No correlation at all. Twist rate needs to be appropriate for the application, but it does not offset barrel length.
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A question - are longer barrels more accurate?
- Thread starter ctshooter
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My experience with this is the majority of airguns are using long barrels to achieve power. I think in some cases the length actually works against accuracy due to harmonics and flop.The more power the more erratic the harmonics will be to tame. I've got a few guns with 10" barrels that are absolutely amazing in accuracy. A perfect example is the mini Evol in .22 caliber with 10" barrel. True shrouded and tensioned barrel that can hang with anything at 100 yards all day.
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The actual definition of "lock time" from a powder burner perspective is the amount of time it takes the trigger to break, the hammer to fall and ignite the primer. In the case of an a spring gun, it could be the amount of time it takes the trigger break, release the spring and push the piston to its end of travel. In a PCP, it could be the time the trigger breaks until the hammer opens the valve and releases air to the transfer port.
The time it takes a bullet or a pellet to make its move and travel down the barrel to the muzzle is known as "lag time". I have also heard it referred to as "lead time." Take your pick I guess.
Lock time plus lag time equals the total time from trigger break to projectile exit and it is not our friend.
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So it seems that the general consensus is that longer barrels are not more accurate than shorter ones. Outside of high power pcp platforms, are there any advantages to longer barrels? Do longer barrels provide more efficiency than shorter barrels?
As a real world example, I have a new HW100 I just got with the standard 24” barrel rather than the 16”(I believe) barrel in the carbine version. I opted for the standard over the carbine, primarily for the larger air tank, ie more shots per fill, but I also figured it would be more accurate. I’m not interested in how much power I can squeeze out of this gun. I actually detuned it when I got it to shoot 10.34’s at 915 FPS and I get 70+ regulated shots per fill. What would happen if I removed the 24” barrel and replaced it with the 16” carbine barrel? Leave all other setting on the gun the same.
From most replies on this thread, it would seem the accuracy would be about equal.
Would the velocity drop with the shorter barrel? If so, the hammer spring would need adjusted to make up for loss of velocity, leading also to a loss of efficiency.
What about noise? Keeping settings the same and using the standard weihrauch moderator that came with the gun, would the shorter barrel be louder?
Are there any advantages to having the longer barrel in this or any other application?
As a real world example, I have a new HW100 I just got with the standard 24” barrel rather than the 16”(I believe) barrel in the carbine version. I opted for the standard over the carbine, primarily for the larger air tank, ie more shots per fill, but I also figured it would be more accurate. I’m not interested in how much power I can squeeze out of this gun. I actually detuned it when I got it to shoot 10.34’s at 915 FPS and I get 70+ regulated shots per fill. What would happen if I removed the 24” barrel and replaced it with the 16” carbine barrel? Leave all other setting on the gun the same.
From most replies on this thread, it would seem the accuracy would be about equal.
Would the velocity drop with the shorter barrel? If so, the hammer spring would need adjusted to make up for loss of velocity, leading also to a loss of efficiency.
What about noise? Keeping settings the same and using the standard weihrauch moderator that came with the gun, would the shorter barrel be louder?
Are there any advantages to having the longer barrel in this or any other application?
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Accuracy will stay the same or improve. Velocity *might* go down if the current air charge takes the entire barrel length to fully expand and impart all of its energy to the pellet. But I seriously doubt it. Without a moderator I think you'd be able to tell that the shorter barrel is louder. *With* a moderator the difference will be slight to negligible. The only advantage of longer barrels is the potential for higher velocity. I have multiple centerfire bolt guns that have 16" barrels and they are just as accurate (1/4-1/2 MOA) as my long barreled (26-28") rifles. The only difference is muzzle velocity. If anything the short barreled rifles are more forgiving ammo wise and have a wider range for powder/seating depth/neck tension than my long barreled rifles.
I think you'll have zero downside accuracy wise and if anything might lose a little efficiency due to having to accelerate the pellet to the same velocity in a shorter distance.
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Flint, your definition of locktime is incorrect. Locktime can be measured without a bullet even being fired, since its over before a bullet even begins to move.
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That is truly a big huge gnarly question.
others are going to have much more technical answers than I will.
if you look at firearm benchrest shooting, In the olden days it was thought that a longer barrel was better. All of the different divisions have weight limits, except unlimited. What they have found is that a shorter fatter barrel, allows the shooter to shoot smaller groups. I firmly believe a big part of this is lock- time. Which I am defining as the time it takes for the bullet to exit the bore after the trigger is pulled. A longer barrel, means a longer lock time. Which means any errors you make in your trigger pull and follow through are going to be magnified by the longer barrel. It is also believed by many that a shorter stouter barrel is stiffer. And I’m not talking about a 5 inch barrel, I’m talking about an 18 to 20 inch barrel versus a 25 to 27 inch barrel.
take a look at spring piston air guns. They used to have very long barrels. Now they all have shorter barrels. Why? Less weight, shorter lock time, and with a spring piston rifle the same velocity.
obviously, FX Put long barrels on their impact, to get more velocity. I believe if you could accomplish the same velocity with a shorter barrel they would use it.
My 2 cents.
mike
they also use the long(er) barrel to ease cocking. I'd love to have shorter barrels on my RX and HW90 but I probably wouldn't' be able to cock them...
one must also take into account, in regard to PB vs. air gun, PB has combustion that continues to expand the length of the tube; an air gun does NOT have expanding gas/air.
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Excellent!,I haven’t read that study before! “GO LAKER’s” my wife and oldest son graduated from GVSU, son went on to U of M as well as my daughter “GO BLUE”
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