125lbs with a synthetic grease that I bought to use on the ball links for my giant scale RC helicopter. (thankfully I came to my senses and sold that thing before throwing anymore visa cards at it!)
Eddie brings up a point. Please indulge another Chad Dixon longwinded dissertation.
Yes, many a BR guy swaps barrels the way formula one teams change tires. They crank them on hand tight and go for broke, shoot amazing groups, and it attempts to destroy all the little cardinal rules we've been taught since first building a rifle.
There's one thing you have to understand/realize though. It's apples and oranges.
I like apples btw.
Two terms to burn onto your hard drive: Group Size and Group Center.
A dedicated BR gun is a very specialized rifle that does one thing. The events are orchestrated so that a shooter can fire off just about as many sighters as he/she wishes. How this becomes relevant is that if you don't like the zero the gun has that particular day, go to the sighter target and start cranking knobs till you get what you want.
All they care about is group size.
Competitive (position shooting like highpower/palma, ect), tactical, varmint, hunting, rifles depend on both group center and group size. We want some assurances that the zero we establish today will be consistent the next time we pull the trigger. A hand tight barrel doesn't offer the assurances we need. Especially if the gun gets the snot shot out of it (like a highpower course gun, varmint rifle) because heat is going to be generated and things want to move around when they warm up. Especially barrel tennons.
To beat this horse a little more:
Hold your arm straight out, lock your elbow, and strain every muscle as hard as you can to hold it still. Now have someone try to move your arm. Doesn't take much effort for that person to steer you in whatever direction they want you to go. Now imagine all the forces at work on a barrel as that bullet is being accelerated from a dead stop to close to/over 2.5 times the speed of sound in a distance of just at/over two feet. You have linear acceleration and rotational acceleration along with crazy pressure, vibration, blah blah blah.
It's amazing these dumb things even hit the backstop!
All of that is managed by a threaded joint that's typically between 3/4"-1" in length and just over an inch in diameter. Amazing!
Thinking of it in these terms is why I habitually harp about the thread fit between barrel tennon/receiver being so very, very important. I try like hell to get mine to where they are just loose enough to not stick when assembling. It's a fine line and on rare occasion it does bite me (not so much anymore) and I end up buying the client a new barrel, but I truly believe the merits overshadow the risk.
Just my two cents on that.