussed with Fredrik, there is no evidence of POI shift in FX barrel liner system
- Thread starter mubhaur
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The reason for that might be that when filling the bottle the compressing air gets warm and less weight of air per shot as a result. When it is cooling down the air weight per shot increase again so more air down the barrel.
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The POI shift after refilling the air tube was a direct cause of pushing on the barrel a small bit with my thumb to remove the fill probe. It took a very experienced airgunner to help me determine the cause.. I would fill my air tube and have to re-zero my rifle every time. My friend explained that I should try a barrel band and if that did not work to try 2 of them and if that did not work try 3 of them. I am grateful my friends knowledge and help and mine only took 2 barrel clamps to consistently hold POI pretty close to prior to the fill. All is good now but one would think that the designers, testers and manufacturers would have corrected that before they launched the product. Wouldn't they?
P.S. For reference, my issue was with my Dreamline about 3 years ago.
Thx
Dan
P.S. For reference, my issue was with my Dreamline about 3 years ago.
Thx
Dan
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A carbon fiber sleeve has corrected a lot of POI shifts for forum members so I'm not sure F.A. is getting the right input.
Glenn in Texas
Glenn in Texas
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This factor was in my mind but I didn't mention it as I thought that since it shows extreme fragility of the barrel system, hence you might not agree to it.
Good to know you already found it and fixed it.
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Whenever you hear an absolute statement you can be sure it is wrong (I am aware I just made an absolute statement).
I think the big question, at least in my mind, is whether the FX externally applied rifling is a plus or a minus. I used to think it was a plus but then heard that boroscopes show a rough interior in FX liners which is not what I assumed. I'd love to know if this is accurate. If the bore of FX liners is not smoother than good cut rifled barrels, then I would say it is a minus. To apply the rifling externally the liner has to be thin. Thin barrels are going to move more for tons of reasons. Their response to the firing pulse will be greater, their response to externally applied pressure will be greater, etc.. This is just basic mechanical characteristics. If the interior of the liners is smoother than other barrel alternatives, it could help offset the lower stiffness of the thin barrel. I think a lot of the dynamic response of the barrel is due to pellet friction. But if it is as rough as other barrels, there is no offset, it is just a thin barrel that will move more easily.
My theory is that FX has the industries best way of tuning their guns with excellent hammer spring changing methods and now even a dwell adjustment on Impacts I think is to offset the thin barrel. They tend to move more so they have to be adjusted better to shoot as well as they do.
If you are feeling like debating thin versus thick barrels please review what the best bench rest shooters use. They have to have weight classes because the heaviest rifles shoot the best. A thin barrel can shoot very, very well but it is a handicap versus a thicker barrel.
I think the big question, at least in my mind, is whether the FX externally applied rifling is a plus or a minus. I used to think it was a plus but then heard that boroscopes show a rough interior in FX liners which is not what I assumed. I'd love to know if this is accurate. If the bore of FX liners is not smoother than good cut rifled barrels, then I would say it is a minus. To apply the rifling externally the liner has to be thin. Thin barrels are going to move more for tons of reasons. Their response to the firing pulse will be greater, their response to externally applied pressure will be greater, etc.. This is just basic mechanical characteristics. If the interior of the liners is smoother than other barrel alternatives, it could help offset the lower stiffness of the thin barrel. I think a lot of the dynamic response of the barrel is due to pellet friction. But if it is as rough as other barrels, there is no offset, it is just a thin barrel that will move more easily.
My theory is that FX has the industries best way of tuning their guns with excellent hammer spring changing methods and now even a dwell adjustment on Impacts I think is to offset the thin barrel. They tend to move more so they have to be adjusted better to shoot as well as they do.
If you are feeling like debating thin versus thick barrels please review what the best bench rest shooters use. They have to have weight classes because the heaviest rifles shoot the best. A thin barrel can shoot very, very well but it is a handicap versus a thicker barrel.
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Rifling that is pressed from the outside is so non-uniform inside that it makes it impossible to lap them. If you push a slug down the barrel an inch at a time you can observe light visible around one side of the slug in one position... only for the position to change after you have pushed it another inch. This is the washboard that you feel when you slug a barrel of this type. This typically goes on all the way down the barrel. If you try to properly lap one of these barrels by casting a lap of any significant size in the bore...the lap will be unable to move because the rifling is so inconsistent.
Mike
Mike
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Thank you for the detailed discussion on the topic. Your input is very valuable.
As per my experience, I can say that FX liners are mostly extremely accurate irrespective of their internal bore consistency issues.
I have found that LW barrels have very consistent bore. Same applies to cut rifled barrels.
FX liners are not very consistent internally when I push a pellet or slug through the liner. But these liners are extremely smooth with a mirror finish.
The issues in some of the liners that we see are some exceptions as I feel. I have also found a few bad liners but bad barrels come in almost every brand.
I understand that the process of crimping the grooves from the outside is so flexible that the manufacturer can change the internal dimensions and choke very easily to experiment what shoots best.
I can tell you that my BSA old stock solid barrels are not very consistent from inside but these are more accurate than LW barrels.
I understand that accuracy is not directly related to consistent bore rather it depends on overall features of the barrel that includes choke, land and groove profile, twist rate etc.
I agree that FX guns provide extreme tunability to the users and in result these liners perform even better.
But believe me I have installed FX barrels on Daystate Delta Wolf and the accuracy was amazing.
So as per my understanding the issue is not accuracy, rather the issue is whether FX liner system provides consistent POI or not.
I see that initially FX gave the liner with O rings, then they offered carbon fiber sleave to make the barrel sturdier. Then FX introduced barrel tension system.
From the above fact one can assume that there might had been some issue and in order to fix it / improve the barrel system FX introduced all these improvements.
When I shoot benchrest, there is negligible issues of POI shift but if I go out in an open jeep, I need to re zero the scope often while my scope and mounts are reliable.
I have also solid barrels for my Impact and those solid barrels behave better when exposed to external factors.
Hence your point appears to be valid that in competitions, seasoned shooters prefer heavy barrels. But in airgunning it is not that necessary as we witness that a lot of competitions have been won with FX guns using their liner system.
So what I feel is that the liners are great and perhaps if we bond them inside a solid pipe of metal or carbon fiber and thus make a solid barrel, these liners can perform even better.
Bhaur
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My POI shifts would still hit a squirrel in the head at 30 yards, with me doing my part. So as a pest rifle, no issues. But hitting a 1/8 in bullseye at 30 yards, different story.
To comment on the end user being happy with the product they have, that is subjective. My expectations are different from someone else. So you can't say its just us as a small collective of noisy folks that means its not widespread. From going to public and private ranges my whole life, you see a vast difference in what people consider good. Forums usually attract enthusiast. So our opinions will be stronger.
To comment on the end user being happy with the product they have, that is subjective. My expectations are different from someone else. So you can't say its just us as a small collective of noisy folks that means its not widespread. From going to public and private ranges my whole life, you see a vast difference in what people consider good. Forums usually attract enthusiast. So our opinions will be stronger.
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The liner is a thin tube inside another thin tube with the possibility of supports between the two tubes and even an external carbon fiber sleeve the full length of the liner. The carbon fiber sleeve seems like an obvious attempt to stiffen it up. It should work well if it is glued on. If it just slides on then the liner can move relative to the sleeve (like from vibrations of a car) and that could easily cause POI shift. Vibration or bumping could also change the position of any external supports on the liner that touch the shroud. That is another potential source of POI shift. The fact that the liner is thin means that any force applied to it will move it more than it would a thicker barrel.
Another potential source of a change affecting POI is the barrel attachment. If you really want POI to be completely reliable you would use a thick barrel attached to the receiver rigidly (like threaded on as in a Taipan) and you would float the barrel, not have other things touching it that may shift around. I don't think that description fits a FX gun very well.
I am not a FX hater, if they made a bullpup that didn't put the big oversize magazine right in my face (I shoot from my left shoulder) it would be on my short list, at least. But I think their thin barrels make them more likely to shift POI than a gun with a barrel several times as thick. Stiffer tubes are just more resistant to movement than thinner tubes. An externally applied force doesn't move or otherwise affect the stiff barrel as much.
Another potential source of a change affecting POI is the barrel attachment. If you really want POI to be completely reliable you would use a thick barrel attached to the receiver rigidly (like threaded on as in a Taipan) and you would float the barrel, not have other things touching it that may shift around. I don't think that description fits a FX gun very well.
I am not a FX hater, if they made a bullpup that didn't put the big oversize magazine right in my face (I shoot from my left shoulder) it would be on my short list, at least. But I think their thin barrels make them more likely to shift POI than a gun with a barrel several times as thick. Stiffer tubes are just more resistant to movement than thinner tubes. An externally applied force doesn't move or otherwise affect the stiff barrel as much.
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Let's modify this statement a little.
The Government very kindly advised that in fact when we examine the perceived issues of UFO's, there is no such evidence.
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Does this mean that all the people who purchased the FX manufactured CF products , barrel bands, etc, from FX to help address POI issues should get with FX and get their money back since the FX founder says there is no known poi problem? What am I missing?
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@mubhaur You just opened up a big can of worms by praising FX especially Fredrik, hope you got your flame suit on!
There is no doubt that FX barrel system is more sensitive and does produce POI if the variables get changed but it is the internet so no one will admit they didn't torque the barrel and nuts correctly or failed to address parallax errors. To be fair there are more parts and o-rings to screw things up. No, we can't drop a FX gun or run it over with an SUV and expect the POI won't change while complaining the gun is too heavy. FX has always been a hunting rifle first but happens to sponsor and win a few BR matches so all of sudden people are comparing a 6lb FX gun to a 10lb dedicated bench rig. But don't forget that it's the internet where everyone is perfect and expert at everything.
The good thing is FX is simplifying their designs so the guns will have less parts/variables to worry about. Worry not, I'm sure there will be a huge line to complain it can't go from high power to low power with a simple dial anymore. Can't please everyone.
There is no doubt that FX barrel system is more sensitive and does produce POI if the variables get changed but it is the internet so no one will admit they didn't torque the barrel and nuts correctly or failed to address parallax errors. To be fair there are more parts and o-rings to screw things up. No, we can't drop a FX gun or run it over with an SUV and expect the POI won't change while complaining the gun is too heavy. FX has always been a hunting rifle first but happens to sponsor and win a few BR matches so all of sudden people are comparing a 6lb FX gun to a 10lb dedicated bench rig. But don't forget that it's the internet where everyone is perfect and expert at everything.
The good thing is FX is simplifying their designs so the guns will have less parts/variables to worry about. Worry not, I'm sure there will be a huge line to complain it can't go from high power to low power with a simple dial anymore. Can't please everyone.
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Dude from the kebab corner told me there was no evidence his servings were not fresh. And then i was on the loo for 2 days....
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100% agree, this is why the choke is so important on FX liners. Personally I only do a polish on the choke on my FX liners/barrels.
BUT each liner is 110 bucks retail and readily ordered from the internet. A FX barrel/liner can never come close to a proper precision cut barrel that is hand lapped and polished which is orders of magnitude more expensive along with the wait time. Then again nothing can, not even the cold hammer forged barrels many think so highly of. For most people and hunting/target shooting applications FX barrels has been more than good enough......at least for me. If want better then people should stop the complaining and open their wallets to order custom barrels just like our PB friends or one of your/Thomas barrels.....if you are even willing to sell one.
EDIT: while the FX liners are clearly inferior in many ways but FX knew that and paid more attention to the choke to address the short comings. Is it ideal? Of course not but it is silly to compare a $110 dollar retail priced metal straw to a proper precision barrel that generally will not cost less than 500-600 bones before fitting. At the end of the day let paper do the talking......especially if we put a price on the targets/groups.
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To Mike's point, so far the only time I've poured a lap that I then could not move was an FX liner. It was at that moment I gained a fuller appreciation for how a choke can salvage what would otherwise be a tomato stake.
The muzzle of this particular example was over 3 thousandths smaller than the breech.
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I hope you had your boots on when Mr. Fredrik was telling you all this.
The bull$#it was getting deep...
The bull$#it was getting deep...
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