FX Is indexing your liner in the FX important?

[huntr]

My questions are:
1. How do you keep the liner from rotating while tightening the 'Liner Lock'? It needs to be snugged, not just finger tight. The o-ring grabs the liner and could move it. Will a sufficient amount of silicone lube completely prevent this? You cannot see your indexing mark once the 'Liner Lock' is in place.
2. What is the point of indexing the liner without having the shroud and suppressor installed?
3. Should you begin indexing with the scope set to optical center? Scope to barrel alignment is also dependent on the base and rings. So, should you zero with your most accurate projectile and then begin indexing?
4. Different projectiles are going to change POI... and not necessarily in a vertical line. Can you really determine the most accurate projectile before indexing? In other words, does group size change with indexing or accurate is accurate regardless?

 

[qball]

My questions are:
1. How do you keep the liner from rotating while tightening the 'Liner Lock'? It needs to be snugged, not just finger tight. The o-ring grabs the liner and could move it. Will a sufficient amount of silicone lube completely prevent this? You cannot see your indexing mark once the 'Liner Lock' is in place.
2. What is the point of indexing the liner without having the shroud and suppressor installed?
3. Should you begin indexing with the scope set to optical center? Scope to barrel alignment is also dependent on the base and rings. So, should you zero with your most accurate projectile and then begin indexing?
4. Different projectiles are going to change POI... and not necessarily in a vertical line. Can you really determine the most accurate projectile before indexing? In other words, does group size change with indexing or accurate is accurate regardless?

Excellent points and additional variables to sort out for the gun regardless and make indexing mostly not useful.

 

[boscoebrea]

For me, the bottom line is consistency.

 

[LDP]

My questions are:
1. How do you keep the liner from rotating while tightening the 'Liner Lock'? It needs to be snugged, not just finger tight. The o-ring grabs the liner and could move it. Will a sufficient amount of silicone lube completely prevent this? You cannot see your indexing mark once the 'Liner Lock' is in place.
2. What is the point of indexing the liner without having the shroud and suppressor installed?
3. Should you begin indexing with the scope set to optical center? Scope to barrel alignment is also dependent on the base and rings. So, should you zero with your most accurate projectile and then begin indexing?
4. Different projectiles are going to change POI... and not necessarily in a vertical line. Can you really determine the most accurate projectile before indexing? In other words, does group size change with indexing or accurate is accurate regardless?

Exactly. My experience so far with FX rifles: I have not had any issues with needing allot of windage adjustment to get my groups centered. My two crowns needed less than 4 clicks to be on. My Impacts have been good minus the time I took the scope rail off and didnt realize they have allot of side to side shift so I didnt properly center it when I re installed it. My shots were way off to the side. I quickly realized how much I could shift the rail side to side when I loosened the mounting screws. It was an easy fix I just made sure it was evenly placed side to side and not shifted in one direction.

 

[huntr]

Excellent points and additional variables to sort out for the gun regardless and make indexing mostly not useful.

Not sure it's "not useful". I can see the advantage to having the projectile travel in a straight line, vertically, to the scope/ barrel alignment. Just wondering what the best way to achieve that is? If it veers left or right of vertical center, with no other influences, it changes windage corrections past your point of zero.

 

[qball]

Not sure it's "not useful". I can see the advantage to having the projectile travel in a straight line, vertically, to the scope/ barrel alignment. Just wondering what the best way to achieve that is? If it veers left or right of vertical center, with no other influences, it changes windage corrections past your point of zero.

Great point, first how many people really make sure scopes and bore is perfectly aligned and tested. Second how many shoot with a bubble level to ensure alignment is prefect while shooting or indexing? You brought up another set of variables many don't take into consideration while indexing. Multiple variables = inconsistent results, and don't get me started on the parallax errors!

 

[Headshots]

I index at the muzzle. The barrel moves freely from the liner. You remove the shroud and the end adapter and boom there's your barrel . Put the 2 things back on and shoot. Then turn your barrel 90 degrees after shooting until you find top dead center .

 

[huntr]

Not much the average person can do to check the alignment of the scope ‘system’ other than the usual scope leveling procedure when mounting the scope. My question was, should you zero then index then re-zero after indexing? Or, should you start from the scope optical center? Or just pick your poison?

 

[Max115]

My questions are:
1. How do you keep the liner from rotating while tightening the 'Liner Lock'? It needs to be snugged, not just finger tight. The o-ring grabs the liner and could move it. Will a sufficient amount of silicone lube completely prevent this? You cannot see your indexing mark once the 'Liner Lock' is in place.
2. What is the point of indexing the liner without having the shroud and suppressor installed?
3. Should you begin indexing with the scope set to optical center? Scope to barrel alignment is also dependent on the base and rings. So, should you zero with your most accurate projectile and then begin indexing?
4. Different projectiles are going to change POI... and not necessarily in a vertical line. Can you really determine the most accurate projectile before indexing? In other words, does group size change with indexing or accurate is accurate regardless?

You are correct about the liner rotating a bit while tightening the lock nut. I found that out while I was doing the tests 4 years ago. It would turn to the right slightly. I didn't use any stopper or glue or whatever to prevent the liner to turn. Once I determined the position of the liner where I though it gave me the highest POI, I simply turned it 1/8" to the left before screwing back the lock nut. Assuming it would turn 1/8" to the right. It was just a guess.

Ideally if I could reset my scope to factory zero with both elevation and windage to be centred, then do the indexing. Of course I would then need a large target area to see the POI first. If that is achievable then just shoot at this large target as is without adjust the elevation and windage. Turn the liner/barrel to see where the POI land. Pick the highest POI then make adjustment to elevation and windage to hit the bullseye.

My thoughts on indexing. Knowing the projectile is spinning clockwise (or counterclockwise) due to the twist of the liner/barrel design, it will continue to spin downrange. So if the barrel position shows that the projectiles are hitting far right, let's say 3 o'clock at 30 yards, then it would hit further right at further distances of 100 yards for example. This would be true for the POI that hit far left as well.

Again, I am no expert by all mean. If I use snooker as an analogy. if you hit the cue ball with a right side spin, it will spin right (technically cue ball would push left first then spin right) and continue to spin right as it travels down the table. But if the cue ball is struck with top spin, it will travel straight down the table. Does that make sense? So if I find the position of the liner/barrel that gives me the highest POI, ie North versus East, South and West, then chances are the projectile would travel on a vertical plane rather then spinning left of right.

Of course you will have to deal with wind factor downrange in order to hit your intended target.

I could be completely wrong with my theory or understanding. But I was able to successfully and consistently hit my targets downrange with this assumption of mine.

 

[huntr]

I index at the muzzle. The barrel moves freely from the liner. You remove the shroud and the end adapter and boom there's your barrel . Put the 2 things back on and shoot. Then turn your barrel 90 degrees after shooting until you find top dead center .

View attachment 443683View attachment 443682

Well thank you for restating what we already knew, but you answered none of the questions.

 

[huntr]

You are correct about the liner rotating a bit while tightening the lock nut. I found that out while I was doing the tests 4 years ago. It would turn to the right slightly. I didn't use any stopper or glue or whatever to prevent the liner to turn. Once I determined the position of the liner where I though it gave me the highest POI, I simply turned it 1/8" to the left before screwing back the lock nut. Assuming it would turn 1/8" to the right. It was just a guess.

Ideally if I could reset my scope to factory zero with both elevation and windage to be centred, then do the indexing. Of course I would then need a large target area to see the POI first. If that is achievable then just shoot at this large target as is without adjust the elevation and windage. Turn the liner/barrel to see where the POI land. Pick the highest POI then make adjustment to elevation and windage to hit the bullseye.

My thoughts on indexing. Knowing the projectile is spinning clockwise (or counterclockwise) due to the twist of the liner/barrel design, it will continue to spin downrange. So if the barrel position shows that the projectiles are hitting far right, let's say 3 o'clock at 30 yards, then it would hit further right at further distances of 100 yards for example. This would be true for the POI that hit far left as well.

Again, I am no expert by all mean. If I use snooker as an analogy. if you hit the cue ball with a right side spin, it will spin right (technically cue ball would push left first then spin right) and continue to spin right as it travels down the table. But if the cue ball is struck with top spin, it will travel straight down the table. Does that make sense? So if I find the position of the liner/barrel that gives me the highest POI, ie North versus East, South and West, then chances are the projectile would travel on a vertical plane rather then spinning left of right.

Of course you will have to deal with wind factor downrange in order to hit your intended target.

I could be completely wrong with my theory or understanding. But I was able to successfully and consistently hit my targets downrange with this assumption of mine.

All of your assumptions make sense to me. I was wondering about trying to determine the average amount of movement wen tightening the liner lock and your 1/8 th turn suggestion is a good place to start.

 

[Max115]

Great point, first how many people really make sure scopes and bore is perfectly aligned and tested. Second how many shoot with a bubble level to ensure alignment is prefect while shooting or indexing? You brought up another set of variables many don't take into consideration while indexing. Multiple variables = inconsistent results, and don't get me started on the parallax errors!

Yes too many variables that we often overlooked when it comes to achieving the best accuracy. Parallax errors are the worst, lol. Good point.

 

[Max115]

All of your assumptions make sense to me. I was wondering about trying to determine the average amount of movement wen tightening the liner lock and your 1/8 th turn suggestion is a good place to start.

All trial and error for me. The bottom line for accuracy is mainly having the proper tune and select the best projectile for your barrel. Lots of other factors involve as pointed by qball. But having a liner/barrel that spin out a projectile on a vertical plane, is a great start to better accuracy at longer ranges.

 

[Ta-Ta Toothie]

Not sure I understand this. How do you determine centered if not by highest POI? If I rotate my barrel and I find the highest POI, then I figure I've aligned the POI with the bore vertically. If instead for example I have the barrel installed with the POI at the 9 o'clock or 3 o'clock position in my indexing, then I would expect a windage difference at various distances which seems to be the point of indexing.

As an aside, I've deleted the after O-ring in the barrel lock nut (muzzle) and replaced it with teflon tape for a spacer, though it does make getting the index mark oriented properly a hassle.

I rotate the barrel until there is no more movement to the left, I do the same to the right, then work it back in between the two. My highest POI does not match up with this, I I just ignore that. Your mileage will very.

 

[Ta-Ta Toothie]

My questions are:
1. How do you keep the liner from rotating while tightening the 'Liner Lock'? It needs to be snugged, not just finger tight. The o-ring grabs the liner and could move it. Will a sufficient amount of silicone lube completely prevent this? You cannot see your indexing mark once the 'Liner Lock' is in place.
2. What is the point of indexing the liner without having the shroud and suppressor installed?
3. Should you begin indexing with the scope set to optical center? Scope to barrel alignment is also dependent on the base and rings. So, should you zero with your most accurate projectile and then begin indexing?
4. Different projectiles are going to change POI... and not necessarily in a vertical line. Can you really determine the most accurate projectile before indexing? In other words, does group size change with indexing or accurate is accurate regardless?

Mark the face of the barrel with a fine tip sharpie so you can see your index mark with the jam nut on.

 

[Headshots]

My questions are:
1. How do you keep the liner from rotating while tightening the 'Liner Lock'? It needs to be snugged, not just finger tight. The o-ring grabs the liner and could move it. Will a sufficient amount of silicone lube completely prevent this? You cannot see your indexing mark once the 'Liner Lock' is in place.
2. What is the point of indexing the liner without having the shroud and suppressor installed?
3. Should you begin indexing with the scope set to optical center? Scope to barrel alignment is also dependent on the base and rings. So, should you zero with your most accurate projectile and then begin indexing?
4. Different projectiles are going to change POI... and not necessarily in a vertical line. Can you really determine the most accurate projectile before indexing? In other words, does group size change with indexing or accurate is accurate regardless?

I keep liner from turn by using silicone grease . Your first question.

 

[Headshots]

I just finished finding my TDC. It takes some time but worth it to me.

 

[trlrman]

Mark the face of the barrel with a fine tip sharpie so you can see your index mark with the jam nut on.

this and a golf tee to keep pressure against the liner so it wont twist .

 

[Headshots]

You see how large the circle is from just rotating the liner . Do you really want it off to one side ? Or the bottom ? Think about that at 100 yards. The circle is at 50 yards.

 

[Ta-Ta Toothie]

I just finished finding my TDC. It takes some time but worth it to me.

View attachment 443717

My rainbow was not as consistent as yours. My highest was more on the left. I also torque down the jam nut to the same every time. That also makes a difference.