Can anyone tell me how many grams a single 64gr. 5.56 round weighs if it were put on a digital scale?  

In particular was curious about the Winchester 64gr. bonded JSP...ZQ3313 RA556B I believe.

Is there a source for this type of information for different ammo?

I know someone selling some he doesn't have the box and I would like to verify that it is what he says it is.  It appears to be, just would like to be sure.

I can't offer the weight of the 64gr bonded (as of yet), but in case nobody shows up with the data,  I can give you some other numbers for reference.

PMC Bronze 55gr - 175.1 Gr (11.346 grams)
Hornady 55gr - 176.0 Gr (11.405 grams)
PPU 55gr - 180.9 Gr (11.722 grams)
Federal XM855 62gr - 184.5 Gr (11.955 grams)
Federal GMM 69gr - 190.9 Gr (12.370 grams)
Fiocchi 77gr - 201.6 Gr (13.063 grams)

Those are all averages of 20 rounds. As you can see from the 55gr differences, the totals can vary a bit. (primarily from the variations in powder charge and case thickness/weight)

verifying with weight is the poorest way,



pull a round, dissect it



 

Would it be safe to assume the 64gr round in question would be somewhere between the 62 and the 69 grain rounds listed above?

The meplat on the bullet its self should be a give away... the Nosler 64gr BSB has a very large meplat compared to all other SP's that I have seen.

With that said, the only way to truly know is by what TaylorWSO  said.... cut one in half length wise.

I am pretty sure Winc. uses Noslers bullet...they just load it to 5.56 pressures.

http://www.nosler.com/defense-rifle-ammunition/

Meplat?

Meplat, from a French term for a flat surface, is the technical term for the flat or open tip on the nose of a bullet. .... in other words, the very tip of this specific bullet.

I just took a comparison shot of 3 popular barrier-blind bullets as seen below, in order from left to right, the 62 gr. Federal Trophy Bonded Bear Claw (XM556FBIT3), 55 gr. Speer Gold Dot, and 64 gr. Nosler Bonded Solid Base (Nosler Defense .223, same bullet as Winchester Ranger RA556B)

http://i62.tinypic.com/2lc8as5.jpg

http://i59.tinypic.com/14lt4ow.jpg

If I had my calipers at my present location, I'd take some measurements, but even from my mediocre iPhone photos you can see the flat area at the front of the Nosler bullet is noticeably wider than the other two bullets. I've never seen a bullet that looks quite like it.

[Duplicate post - was trying to edit to get photos to show up directly on page rather than us URL]