.762 X 39 Bullets vs .762 X 51 Bullets

[BeeKay]

I bought some bullets a few years ago and they've been in storage til recently, so returning them isn't an option.
I'm thinking they may be .762 X 39 or 300 AAC bullets because the chanellure  is located a bit higher than the usual .762 X 51 bullets .
Also the drive band is more cylindrical and transitions more abruptly where it meets the ogive, See attached pic.
(sorry if 'drive band' is the incorrect term - I'm borrowing that from handgun reload terminology)
The channellure being positioned where it is, means that if I crimp the neck on the chanellure the OAL is about .060" shorter than typical OAL. 
The bullet on the left in the pic is the one I'm referring to - Compared to a typical 150 gr .308 bullet
Both bullets are 150 gr
So I'll have to experiment
But if anyone has experience with those type of bullets, and can provide any helpful info, that would be appreciated

So - Thanks in advance

 

[BeeKay]

Excuse the decimal point on 7.62 
Too late to edit

[dpete]

7.62 is 7.62 no matter what American rifle you shoot it in.  A 7.62X39 is actually .311. You can ignore the channelure for crimping purposes.  Get the length you want and don't worry about it.

[shooterrex]

Measure them if .311 they are 7.62x39.

If .308 load and crimp where you wsnt.

Edited November 13, 2023 by shooterrex

[98Z5V]

What these guys said.  ".308" Russian is a projo diameter of 0.311".  US and NATO ".308" are .308" projo diameter.

The Russians designed "backwards compatability" into their projectile.  Don't work the other way around, for the projectiles.