A technical question about BARREL LENGTH

[Shooter22UK]

I was just looking at a picture of an ULTRA and a Leshiy and some Weirauchs, and between them they appear to have barrels ranging from 11 inches to over 20 inches in length, and I got to wondering, Is their an OPTIMUM barrel length for 12 ft pound air rifles in .177 and .22 calibres? . I'm told by wiser people than myself that some airguns barrels are long to make them easier to cock (Break Barrels and UL's) and barrels dont need to be very long to obtain maximum velocity / energy?? .

So is there an optimum barrel length for 12 ft pound .22 and .177 air rifles??

[mattyw1987]

I was just looking at a picture of an ULTRA and a Leshiy and some Weirauchs, and between them they appear to have barrels ranging from 11 inches to over 20 inches in length, and I got to wondering, Is their an OPTIMUM barrel length for 12 ft pound air rifles in .177 and .22 calibres? . I'm told by wiser people than myself that some airguns barrels are long to make them easier to cock (Break Barrels and UL's) and barrels dont need to be very long to obtain maximum velocity / energy?? .

So is there an optimum barrel length for 12 ft pound .22 and .177 air rifles??

I'm sure I've read on springers it's 14" ish and that's only because below that you will need more spring to make up for efficiency.

On a pcp I don't think it will matter as recoil is near none existent but you would loose a lot of shots with a short barrel.

[Ryan hw99s]

12" is good for springers, pcps are batter 12 + mostly due to shot count , as a falcon fn12 is as accurate as a fn19 but shot counts improves hope that helps
the exeptions are air arms that shoot well with shorter barrels but i find tx200 is better than the shorter hunter carbine

[HW777]

Theoben used a 7 inch barrel and it was accurate at that, which lead to a phase where spring gun shooters shortened their barrels a tad to much around that period

I think Hw have gone a tad to short with their carbine break barrel rifles, I'd say a 345mm barrel squares it off nicely.

[Rikimaru]

Theoben researched barrel length for springers & ram guns & they found that the pellet developed full velocity only over the first six inches of the barrel. Spring guns develop the power in a different way to PCP'S.
Precharged guns deliver the charge of air over a longer period of time & need barrel length to reach full velocity. Springers deliver the charge of air much quicker & do not need long barrels to develop velocity.
all my springers have barrels of 11 inches or less (down to 9"). The Longbow has a 13 "barrel & my Fenman is famous for its ultra short barrel. All of them are accurate & running at 10.8ft lbs (I set them up at that power, nothing to do with reduced barrel length, most of the Vulcan's were doing 11.5 to 11.8 before tuning before reduction of barrel length). ).

The fact that most airgun manufacturers are supplying guns with shorter barrels as standard more & more should tell you all you need to know.

None of my springers have needed any modification to restore power after barrel shortening, no changing of springs or transfer port mods. If the velocity is built up over the first six inches then as long as the barrel is over that 6" it's fine.

The only reason 6" barrels are not used is leverage, The Fenman could have had a 6" barrel but they extended it by a few more inches to help ease cocking effort. Same reason mine are between 9" to 11" purely to ease cocking effort, not for efficiency.

If you prefer longer barrels then that's good but having shorter barrels on springers is not a detriment. We all have differing preferences & unless something really messes up a gun or makes it dangerous then go for it. I love ultra carbine & would never knock anyone for owning a 22" barreled air rifle.

[Travis299]

Barrel length = 15.75”, 400 mm, from end of moderator to breech block end. HW95 barrel is 16 mm diameter. Barrel without moderator = 12.188”, (12-3/16”, 309.575 mm), from thread end to breech block end.

[WILBA]

Barrel length = 15.75”, 400 mm, from end of moderator to breech block end. HW95 barrel is 16 mm diameter. Barrel without moderator = 12.188”, (12-3/16”, 309.575 mm), from thread end to breech block end.

Many years ago i had a hw80 with same barrel set up ad yours. Accounted for hundreds of bunnies over the years i owned it.

[WILBA]

Theoben researched barrel length for springers & ram guns & they found that the pellet developed full velocity only over the first six inches of the barrel. Spring guns develop the power in a different way to PCP'S.
Precharged guns deliver the charge of air over a longer period of time & need barrel length to reach full velocity. Springers deliver the charge of air much quicker & do not need long barrels to develop velocity.
all my springers have barrels of 11 inches or less (down to 9"). The Longbow has a 13 "barrel & my Fenman is famous for its ultra short barrel. All of them are accurate & running at 10.8ft lbs (I set them up at that power, nothing to do with reduced barrel length, most of the Vulcan's were doing 11.5 to 11.8 before tuning before reduction of barrel length). ).

The fact that most airgun manufacturers are supplying guns with shorter barrels as standard more & more should tell you all you need to know.

None of my springers have needed any modification to restore power after barrel shortening, no changing of springs or transfer port mods. If the velocity is built up over the first six inches then as long as the barrel is over that 6" it's fine.

The only reason 6" barrels are not used is leverage, The Fenman could have had a 6" barrel but they extended it by a few more inches to help ease cocking effort. Same reason mine are between 9" to 11" purely to ease cocking effort, not for efficiency.

If you prefer longer barrels then that's good but having shorter barrels on springers is not a detriment. We all have differing preferences & unless something really messes up a gun or makes it dangerous then go for it. I love ultra carbine & would never knock anyone for owning a 22" barreled air rifle.

My skan R32 ultra has a short barrel 10-12" roughly and that is pretty dam accurate. My theoben olympus barrel is 10" and i find that as accurate as my full length sirocco. Theoben got it spot on with their barrels. Shame the triggers are shite though

[TonyL]

The accuracy of many shorter barrelled guns proves that we don't need long barrels for accuracy.

For efficiency, it's generally regarded that 14" or more is better for a 12ft.lbs springer. And, as said, if a break barrel or under-barrel underlever, the length helps with cocking effort.

Pneumatics (both PCP and pump-ups) and CO2 benefit greatly in efficiency / output / shot count from longer barrels.

[Black Beard]

If you cut springer barrels very short you will need to tweak the preload to push up the power. Short barrelled guns are noisier but a short barrel with a silencer will be quieter (and probably lighter) than the equivalent long barrel.

Taller people tend to prefer the balance of longer guns.

[TonyL]

Yep, and a few years ago the terms "barrel time" and "action time" were oft used. A fair few people held the belief that it was beneficial to get the pellet out asap so the shooter had less time to influence the direction of the pellet, so some viewed the very short barrel as a "good thing". However, as mentioned above, due to lower efficiency, more spring force / preload / piston momentum etc. were required to achieve the same power output, potentially resulting in a harsher, harder to use action. "Quicker" action, yes, to please those who were also chasing that "holy grail" of a quick action and less barrel time. Better? Maybe, maybe not. Only testing would reveal the results. And personal preference will also come into it and the "shooter feel good factor".

[ballisticboy]

As with all guns, not just airguns, there is an optimal barrel length for the maximum muzzle energy. That length will vary according to the details of the system inside the gun, i.e. PCP or springer, short stroke or long stroke, heavy or light piston, etc. etc. The barrel length will also vary with pellet mass, start pressure and just about everything else you can think of. So trying to optimize barrel length is OK if you are only going to fire one design of pellet with one spring piston setup, or at one pressure from a PCP with a consistent air usage per shot. Having said that, some of the effects do not change the optimum value very much, so you can optimize to a certain extent.

[Ryan hw99s]

Theoben i forgot about them i had a fenman it was very good easy to shoot 7 or 8" barrel but worked well, the reason i put 12" was something i read years ago bowkett tested for optimum barrel lengths and im sure he said 12" for a springer ,but that was many years ago times and materials have changed a lot
bowkett files i think good to read the guy knows his stuff, also bluenose examins was that theoben ?????

[WILBA]

Theoben i forgot about them i had a fenman it was very good easy to shoot 7 or 8" barrel but worked well, the reason i put 12" was something i read years ago bowkett tested for optimum barrel lengths and im sure he said 12" for a springer ,but that was many years ago times and materials have changed a lot
bowkett files i think good to read the guy knows his stuff, also bluenose examins was that theoben ?????

I think john was on about if the barrel is shorter than 12" the cocking effort goes up to get the same output power wise.

[TonyL]

Someone posted relatively recently with a link to one of those excellent "The Bowkett Files" articles relating to barrel shortening, barrel & action time. I think the rifle was a 95?
As we'd expect these days, shortening the barrel in steps resulted in gradually decreasing power outputs, leaving the internals the same. Obviously, cocking effort will have increased at each step due to less leverage.
Power was then restored in steps, I seem to remember, with a combination of more preload and piston weights. The increased preload, obviously, increasing cocking effort further still. Recoil acceleration will also have increased, giving that perceived "quicker" action time. Increasing piston weight will have increased recoil displacement ever so slightly.