350 Legend is intriguing...I could run it suppressed. I'd have to look and see if there's enough difference between it and blackout to justify.
I did a lot on pretty much all the oddball AR platforms.
350L is an absolute beast in an AR15. Kinetic energy wise in my 16 inch rifles, they have the same energy as my 308 Winchester. Solid copper bullets excel in this caliber up to the 165gr bullets made specifically for it. I use 9mm solid copper and lead core in it. As well as some of the 165/170 350 legend specific ones.
6.5 Grendel sort of falls off as a high contender in an SBR length.
300BO excels as a SBR as subsonic, but above that you’re really shedding a lot of velocity and energy.
458 Socom is great as both sbr and carbine length, but the fireball and muzzle report on a SBR is godawful (unless running subs). Even as subs, a 458 Socom will equal a 4570 trapdoor level load, and no one in their right mind would argue that isn’t effective against a host of threats and game.
450 bushmaster is a good sbr and carbine length, but is also quite boomy and flashy in an sbr outside of subs.
7.62x39 is cheap to shoot, but performs fairly so so as a sbr.
My cousin is partial to the 6.8, but gel and energy results made it basically the equal of 6.5 Grendel. So it’s really a “pick your caliber name” between those two.
.50 Beowulf is wholly underwhelming aside from being able to say you have a “50 cal rifle” or if you have to hunt in places requiring straight wall cartridges. It’s also so so accuracy wise in my experience.
224 Valkyrie is pointless as an sbr as you’ve basically just made an expensive to feed 556 at that point.
Pistol cal carbines (mostly 10mm and 45 Acp) are beasts as an SBR and carbine, even without a can. My 10mm and 45 Acp In carbine length put out energy levels equal to and above 556.
If you look at the rest of the forum you can probably find all my gel testing results for all those calibers as well.
350L is an absolute beast in an AR15. Kinetic energy wise in my 16 inch rifles, they have the same energy as my 308 Winchester. Solid copper bullets excel in this caliber up to the 165gr bullets made specifically for it. I use 9mm solid copper and lead core in it. As well as some of the 165/170 350 legend specific ones.
6.5 Grendel sort of falls off as a high contender in an SBR length.
300BO excels as a SBR as subsonic, but above that you’re really shedding a lot of velocity and energy.
458 Socom is great as both sbr and carbine length, but the fireball and muzzle report on a SBR is godawful (unless running subs). Even as subs, a 458 Socom will equal a 4570 trapdoor level load, and no one in their right mind would argue that isn’t effective against a host of threats and game.
450 bushmaster is a good sbr and carbine length, but is also quite boomy and flashy in an sbr outside of subs.
7.62x39 is cheap to shoot, but performs fairly so so as a sbr.
My cousin is partial to the 6.8, but gel and energy results made it basically the equal of 6.5 Grendel. So it’s really a “pick your caliber name” between those two.
.50 Beowulf is wholly underwhelming aside from being able to say you have a “50 cal rifle” or if you have to hunt in places requiring straight wall cartridges. It’s also so so accuracy wise in my experience.
224 Valkyrie is pointless as an sbr as you’ve basically just made an expensive to feed 556 at that point.
Pistol cal carbines (mostly 10mm and 45 Acp) are beasts as an SBR and carbine, even without a can. My 10mm and 45 Acp In carbine length put out energy levels equal to and above 556.
If you look at the rest of the forum you can probably find all my gel testing results for all those calibers as well.
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6.5G in 12.5” is a great setup.
Don’t know why it has to be a different caliber when different barrel lengths already offer different rifle characteristics, especially if one is reaching for a different caliber to want. It seems backwards. If anything wouldn’t you identify a niche you’d like the rifle/upper to fill, then set about considering caliber/length/optic etc?
Anyway, 10.5 or 10.3 works great in 5.56 especially with appropriate ammo. 300BLK is great too but I feel it shines in single digits. 6.5G is a great round but I feel it shines (and is most available) in 12.5 and up.
I put together a 10.5 7.62X39 with a Faxon and it’s been amazing. It shoots the cheap steel case into around 3 MOA and premium Hornady around 1 MOA. It really breathes some life into a caliber considered by many to be ‘inaccurate’ largely due to the trash can rifles firing it.
Anyway, 10.5 or 10.3 works great in 5.56 especially with appropriate ammo. 300BLK is great too but I feel it shines in single digits. 6.5G is a great round but I feel it shines (and is most available) in 12.5 and up.
I put together a 10.5 7.62X39 with a Faxon and it’s been amazing. It shoots the cheap steel case into around 3 MOA and premium Hornady around 1 MOA. It really breathes some life into a caliber considered by many to be ‘inaccurate’ largely due to the trash can rifles firing it.
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