On my desk here I have a 10" Stiffi and a 14" C-Series. I will go into detail on how they differ.
Unfortunately it is hard for me to compare the weights of the two since they are different lengths. However I would imagine that a C-Series of the same length would be heavier than its Stiffi counterpart. The threaded aluminum portion is longer on the C-Series than on the Stiff. In addition, the C-Series has an aluminum piece affixed to the end of the barrel for attaching those cute (and otherwise useless) barrel tips.
But lets be honest with ourselves, they're both so darned light that it really doesn't make any difference.
As far as a paintball is concerned they are both the same material. Why? Because the paintball will only ever touch the fiberglass resin (or "E-Glass", as Stiffi calls is, maybe they have a special formulation of resin they use, I don't know) but will never touch the carbon fiber or kevlar underneath it.
On the C-Series there is a kevlar or carbon fiber layer exposed on the outside to give it texture. On the Stiffi it's clear, smooth resin. According to SpecOps the weave used in the C-Series is kevlar. I have no way of confirming this but I'm going to assume it's true. What does this mean? It means it's neat. That's about it. It doesn't really give any advantage over standard carbon fiber in this particular case. Perhaps it's stronger as a result, but carbon fiber is already plenty strong enough for this use.
The C-Series has three parallel lines of porting going halfway down the end of the barrel. The Stiff has the same porting except near the tip of the barrel where it has six parallel lines of porting. The holes are the same size on each barrel.
Internally, Stiffis have a "stepped bore" design. In other words, the first part of the barrel is the advertised bore size and the second part of the barrel is slightly wider. If you look down the barrel from the threaded end it looks like it's smooth. If you look down the barrel from the business end you can see what looks like a ring around the inside. The C-Series is identical to the Stiffi in this case. Even though my Stiffi and C-Series are different lengths the bore changes size roughly 4" from the threads on both of them.
12" C-Series: $58.95 on SpecOps
12" Stiffi: $91.99 on ActionVillage
The C-Series, while still being essentially the same thing as the Stiff, is cheaper.
But what does it all mean, Basil? It means that, side by side, the two barrels should perform nearly the same in almost every aspect. They are, without over analyzing things to the extreme that I have, the same barrel. I hope this clears everything up. Also, both of my barrels are .691 and they both shoot paint well. Honestly, I can't tell the difference between the two from a performance standpoint. It also might be worth pointing out that the fancy tips (the ones that aren't flat, anyway) for the C-Series make getting a barrel cover on more difficult.
This post has been edited by BlueDragonX: 18 May 2008 - 08:40 PM