Military round comparisons

[woohoo]

Agreed, plus the other problem is that the weight of high-BC 7mm bullets means that the weight saving over 7.62mm M80 may be too small to be worth bothering with.

The Grendel provides the superior long-range performance needed to replace the 7.62mm combined with a very worthwhile weight saving, but only from a long barrel and firing high-BC lead-cored bullets. Combine the use of short carbine barrels with the current insistence on lead-free bullets (which will protrude more deeply into the case, reducing powder capacity - especially with tracer bullets), plus the potential for a polymer/metal hybrid version of the case (the coming thing) which reduces the case capacity by maybe 10%, and you get a performance shortfall which can only be made up by a bigger case. Something like the 7x46 UIAC necked-down to 6.5mm should do nicely.

And by the way, the performance from 20" barrels does matter, because that's likely to be the length of the tube of a GPMG firing any new intermediate round. At long range, a GPMG is surely more important than a carbine in terms of effective squad firepower.

I haven't talked to Murray in a few months but the last I heard was he had submitted a mag design to handle 2.5" long PPC/.450 diameter cases for manufacture.
He had a few converted MGs that were being tested along with the AR10s but he was still working on his MG design receivers. His main goal is a LW MG so he is more interested in suppression fire and barrier defeating performance. With his testing he is convinced the 7mm bullet is the way to go for that purpose. I think it is possible to have one round to do everything, again if it was me it would be in 6.5 or .277 caliber where bullets in the 130gr range have good BCs. 1 round to do it all might gain military attention more than 1 more special purpose round. Later this year we'll have some AR12s in 6.8x45 (based on the Carcano case) and 6.5x45 if we can get 6.5 barrels made.