As a follow-on to my earlier post analyzing the LSAT project, I provided this table with the best comparative data that I can find. Note of course that LSAT systems are prototypes, and weights might change should these come into production. All LSAT data is for the more successful polymer-cased, telescoped (PCT) rounds.
First, the machine gun table:
| Weapon | M249 SAW | Stoner 96 | LSAT LMG | M240B | LSAT GPMG |
|---|---|---|---|---|---|
| Unloaded Weight | 17 lbs | 10.5 lbs | 9.4 lbs | 27.6 lbs | 14.7 lbs |
| Caliber | 5.56 NATO | 5.56 NATO | 5.56 PCT | 7.62 NATO | 7.62 PCT |
| Ammo weight (200 rd belt) | 6.92 lbs | 6.92 lbs | 3.8 lbs | 13.4 lbs | 7.5 lbs |
| Loaded Weight | 23.92 lbs | 17.42 lbs | 13.2 lbs | 41 lbs | 22.2 lbs |
The 6.5 mm PCT round is very nearly the same size and weight as the 7.62 mm PCT round, so the 6.5 is omitted for simplicity. This also provides a better comparison with the existing M240B. A 200 round belt was used for ease of comparison, though 100 round belts are also commonly used.
Now, the carbine table:
| Weapon | M4 Carbine | LSAT Carbine |
|---|---|---|
| Unloaded Weight | 6.5 lbs | 6.5 lbs |
| Caliber | 5.56 NATO | 5.56 PCT |
| Ammo weight (30 round magazine) | 1.05 lbs | 0.69 lbs |
| Loaded Weight | 7.55 lbs | 7.19 lbs |
The carbine designs are less well developed. I don’t have enough data on the prospective 7.62 mm/6.5 mm PCT ‘battle rifle’ to include it in the table (specifically, I lack the weight of a loaded magazine). We can see that the weight savings are much less significant here, amounting to 2.5 lbs for a standard combat load of 210 rounds. Which is nice, but not quite as massive as the savings for machine gunners.