The front ring is only as straight as you can eyeball it to be as you rotate it in the base.And the rear ring can move all over the place with no real zero point.
The base also only utilizes one screw at the rear whereas the rifle's receiver is tapped for two screws at the front and two screws at the rear. I just wish that a model specific design actually fit the model.I have been a loyal Leupold user for over 38 years.Davis recognized that the Model 14 pump-action, which was introduced in 1912, was by then outdated and too expensive to manufacture. Model 1903A3 during World War II and later the Remington Model 11-48 autoloading shotgun.The Model 141, a cosmetic update of the Model 14, appeared in 1935. Loomis and his design team were authorized on January 20, 1936 to develop the Model 49 pump-action rifle as a replacement for the Model 141, but work on it was stopped in 1939. Crittendon’s pump-action rifle, based on the dimensions of the 28-gauge Model 11-48 shotgun receiver, was selected over the Du Pont design, and subjected But all Remington commercial projects were put on hold after the Japanese bombed Pearl Harbor on December 7, 1941, so the company could focus its efforts on the war effort. By 1947, there were actually two design teams working on a pump-action rifle ‘ Remington’s Technical to extensive function and endurance tests.Just purchased my dream rifle and scope combo to celebrate 50 years and do some bucket-list hunting. Don't believe those who say that you can mix different brands of dovetail mounts.
Leupold STD are not compatible with Millett turn in mounts,for instance. If someone asked me to design a system with as many opportunities for error as possible, this would be it.
The steel bridge base can only strengthen the rifle and scope, creating a solid, durable, and reliable sighting system. This is a FYI not necessarily a complaint for the most part I've always been satisfied with my Leupold products.
So i recently purchased a NIB AB3 with DD bases along with some standard rings for another rifle.
I have used these bases for decades, and sold and mounted dozens to experienced hunters and shooters.
The design allows for windage to be adjusted at the base if you want to keep your scope's windage adjusted near zero.
You just hope you tighten the left and right "windage" screws equally to find the middle. Purchased the STD Savage 10 RH-SA Round Rcvr 1-pc for my Savage 10 and the base doesn't fit gun.