Tuning Barrel Indexing Question

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kaylaindy

kaylaindy

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Jun 3, 2017
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I am about to index the barrel on an M3. I have a question about the indexing process. 

12 is the point of aim at 12 oclock barrel position.

The goal is to get one of the other points to be above or below 12 oclock. I will be turning the barrel to 3 oclock, 6 and 9. 

My question: will there automaticly be 2 points that are stright accross from each other like in the bottom illustration and then I bring one of these 2 points to be straight up and down?...so 3 or 9. ? or will it be like the top illustration, nothing straight across, and I just pick any of the 3 dots to bring into and up/down position? ...in this case #3. / or am I missing something about the 12 position?... if so please draw or explain. Thank you! 

20211211_080740.1639240335.jpg


going off this video. I'm about to watch it again. 

https://youtu.be/E-l4tt8UkN8?t=226
 
Your 12 o'clock would be where u start where you're all ready sighted in to which was his first dot he put on the paper then index to 3 it can be anywhere on the paper then 6 which can also land anywhere on the paper and so on once you get to the 12 o'clock position again it should be back to where you started or where your sighted in to then looking at the paper I would pick the highest point where the shot landed when indexing if it is off to one side or the other then you would have to index in-between. Say your highest is at 3 o'clock but it's off to the side of your original 12 o'clock point that your sighted into depending on which way it is off you would reindex between 3 o'clock and 12 o'clock or 3 o'clock a ND 6 o'clock so the highest point would be in line or straight above you original point of impact or the 12 o'clock 
 
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In my case the POI straight above or straight below to the POA - would result not enough rail + rings adjustment (to the Left) but also moving out the scope optical center as well. The difference would be about 7-8 MILL/MOA.

For this same reason me personally I left the adjustable rings centered also the scope optically centered, and I moved the rail only as much the screws allowed (Impact have a loose rail).

And I call it a done deal. I am not calling this my step perfect, but at least my scope is not stressed.
 
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Your 12 o'clock would be where u start where you're all ready sighted in to which was his first dot he put on the paper then index to 3 it can be anywhere on the paper then 6 which can also land anywhere on the paper and so on once you get to the 12 o'clock position again it should be back to where you started or where your sighted in to then looking at the paper I would pick the highest point where the shot landed when indexing if it is off to one side or the other then you would have to index in-between. Say your highest is at 3 o'clock but it's off to the side of your original 12 o'clock point that your sighted into depending on which way it is off you would reindex between 3 o'clock and 12 o'clock or 3 o'clock a ND 6 o'clock so the highest point would be in line or straight above you original point of impact or the 12 o'clock
Click to expand...

Perfect! Thank you for explaining that. -Nate 

I left the adjustable rings centered also the scope optically centered,
Click to expand...

Awesome tip! Thank you! 
 
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A good FX stx liner with good barrel shell should make a repeatable circle on paper with pellets when you rotate the liner gradually in 360 degree.

A solid barrel does it almost every time.

Sometimes stx barrel doesn't show this phenomenon and that is alarming for me as it means that there is various pressure forces at various points of O rings on the liner.

If a comple circle is achieved by shooting pellets while rotating the liner in 360 degrees then either 6 O clock or 12 O clock are best positions to keep the barrel well indexed.

If there is any issues in the liner, shell or O rings then the rotation of complete barrel at 180 degrees having two holes in TP, one (dual) for slugs and one single for pellets will not keep the POI along the same vertical line.

Have I communicated successfully?

Bhaur
 
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I have been competing in archery for over a decade and learned the CF tubes = arrow shafts. Also pro golfers and pro fisherman learned their tools.

The blank arrow shafts for competition starts about $450-500 a dozen, and you assemble those for next $ 150 test and tune and filter out the defected, and only then we can go scoring perfect X's. From a dozen finished arrows maybe 80% flying as you aim. Sometimes need tree dozen arrows to test and put one perfectly flying dozen arrows = lets talk about $1500-2000 a cost.

From these view please tell me what you are expecting from a CF tube for $10-20 a piece? Maybe you shall buy a dozen and try every each there would be a better chance.
 
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Unless I’m wrong, but to me indexing is to find out out of all the chosen points that you shoot groups of five at while going around the clock, is one of those clock points or even in between clock points will give you the closest of groups. Who cares if the tightest group is 2” left and 3” low. If it’s the group with the 5 pellets more on top of each other, set your final scope adjustments to that.



Once set, tweak on gun controls and adjustments to tighten that group even further.



edit- this is of course done after desired tune speed is found, and an optically centered scope is mounted properly with no cant whatsoever
 
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I think that isnt the point of indexing here the point of indexing they are describing is to get the extreme up or extreme down of the barrel whip centered or timed f class builders do infact take this Into consideration when building the gun and infact have the barrel timed or indexed to have this point of the barrel straight up and down otherwise the gun may not shoot straight and farther you go out the farther off you are it will intersect at the point of sight in but not anywhere else if you get it right I would assume it means less dialing left or right which will still have to be done to some degree but less is better I understand what you are saying as well for indexing but don't think that is what they are discussing here with indexing but I maybe wrong 
 
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Unless I'm missing something, I think that the indexing "goal" is described incorrectly and there is little understanding of the indexing as it's supposed to be. Indexing to me means what Augie described, the tightest group no matter where. Once the correct pellet and speed are found. Of course, that would change with using another pellet. So, finding the 12-6 o'clock position may have poor accuracy even though the scope was easier to adjust. Why do that (unless it happens to be the most accurate)?

There are better YouTube vids on this subject and perhaps the OP should review some of them to assure that is in fact what is needed?

mike 
 
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I have very little experience with barrel indexing, but I think maybe two different things are being discussed under this general topic. The orientation of the barrel can affect both accuracy, and shifting POI with increasing range. My experience is with the former, as I am not a long distance shooter. Rotating the barrel has a tuning effect, and there may be a specific position at which the best groups are produced. That may not be the best position for the most consistent POI with increasing distances. So, I believe one's interest in barrel indexing depends very much on the goal. The size of your target and the degree of precision required will also have a big impact on the process. Just my opinion, may be wrong. 
 
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