I've owned my Tippmann A-5 for about a year and a half and I've only bought one mod for the marker--an aftermarket barrel.
The Lapco Bigshot is a one-piece barrel that comes in either a polished black anodized finish or a bead-blasted finish. It it available in 8", 12" and 14". Bores range from .687, .689, .690 and .693. The Bigshot is available in A-5/BT/X7, 98c, Autococker, ION, Shocker, and Spyder threads. As you can see, the barrel is ported with "muzzle break" at the end to reduce your sound signature. According to Lapco, the Bigshot is gun-drilled from a solid piece of military-grade aluminum, and is precisely bored with a "smoother than mirror" finish. This finish, according to Lapco, gives the barrel "self-cleaning properties." UPDATE: I forgot to mention, the Bigshot is also available Apex-ready, so you can easily add the Apex head if you wish.
I chose a bead-blasted, 12" Bigshot in .689 bore. The bead-blast finish matches the rough matte finish of my A-5 nicely. Since the trend for paint sizes is to grow from .689 and up, I decided to compremise with .689 so I wouldn't be massively overbored if I had to shoot smaller paint. So far, .689 has worked very well for me, as I've never come across anything too big for that barrel. If you're shooting less than 15 bps and up, I would suggest you go with a smaller bore, preferably, .687, so you have a tighter, and therefore more accurate, paint-to-bore match. The Bigshot has given me superb performence, unfortunately, even with HPA, my A-5 is wildly inconsistant so it's a bit difficult to get ball-on-ball accuracy. However with a more consistant marker like a 'Mag or a mid to high end electro, ball-on-ball accuracy would be a cinch to lock in. I've only broken 2 balls in this barrel using old, cheap paint but I was able to shoot through them.
Since the A-5 is such a long marker a 12" barrel is a little too long. The gun's rather clumsy length means the barrel can snag when running through brush. In retrospect, 8" would have been a better choice. But that's the marker's fault not the barrel's.
The Bigshot sells at $47 at ActionVillage.com and ZepherPaintball.com (my favorite online retailers) and $57 at Lapco.net. A little steep perhaps, but the quality of the manufactureing is well worth it for this superb barrel rivaling Palmer's Brass.
Thanks for reading. I hope people find this helpfull and informative. If you have any questions, comments or disputes please post them below.
This post has been edited by MaDuce: 15 July 2008 - 11:02 AM