Rail Size...Do They Vary?

[dart368]

I put an after market rail on the bottom of one AR and installed a forward grip on it (I have to say it didn't SLIDE right on but will slide off and on with a little effort). I tried to put the same grip on my AR with the free floating barrell slides on it and it does not fit AT ALL!

Do they make different forward grips with different opening sizes? Thanks.

[dart368]

I forgot to mention that for legality sake, I did NOT mount the upper to a lower and it is a .22 caliber upper.

[glock_this]

nope.. same opening size & same rail size. it's a universal mount, that is the whole point really.. modular and universal across rails.

but there is a diff, technically speaking, between a Weaver and Picatinny rail

"The only differences between the Picatinny rail and the similar Weaver rail are the size of these slots and the fact that they are standardized. Weaver rails have a slot width of 0.180 in (4.57 mm), but are not necessarily consistent in the spacing of slot centers.[2] Because of this, accessories can be and are designed to fit on both Weaver rails and Picatinny rails; but most Picatinny devices will not always fit on Weaver rails."

[dart368]

So then I am guessing that it is the front grip that I have is defective?

[glock_this]

defective? not so sure. I have had rail products, mostly VFG's, that can be tight at times. I think it more a variation in the plastic mold than the rail.

[dart368]

That makes sense. Thanks for the help. :-)