Readers often ask “What’s the difference between a Weaver scope rail and a Picatinny Rail?” The answer is not as simple as it seems. The dimensions of a Picatinny Rail should be consistent (from one rail-maker to another), since there IS a government spec. Conversely, there is some variance in “Weaver-style” rails. The width of the groove is the most important difference between Picatinny Rails and weaver rails. “Mil-spec” Picatinny rails will have a grove width of 0.206″ while Weaver rails typically have a narrower, 0.180″ groove width.

Brownell’s has a helpful GunTech™ Article that discusses the Picatinny Rail vs. Weaver Rail. That article explains:

“What are the differences between the ‘Picatinny’ and the ‘Weaver’ systems? The profile of the two systems is virtually identical. Depending on the quality of the machining done by the manufacturer, the two systems should be indistinguishable from the profile. The key difference lies in the placement of the recoil grooves and with width of the grooves. MIL-STD-1913 (Picatinny) grooves are .206″ wide and have a center-to-center width of .394”. The placement of these grooves has to be consistent in order for it to be a true ‘Picatinny’MIL-STD system. Weaver systems have a .180” width of recoil groove and are not necessarily consistent in a center-to-center measurement from one groove to the next.

In many instances, a Weaver system has a specific application that it is machined for, so interchangeability is not necessarily an issue. A MIL-STD-1913 system must adhere to the specifications listed above in order for it to be considered MIL-STD, since the military desires uniformity in the recoil grooves to allow for different systems to be mounted on the weapon with no concern for compatibility.

Now, what does this mean to you? Boiled down, it means that accessories designed for a Weaver system will, in most cases, fit on a ‘Picatinny’ system. The reverse, however, is probably not the case. Due to the larger recoil groove, ‘Picatinny’ accessories will not fit a Weaver system. There are, of course, exceptions to every rule, but for a good rule-of-thumb, [full-width] ‘Picatinny’ won’t fit Weaver, but Weaver will fit ‘Picatinny’.”

With the M.O.A.B. 150, a shooter has more than 150 minutes of angle (i.e. vertical adjustment) calibrated in 1/4-MOA clicks, with a handy zero-stop. This allows you to stay centered in the vertical elevation range of your scope. In addition, the amount of elevation travel is sufficient to adjust for drop at extreme long ranges — a mile or more.

Some users will employ the dial-in adjustment just to set an elevation pre-load for a shooting session (more preload for longer range). However, because the M.O.A.B. offers precise 1/4-MOA clicks, you can actually use the M.O.A.B.’s click-wheel to fine-tune elevation settings, just as you might use the elevation turret on your scope. This saves wear and tear on your scope’s internals.

The price for the M.O.A.B. 150 is $399.95. Note: a +300 MOA version is also available for the same price — but we don’t know why anyone would need that much elevation. Made in the USA, the M.O.A.B. 150 (and 300 MOA version) come with a lifetime warranty on materials and craftsmanship.

Editor’s Comment: We are intrigued by this system. We like the idea of external elevation adjustment with 1/4-MOA clicks. However, the precision of such a system is dependent on the fit of the front hinge cross-bolt and the tolerances of the rear rotary riser. With a design like this, if there is any “slop” in the system, you could see a POI change from shot-to-shot. We have NOT tested the M.O.A.B. 150 so we cannot evaluate if the tolerances are up to snuff — this is just something you should consider before shelling out your hard-earned cash.

Bolt-On Version for M1A and M14 Rifles
Cold Shot also offers an adjustable scope base for M1A and M14-platform rifles. This unit has front and rear attachment points for a “no-gunsmithing” installation. Like the standard M.0.A.B. 150 scope base, the M1A/M14 version offers up to +150 MOA elevation travel in 1/4-MOA clicks.