None of the action cams have zoom, so you won't be able to see what you are shooting at unless they are 40 feet away or closer...
I bought a nice mini Sony HDR-cx210 1080HD camcorder (one of the tiny ones) and built an enclosure around it, and I play with my zoom at 15X. Works great, if you want to take the time. I got my camera on ebay for $199.
My helmet cam is a Contour Roam, which you can find for around $100 if you look for a while.
You can see my game footage in my "blizzard" thread. It works really well!
Sorry, no I can't. I see you writing on the screen that you got someone, but I can't see the paint hit them. The one guy at :35 that ran up to you, THAT one I could see, but he was like 20 feet away or closer when you shot him, proving my point.
Look at my videos, those are long range shots, and yet, the shot 100 feet away, you can actually SEE the paint hit them, and it leave a mark. Over 100 feet, you can see them react, and call out.
If you have to write on the screen to tell the viewer what is happening, that defeats the point. Action cams are great for close up and first person perspective, but for showing the hits in paintball... They weren't made to do that...
You need Zoom.
Here I made this video a while back to show the difference between any of the action cams on the market (I use a contour roam 170 wide angle lens at 720HD, but they all are similar, and none have optical zoom).
Like I said, action cams are great for showing what you are doing on the field, but as soon as you pull the trigger, you need a camera with zoom for the viewer at home to SEE what you are shooting at...
Here is another example, the first shot in this video I zoomed in digitally on my contour roam footage (didn't have my zoomcam on that gun, as that was later in the day). I was SUPER close to them (which is why I only fired one shot at each of them) about 20 feet away or less. The later footage again was with my Roam, and if I had my ZoomCam you could have seen those guys I was shooting at, instead of just a tiny glimpse of them far away in the woods.
Now for barrel tags, it works great as they are right in front of you. As that is what action cams were made for, the person doing the action right there around them. Biking, skiing, skateboarding, base jumping, ect. Paintball, they fail, as they don't show the hits... Unless you are super close.
I use a Hero3 black edition it is a really light and small camera and it shoots at 120fps at 720 also it has 240fps options too so you cam shoot some super slow mos shots take a look at one of my videos. Also if you want super crisp video and you don't want the slow mo you can shoot at 2k resolution.
I have a GoPro Hero3 Silver edition and it works pretty great. With the handlebar mount, you can put it on the barrel, right up against the front of your loader and it doesn't add much to your profile. The wide angle and picture quality are good, but you kinda wish it had an optical zoom for sideline views, but you can zoom the frame a bit while editing. It works pretty great as a barrelcam and is more versatile to do more than just barrelcam.
Yes I think the Sony HDR-cx210 is the best option, but for my personal uses I would need a minimum of 120fps. I will have to look at sony's line and see if they have something in the lower price bracket. On thing I would recommend to everyone is a polarized filter, very cheap. Also, if you want a fixed zoom that can take shots, you can always get a lens adapter and a fixed lens, also fairly cheap.