Curving Pellet / Need Advice

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Hey guys. I have a slight issue here and I'm not sure which way to go with this. This is my first gun with the ability to tune and I'm new to the pcp world. The gun is a FX DreamTac .177. Shooting the JSB Beast 16.20 gr @ 900 fps avg deviation of 4.7. The way the gun shoots them seems as if I'm in a sweet and sour point of tune. Hitting targets out to 80 yards with precision. Any further past that the pellet will curve hard to the right, sometime it will spiral. And sometime it will hit the target. Sometime shooting targets within 35 yards I will notice a hard shift in poi, but not often. I've tried the jsb monster rd, heavy, and I started out shooting the exacts. All of these pellets will spiral at certain ranges. The barrel is clean. Any suggestions or similar experiences??

https://youtu.be/vXl1QUZ_600
 
80 yards is a pretty long shot for a .177 pellet. We have entered a brave new world where we expect laser precision at 2-3 times the distance that was shot just 10 years ago. Not that I disagree with pushing the development envelope, but keep in mind that 80 yards is danged long shot even for a . 22 long rifle for the average shooter.

In my .22 PCP, I can shoot great groups with a certain JSB at 40 yards, but at 44 yards the group blow up wildly. The same manufacturer but different weight and or shape, shoot beautifully to 100 yards plus. 

There is way more science to these pellets than I can begin to claim to understand.
 
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Could be the pellets, even if you weigh them that is not telling you the entire tale.....the nose or tail (see what I did there) could be a bit more or less heavy then the last one.



This is why pellet testing with A BUNCH of pellets is key.



What I do is decide out of a group of pellets what shoots the best....and by group it looks like I looted PA or something by looking at all the different pellets I carry out.

Once I get that down I will run the gun on the bottle with those pellets for around 100 shots, not all in the same day, but different days....I try still days, but nice days, humid days...you get the idea. Then when a winner is found that is the tin and the pellets I will use in that gun. When that tin is gone I will re run the 100 shot test on the next tin, if the results suck then back to the runner up.
 
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I suppose it may be worthwhile to add, any damage that gets introduced to the pellet will have a similar effect on how sensitive or insensitive it is to destabilizing. Something like a burr at the barrel port that scores the pellet upon chambering, a sharp from the leade into the rifling, a burr at the crown, damaged rifling, clipping (or nearly clipping) a baffle to name the most common ones. I neglected to bring up these items on the basis of you saying you're getting good precision at 80 yards. That suggested to me these things are not at play, or if they are, their effects are so subtle as to mean they would be quite difficult to identify. I show some examples in this DIY guide if you are interested though.
https://www.gatewaytoairguns.org/GTA/index.php?topic=130555


 
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That's alot to consider. But you are right as well as the others. The other 3 jsb pellets I've used never curved hard like that. They would only spiral at certain distances. I'm totally happy with the 80 yard accuracy... But I would like to be on point further down range. I will start out by lowering the fps by 50. And I will sort out a couple of maginzies of the Beast and give it another try. Thanks for all the replies guys
 
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1591142766_9191508965ed6e96e12e064.41544452.jpg
1591142767_19323875105ed6e96f246155.04878625.jpg


See that gray ring around the first baffle? See how close it is to the face of the muzzle? There is nowhere for that initial blast of air to go, and in my theory it was destabilizing the pellet.



Put it on three different guns and neither were as accurate with it on. I put it in the lathe and bored out the first baffle to muzzle diameter. Fixed it on all three guns. Another issue is the thread tolerance on this are floppy loose. Looser than all the other moderators I've owned. 

When I threaded the barrel on my HW100 I used the Tanto for my fit check, since it was going to stay on it, and none of my other mods will even go on the threads. 

Putting an oring between the moderator and barrel face will destroy the only thing that keeps the moderator square to the bore. The interface of where the rear of the moderator meets the square face of the rear of the threads ensures all is square. Loose andfloppy threads can cause a loss of concentricity. Hence the reason for fitting the threads to the Tanto when I cut them in. Later on if I want to use a different mod, I'll have to chuck the barrel back up and cut them deeper to fit the new one. IMO it's the best way to make sure everything is lined up the best it can be. 
 
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1591142766_9191508965ed6e96e12e064.41544452.jpg
1591142767_19323875105ed6e96f246155.04878625.jpg


See that gray ring around the first baffle? See how close it is to the face of the muzzle? There is nowhere for that initial blast of air to go, and in my theory it was destabilizing the pellet.



Put it on three different guns and neither were as accurate with it on. I put it in the lathe and bored out the first baffle to muzzle diameter. Fixed it on all three guns. Another issue is the thread tolerance on this are floppy loose. Looser than all the other moderators I've owned. 

When I threaded the barrel on my HW100 I used the Tanto for my fit check, since it was going to stay on it, and none of my other mods will even go on the threads. 

Putting an oring between the moderator and barrel face will destroy the only thing that keeps the moderator square to the bore. The interface of where the rear of the moderator meets the square face of the rear of the threads ensures all is square. Loose andfloppy threads can cause a loss of concentricity. Hence the reason for fitting the threads to the Tanto when I cut them in. Later on if I want to use a different mod, I'll have to chuck the barrel back up and cut them deeper to fit the new one. IMO it's the best way to make sure everything is lined up the best it can be.
Click to expand...

Do you agree the only way to fix this kind of issue to guarantee harmonics and air blast uneven turbulence nonconcentricity or whatever etc can only be fixed is to permanently epoxy the LDC onto the gun and keep it specific to that gun? The worlds best airgun tuner threw that one at me before when discussing ultimate accuracy. Yo!
 
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