I’m hoping DocGKR can help me out on this. Let’s say, theoretically, that a guy had a shiny new MK17 (SCAR heavy) in Afghanistan. He has shipping containers full of ammo and can basically feed it 7.62 Long Range, delinked 7.62 ball, or delinked 7.62 AP (black tip) and even some SLAP. He’s expecting engagements up to 1000 meters but usually less than 500. What load should he use? He can also put a 13", 16", or 20" barrel on his rifle. Is there much of an advantage to going with the 20" over the 16"? Does a 13" barrel lose much velocity to a 16"? What barrel length was military 7.62X51 designed for? Thanks in advance.
I will let DOC fill in on the ballistic side of the house…
But, for reliability (RE:Feeding) purposes I would go with 7.62 Ball in an auto platform. Though I would not waste my time de-linking it as the same stuff comes on 5rd clips:D
The Ball 7.62 was designed with auto loaders in mind.
The 7.62LR is a little longer than the Ball and I have seen LR cause problems in guns not specifically designed for it. The Black Tip is to rare and logistically hard to be consistent with (I like to DOPE in with what I will be using and what is accessable).
Thank you very much for the input. The black tip looks about the same as ball, do you know if it’s dimensionally the same as ball. Also, come to think of it, it seems like the stadia lines on an issued Spectre DR 7.62 would have been calibrated for ball, another reason to use that round unless AP has a similar grain weight and prests some advantage (assuming there are 6 or 8 cases lying around).
If at all possible, I would use the ammo specifically designed for the Mk17–Mk319 Mod0, especially for engagements under 500m. For shots over 500m, I’d go with the new Mk316 ammo (a product improved M118LR with greater accuracy and consistency) or if that is not available, M118LR. M80 ball (especially the variant with steel jackets–use a magnet to check) is an acceptable GP load. I’d definitely want a mag or two of M993 AP for use against vehicles or bad guys who think they are hiding behind cover, only to find out the AP round rendered it merely concealment…