Quote Originally Posted by Kiwigrunt View Post
If and only if that could get us to something like a (stretched-case?) 6.5 Grendel GPMG that can competently replace both the 7.62 MAG and Minimi type guns and the 5.56 Minimi types, without loosing so much punch that we are still going to want the 7.62 back, then we could look into using that same calibre for rifles.
I must ask why you think adopting one caliber would be a better option than using 2 different calibers. Keep in mind that the weight saved with the 5.56 compared to a hypothetical mid-range cartridge could be used to help carry some of the slightly heavier 7.62. As you've read in the article, they are trying to reduce the weight of 7.62 so that it becomes more user-friendly at the platoon and squad level. Do you feel that pursuing an entirely different caliber is a better pursuit than this route?


I am by no means an expert in ballistics so I’ll refrain from arguing the sabot suggestion, other than to say that the concept comes across to me as promising for niche roles like armour piercing and perhaps less so for much else.
It can be used to create an effective AP cartridge, but it doesn't have to. Let's take the M855 as an example... A lot of people seem to claim that it's only effective at ranges where it fragments (not saying it's true or untrue, just that people say that). I've heard 200m from a 20" barrel, so I'll go with that for the sake of this discussion. If you were to fire an M855 bullet wrapped in a sabot from a 7.62x51 case (doesn't have to be 7.62, just using it as a reference), it would maintain that vaunted fragmentation velocity to a much greater distance due to its increase in velocity, and fragment more violenty/reliably at closer ranges.

Also, if for some reason you need the greater momentum of of 7.62 ball... simply use 7.62 ball, it would be perfectly usable in a firearm designed for 7.62 Sabot.

There would also be the significant increase in flatness of trajectory, which is (to be a bit redundant) significant.

Increasing powder weight to save weight….hmmm, dunno. A M193 has more powder per unit of bullet weight than a Mk 262.
Ahh, no no, I meant absolute powder weight, not relative powder weight.

Typically, the 2 heaviest components of a cartridge are the bullet and casing. You rarely hear someone say that 9mm NATO is more effective than 5.56, even though the 9mm uses a heavier bullet. Why is that? Obviously it's because the 5.56 is launched at a much higher velocity due to the significantly higher amount of powder behind it. 5.56 and 9mm also weigh almost exactly the same per cartridge!

My point is to draw a parallel with the 5.56 and 9mm, to 7.62 Sabot and intermediate cartridge x, respectively. While both would weigh roughly the same, I feel that the former would result in a better increase in effectiveness, with more quantifiable perks than "stopping power".