Help with pellet spiral

[Ziabeam]

"oldspook"

"Ziabeam"From my perspective every pellet fired in carpp's videos exhibited an uncannily similar corkscrew/flight path, almost as though the same distorted pellet was fired over and over and over... or, more probable, every single pellet was distorted in the same way, by the same anomaly in the barrel.

Absolutely! They are very consistent, more than that, none of the video shows a complete spiral. What we see looks like a canted scope being shot up into the sky with a cross wind. I see nothing in his video which can serve as a reference to judge the magnitude of the spiral.

First off (my OCD moment) the "spiral" of which we are striving to either "see" or "rule-out"... may we instead agree to call it a "corkscrew" ??
I ask this because I definitely think I see a corkscrew, with the pellet straying towards the right, then abruptly crossing the canted crosshair over towards the left side, followed quickly by a similarly abrupt wandering back towards the right, at which time it tends to be taking a dive if not a harder right turn than seen in some of it's previous flight paths.... i.e. a distinct corkscrew to my eye. Admittedly one definitive component is lacking in order to verify or nullify that perception... a background or point of reference other than the crosshairs to corroborate what the crosshairs seem to indicate as a stand-alone optical comparator.

 

[BRS]

Without taking a 'side' here, I agree with Oldspook's evaluation:

The pellet appears to rise and arc over from the left then fall near the 'zero' (ie: be on the left of the 1st or 'point blank' zero then fall back to the right to be near or on the 2nd zero ((the correct zero to use)) - that's just my reading of the video and ignoring the cam mount being off-kilter).

I do not see a Spiral, I see an Arc, which is canted over to the left. 

As the video is unable to show any detail beyond my above 2 zero points and with no range data shown ...

 

[Ziabeam]

Alright everyone...
Please pardon my obsession with this thread, which I find fascinating to say the least. This is coming from a re-barreling sadist who has toured Bartlein's facility, Liberty Barrels and Satern's facility, have a friend I've known since he was in diapers working at Benchmark, and have re-barreled over half the air rifles and powder burners I own, including using hypodermic tubing to re-barrel a Daisy Red Ryder... all the way up to turning/fluting and chambering my own custom .50 BMG barrels, along with re-barreling countless government owned match rifles. Barrel performance fascinates me.

Which brings us to the present, the perceived corkscrew in carpp's video.
I have watched it a few times, and annotated the corresponding time of each shot to save time for anyone else who cares to take the time;

Eight shots in video... shot # and time;

1. :30
2.  :58
3.  :1:25
4. 1:52
5. 2:19
6. 2:47
7. 3:13
8. 3:39
   [/LIST=1]
   Corkscrewing ??
   My "guess" is a firm yes, with such repeatable choreography that I'm convinced the barrel is deforming each and every pellet the same exact way.
   May be wrong... but I'm trying for carpp's sake to pinpoint the cause.
   

 

[Guest]

Looks like you have a damaged barrel.
I have seen many of such barrel problems.

 

[fe7565]

I am pretty sure those lines are not damage, albeit there may be other damage not visible from the photos. Those lines are from FX's twisting machine leaving a mark on the barrel's outside.

3:11 minute mark

I think at this point we need more shooting tests from OP with the naked barrel only, hand-loaded pellets, chrony the pellet velocity for Heavy and King JSBs at 50 yards and 100 yards or at least 75 yards. Since the rifle can only do 780fps with the Heavy, it still should be able to do 900fps with the Kings. If the Kings fly at 900 fps MV in a straight path past 50 yards to 100 yards then very likely the velocity for the Heavies is too low for it to fly stable. If the Kings corkscrew between 50-100 yards at 900fps,muzzle velocity than something is wrong in the barrel, either at loading or at exit that damages or deforms the pellets.

 

[carpp]

"oldspook"

"Ziabeam"
He said it grouped marginally since new.

What does that mean? Frankly I've asked repeatedly in the thread how the damn thing groups and have never gotten a response. His marginally might be my superb or vice versa. How does the damn thing group? I feel like I am talking to a troll here, or someone who just wants to tell me every single way that it is impossible to solve this problem. We have discussed every possible solution and he has tried them ALL but NONE of them work. Then you ask him how the gun groups and you don't get any real answer. You want help? HOW DOES THE GUN GROUP... Pictures are nice. What do 100 yard groups look like?

-- carpp "Ive got a spiralling pellet issue with my .25 fx 500 at 50 yards it groups nicely but beyond that pellets start to spiral wildly"

A 5 shot group at 50yards that is covered by a 2pence coin is what would consider ok and thats what the gun will do, probably better if i put more range time in, over the next few days i will get some targets of 50/75/100 with a bare barrel and hand loaded as suggested and post the results hopefully that will be before the weekend.

 

[BRS]

I would suggest targets set out at every 5 yards over 50 upto 75 max with 2 shots at each. Those 'targets' should be no more than a felt tip pen 'Dot' on a sheet of paper (using say A4 paper, just a dot in the top 1/3 ... obviuosly the same place on each

You would then aim to hit an inch or so above the Dot regardless of where the pellet actually falls on the target.

Best of luck and we look forward to seeing the results !

 

[carpp]

Only had time for 2 targets today and the slow motion camera wouldnt hold a charge, these we shot with no shroud/airstripper/crown protector and single loaded by hand first target is 50 yards then second is 75 8 shot groups, had two flyers at 75 that i circled other than that i think it looks ok. 

 

[Ginuwine1969]

I have an FX Impact and i get a lot of corkscrewing and been doing testing with Kings, MK1 & 2's and I can shoot the MK2's a min power about 500 FPS and get groups 1/2 inch at 50 yards so its I don't know if too slow is an issue. I do believe that after a certain point speed matters (maybe between 700-950 but i don't know. Too windy here to call my test conclusive so i've been pretty much wasting lead and air. Will do some real test when the winds slow down its about 15-20 knots here now.