Hoot, question for ya! Barrel length
In another thread, you said,
A short barrel can shoot as straight as a 24″ barrel, and for as long a distance, however that performance comes at a price and that price is sufficient air volume to produce the results you want.
Can you explain a little further? I’m confused in my noob ignorance. I always thought the longer the barrel, the more air it took to push the pellet. The result was greater accuracy and more power down range but at a loss of shot count/air efficiency. I read your statement to say the opposite.
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Great explanation, Pablo.
Thank you.
Say you tune your rifle with a 24 inch barrel for 40 yards and have it set up perfectly for your purposes. If you then change to a 12 inch barrel, you are basically you are wasting air because you don’t need as much air to push the pellet the same distance because of the decrease in barrel length. So without changing the power output, you are wasting air. But you’ll lose accuracy because a longer barrel is inherently more accurate than a shorter barrel, all other things being equal. Is that correct?
No.
Ok, lets say you got your 24″ barrel set up. It shoots X pellet at 900fps. Now, you set your rig up real nice, your hammer and tophat and fill pressure are set perfect to deliver just enough air to get the pellet at 900.
If you now use a 12″ barrel with the same settings, 2 things are gonna happen. 1st is you’ll lose fps. Basically, you’ve shortened the ‘launch runway’ You’ve got the same powerplant putting out the same power, but your runway is shorter. So you get less fps. 2nd you’ll be wasting air because your using the same amount but the pellet leaves the runway a lot sooner .
So you’ve lost fps and you are wasting air. If you want to get back up to your 900fps with the 12″ barrel, you’ll have t waste even more air because its got less launch time so it needs a bigger kick up the ass.
Thats why a longer barrel uses less air for a given fps. Because it can use that air for longer..
A longer barrel does not make it more accurate, it gives it more power. A 12″ and 24″ are as accurate as each other, though it could be argued that if they are shooting at the same fps/pellet, the 24″ would be more accurate at longer ranges as it has less blast(wasted air) behind the pellet, making it more stable..
Thanks guys, that helps a lot. I hope you don’t mind if I repeat it back in my own words to see if I got it right.
Say you tune your rifle with a 24 inch barrel for 40 yards and have it set up perfectly for your purposes. If you then change to a 12 inch barrel, you are basically you are wasting air because you don’t need as much air to push the pellet the same distance because of the decrease in barrel length. So without changing the power output, you are wasting air. But you’ll lose accuracy because a longer barrel is inherently more accurate than a shorter barrel, all other things being equal. Is that correct?
A puff of high-pressure air expands until its pressure equalizes with the atmospheric pressure.
So if you release just enough air to keep accelerating the pellet all the way to the end of the barrel, the same puff of air will be more efficient in the longer tube.
If you tune for a 24″ barrel and get great efficiency, when you shorten the barrel you will lose a lot of the air when the pellet leaves the muzzle as it is no longer pushing the pellet.
You wont really “lose” air, rather you would be wasting it because:
A short barrel needs less air to hit maximum efficiency than a longer barrel.
No you cannot achieve the same maximum velocity from both barrels, the shorter one will ALWAYS be slower.
a longer barrel allows more time for a given amount of air to push the pellet.
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bear in mind also, that a short barrel is slightly more forgiving of shooter technique by marginally reducing lock time. however, pab is correct in so saying that a long barrel will have greater POTENTIAL accuracy due to less excess air blowing out with the pellet. if you want efficient use of your air, you need all the barrel you can get…