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Posted: 7/24/2026 1:12:08 AM EDT
| Hypothetically , what might be possible with such a thing? |
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Originally Posted By SpyHawk: If you could get 5.56x45 velocity out of 5.7x28, then you might be on to something. You might need Peak Alloy; I'm not sure which is safer at extreme pressure, Peak or NAS3. Definitely peak, less expensive/cumbersome than the two piece hybrid cases. Problem is going to be getting someone to load it to its potential. Fuckin' assholes have pud loaded everything 5.7 because retards have been screeching "errrmahgerrrd cup-killah boolits!!1!" about 5.7 since its inception. Problem 2 is going to be cost and ROI, 55gr probably won't be capable of hitting 2400 out of a 5" barrel, just not enough case capacity. Plus you really need to get up to 2700 to get the full effect of fragmenting 55gr FMJ, you would need more barrel. Maybe a PDW can get that depending on the design? 40gr or lighter might get high enough velocity, I'd definitely lean towards something around 30gr pumped up to 2500+ FPS, that would make it worthwhile. M855A1+ is capable of picking up ~300 FPS with equivalent barrel lengths, so around a 10% increase in velocity. If the numbers equate 1-1 for 5.7, high pressure 28gr SS198LF in peak cases could reach high 2400's to very low 2500's out of a 5" barrel. A 6" to 8" barrel would get you pretty consistent mid 2500 FPS, so you're looking at a very effective close range weapon. That could be worth the tradeoffs, getting rifle terminal effects out of a tiny PDW/SMG, without a massive increase in recoil. From there, you'd almost certainly need a new weapon designed around the higher pressure ammo, closest to this currently is PSA's X57. HK MP7 is a shit show in 4.6 as it is, they'd have to do a ground up redesign to make it worth a damn with higher pressure ammo, lol. |
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