Air rifle barrel twist rate !

[salop sniper]

Do air rifles have different twist rates in there barrels ?

The reason I ask that is I have a Daystate Mk4 .177 and my old man has a AA S410 .177 carbine.
Both rifles side by side, both sub 12ftlb, both shooting the same pellet (AA 4.52)...... But the AA is perceived as giving better kills, we have both shot each rifle to rule out anything to do with shooters. But over the last 3 years we have both come to agree the AA gives a better kill, but why ?
It isnt different powers, shot placement or pellet so I can only think its how it (the pellet) is delivered, IE a faster spin on the pellet from the AA giving more effect on quarry down range.

Any thoughts ?

ATB

Matt

[Peter Dunkley]

Nice try mate I very nearly fell for it and gave what I thought was a sensible answer.

Pellet in the brain, fast or slow twist.---------- What's a "no kill"?

[salop sniper]

No joke, genuinely.

Am after a reason why it appears one rifle gives far better kills on quarry than the other when there is so much similar, am just trying to find the differences and rule them out one by one to try to deter what makes or seems to make a more effective rifle over the other !

ATB

Matt

[air-tech]

Unless your pellets are threaded, I don't see the connection.

[TonyL]

I really think this is down to pure coincidence.

Now, I'm no ballistics expert, granted, but:-

The difference in twist rates would be very, very minimal. If, say, the pellet has 2" of matter to displace, with a barrel giving 1 twist in 16 inches, it's still only going to rotate by an eighth of a turn, to my way of thinking. If a barrel had a slightly faster twist rate, this would make no difference.

You state that both rifles are sub 12ft.lbs., but how close are they in muzzle energy output? If the difference was big then, yes, that would make a difference.

If muzzle energy is similar, one might look to how each different barrel may affect the BC, but then there would have to be a drastic difference on terms of retained energy downrange.

If muzzle energies are similar, I really think that this is pure coincidence. No one kill and pellet strike will be 100% the same.

If we were talking different calibres, weights, velocity, energy, pellet configuration and hardness, then yes. But two guns shooting the same pellet at very similar velocities, my contribution is "coincidence".

[salop sniper]

Cheers Tony, maybe its just our incorrect perception as yes everything is very near identical.

ATB

Matt

[radiofan]

I recall in some article I read, that the twist rate can affect accuracy at the far end of the shooting range.

A fast spin will stabilize the pellet more quickly and is better for close-range, whereas a slightly slower spin will allow the pellet to more easily follow it's natural curved trajectory, requiring less correction from the skirt. This, apparently, results in better accuracy at long range.

You can measure the twist rate with a cleaning rod. Most rifles use a very similar twist. I doubt it has anything to do with it.

[angrybear]

Do they both give identical grouping at various ranges ?
I suspect the AA is fractionally more accurate with that pellet, have you tested with other pellets?

[Two200's]

Too many variables to support or deny the theory.
First step is to chrono the guns at different ranges, then work back from that with other tests at similar ranges, ballistic putty etc.
I genuinely think there is something in twist rate besides accuracy.
I may be wrong, probably am, but this has been brought up before.
If anyone has time on their hands to be inventive with tests and observations, this could be interesting. Likewise it may be a waste of said time invested.

[TORNADOS7]

No two barrels are the same this even extends to barrels by the same manufacturer from the same batch so I would suggest the Daystate might prefer another brand of pellet better, just because the muzzle energy is all but the same it doesn't necessarily mean down range characteristics will be the same !!!

By the way the Air Arms barrel characteristics were specifically tailored to run air arms pellets, in fact the whole rifle is designed, built and tweaked to work specifically with them unlike the Daystate !!!

[landymick]

Twist rate on Daystate LW usually 1:17.71 not sure on AA but will be similar.Your issue i can't say i have noticed any difference in same power & same pellet shots on vermin.

[RobF]

No two barrels are the same this even extends to barrels by the same manufacturer from the same batch so I would suggest the Daystate might prefer another brand of pellet better, just because the muzzle energy is all but the same it doesn't necessarily mean down range characteristics will be the same !!!

By the way the Air Arms barrel characteristics were specifically tailored to run air arms pellets, in fact the whole rifle is designed, built and tweaked to work specifically with them unlike the Daystate !!!

What even though JSB make their pellets. And the ones for daystate?

[landymick]

Not the same but my MKI Rapid is 1:14 Twist which is slightly faster than the Daystate & i can't say one delivers results better than the other only to add the Rapid is better overall IMO.
Cheers all.

[Two200's]

As i said, i really do think there is something in it.
But its only on observations with pellet strike on paddles of ft targets, its less than definitive when hunting, simply because of so many variable issues.
But a replication on measured targets may get some results. I can't say that i have noticed any consitent similarities or differences between guns of the same calibre and power when hunting.
But when setting up on ft targets definitely. But i don't know enough to give specifics.
On paper it makes no sense at all, in hunting you cannot measure it accurately at all, but i have seen different guns at the same power leve, with the same pellets (all my own equipment) hit differently and with more noticeable impact.
I have wondered about this before, but have no test gear. well i do have a combro, but doubt i vould get the pellet through it at 55 yards - i am capable of clipping my combro while it is on my muzzle!
ta

[TonyL]

We have had threads before where it's been shown that some springers seem to hit harder downrange, even given the same pellet and muzzle velocity. And it was down to the harder pulse of air belling the skirts out, thus altering the BC.

Can't remember the definitive outcome (if any) - would have to start digging.

Would different twist rates alter the BC?

The only way to find out would be empirical and scientific testing....control pellet, springers and PCPs, different twist rate barrels, all set up to deliver the same muzzle velocity and take residual velocity readings. But then, to eliminate another variable, all barrels would have to be EXACTLY the same diameter too, as that would also affect the BC.

If a pellet seems to strike harder downrange, it's got to be down to better retained energy rather than how quickly it's spinning??