Wing Commander
Member Extraordinaire
If British Rail made pellets, they would blame any differences in POI to being fired in the wrong type of air. 
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the Daily hi thread
Something has always puzzled me...
- Thread starter TonyBeau
- Start date
If we know what rifle it is, we can all nerd out over barrel length, spin rate and if it’s under or over a full turn before exiting.
I found this on AGF in 2023, that could explain why different pellets require different optimal muzzle velocities. I have noticed that some tuners require a tin of the pellets most used so that the rifle can be tuned to suit them. Thanks @chouchin66
It matters greatly. For example, rws super heavy 9.7grain in my barrel group well on the very cusp of 12ft lb 745fps, back of the hammer and drop them down to 715-720fps and they are laser accurate at 25M. That 25fps opens up the groups, could be turbulence exiting the barrel at higher fps or that it’s just spinning a little to fast
Backgardenplinker
Member Extraordinaire
What an interesting thread 
webley00
Busy member
I have often wondered if a finished barrel is mounted onto a rifle do they bother to align the rifling in the same place or are they random.
I wonder if this makes a difference to whether it shoots high, low,left or right.
I guess the only way of knowing would be to mount a barrel absolutely rock solid and test pellets in that way.
Then I guess temperature,humidity etc would have to be consistent.
No sod it inconsistency is all part of the fun.
I wonder if this makes a difference to whether it shoots high, low,left or right.
I guess the only way of knowing would be to mount a barrel absolutely rock solid and test pellets in that way.
Then I guess temperature,humidity etc would have to be consistent.
No sod it inconsistency is all part of the fun.
chouchin66
Top Tier member
Twist of rifling & it's rate will be a constant, no matter it's " clocking" or length of barrel...
I think any problems that arise are from the " drinks straws" used for PCP barrels , (allowing " bendiness" ) & ease of alignment issues from barrel bands used or lack of support along their length...why full diameter( ala springer) barrels aren't used is a mystery to me
Philthunder
Member Extraordinaire
Leaves on the riflingIf British Rail made pellets, they would blame any differences in POI to being fired in the wrong type of air.
again
webley00
Busy member
Weight I suppose.
A springer needs the weight to contract the spring rebound.
Dan giliballs
Member Extraordinaire
I’ve had the same thing, tight group but looping off to the left, zero at 20 yards it’s spot on, go out to 30 and it’s off to the left again, not cant or incorrect scope fitting or parallax error, I can see the pellet in flight
chouchin66
Top Tier member
A bunch to be said though for a barrel substantial enough to stay true, no matter the knocks it may take...PCP users are hardly effeminate weaklings.
if you'd zeroed originally with the aa express or exacts you'd be asking why some other pellets are groupimg high and right 
i exchanged emails with a fella from jsb about 15yrs ago and he said that a jsb exact die 1 must be treated as a totally different pellet altogether from a jsb exact with any other die number, even though they look and weigh identical
if i zeroed with aadf die 51, die 28 would shoot low/left, had the same with exacts die 30 and 48, but no matter which one i zeroed with they were accurate out to 35/40yds, never tried em any further
i exchanged emails with a fella from jsb about 15yrs ago and he said that a jsb exact die 1 must be treated as a totally different pellet altogether from a jsb exact with any other die number, even though they look and weigh identical
if i zeroed with aadf die 51, die 28 would shoot low/left, had the same with exacts die 30 and 48, but no matter which one i zeroed with they were accurate out to 35/40yds, never tried em any further
1260engineer
Member Extraordinaire
Experiment for you to do 
shoot the same pellets again in the same order . write down which pellets do what .
Then push a couple of each pellets through your barrel in the same order.
Then have a good look at the rifling marks on the head and skirt of the pellets .
Then you can compare the pellets fit to the target .
Now find some other pellets and reverse what you just did .
push a couple of pellets through your barrel from each type.
Then cross reference the rifling cuts with the previous result on the push though.
Now see using that info .
See if you can predict what each of the pellet types will do on the target by the rifling marks left by the push through.
shoot the same pellets again in the same order . write down which pellets do what .
Then push a couple of each pellets through your barrel in the same order.
Then have a good look at the rifling marks on the head and skirt of the pellets .
Then you can compare the pellets fit to the target .
Now find some other pellets and reverse what you just did .
push a couple of pellets through your barrel from each type.
Then cross reference the rifling cuts with the previous result on the push though.
Now see using that info .
See if you can predict what each of the pellet types will do on the target by the rifling marks left by the push through.
As asked I have repeated the pellet test this morning, I slightly adjusted the zeroing before I started after trying the Baracuda 8's. As you can see, the results are very near identical, I consciously didn't let any bias occur, it was the same scope settings for all the pellets as I was more interested in the group size rather than hitting the bulls eye. I have found this very interesting, it now explains (at least to me} why some pellets in the same batch go wayward from the others when aiming at a target. My theory is that pellets do spiral when fired and if everything is perfect the pellets hit the target consistently at the same point in the spiral, if something is different to change the spiral like weight, size and mishape of the pellet then the target will be hit at a different point of the spiral which can be any point in a circle around the target. Your comments are welcome.
@1260engineer , I very much appreciate your response and there is a lot of sense in it but I have had a lot of problems getting the rifle to this level of accuracy and the thought of taking the barrel off and on to carry out experiments fills me with dread! I will use the pellets that have the best grouping and leave it at that. I would of course be interested if anyone else decides to do it.
You can put a balled up old T-shirt in a pellet trap and fire, then inspect the riflingView attachment 762080View attachment 762080
As asked I have repeated the pellet test this morning, I slightly adjusted the zeroing before I started after trying the Baracuda 8's. As you can see, the results are very near identical, I consciously didn't let any bias occur, it was the same scope settings for all the pellets as I was more interested in the group size rather than hitting the bulls eye. I have found this very interesting, it now explains (at least to me} why some pellets in the same batch go wayward from the others when aiming at a target. My theory is that pellets do spiral when fired and if everything is perfect the pellets hit the target consistently at the same point in the spiral, if something is different to change the spiral like weight, size and mishape of the pellet then the target will be hit at a different point of the spiral which can be any point in a circle around the target. Your comments are welcome.
@1260engineer , I very much appreciate your response and there is a lot of sense in it but I have had a lot of problems getting the rifle to this level of accuracy and the thought of taking the barrel off and on to carry out experiments fills me with dread! I will use the pellets that have the best grouping and leave it at that. I would of course be interested if anyone else decides to do it.
I’ve done this a few times, works a treat
webley00
Busy member
tac
Super member
I will use the pellets that have the best grouping and leave it at that. I would of course be interested if anyone else decides to do it.
Well, that's what most is us do, having established what pellets work best....
1260engineer
Member Extraordinaire
What rifle is it mate ?View attachment 762080View attachment 762080
As asked I have repeated the pellet test this morning, I slightly adjusted the zeroing before I started after trying the Baracuda 8's. As you can see, the results are very near identical, I consciously didn't let any bias occur, it was the same scope settings for all the pellets as I was more interested in the group size rather than hitting the bulls eye. I have found this very interesting, it now explains (at least to me} why some pellets in the same batch go wayward from the others when aiming at a target. My theory is that pellets do spiral when fired and if everything is perfect the pellets hit the target consistently at the same point in the spiral, if something is different to change the spiral like weight, size and mishape of the pellet then the target will be hit at a different point of the spiral which can be any point in a circle around the target. Your comments are welcome.
@1260engineer , I very much appreciate your response and there is a lot of sense in it but I have had a lot of problems getting the rifle to this level of accuracy and the thought of taking the barrel off and on to carry out experiments fills me with dread! I will use the pellets that have the best grouping and leave it at that. I would of course be interested if anyone else decides to do it.
Try catching the pellets in something soft as far away as possible. you can get a bit more range by shooting diagonally from corner to corner of your garden if possible.
Personally I never polish my barrels i like deep cut sharp edge rifling marks. So I look for pellets that come out on a push through looking like this or deeper . on my conventional rifled barrels.
Rifling markes on both the head and skirt . the cutting seems to act like a defuser around the head of the pellet . this also means the pellets is square in the bore ( parallel) this also means the pellet is leaving straight .
Rifling marks and the shape of the skirt can tell you so much about your barrel and the way your rifle delivers the charge to the rear of the pellet .
Just take the skirt .
1 . see the slight roundness to the body . this means the charge is sharp enough to expand the skirt properly.
2 . is the depth in the rifling groove. means you have a good seal .
if you look back at the pellet above you will see it seals around the head too.
Removing barrels is one of the things i do on purpose during testing. i like to know that the barrel automatically locates back in the same place where it was when refitting .
Martin T
Super member
This is what I think is going on, the YouTube channel TedsHoldover showed it years ago with slow motion video. I won’t link them because they show hunting.
