AOSC Forum Archive

World. What in the world.

Ok while working on a gearbox of a gun, I've stumbled upon a barrel with holes (professionally) drilled through it, labeled "madbull/echo1usa special tightbore barrel project".

Its m4 length, with 5 holes drilled through it aproximently 2 inches from the hop up unit. About 1/8th inch in diameter. Then another inch and a half down the barrel there are 2 rectangular cut outs, same diameter, about 3/8ths long. All of the holes go through both sides of the barrel.

Any ideas as to what in the world this is? ??

There is a storm over my house right now, so the internet on my computer isn't working. And I don't really want to go through the trouble of posting pictures from my phone. I will post them later when the computer works again.

I understand the theory of porting the barrel... but why on a m4 gun with a stock gearbox? (It should already be set up for a good volume ratio)

The second question would be, does any air really even escape, since the inner barrel is snug inside the outer barrel...?

I figure someone just didn't know what they were doing, but why is this product even produced? And.... why doesn't it show up on google when I search for it? Lol

Why would they port it near the hopup unit? This is indeed interesting, now I want to see it. If I can think of something probable I will share, but until then I will just be scratching my head.

How did you acquire the gun?

Im working on it for somebody else. It wasn't working, but it was a simple electrical fix

BWAHAHAHAA!

I know something you don't know.

I mean, wow... these things have been around for years.

This is a Madbull Crawler barrel. Those ports are meant specifically to bleed off air to lower the FPS. For example, you could have a M120 gearbox built to perfection, and simply drop in a different barrel/hopup assembly and use it for CQB.

Hmm ok that makes sense I guess... that is, if air can escape between the inner and outer barrel.

And why is it a madbull/echo1 product? That seems really weird to me

Probably for the same reason that Classic Army Sportlines are Gameface "products".

They certainly work, but the most you'll lose is about 100 FPS. I saw a few chrono videos a while back where the guns were only losing 30-50 FPS.

Well 30-50 could be all the difference in FPS that some one would need to go from field to CQB

Well then, that makes sense. I was trying to think of how they could do that without losing a lot of FPS, especially being ported further back when there is still a lot of pressure. I guess if you want to lose FPS, then that is the way to do it! I learned something today. The more you know!