07-13-2011, 07:04 AM
Stan,
I've been turning the gears over this AR12.5 receiver set for a while now. There is one option that might not require that route, using existing AR15 receivers, and that would be with the MGI system and a new magwell. I see more hurdles with the magazines than I do the receivers, really. MGI was working on a 7.62 magwell for their Hydra that used M14 mags, but couldn't get it to run reliably. They did fit a 7.62 magazine into an AR15 lower profile, using their modular mag well lower, but lost the space for a bolt catch.
We know the upper will accommodate a 2.5" cartridge I think, although I wonder about live round ejection and clearance. The next option would be to fabricate a billet set from scratch around these new intermediate cartridges, and make mags for them. Using as many existing AR15 small parts, and an enlarged bolt, costs could be kept under control. The bolt carrier group would need to cycle a bit more rearward than a 5.56 though. I think it's very doable. I would propose a magazine that is no taller than a 30rd 5.56 mag, but uses a semi-coffin shape to hold 30 rounds. This would make a great SASS rifle, but I think I would still prefer and "M4A2" (SOPMOD II) for most riflemen.
A 6.5 or 7mm DMR/Sniper SASS with significantly less weight than an M110 would be great, but in the end...what performance advantages will we gain over a 5.56 SPR with 18" pipe pushing 77gr SMK's? It would have to be significant enough to overcome the benefits the SPR currently has with ammo compatibility, lightweight, and mag capacity-per-volume.
This makes me look at these new intermediate cartridges as proponents for 7.62 NATO replacement if they can match the ballistics.
LRRPF52
I've been turning the gears over this AR12.5 receiver set for a while now. There is one option that might not require that route, using existing AR15 receivers, and that would be with the MGI system and a new magwell. I see more hurdles with the magazines than I do the receivers, really. MGI was working on a 7.62 magwell for their Hydra that used M14 mags, but couldn't get it to run reliably. They did fit a 7.62 magazine into an AR15 lower profile, using their modular mag well lower, but lost the space for a bolt catch.
We know the upper will accommodate a 2.5" cartridge I think, although I wonder about live round ejection and clearance. The next option would be to fabricate a billet set from scratch around these new intermediate cartridges, and make mags for them. Using as many existing AR15 small parts, and an enlarged bolt, costs could be kept under control. The bolt carrier group would need to cycle a bit more rearward than a 5.56 though. I think it's very doable. I would propose a magazine that is no taller than a 30rd 5.56 mag, but uses a semi-coffin shape to hold 30 rounds. This would make a great SASS rifle, but I think I would still prefer and "M4A2" (SOPMOD II) for most riflemen.
A 6.5 or 7mm DMR/Sniper SASS with significantly less weight than an M110 would be great, but in the end...what performance advantages will we gain over a 5.56 SPR with 18" pipe pushing 77gr SMK's? It would have to be significant enough to overcome the benefits the SPR currently has with ammo compatibility, lightweight, and mag capacity-per-volume.
This makes me look at these new intermediate cartridges as proponents for 7.62 NATO replacement if they can match the ballistics.
LRRPF52