![]() Ignoring all the specifics of this, I'd say (in general) when you get 24" or greater in a. And another factor is the material the barrel is make out of and the construction specs (a tight barrel will produce more friction than a lose one). We do know that depending on the amount of powder and it's burn rate will produce different velocities out of various lengths of barrels. My planned use is PRS style shooting but I’ll still be doing some bench 100-200 yd stuff as well. If a 26” barrel was more beneficial I would have no problem running one of my 22LR, but if a 16-20” barrel yields the best MV then I’ll go that route. I use a 26” barrel length in my 6.5 PRS comp rifle so, For Scott's projectiles, I produced a new drag law, I am not sure how effective it is yet, but it is available in MERO and the associated software.Thanks man, I do agree that intended use should dictate Barrel length however, if a shorter barrel gives a maximum muzzle velocity, then why would a bench rest shooter, looking for groups and wind bucking ability at 100 yds go with the longer barrel? If the bullet reaches maximum velocity at 16”, then with a barrel length of 28”, the bullet is slowing down considerably due to bullet drag on the rifling on top of the fact that the longer the bullet is in the barrel there is more opportunity for shooter induced errors imparted on the bullet, why would the shorter barrel not be suitable for bench rest? I can understand why a long barrel may not be as suitable for PRS type, as it can make it unwieldy, but not getting a firm grasp on how that works the vice versus scenario. This is why so much effort has been put into developing new reference drag laws for airgun projectiles. The trajectory model suggested earlier would not help, as none of its reference drag laws are suitable for pellets or airgun slugs at subsonic speeds. However, trajectory modelling has been a problem for Scott, as none of the available reference drag laws works well at long ranges. On the subject of Scott's 7 mm long range projectiles which was mentioned, Scott has been using a projectile designed by Bob Sterne with boattail dimensions based on suggestions I made to him. There are large increases in yaw and drag, but not tumbling. However, in all the hundreds of cases where I have tracked bullets by radar out to splash down kilometres away from the gun, I have never seen one which tumbled going from supersonic to subsonic. Subsonic bullets are generally a different shape to supersonic bullets, and the two do not fly well in each other's territory. For each combination, there will be an optimum length for maximum muzzle velocity, but there are people on here who know far more about how they interact than I do.Īs for powder burners and projectiles, as has been said, while the physics may be the same, the necessary input data and the speed regime is not. The barrel length will be more dependent on the air delivery system, the projectile type and weight. Barrel length may have an effect on the barrel pellet interaction and on how well the shooter aims and holds the gun, but it will not affect pellet stability. On accuracy, all that matters in the external ballistics is the amount of pellet wobble, which will be dictated by what happens in the barrel and just after it has left, and how the pellet reacts to the wobble. ![]() In stability nothing else matters, unless you have a pellet with a very serious problem, so barrel length is not a factor. For stability all that matters are the pellets physical properties (inertias and CG position), the pellet shape and the airflow it produces and the barrel twist rate which dictates the ratio between the spin rate and the forward velocity. For pellets, as has been said, a pellet does not have a memory. ![]() Once an airgun projectile has got into the external ballistic regime, it does not matter what barrel it came out of. There are internal ballistics, obviously what happens inside the gun, intermediate ballistics, which is immediately after the projectile has left the barrel, and external ballistics when the projectile has left all the gun gasses behind. There are three different ballistic regimes when any projectile is fired from any type of gun. A lot has been said in this thread, some of which is valid and some not so valid. ![]()
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