Why 2 O’Clock High?

[UlkaHuren]

I usually love H&N FTTs. In my other guns they are one of my preferred ammo, but in my Gauntlet 25 they hit at around 2 o’clock off target center and not so tight. The JSB Kings and Heavies hit dead center in the same hole every time. The thing I’ve never figured out is why a pellet would do that. I could understand it if they shot a wider group randomly around the center from pellet size variability, but not why they choose to group consistently off center diagonally. How does that bit of physics work? lol

 

[Tweeter]

Two different pellets can be equally accurate but have completely different POI's. Just the way it goes.

 

[mmahoney]

I've wondered the same thing. All I can think of is that maybe the pellet diameter is different and one of the pellets rattles down the barrel slightly and is knocked off center when leaving the barrel - sort of like what happens when a pellet clips a moderator on the way out. It would seem that the consistency would suffer more than it does for those pellets though, so I don't know.

 

[Tweeter]

On my old s510 if I turned the power adjuster down the lower the fps the more to the left my groups would land (still accurate) instead of dropping straight down. Different harmonics when shooting different speeds or pellets? If the barrel moves slightly when you take the shot then depending on where the muzzle is when the pellet exits could change the groups poi?

 

[fishinwrench]

I have noticed that when I fall off the sweet spot on my P-rod my group shifts from dead on at 30 and 40.... to low and considerably right.

Why the RIGHT is a mystery. Makes no sense.

 

[Guest]

The pellet is leaving the barrel during a different stage of the harmonic whip(barrel movement) induced when firing the gun.

 

[Mike_Lenardon]

I have a Wildcat in .25 Just tried some H&H FTTs and they didn't group well at all. I would get a couple spot on but mostly they were all over the place. Oh well just another day playing with toys. 

 

[nomojo65]

Barrel HARMONICS! As others have already stated...

 

[UlkaHuren]

Harmonics? Sounds plausible. My Octane Elite 22 loves FTTs, but it did a similar thing with another pellet, but at a different position. I’m physics minded, but I can’t visualize how it veers off in one particular spot. Mostly if a gun doesn’t like a pellet it just doesn’t group well randomly. 

The Kings and Heavys are my favorites in 25 and the BC is good too. 

 

[fishinwrench]

It's nice to have something to blame my misses on......Harmonics !

Now if only we could learn to TUNE harmonics and make whatever pellets we want group perfectly.

 

[DirtyDovi]

Switching between Crosman, JSB, and H&N pellets a lot, I noticed the same thing.. 
Not a big deal - because I know it happens, just a pain to have to re zero the scopes each time..

Harmonics.. Yup. I wish I had more time to play around with my rifles to learn about that more in depth. 
I wanted to make a few 'universal harmonic tuners' to slide around the barrels to see what differences it would make. 

Basically a cylindrical metal weight with rubber bushing / gaskets that can be slide around, then locked down 
I'm sure it would work. I'm just not sure how well. Or for better vs. worse. haha

For now, I just deal with zeroing for each brand pellet.. 
After that, they're dead on anyways.. 

 

Sam -