This is what Posi-Lock is, and what Burris claims it does (it comes from their website):
The key to understanding accuracy is looking inside a scope before looking through one. Then it all seems simple.
A scope is a tube within a tube.
When you make sighting adjustments you're really moving an inner tube that holds the crosshairs and internal lenses. When it moves just 1/1000th of an inch your point of aim-and bullet impact-shifts one inch at 100 yards. The inner tube must move so you can sight in but needs to stay in exactly the same place the rest of the time-or your point of aim changes. So the tube is suspended in place by a spring. A little spring that doesn't always work. You see, the recoil of every shot knocks the inner tube, and your zero, out of position, So do the hard knocks of hunting. All because one little spring can't always bring it back right.
Most scopes use a single, 7 lb. bias spring to hold all these internal optics in place. It's not much, but it's easy to say "that's the way it's always been done."
The original Burris solution to this problem was to add a second spring. We use two 7 lb. bias springs, in every scope, excepting models with Posi-Lock. This effectively doubles the force holding the internal adjusting system against the adjusting posts. We get consistent praise from customers over well "standard" Burris scopes hold point-of-impact.
The Posi-Lock Advantage.
Posi-Lock replaces the springs with a retractable steel post. It locks the inner tube, and your accuracy, firmly in place. You get accuracy and dependability you can't find anywhere else. Posi-Lock is the best accuracy insurance money can buy. A simple turn of the key unlocks Posi-Lock, letting you make precision windage and elevation adjustments. When you tighten it back down the scope is locked on target. And it stays there. no matter what.
Posi-Lock will change how you think about scopes.
After all some things, like accuracy, should never change. Posi-Lock is available on most Signature Series, Fullfield and Handgun Scopes. It's but one of many reasons to change to Burris.
To me, and many others I know who actually have Burris scopes with Posi-Lock (and those who sell them), it may sound good on paper, but in practice its really an uneventful device. :roll:
Zachary
