Weaver vs. Picatinny Scope Rails

[AdminMASTER]

credit: http://bulletin.accurateshooter.com/201 ... ope-rails/

..as Jon previously alluded to...here's the difference... as some of us are non the wiser thinking 'all the same' ....

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 Article - http://www.brownells.com/.aspx/lid=1072 ... Difference_
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.

but for a good rule-of-thumb, “Picatinny” won’t fit Weaver, but Weaver will fit “Picatinny”

[Jon]

Its a lot deeper than the spacings, I was unable to find any spec for a weaver going back some years meaning theres no set sizes or dimensions. Notorious for it are people calling them 20mm, 25 even 35mm weaver, Picatinny/Stanag are 21.2 wide only.

Both clamp totally different, weaver when made to similar size as picatinny rely on the two 45 degree angles only. Most weaver dont have sharp 90 degree angle rather a flat so no mount who ever makes it wont be substantial then add on whether the actual mount has 90 degree or rather just a relief or radius at the two 45's. Weaver also when mounted could see daylight in between top castelations and mount.

Picatinny only rely on bottom two 45 degree angles and pull down on to top castellation flats, solid. Top two 45 degree angles are purely for relief and do nothing.

Mounts are different also, take first attachment above looking at mount, that would be a weaver of some description.

Picatinny will only have two 45 degree angles and a vertical flat above it.