Sir:
I'd suggest next year, since you are from Ohio, is to go here:

http://thecmp.org/competitions/cmp-national-matches/

The National Matches are held every year in your home state at Port Clinton.
If you think an AR "maximum effective range of an AR15 type rifle in 5.56 is 300 yards".............. you will be stunned by the shooting there.
They do allow spectators................

Great!

Then he should understand one of the points I'm making:

At distance picking a bullet with a high BC is important and certainly valuable.
But almost equally important is the shooters ability to take advantage of the better bullet.
He has mentioned several times the problem of high winds.........so I'll use that again as the example.

You can take a 6.5CM with the best bullet out there but it means nothing if the shooter can't read the wind.
He'll either under or over compensate and shoot a poor shot.

OP:

By all means shoot the M193 out to 500yds.
See for yourself what results you get.  

Don't be surprised if it's alot like Pop is suggesting though................

https://www.youtube.com/watch?v=4hKYqQaZfAU

Here is a video of a guy claiming to hit targets from 800 yards away with XM193. Is it real? cant say, but then again I cant tell if its fake either. Guy has a spotter and it looks like a nice day with no winds. Still, hitting a 12" steak target with a ACOG from 800 yards is not easy, even with a spotter.

Yes it is real( believable), that's about what you can expect, "1 foot high, 1 foot left" bang "2 foot high just off the edge", he was all over the place.

Bullets don't always loose stability when they go below supersonic, some can and do stay predicable and on track. But once you get below 1300 fps you can question your choice of bullet or distance.

Supersonic distance(mach 1.2 really, not into transonic ) is a good measure of what distance you can reasonably shoot with any given round.

You're right he was all over the place. I think he said they hit the target once.

55gr Tula at 500 yards on 18" steels with AR-15s and Remington 700 with high hit regularity

I'm going to have to respectfully disagree with you here.  55gr @ 600 in a EIC match doesn't work just fine.  What kind of score @ 600 yards did you shoot with 55's?   69's IMO are the lightest you can go @ 600 to be remotely competitive. Not to mention if there is inconsistent wind you're going to have a frustrating match.  Highpower shooting is 90% mental, I sure wouldn't want any newbie I was showing the ropes to shooting 55's @ 600.   I'm glad you stuck it out, but 55gr in a match @ 600 on my range would be a pretty miserable experience.

And this guy is shooting M193 at 600yds...............

5/5 after the first round as a spotter..................  He says the gong is 8" diameter..............

https://www.youtube.com/watch?v=WtBcJEpPy50

Yes, I'm well aware of the national matches. You should also consider in your quote of myself, that the figure is heavily weighted with terminal ballistics. Ya know, simply hitting the target isn't all there is to shooting stuff. In a more practical sense, in real world conditions, it's likely not worth the time and effort to engage (remember, we're also talking about a man size target, ie combatives). Unless you're already in a good position of advantage (which has many more important factors than choice of rifle).

Noone is doubting the ability to hit a target that far out, but is it worth the effort and wasted ammunition? The OP is also not about precision ammo, but generic m193. I doubt that even the best shooters of the NMs would place if they shot using a service grade rifle and m193. Especially if they were required to use field equipment (no mats, jackets, loop slings, spotting scopes, wind flags, data books, no feeding single rounds, no cycling the FCG on a burst trigger...). Just plain clothes and a hasty sling, maybe microterrain could provide support in an ideal situation.

While I would not talk shit about these competitors, because they can most likely shoot circles around me in any scenario of equal playing field, the equipment makes a huge difference.

Just because my tacoma can do 100mph, doesn't mean I should try to race a sports car. Just because I can fill the bed with lead blocks doesn't mean I should try and haul them around.

I see the confusion here....................

You're adding alot of qualifiers to this..................... "terminal ballistics"........ "a service grade rifles".............. "M193"

So when you wrote............. "I do agree the maximum effective range of an AR15 type rifle in 5.56 is 300 yards. This also majorly factors in terminal ballistics. I still expect a hit at 500 though, knowing full well it's lucky to be making .22 holes, but a .22 hole is better than no hole when the target wishes you harm...."

What you meant was ......"maximum effective range of an AR15 type rifle in 5.56 average shooter shooting a service grade rifle with M193 using field equipment is 300 yards".

But the youtube videos show guys shooting off of packs, off logs, off bipods and shooting m193.
There are actually quite a few videos of guys shooting M193 at distance and except for maybe a scope, doing quite well,especially using a "man sized target" as the ideal.  

As far as terminal ballistics..............that is whole entire separate question.......
But as you point out........... a hit is better than nothing, even a 22...........
Especially if you are going to miss with something else...............

What's curious to me is that if lighter (<69gr), fmj  rounds are so unsuitable for distances over 300m, then why is the accuracy requirement in the spec for M855 listed at 600m outdoors (or 200m indoors)?

Yes, we're now on the same page. Typical... Your average infantryman, or asshole with a rifle... precision shooters use precision rifles for a reason.

The guys doing the shooting are fairly good. I've yet to have to opportunity to stretch out that far, but I don't see why it's not possible in good conditions. Where you and I differ is in the mindset. I don't consider it practical to use it past around 400 yards. At that point I should be moving or communicating. Note the other marine in this thread references match quality tools for this type of shooting, where I just don't consider doing it. The two of us are basically in agreement that it's not the proper tool for the job, we just use different reasons. I don't know of his experience in combat arms (this is NOT a personal call out, nor am I saying that I'm a combat vet let alone operator), but to me it seems he's a match shooter more than his mindset on the combative side. I appreciate the knowledge and skill of the precision/match shooters, and their arguments presented to do much weight, but I feel it digresses from the purpose of the rifle.

Maybe I'm wrong here, but I really only consider the weapon as an instrument of war. A match rifle is just that. Not that either couldn't swap places, but neither are suited to the other purpose, or there wouldn't be a difference.

Now I ask you, (certainly not as a personal attack or anything) what is your experience in this matter? Do you truly believe under typical conditions with a typical shooter using typical equipment, that 80% of shots fired will result in a hit on a man size target at 600 yards? Didn't another poster state (I could have misinterpreted his post) that it's only an 85% chance to hit at 500, and it goes down to 65% at 600? As figured by the ballistics calculator...

The whole thing seems like an exercise in futility just to hit the target (also, keep in mind my mindset of combat) for it to most likely not do much when you do connect the shot? Or even as a hunter, that really raises the question of an ethical harvest.

No, you got it right. That is considering getting the cross wind estimate within +/-2mph.

Calling cross wind within +/-1 mph brings it to 89%........ or if there is a tail or head wind that brings it to 97%, horizontal error is reduced by 2 feet at 600 with head or tail winds.

As with all long range shooting wind uncertainty is the biggest factor. High BC bullets have less wind drift, 55gr fmj is very low BC.


As long as the bullet remains stable you could do great or terrible  depending on the wind.

 That's why I shoot 90s in my .223, 140s in my 6.5G and 230s in my .308, wind drift resistance due to high BC.

I'll firstly respond to a few things and then tell you my experience in the matter...................................

-You are the only one to attach some sort of "combative side" to this.  That is not what the OP stated his purpose was, nor have I included any comments about that.  But what I will say this now:  any attempt to say what the ideal rifle is or isn't for combat is foolish.  There are too many variables to do so.  In Iraqi cities or in armored vehicles, the M4 was great.  In the open areas of Afghanistan longer range was needed.  What was ideal in the jungles of Vietnam probably isn't for the Arctic.  What the Delta or SF guys use is different from what a Marine clerk uses.  What makes an AK great may not for an M16.  What an illiterate Iraqi could best use is different than what a skilled US sniper should be using.  etc etc etc  

-Noone is talking about hunting.  We are talking about target shooting...........    

-Whats the point then?  Why do people golf?  The OP is curious to see if he can.   Why do people race cars?  

-What I can't answer for you is what an "typical" condition, shooter or equipment is either.  In other words, the Ballistic calculator is a useful tool to look at........ballistics............
You can't put in data for how the a "typical" shooter or equipment will affect those groups.  
So it's a tool that, if you put in accurate information, can tell you alot of about the ammunition data you put in.
It's up to the shooter and his equipment to make the most of the data..............

Which brings me to my experience:
I routinely shoot out to 600yds and often out to 1000yds with AR's.
I and others have no problems hitting a "man sized" target out to 600yds in even bad conditions and if the conditions are good at a 1000yds it is very "doable."  
What I learned from that is all that is dependent on the shooter, his equipment and ammunition.

Now the OP is asking about M193 but I don't know his equipment or his skill.  
I've shot M855 out to 600yds and it mirrored the groups Pop thought they might with M193.
And all these youtube videos show the same thing................

Shooting M193 at 600yds and getting hits is quite possible and if the conditions are good, even easy to do...............depending on his skill and equipment..........and the size of the target.

Is it ideal?  No. Is there better ammunition out there to shoot at 600? Yes.
Does it have any thing to do with Combat or hunting?  No.  
Is there any reason for the OP not to try it?     No.

I cannot disagree with you, especially your last couple points.

It seems we do both agree, since I see you stating things like ideal conditions, etc. We just have a different mindset and points to argue because of it.

Yes, I do occasionally get stuck on the concept of using it to kill the enemy. That's what I train to do when I pick up an ar15. When I pick up my 20ga, I only think of clays and birds, or cans and squirrels with my .22lr. Each tools has its purpose.

That being said, I'll have to concede that I may have been "projecting" or such (subconsciously of course). To which I apologize for going off topic.

We both know it's doable, but I hope you see my point that it's likely not worth the effort or focus, especially if you don't have the skill or gear.

Yes, of course I have shot beyond 300 yards. The difference in 6.5 CM from a stock RPR and a Crane built Mod 1 SPR even at 300 yards was an astronomical difference. We are talking 100% head shots with a 15 mph crosswind vs 100% body shots. At 400, when the wind gusts just as you are releasing the shot, you'd occasionally miss a body shot with the SPR, frequently with M193, occasionally with 77 SMK. The 6.5C would never miss a body shot at that range.

We all agree that wind is the major issue once accuracy is reasonable. We just disagree about what is "maximum reliable range" which, to me, includes gusts of wind you don't see. Wind is always shifting, but you will see on a wind meter the range is is usually in. You dope to the middle of that. It could be higher lower than what you dialed and occasionally you will get a large anomaly... a large gust or drop in wind. This causes many inches of drift shift. It was not on your meter. It was not in your scope view as mirage once you got lined up and decided to shoot. It snuck up on you. It was a down range wind shift you did not see or feel at the shooting position.

As for that shot distribution of over 85%... turn it vertical and tell me the hit percentage. The software also does not account for the occasional wild shift above. Just off the top of my head I'd guess the shift of the M193 vs 140 grain 6.5C to a shift in wind would be around double. At 440 yards head shots become difficult and frustrating with 6.5C but in low winds, easy 90%+ and I'd even conceed it was me that was the problem. These were 4" and 5" steel poppers I'm talking about. With an AR15 in the wind? Please... I don't evendors try anymore.

It's funny because time and again I have had people shoot AR15s and they will be happy with a 1 MOA or 2 MOA group in wind at 100 to 300 yards, then swap over to 6.5 and they get upset all the bullets quit touching. I have taken people who have never shot a gun of any type before, from other countries, shown them the basics using a prone bipod and rear bag, then shot a qualifier target at our local range. The qualifier requires 5 and only 5 shots be in a 5" circle at 300 to qualify to shoot the longer ranges. This means if you shoot a 1" group but one of the bullets is outside the 5" circle by .1" you fail. I have seen time and time again AR15s shooting 5.56 fail this in the wind. I have failed this before on occasion and it is always that 1 shot that got away due to wind, a crazy factory round, me not paYong attention late in a string that the wind died down, or something. The inexperienced shooters will fire 2 to 6 practice shots, then qualify the first time everytime with 6.5C no matter what the wind is like. This type of reliable accuracy is where I draw the line. Where I know it is me, not the gun or ammo. Where wind does not get me, ever.

As for terminal ballistics, 5.56 TAP T2 stops fragmenting from 175 to 245 yards in my guns, 77 TMK at around 300 to 350ish. M193 way, way less. 6.5 Creedmoor, 600 yards.

Also, I shoot at sea level, where we have high humidity. Our 10 mph cross winds are a thicker air and the bullets slow down a bit faster. Perhaps this colors my views more than a guy shooting at higher altitude, in dry, thin, crisp mountain air, where perhaps winds tend to stay steady. Here your bullet can go subsonic at speeds of up to 1200 fps in high summer heat and humidity, not 1050 to 1150, so even that effects your calm/steady wind max range, not to mention the bullet reaching a given distance at a particular velocity being shorter in dense air.

I just feel like people over estimate their guns capabilities in most non precision forums. If you got to set up and deliver a SINGLE shot on a 5" circle at an "unknown" distance that was actually between 300 yards and 300 meters, with no practice shots or foulers, I bet most of the people on ARFCOM, about 51% at least, would miss it, yet we think the rifle is capable of twice that range, as a collective, using M193.

I feel like 6.5C is reliable to 600 yards. I seldom get to shoot further around here. In steady winds I'm sure its a 1000 yard gun, I just don't have access to ranges of 1000 yards more than once or twice a year at present. In calm wind it should be a 1200 yard gun with handloaded ammo. Past that, it's transonic/subsonic, plus the drop per yard or fps muzzle velocity difference is insane. As for a 18" SPR shooting a TMK, here in summer, it is possible for it to go subsonic before 1000 yards. For that reason, I don't think an AR15 is a 1000 yard gun with any ammo, not to menton the huge vertical shift due to ammo velocity variations and AR15 velocity spreads in general. Black Hills 5.56 77 TMK has about a 20 fps SD, as does Hornady 6.5C 140 ELD-M factory ammo. That alone limits max effective range if discussing factory ammo.

In my experience, no M193 load has a 20 fps or less SD. It is always more, often MUCH, MUCH more.

The 52 SMK is notably one of the most accurate bullets at 100 yards ever made. It's not got a good BC but at 100 yards BC does not matter. It has been said you can't handload a 52 SMK to get a sub MOA group, it just will not happen.

Ok...........I think , I think I understand your position and have some comments back.  
I apologize if I seem insulting but I want to be as clear as I can.

You need to shoot at distance (+300) much more than you do.  I can tell from your comments that you have rarely if ever done so.  That is limiting your assessment of "all this."
Now, I would agree that alot of people haven't shot past 300yds either but they aren't the ones posting here.......... you are.  

You are making a short cut in your comments that I'll get to in a moment but you are (to repeat myself) limiting the "maximum reliable range" due to that.  I've watched endless times AR's being shot extremely well out to 600yds and 6.5CM EASILY out to 1000yds.......... regardless of the conditions.....  

The "short cut" you are making seems to be this:  This "maximum reliable range" (whatever that is) seems to be based on some idea of whether a target can be hit regardless of the wind conditions and the shooters ability.  That is flawed as it doesn't account for the three things at play here:  the shooter, the rifle and the ammunition.  Lets use your qualification example.....  You see it as an indication that the AR's can't shoot past 300yds.  I see it as an indication that the majority of shooters who fail, don't know how to compensate for the wind.  That same ammo/rifle combo if shot by a better shooter means the better shooter passes.  That doesn't mean the ammo/rifle combo sucks past 300yds, just that the shooter isn't experienced enough to shoot that far.  Those are 2 different things..............

When you say..... "This type of reliable accuracy is where I draw the line. Where I know it is me, not the gun or ammo. Where wind does not get me, ever......" you are actually mistaken.  You are ignoring the wind because the 6.5CM at 300yds would need a HUGE amount of wind to be blown off course.  You're allowing the ammunition to compensate for your lack of wind reading and in this case it works.    

Am I saying the "maximum reliable range" of an AR is 600yds?  No.  I have no idea what that means.  What I am saying is this:  I've watched 1000's (YES 1000's of shooters) at Camp Perry shooting AR's in competition.  All sorts of ammunition and all sorts of experience in the shooters.  (The rifles themselves are pretty close to one another, due to the rules in place).  Some shoot well, some don't.  But with a moderate amount of training in things like the reading the wind and moderately accurate ammo, they shoot moderate scores.  And as they gain experience, those scores jump up at 600yds regardless of the conditions................

The wind "out west" is actually generally much harder than in the east.  Your guess about the elevation and the air density is a good one but is over shadowed by a more practical influence.  I've shot at Camp Butner NC (Eastern Games) and Colorado Rifle club, along with numerous ranges across the US.  Google them and they illustrate my point quite well.  CRC is literally out on the open prairie, nothing stops or channels the wind.......... we shoot in alot of wind.  Camp Butner, like alot of ranges in the east, is surrounded by naturally growing trees.  It like like alot of ranges has the wind buffered or channeled by the trees.  

It's funny you should talk about shooting 1000yds in Texas in this thread............... Popnfresh is from Texas and in another thread, he and others did just that........... shooting an AR accurately out to 1000yds................  

If nothing else you should start reading around in here:

http://www.ar15.com/forums/b/16_Precision_Rifles.html

Humid air is less dense than dry air. Hot humid air is a positive in long range shooting, good for ballistics, not so much for the shooter....

It would have to be over 146° to have 1200fps be subsonic.

I go prairie dog shooting in South Dakota. My Longest confirmed shot with a dead dog Is 671 yds with a 55gr nosler ballistic tip, out of an 18" ar... I'm sure I got a lucky hit but I'll take it.

Ive easily used fed 55gr factory rounds to reach out to 400 yds and kept rounds inside a silhouette with a bolt gun and gas gun.

I used the 1-8x PA scope and the subtensions were dead on. Wind really starts to test your skills at that range, so ide imagine at 600 it would be even more challenging.

I had this out last Sat shooting the steel plate out to 560 yds using .55gr Wolf Gold and was hitting about 80%.
5x with a BDC. Next time I'm going to dial in Come ups and see how that does.

600 yards is possible with a 20" barrel, a little harder with a 16" and IMO nearly impossible with a SBR.

if you routinely shout out to 600+ yards you might want to upgrade to a 308, 300 win mag, or 338 lapua

Normally with a 3x BDC, 16" FF rifle, using wolf gold I can tag man size steel 9/10 times at 400 in a basic sitting position with a hasty sling. That's WITH a 25mph cross wind. On that particular range I have no wind flags or instruments, so 2-3 shots to get the wind call are required. Doesn't help the shooting position is inside a bay, which blocks the wind, you can only hear it and watch it carry your dirt splash.

PSA rifle, wolf gold, hasty sling, sitting... truly not ideal, it's a little more realistic... but it works. Prone was a PITA on that range because the targets are uphill, so seldom shot prone.

Now yesterday, I entered into an exercise in futility. That CBC m193 refuses to group less than 7" in the above mentioned rifle. Where WG usually shoots around 2.5-3". The CBC works fine in my other rifle though, quite strange, I guess the barrel/bullet don't like eachother. I wasn't expecting it to be 7" bad though, I could see 3-4", but 7" just blows.

For some reason, that's about how well 55 grain american eagle groups in my recce.  It's baaaaaaad.  Some brands just don't jive with a certain barrel.   Or certain barrels don't like certain loads.  They're all prejudiced.

I used to shoot 77gr but my current Voodoo 16.5 shoots 55gr Hornady reloads very well.  Last year at Hard as Hell, they had a 24"? target at 625 yards that I was able to get on the first shot.  A little luck involved as my VX6 doesn't have that BDC drop so I had to estimate.

At first I figured it was because the barrel was bare, as i had very thoroughly cleaned it of excessive copper fouling. Figured it would settle down. After 5 shots with wolf gold it settled in for the WG and AE, but the cbc still held fast at 7". Very disappointing. Since my other rifle wears a red dot and carbine length irons, I don't really shoot it past 200 (YUGE dot). So I basically have 2.5k rounds of cbc that I can't use. I don't want to have ammo that's only good in one rifle and not the other.

Anyone around Dayton wants to buy it, PM me.

I'm sure this seems obvious now, but it's always good to test before buying in bulk.    Can't you just burn it through the other rifle that likes it?  Then you have a stash for at least that rifle.  But I know what you mean, it's nice if you have something that works in both.