barrel length question

[Motorhead]

Have personally witnessed a 12" barrel PCP pistol in .177 shoot @ 3/8" 10 shot at 50 yards. At the same session not a RAW or a STEYR shot along side could match it

Within realistic range, caliber & power being equal BARREL LENGTH generally does not matter.

Now a shooters skill, their hold stablity etc and if or not able to shoot said Air Gun to its potential is the greater issue at hand.

 

[AirNGasman]

Just some thoughts here...
Barrels were originally long to give a greater sight radius , which enhanced accuracy in non scoped rifles. As your last article explains, the lost velocity is not related to accuracy itself, but more about the effective range.
In pcp's, you can get more velocity in any given barrel length by using more air or higher pressure. As shown in several threads, including my own, pellets have an optimum velocity so faster is not necessarily better. It then becomes a choice of HOW to get there. A short, high pressure blast in a short barrel may get you to the same speed as a longer lower pressure blast in a long barrel but which will give you better shot count? Also to consider are the harmonics... short being higher frequency but less amplitude, and balance... longer putting mass further from center thus helping damp movement (easier to shoot).
In EBR type benchrest, pushing the heavy pellets fast enough is easier with longer barrels so you'll likely only see long barrels where 25 meter doesn't allow or need that power so SOME airguns have been made with shorter barrels with no detriment. In AAFTA style FT, power is limited and you'll also see barrel length vary a good bit.
Aiguns are a huge collection of tradeoffs so weight, ergonomics, power, balance and shot count are just SOME of the things barrel length will affect more than accuracy .
Bob

Not to put words in Bobby's mouth, but his excellent explanations sound like (a much less LAZY way of saying), "Achieving the right BALANCE of all the variables."

 

[Healthservices]

Well in a way your question(s) are totally loaded. Rules, laws of physics, dictate the length barrels that can be used in each competition.


For example in the most basic field target 20 ftlbs is the limit. Having a long barrel will make that gun no longer qualify as that would make it shoot too fast. Plus it may not be as balanced as a shorter gun to shoot off hand.


Allen

 

[rcs9250]

I did a quick trig calculation where if your muzzle moves .002” ( about the thickness of a piece of paper) as it exits the barrel it will be off point of aim by .122 (almost 1/8”) at 50 yards. Two thousandths is nothing, I’m guessing it’s very easy for the muzzle to move double that amount which of course would equate to about 1/4”.
And that’s assuming a perfect pellet.

 

[cavedweller]

I did a quick trig calculation where if your muzzle moves .002” ( about the thickness of a piece of paper) as it exits the barrel it will be off point of aim by .122 (almost 1/8”) at 50 yards. Two thousandths is nothing, I’m guessing it’s very easy for the muzzle to move double that amount which of course would equate to about 1/4”.
And that’s assuming a perfect pellet.

We are getting somewhere BUT. Let’s take the variables like people and wind and rotation of the earth out of the equation….. for the sake of discussion let’s clamp the various barrels being tested in a vice so we can then determine how a specific barrel length with varying twist rates or none, function at various pressures. There’s a reason a Thomas or MAC1 have shorter barrels. That’s where I am going with this. Certainly somebody’s invested all the time and money to do this. I am well aware that form often follows function, and in this case I’m looking for the data that’s saying “why”? Scientifically speaking even animals have varying length peckers according to a biological imperative to survive / procreate with the highest degree of accuracy. Sorry analogy and pun were relevant at 4:30 am.

 

[l8apexing]

For me a longer barrel allows me to easily shoot faster with less air. But don't get greedy on speed. Speed does not mean accuracy. Accuracy trumps speed in competition. The longer it is the more time it is in the barrel. With heavier projectiles the barrel will kick or move more than a shorter barrel, making it more hold sensitive. So I guess only use as long as a barrel as you need.


Allen

Is the air savings significant?

 

[Healthservices]

Is the air savings significant?

That really is dependent on how fast you are shooting, how heavy of a slug, and how efficient the shorter barrel was.

If you are really pushing your short barrel to go a fast speed, going to a longer barrel will be easier and waste less air and you will get more shots, that is if both are going the same speed.

But in general if nothing is done other than putting in a longer barrel the same projectile will go faster.


Allen

 

[Healthservices]

.... There’s a reason a Thomas or MAC1 have shorter barrels. That’s where I am going with this. Certainly somebody’s invested all the time and money to do this. I am well aware that form often follows function, and in this case I’m looking for the data that’s saying “why”?

I'm not as familiar with these two guns but I would venture to guess that there is a power limit to the class. If that is true there is no need for a longer barrel because if you can get to the speed you need with the shorter one. Besides, excess speed is more power, more power is against rules. Whoops I already said that.

Allen

 

[l8apexing]

That really is dependent on how fast you are shooting, how heavy of a slug, and how efficient the shorter barrel was.

If you are really pushing your short barrel to go a fast speed, going to a longer barrel will be easier and waste less air and you will get more shots, that is if both are going the same speed.

But in general if nothing is done other than putting in a longer barrel the same projectile will go faster.


Allen

Thank you for the detailed answer

 

[.20calguy]

Depends on the goal for your slinger.

View attachment 340473

A well balanced rig.

 

[beerthief]

i still want a HW77 long .

 

[iAMzehTOASTY1]

A well balanced rig.

Thanks!!
Gifted that one.
Been chomping at the bit to make another

 

[.20calguy]

Thanks!!
Gifted that one.
Been chomping at the bit to make another

That sounds like me.
I got this one from a dad who took it from his son for misuse. I rebuilt it and gave it to a boy who lost his dad.

 

[.20calguy]

Thanks!!
Gifted that one.
Been chomping at the bit to make another

 

[iAMzehTOASTY1]

View attachment 364896

That warms my heart so much! and i thank you very much for you sharing
it's felt dark these past few days which have also felt like a blur/haze of sorts; this is one of those things that I needed to see in order to help warm my heart back up
much love

 

[Motorhead]

Slide breech pumper .. Ah the classics .. nice save to become an AWESOM gift for this young man.