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!