The M4 Carbine at 750 Yards and Beyond

The M4 Carbine at 750 Yards and Beyond: Three Simple Things to Know

We took our 14.5-inch BCM M4 carbine upper to the Best of the West shooting range in Liberty Hill, Texas, to try our skill (and luck!) on their long-range, reactive steel targets. It may seem completely counterintuitive to all common knowledge on the Internet to take a non-free floated, 14.5-inch barreled 5.56 NATO with a mil-spec trigger out to 1,000 yards, but we live in the real world, with people crazy enough to try it.
And here are our three main conclusions after an incredibly fun day at the range.

Your rifle doesn’t really matter

A standard AR-15 with a non-free floated barrel is far more accurate than many shooters think, and it makes sense if we consider how an AR-15 is built.

Never judge a book by its cover…or an AR-15

It doesn’t have a complex, multi-faceted action to bed, operating rod or finicky top handguard like other military rifles (we’re looking at you, M14 and M1A). In theory, the AR-15 is actually configured more like a standard bolt-action rifle in terms of how the barrel is mounted to the receiver and how the handguards interact with it: straight in, with consistent outside influence. This makes the overall design inherently accurate, and the fact that an AR-15 doesn’t need bedding helps as well.
While our little gun isn’t an M4 carbine in the purest sense—it lacks a full-auto capable lower—the upper half is true to form, right down to the side-mounted sling swivel. It also has an extended and pinned flash hider, to comply with arbitrary federal barrel length laws.
The gun was configured with a standard, single-stage AR-15 trigger housed in a Rock River Arms lower. While having a crisp, lightweight, two-stage match trigger like a CMC would certainly help, it’s not a requirement to get good hits on practical targets. After all, ample practice with a standard trigger beats no practice with a match-grade unit every day of the week.
We’re not going to be shy: shooting an AR-15 without a free floating barrel at long distance isn’t easy, even off the nice concrete shooting benches at Best of The West. It takes practice, practice, and more practice. But with that practice comes ability, and the AR-15 is more than capable enough for the job… as long as the shooter is.

Your ammunition does matter

Quality ammunition will make a bigger difference at 750 yards than a match-grade rifle will. Take an off-the-rack M4 carbine to the range with excellent ammunition, and you’ll likely see better results than you would with a custom-grade rifle shooting crummy ammo.
We originally started out with standard, non-match PMC XP193 ammunition, which shoots a 55-grain ball projectile at around 2900 feet per second out of a 14.5-inch barrel. This round perfectly mimics the old military-issue M193 load, right down to the tar sealant on the case neck.
Unfortunately, making contact with the steel targets at 500 yards and further was difficult at best. The bullet simply isn’t heavy enough, and velocities aren’t consistent enough to produce a consistent group. Additionally, the light bullet doesn’t fare well in the wind. It’s just not very ballistically efficient, which, incidentally, is a big reason the military switched to the heavier 62-grain M855 round.
That being said, the XPM193 performed very well on 10-inch steel plates out to 250 yards. Missing was pretty much impossible at these close ranges; point and click accuracy was the norm. It’s still fantastic, clean ammunition for stockpiling and general target shooting.
Thankfully, we had brought the “big guns” for everything past 250 yards: Reloads carefully crafted with Hornady 75-grain BTHP bullets and a stiff charge of Varget powder, as well as factory Hornady steel match, also in a 75-grain flavor.
Switching to the higher quality bullet and hand-weighed powder charges made a night and day difference. We went from occasional hits at 500 yards to consistent performance all the way out to 750 yards.
With high-quality ammo, making contact with the 18-inch x 24-inch steel plate at 750 yards was simply a matter of calling the gusting winds correctly. The 10-inch plates were slightly more difficult, and required a precise elevation hold and exact wind call.

Your optics matter

Right after good ammo, you need to have good glass on your rifle. It’s certainly possible to hit what you’re aiming at with iron sights, but it’s going to be incredibly difficult (if not impossible) to call wind corrections without some kind of optic.

The Vortex Razor HD Gen II 1-6×24 is definitely up to the task

We were shooting the excellent Vortex Razor HD Gen II 1-6×24, and were clearly able to see 5.56 impacts at 1,000 yards. Much like the idea that a standard rifle is good enough to make hits, this is another slightly counterintuitive principal: more magnification isn’t a good thing, unless the quality is there.
I would readily choose a 6x riflescope with the quality of the Razor HD series over a 25 power optic of lesser repute. Magnification isn’t everything.
No doubt, the Vortex Razor HD II 1-6 has the resolution needed to shoot past 500 yards. It also has an appropriate reticle.
Thanks to free ballistic programs and apps, figuring out your bullet’s exact rainbow-like trajectory at extended ranges is no longer guesswork. Furthermore, this drop can be expressed in useful angular measurements like milliradians (mils) and minutes of angle.
Conveniently, the Vortex Razor HD Gen II reticle has seven mils of drop built right in, represented by hashmarks along the vertical stadia line. This made it easy to look up on a computer-generated ballistics table how many mils the bullet dropped at a given distance, and hold over at the proper mark.
Once that was accomplished, it was a simple matter to favor left or right of the target depending on how far the wind pushed the bullet. The day we went, wind holds were typically one to two target widths left.

View through the Vortex Razor HD at 750 yards. Targets at 1,000 yards can be seen to the left.

Most of our time was spent on the 750 yard targets, with only a handful of shots taken at 1,000 yards. Winds were fluctuating wildly, and our heavy 75-grain bullets had definitely crossed the sub-sonic threshold at that distance.
It’s not that the 1,000 yard targets were impossible to hit; they were merely improbable. Lighter weight match bullets in the 62-69 grain range would probably help this.
It was far more fun to shoot at 750 yards with reliable results, so that’s what we did most of the time.

Give it a try!

The 5.56×45 cartridge should definitely not be your first choice if you’re going to be shooting at long distances, especially at the reduced velocities that a compact 14.5-inch barrel brings. There are far too many ballistically superior chamberings currently available, if your primary goal is hitting tiny targets ten football fields away.
That being said don’t stay home from the range if you don’t have a fancy match-grade rifle or a non-free floating barrel. Load up some quality ammo from Hornady, Winchester or Prvi Partisan, grab the gun you already own, and get out there!