Barrels are certainly one of the more important parts of the rifle in terms of accuracy and grouping. The three things to understand here are quality, bore and length.
Quality first. There are many barrels available on the market ranging from the £5 stock one inside your gun that looks like it was hashed together from recycled coke cans, to £140 lapped steel perfection (most expensive I could find). To touch briefly on the different materials;
- Aluminium – is cheap, lightweight and scractches easily. Avoid
- Coated – If you get something with a coating on, like a nice black finish, make sure it’s on the outside and not the inside of the barrel, because that coating will come off. Similarly, plated barrels. Avoid.
- Brass – Cheap, easy to polish and softer material. Generally, you’ll get a smoother finish on the inside but they’re not as durable as a :
- Steel – The toughest material, less prone to bending and warping, and not easily scratched. A good quality steel barrel will last.
Obviously the more you spend, the more you get in terms of the quality and the finish. However, if you’re on a budget there are some great options that perform very well, in particular the ZCI steel barrels and the Maple Leaf Crazy Jet barrel.
Special mention to Maple Leaf for this – it’s just a really great barrel and one of the cheapest. In case you’re wondering about the name and that steel section on the end, the idea is that some of the air is vented through that tiny gap at the end to produce a “cushion” of air surrounding the bb as it leaves the barrel, so it doesn’t hit turbulence upon exit. Does it work? I think it sounds a bit too much like a gimmick, although it might do something, but even without this feature, the Crazy Jet is a superb barrel. Personally, I’ve also tried Action Army, Modify steel and Modify Hybrid, Guarder and Madbull in my VSR’s, and the only one I had a major problem with was the Madbull python, which was coated but also aluminium, and bent just from fixing a hop unit on. Currently I run the Modify steel, a gift from LongbowBB, which is excellent quality but also has a wider hop window, to accept the bigger contact patch of the Modify XRange bucking, but I’d happily recommmend ZCI and Crazy Jet for any rifle build.
Bore is the diameter of the barrel, and a number a lot of players obsess over. Bear in mind we use 6mm bb’s (I use Longbow, which are around 5.95mm). Your stock barrel is probably around 6.05 or 6.08mm wide, which is just enough to get a bb through. Although hard to test or prove, the bb will bounce around a little as it is fired. Therefore, the common advice is to get a tightbore barrel, ie one that is narrower. 6.03mm is common, 6.01mm are available albeit usually more expensive, and highly prized by players who think they know how to tech. The other argument being that you gain fps because less air is lost around the bb. Going the other way, you can get 6.28 widebore barrels too that ensure a cushion of air travels around the bb to stop any bouncing around, but you will need a bigger volume of air behind it otheriwse your fps will drop a lot.
Yes, I realise we’re talking about tiny fractions here…
The problem with going too tight, is that any dirt, dust and residue in the barrel, no matter how microscopic, is going to make that a very tight squeeze, and you’ll need to be using expensive, high quality ammo to make sure it doesn’t jam in the barrel. But the bore measurement is only part of the story. Because it’s an average diameter through the length of the barrel, and on a cheaper barrel (even if it is marketed as a tightbore) those tolerances will be poor, through cheap machinery and materials.
The last thing to look at is barrel length. It’s always ignored, but vitally important. No, long barrels do not increase fps or accuracy.
To make your rifle as efficient as possible, there’s a ratio between the volume of air in your cylinder, and the volume of air in front of the bb in your barrel. In addition, there’s a ratio between barrel length and weight of bb too. And on top of that, there’s the noise factor. Yep, maths. The easy answer, if you’re not sure, is just to keep the same length that the rifle comes with, and forget any ideas of some sawn-off, pocket sized cqb rifle.
Cylinder Volume – needs to be matched to the barrel length. There’s an amount of air in the barrel in front of the bb, that needs pushed out first and remaining air is then used to power the bb. So if the barrel is too long, you’ll lose power trying to expel that extra air out.
Barrel length – Too long reduces power as above, but too short reduces power. Make sense? If you have a barrel too short, the bb exits the barrel too soon without the full volume of air behind it (ie before the piston has reached the end of its travel). Additionally, too short also makes the rifle louder, as the bb exits before the sound of the piston hitting the cylinder head, which is then allowed to “pop” out of the barrel behind the bb. If the bb is still inside the barrel, the sound is trapped behind it.
BB Weight – A heavier bb travels slower than a lighter bb. That will be a factor in the length of your barrel. Usually, you’ll find people recommending to just go with the absolute heaviest bb you can buy, and many will listen without question. But there’s actually a most efficient weight (in terms of energy) depending on your fps output.
Bet you’re glad that you read all this before you went and bought a 430mm, £140 barrel for your 0.48g Novritsch bb’s, eh?
Efficiency is criminally overlooked in airsoft, but thankfully there are people out there who have taken the time to do the maths and make it available for all, and for snipers we are indebted to 1Tonne on the airsoft sniper forums for providing us with this data;
The other information 1tonne has blessed us with is a guide to how long the barrel should be, for the bb weight, using an AA cylinder on his VSR. (Obviously as a serious player and tech, he uses the correct platform).
So work out your fps first, then…
He adds that if you’re using an airbrake, you can run slightly shorter. The 1Tonne advanced VSR guide is an absolute bible for any VSR user and it’s well worth a read.