Pellet stabilization
Shooting for several hours each day for the past couple of weeks, I’ve observed that certain pellets need a certain level of twist in order to be stabilized in flight, thus becoming accurate. In my Condor SS (everything is the same with the exception of a 12″ barrel) and even with the 24″ barrel, CPs become stablized at around 780-950 FPS. With Kodiaks, they need to be shot at a minimum of 780-800 FPS in order to keep stability in flight. Bear in mind that the faster the pellet flies, the faster it twists. With both pellets, at speeds lower than what I posted, POI can be anywhere. I suppose that they tumble a bit when they don’t fly at the speed they need to in order to fly straight. What do you think?
By the way, what is the twist rate for the 12″ and 24″ barrels on the AF rifles?
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Good Lord man—what possessed you to do that? :?[/quote]
Okay, fixed now 😆
This is part of a post I made on the TOG (gag…) a while back. The thread has since been decimated but here it is anyway—>
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http://www.talonownersgroup.com/modules.php?name=Forums&file=viewtopic&t=7000&highlight=
Yep-need more twist. A stock Condor barrel is 1:16 (1 twist per 16″). A lot of 24″ .22 LR barrels are 1:12-14 and Ruger has a new barrel for the heavy 60Grain .22 LR round that’s 1:9. U need to spin the piss outta those heavier bullets to make ’em fly straight! But more twist would mean more air/shot.
p.s.–Interesting M16 barrel tests HERE
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I know we were talking about SOLID bullets but I think a 1:14 Condor barrel would be fun to play with ’cause of the higher velocities it can reach. The “boattail” at the end of bullets minimizes the effects of the trailing sound barrier pressure wave.
Some light reading–>
http://www.nennstiel-ruprecht.de/bullfly/stab.htm#Dynamic_stability
Good Lord man—what possessed you to do that? 😕
it’s not actually the rate of twist…. if a barrel is 1 in 16 no matter how fast the pellet goes it can only spin 1″ in 16″‘s. But compare it to this a football player throws a ball half hearted and it wobbles so the next time he puts the same amount of spin on the ball and puts his but into the throw and it flys beatiful…. each pellet has a happy place ( speed wise ) i have ran into cases where the gun would get more and more accurate the faster it went, then the group would blow out. I suspect at some point you can push a pellet to fast and skip riflings.. Depending on design of course….you hit on a good subject..
The way that pellet is initially seated in the breech is important too. But I’m probably like most and have a “calibrated” thumb. 
http://www.straightshooters.com/general%20shooting%20items/b7199pellseat.html
I picked up the gun and was shooting full power with CPs and it was dead balls accurate one hole at 15 yds over and over again. Come back out later and turn the gun down to 0-1 and the POI shifts left 1/2″. So I regroup and check my shooting technique and proceed to shoot. Dead on again and then to the left. Went back and fourth for awhile. The good thing of shooting at the low setting is no report at all and it is shooting around 550fps. I put the gun away and come back later. I turned it back up to full power 900+ fps and it is dead on again and I shoot about 80 shots or more and it starts to shift to the left again. I then realized that the real low velocity as the tank ran out and the low velocity of PW 0-1 caused the the change in POI.
So I refill the tank and put it on 0-1 and it is to the left I turn it up to 7 and it is dead on the cross hairs. So my barrel does not like pellets a very low velocitys but it will drill them into a hole like a laser on full power. So another POI changed figured out. At least with CP’s
I’ve experienced the very same problem, Walkon, exactly the same situation!
http://www.airforceairguns.com/condor.html
Thanks martin!
Walkonking, yeah, I think that in between supersonic pellet speeds and a speeds that are not at least at the minimum of the threshold of accuracy, pellets become super accurate. Different pellets have different dimensions and weight, thus their twist rate requirements will differ from the rest. I believe that there must be a certain rate of twist for each pellet to become accurate. I think that this is the reason why some pellets are not accurate in some guns but are in others. Therefore, I think that the problem all boils down to just that – pellet twist rate. Having said this, guns with adjustable power are thus more accommodating to a variety of pellets. Personally, I think that a very fast twist rate is good as long as the pellet doesn’t go supersonic.
Interesting, I was shooting my new 16″ LW poly barrel and noticed something that was a little frustrating at first until I realized what it was.
I picked up the gun and was shooting full power with CPs and it was dead balls accurate one hole at 15 yds over and over again. Come back out later and turn the gun down to 0-1 and the POI shifts left 1/2″. So I regroup and check my shooting technique and proceed to shoot. Dead on again and then to the left. Went back and fourth for awhile. The good thing of shooting at the low setting is no report at all and it is shooting around 550fps. I put the gun away and come back later. I turned it back up to full power 900+ fps and it is dead on again and I shoot about 80 shots or more and it starts to shift to the left again. I then realized that the real low velocity as the tank ran out and the low velocity of PW 0-1 caused the the change in POI.
So I refill the tank and put it on 0-1 and it is to the left I turn it up to 7 and it is dead on the cross hairs. So my barrel does not like pellets a very low velocitys but it will drill them into a hole like a laser on full power. So another POI changed figured out. At least with CP’s
Both are 1 twist in 16 inches.
http://www.airforceairguns.com/condor.html
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My better judgement says this may not be cool but I’m gonna do it anyway as it adds to the context of this thread.
Velocity: Anything greater than about 950fps is only going to rob you of accuracy, so aim to run at that speed and as heacvy as your twist rate allows?”
http://www.talonownersgroup.com/modules.php?name=Forums&file=viewtopic&t=8553