*or beer can

A slightly more in depth look at the now infamous Coke Can Mod for your spring sniper rifle. This has already been mentioned in the Silent VSR Guide (which works for many bolt action spring sniper rifles) but after a few questions this last week, I thought I’d expand on it a little bit. In a recent WhatsApp group chat for one of the novelty bullpup spring rifles, one guy claimed it broke his gun (comes to something if your gun is weaker than a coke can), another suggested using thick grease instead which I’ve seen mentioned in a few places, so here I’ll discuss how it all works and why.

So, what is the Coke Can Mod? Primarily, it is a means of dampening the sound of your rifle by reducing the “twang” noise from your spring that is responsible for a good portion of the noise you get when you fire. As a sneaky ninja sniper, it’s obviously a huge benefit to be able to operate as silently as possible, so that you remain hidden and avoid being lit up by the enemy team. There are a lot of guys out there who are looking to increase range, fps, accuracy etc on rifles. My obsession is simply to have it as quiet as possible, which resulted in the Silent VSR Guide a few years ago.

There are generally two approaches to rifle upgrading. One is to simply keep buying all the shiny new upgrades as they come out and keep chucking stuff in your rifle until it works. The other is the more old school approach of DIY mods. I like mods, because I remember the good old days where people had to get creative in order to correct any issues they might have had with the rifle. It also required more of an understanding of how everything worked, instead of just buying new parts.

The coke can mod, which can be done with any drinks can (most of mine are from cider cans), looks a bit like this;

But why?

Well, the noise of your rifle invariably comes from firing it. The piston smacks forward into the cylinder head and if you’ve read the Silent VSR Guide, I’ve talked about how these vibrations travel throughout the gun like a resonator guitar. To focus on one area though, the spring when it flies forward will expand and start to wobble and vibrate with the force of being released. Now, the spring will be steel, the cylinder will be metal, and a lot of the newer pistons are metal too. What the spring will do is send these vibrations, as sound, to everything it’s in contact with. There is usually a gap with most pistons where the spring fits in, and the idea behind the coke can mod is that it fills that space in and restricts the movement of the spring inside the piston, like a shim. Pretty simple. The only piston I’ve not been able to do this to so far is the Stalker Scorpion piston, and the reason is that the spring guide supplied fits a Rapax spring perfectly, and that in turn fits inside the Scorpion piston perfectly, so there isn’t any room to fit a can in. I like the setup because the performance is amazing, and I’m reluctant to change that, but it is noticeably louder than my other setups, so that’s the trade off. It’s down to the fact that I can’t put anything in to dampen that vibration.

Why use a metal piece of can to dampen noise? It’s metal too…

Yes, but its a pretty soft metal in comparison and absorbs the vibration better. You could use all manner of materials in there if you could find something suitable, but remember this – it’s going to see a lot of wear and tear through use. What you don’t want is a soft material which will come apart inside your cylinder after a while and start putting tiny pieces of crap into your system. The metal will survive inside your gun better than any kind of foam or rubber. So yes, you could make it quieter still but in the interests of survivability the can is fine, and the primary job is to reduce the space for the spring to move.

You could just use thick grease…

Yes. I could use custard too, but the problem with any material like that is that it isn’t rigid, so it’ll give way to the spring movement. It might put a very fine coating on surfaces but under pressure the spring will push through and contact the piston anyway. Also on that note, Under Pressure (Queen, Wembley 1986)

It goes on the spring guide…

I see this comment on a lot of posts. Yes, by all means if you can fit a piece in, go for it, because it’ll help. Every spring guide I’ve had so far fits a spring so tightly that I haven’t been able to do it. There was a very old mod on the sniper forums years ago which involved heat shrink on the spring guide for the same effect. I did try it on an L96 once, and the spring just shredded it and I had quite a job on cleaning it up afterwards. But don’t just do the spring guide end. Piston first, it’s hollow and moves where the spring guide doesn’t so fix that bit first.

I broke a spring guide and piston because of coke can mod…

Had to laugh at this in a WhatsApp chat. The only way a bit of drinks can is going to break either piece is if that piece is made of cardboard or sliced potato. Most of the innards of your gun are metal anyway and designed for the high impact forces of the spring. No, it’s not going to break your gun.

It’s a popular mod, most players will do it, and if you haven’t then you totally should. And I wish it had been called the beer can mod. Hope this gives just a few more details and answers some questions.