I’ll apologize if my challenges to statements made in this thread seem combative, that’s not my intent. So if you’ve read my posts as combative, indulge me a little reading to explain my position: I’m largely interested in the comparative experience and information out there, but I always want to be sure to understand the context of the “data,” especially when it conflicts my own experience.
Admittedly, I may also be too stuck in the original premise/premises of this thread, which has diverged into specifically discussing military documentation standards for specific weapon systems - as I assumed this wasn’t a “what could soldiers do?” thread, since it mentioned AR-15’s, but rather “what can civilians do?” since we have access to better options in ammo and optics for the task.
If @JCooperfan1911’s intent was originally meant to discuss military application only, I missed it. I read the original questions quoted here and answered accordingly based on my observations, experience, and limited personal ability.
Is it really possible for the small caliber .223/5.56mm to reach out to 500 yards with a 20” barrel?
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How realistically possible is it for a solo shooter in a field type situation, with an iron-sighted 20” AR-15, to hit a man-sized target at 500 yards assuming the rifle is capable of grouping well and the shooter is skilled?
In my first response in this thread, I pointed out my limited ability with irons, which I remain to protest here, but pointed to ONE simple parameter change which easily doubles what I would expect for my “effective range”. And I remain to believe what I originally answered SHOULD be true for most “skilled shooters.”
Other than ironsights prescribed in this thought experiment, there’s nothing about a 20” AR I would find unreasonable or unmanageable for hitting a man sized target at 500yrds with very little practice or prior prep.
If I’m crippled with irons AND Mil-spec ball ammo, AND an issue rifle barrel and trigger and 10 rounds to impact a man sized target... eh, I’m betting against myself at 200 no matter what cartridge you offer me... Maybe this is a sign I need to get out my ONLY iron sighted rifle more often (my eyes absolutely suck, can’t resolve my front sight post any more)...
So as I’ve read through and chatted in this thread with you folks, the same experience keeps rolling around my head and it just makes this 500yrds thing itch for me - the most recent 20” AR I built for myself was assembled during a one-on-one instruction/coaching session in which I taught a new shooter to build his own AR (a 20” Grendel), then took him and his rifle, and the rifle I’d built for myself to the range. We shot both rifles at 50yrds with a rough boresight, then we walked him out to 100 and 300, then 500. Once he was comfortable on the 875yrd target and just enjoying Trigger Time with his new rifle, I opened my rifle up again at the 500 yard plate - three shots down the barrel at 50 yards with factory ammo, 73 ELD’s, then straight to 500. I recall dialing a bit to raise my waterline, since I didn’t have an accurate velocity, but the first round was on steel (66% IPSC, 12”x18”). Yes, this was prone on a bipod, but even my son, 4 or 5yrs old at the time, was able to crawl behind the rifle and deliver hits on target. The kid keeps me humble, and largely confirms my contention that if I can do something, most people can do it better.
Equally, with x39, I hunted for several years on properties which would let me knock down multiple doe on the same day to help fill the 9 tags I was allotted, and I used a scoped SKS for faster follow ups, and cheap Remington Core-lokts. This was 20yrs ago, as a young student in college, filling my freezer, just starting into Service Rifle competition (and floundering miserably), and even then from sitting behind shooting sticks, I took deer at 250yrds with the Norinco paratrooper and a TERRIBLE import 3-9x compact scope. The Core-lokts would hold about 4-5” at 250, about the size of a deer’s heart, so that was my limit. Reading 300 as a documented maximum effective range is puzzling to me, as I could be sure I wouldn’t have been falling off the edges of a much larger man-sized target within in the next 80yards with that rifle. Given a corresponding optic, 5” at 250y would still be on a 12”x18” 66% IPSC beyond 500yrds, which would be a small man’s torso, and x39’s not falling transonic until 500-550... And if I’m any kind of marksman today, I can say with certainty, I wasn’t back then, and I don’t particularly find myself to stand out as a marksman even now - just a hell of a lot better than I was then.
We can point to Black Powder shooters throwing slugs with BC’s on par with VW Beetles with tang mounted ladders out to 1000, or Highpower Match shooters... lots of guys shoot a LOT better than myself... So if I can do it - most people should be able to replicate it.
My question about “effective range” was also earnest too - I assumed the answer would be as it was, based on hitting a man sized target (OR based on impact velocity for fragmentation), BUT, if the 300m effective range was based on wounding/mortality potential, I’d have been intrigued to hear the gap is so large between Rem Core-lokts quickly killing deer at 250y and Mil-spec x39 ball being ineffective beyond 300m. Any killing I have done past 250 hasn’t been with x39, so I can’t speak directly, but extrapolating... THAT reduction in performance in such a short range surprises me. Heck, an x39 at 700-800y is effectively hitting like a 38spcl at the muzzle, but with a higher sectional density...