I've had a viper for close to 10 years now and use the shit out of it. Everything from torquing barrels to holding geissele reaction rods while working on AR's, torquing muzzle devices, and even holding rifles for cleaning and other stuff.
The only issue I've had was a couple of the nuts seize up on the studs so they would unscrew from the base. When they seized they were really on there too, I had to order new studs which were cheap. This was honestly my fault though, I should have kept some grease or anti seize on the studs. I do now and haven't had another seize up since.
A few tips:
Get yourself a few pieces of leather in various sizes for anything that you don't want to marr. The ones I use the most are usually about a 4"x4" piece wrapped around the barrel or two strips about 2"x4" one on top and one on the bottom. Be careful inserting the barrel into it as well, it can scratch the finish, especially the proofs. The two strip method allows you to lay one in the vise on the bottom, carefully slide the barrel in and insert the other in the top and then torque the bolts. Keep the leather somewhat clean and check for debris before use, if the vise isn't tight enough and the barrel spins, you will damage your finish if there's any hard debris.
Get some powdered rosin as well, you can find it in most sporting goods stores around the baseball stuff. Use this between the leather and the barrel by either rubbing some on the barrel or on the leather. If you do a good bit on the leather it will be good for a few uses. This will help keep the barrel from spinning.
If the barrel has a cylinder try to get that in vise if the depth of your bench (assuming against a wall) will allow it. This gives more surface area as well as a straight surface area with little or no taper. On the proof of will also keep you off of some of the carbon fiber. This requires you to remove the action from the stock but it's worth the extra few minutes to keep from jacking something up.
Buy top quality wrenches, they're worth it! If the Surgeon action wrench works on the Bighorn (I'm unfamiliar with them) I would highly recommend it over any others. They work great. Don't skimp on a torque wrench either and make sure you're not using one that your torque spec is at the very top or bottom of the range as they're most accurate towards the middle. I use a 1/2" 50-250ftlbs snap on. You can pick them up in good shape at pawn shops for about $100 or so. If you buy used track down a local snap on guy and have him check calibration, they will typically have the tool to check it on their truck. They usually don't charge to check but if you're not a regular customer a tip would be encouraged. If it needs calibration they send it in to snap on who charges about $50 to calibrate. They're very rarely out of calibration though. Use a breaker bar or ratchet to break a barrel lose, do not use the torque wrench. Also make sure you run the torque wrench back down after use, they will typically go a way below the minimum setting. All of this is incase you're unfamiliar with torque tools.
Also if you're not bolting it down (I wouldn't to save the bench space) get some heavy duty c clamps. They don't need to be machinist grade or anything but just don't use the woodworking stuff. They're not really suited for this stuff.
Hope this helps, it probably won't help your wallet any.
