Does a longer inner barrel make the gun more accurate ?

36425 Views 28 Replies 17 Participants Last post by Guges Mk3, 15 d ago

OMOMAirsoft

Discussion Starter · Apr 7, 2013

Is it true a longer barrel makes a gun more accurate ?

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theonlyBuster

· #2 · Apr 7, 2013

Yes and no. This answer depends on the barrel and the gun's internals.
Remember there are copper, aluminum, other material, and brass barrels. It also depends on how your stabilize the barrel, if you stabilize it at all.
That is to say, a tightbore isn't always the best option for accuracy.

Biohazard

· #3 · Apr 7, 2013

OMOMAirsoft said:
Is it true a longer barrel makes a gun more accurate ?

No, it is not true. The reason for this is because there is more space for the barrel to affect the BB's flight path negatively. For example, if you have a small bend in a long barrel (very minute one), it will affect the BB trajectory more so than a barrel that is shorter, but bent the same way.

Another adverse effect of a longer bore has to do with volume ratios. If the ratio of air being pushed out of the cylinder compared to the volume of the inner barrel is too little, the BB will stop accelerating before it reaches the end of the barrel which can cause a few issues. If the ratio is too high, the barrel will be overvolumed which can cause inaccuracy. In this case, its usually the undervoluming that gets ya.

Perhaps another reason has to due with the hop up and the bb reaction in the barrel. The BB is thought to ride the top of the bore. When the BB rides the top of the bore, it tries to stabilize itself. Once the bb is stable, you want it out of the bore ASAP to avoid any off-axis rotation to help prevent flyers and other accuracy problems. That brings up stabilization in the barrel.

Generally, its easier to stabilize a shorter barrel due to the lesser surface area. That also means it will be more consistent because it won't vibrate much. That's not the case for longer barrels though. They're generally harder to keep stable.

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Luftsoft

· #4 · Apr 7, 2013 (Edited)

Real Steel is the complete opposite of airsoft. Barrel length doesn't do much. A TBB may give you a little accuracy change but it will increase the FPS. Wider bores(6.08+) were said to be a better option because the bb rides on an air cushion.

Biohazard

· #5 · Apr 7, 2013

Luftsoft said:
Real Steel is the complete opposite of airsoft. Barrel length doesn't do much. A TBB may give you a little accuracy change but it will increase the FPS. Wider bores(6.08) were said to be a better option because the bb rides on an air cushion.

A TBB will not necessarily give you fps change. It depends on your cylinder volume/porting. Wider bore barrels are not better because of the reason you listed, but that is still kind of how it works.

Wider bores are better because there is more room for the bb to stabilize, but not hit the barrel walls. This prevents off-axis rotation from contacting the barrel walls.

Honestly, bore quality/smoothness is the most important factor. It directly affects your shot consistency. Bore width is next in order of importance. Bore material is after that. The least important (though still very important) is bore length.

A wide bore is generally classified as 6.08mm and wider. You made it seem like widebores are only 6.08mm. I think I'd call a 6.06 a wide bore though too so let's say wide bores range from 6.06mm-6.2mm for now. You can definitely go higher, but I don't see the feasibility of that due to an insane amount of air loss widebores can create.

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Drags

· #6 · Apr 7, 2013

OMOMAirsoft said:
Is it true a longer barrel makes a gun more accurate ?

Consider as well FPS you will have and bb weight for the accuracy...not many people take in to the consideration weight and initial speed vs. air resistance... With some math in place you can see that while .20 bb will have faster initial speed, on the longer run .25 or .30 will have retain more speed, thus having more energy and as a result, being more precise or even having longer flight path then lighter bb's... So what you should consider for precision is:

Hop up unit and bucking
Quality of bb
FPS - to be able to decide proper bb weight
And yes even TBB up to certain extend...

But most important will be your hop up unit and bucking....

Lefse

· #7 · Apr 7, 2013

The quality and stability of the barrel is more important really. My most accurate AEG's have relatively short barrels, around 300mm. My least accurate AEG's have 509mm barrels.

LegacyAirsoft

· #8 · Apr 7, 2013

Guys, accuracy and range are two different things.

A longer barrel WILL give more range, however if you just drop a longer barrel into your gun it will give worse range. You need to first match the volume of the barrel to the cylinder, then polish your barrel, tune your hop up, stabilize your barrel, etc.

HOWEVER, the bore quality and material will give more of a noticeable difference in range/accuracy than just barrel length. That being said, a well made 363mm barrel will out range and outperform a 509mm barrel that is poorly made.

Lefse

· #9 · Apr 11, 2013

Exactly why will a longer barrel increase the range? If the same energy is put behind the BB, then a 300mm and 500mm barrel should in theory yield exactly the same range.

Carpathia

· #10 · Apr 11, 2013 (Edited)

It's like L3gacyAirsoft said, if you simply drop in a longer barrel, it will be worse because you've set yourself up with an undervolumed gun. This means that the piston finishes pushing air through the air nozzle before the BB reaches the end of the barrel and the BB must exit the barrel under it's own power, causing it to slow down before it even leaves the barrel.

To rectify this, you've also got to get another cylinder and match the inner barrel volume. That in mind, with a longer barrel, there is a higher volume of air being used to push the BB out. Taking into account that the spring/piston accelerates after it's released by the sector gear, and continues to accelerate until it hits the cylinder head, and taking into account the increase in volume of air thanks to the new cylinder, this means that the piston has pushed more air and an overall higher velocity, which means more FPS and, as a result, more range.

Bottom line, though, a longer barrel won't make your gun more accurate.

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Lefse

· #11 · Apr 11, 2013 (Edited)

Then the increased range is thanks to the increased energy, not the increased barrel length. What if you put the same amount of energy behind the BB with a shorter barrel, what then? A 250mm barrel with optimal cylinder/barrel volume ratio and an M120 spring will put out about 1.5 joules of energy, the same as a 500mm barrel with optimal cylinder/barrel volum ratio and an M120 spring. Both barrels propel a .30 gram BB, explain to me why the 500mm barrel somehow has increased range when the kinetic energy in the BB is the same? Also explain to me how my MP5K with a 140mm barrel shooting 1J has barely any shorter range than my AUG with a 509mm barrel shooting 1.4J when using the same BB weight? Both have a traditional type hop-up. If they both had the same energy output, the range would be very similar, my MP5K would most likely have a longer effective range due to better accuracy though.

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LegacyAirsoft

· #12 · Apr 13, 2013 (Edited)

Lefse said:
Then the increased range is thanks to the increased energy, not the increased barrel length. What if you put the same amount of energy behind the BB with a shorter barrel, what then? A 250mm barrel with optimal cylinder/barrel volume ratio and an M120 spring will put out about 1.5 joules of energy, the same as a 500mm barrel with optimal cylinder/barrel volum ratio and an M120 spring. Both barrels propel a .30 gram BB, explain to me why the 500mm barrel somehow has increased range when the kinetic energy in the BB is the same? Also explain to me how my MP5K with a 140mm barrel shooting 1J has barely any shorter range than my AUG with a 509mm barrel shooting 1.4J when using the same BB weight? Both have a traditional type hop-up. If they both had the same energy output, the range would be very similar, my MP5K would most likely have a longer effective range due to better accuracy though.

Guys stop. BOTH of you are smart enough, or at least I thought, to know what the barrel can and can't effect. As a drop in it won't do much (reasons stated above) but it will still do something. The increased bore quality and tightness (if its a tighter bore) will give you better accuracy and range results, slightly. When you increase the hopup effectiveness of a correctly tuned/volumed barrel THAT'S when you see range increase. For example a flathop/rhop will yield MUCH better results for range than a new barrel.

BTW: what Lefse was pointing out is correct in that argument, but range is affected by much more than just the energy of the bb.

crankestein

· #13 · Apr 13, 2013

On a Scar I got, which comes with an extension outer barrel (gun, barrel, flash hider).

With the extension barrel (similar to a longer inner barrel, but of course not exactly), an increase of average 10fps was achieved. Could tell the BBs where not that spread out as much when going beyond 100 feet.

LegacyAirsoft

· #14 · Apr 13, 2013

crankestein said:
On a Scar I got, which comes with an extension outer barrel (gun, barrel, flash hider).

With the extension barrel (similar to a longer inner barrel, but of course not exactly), an increase of average 10fps was achieved. Could tell the BBs where not that spread out as much when going beyond 100 feet.

I have the same gun, that external barrel extension did nothing. It is your terrible air seal and inconsistent spring.

Hydra572

· #15 · Apr 13, 2013

I would think that the collision between the BB and the burst of air that the gun delivers takes some time to fully transfer energy to the BB. Thus, a longer barrel could potentially increase muzzle velocity, allowing or requiring a lighter spring, and I think the higher efficiency this would grant could only be a positive thing for accuracy. As discussed, the most important factors are the smoothness of the bore, the hopup, and the barrel stabilization. These factors are important for both accuracy and range. In Airsoft, accuracy and range are quite linked. Accuracy is provided by consistent spin, and if the spin can not be kept consistent, range suffers immensely, because the BB loses it's flat trajectory. I've gotten good performance out of many barrel setups, hopup seems to be a much more pertinent factor. Also, the problem of undervoluming is handled relatively easily, as mentioned, look up one of the many available charts, or just look at cylinders on a retailer's website, and buy one to match the barrel you're putting in. Taking the GB apart will give you a chance to do some preliminary tuning, which most guns can benefit from.

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Lefse

· #16 · Apr 13, 2013

This is why we have ported cylinders.

TheAirsoftTech

· #17 · Apr 13, 2013

I have this argument at least once or twice a month at a game. I just ask them how then my P90, with a 247mm brass 6.08mm barrel, has more range than their KWA with a dropped in 450+mm Madbull 6.01mm barrel. Lol

Lefse

· #18 · Apr 14, 2013

P90's can achieve surprisingly good results, very stable barrel assembly, and very stable hop-up chamber.

TheAirsoftTech

· #19 · Apr 14, 2013

Lefse said:
P90's can achieve surprisingly good results, very stable barrel assembly, and very stable hop-up chamber.

They're just so easy to work on- V6 gearbox, open barrel (easy to stabilize), and a strong/stable hopup. The only problem I see with them is the battery compartment is decently tiny.

Lefse

· #20 · Apr 14, 2013

The battery compartment isn't that bad, it can hold a 56 amp 11,1v li-po, plenty power for most setups.

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