Thursday, May 20, 2010

Handloading .223 for the AR

Military style rifles are not usually known for having match grade accuracy, but the AR-15 can be easily upgraded with just a few parts to be more than capable of shooting sub MOA groups out to distances exceeding 600 yards. Swap out the trigger for a Timney and replace the barrel with a heavy stainless steel varmint or match barrel and you'll be surprised by the significant increase in accuracy. But the biggest improvement may not come from the rifle at all, but from the ammunition you use.

I got started shooting cheap military surplus 5.56mm NATO rounds in my AR, along with cheap Winchester white box and Remington .223 FMJ plinking rounds. These cartridges were usually 55 or 62 grain and had decent accuracy. I still use them for plinking and just having fun at the range. But when you want to get serious about target shooting, you need better ammo. The biggest differences between mass produced ammunition and match grade ammunition is the quality of the components and the attention to detail to ensure every round is exactly the same.

Getting Started
You can buy match grade ammunition from a number of manufacturers. Remington and Hornady both manufacture excellent match grade ammunition. Varmint ammo from Remington and Hornady is just as accurate as the match grade ammunition, but is loaded with lighter bullets weighing between 40 and 55 grains. This factory ammunition is easily capable of shooting half-MOA groups is an excellent place to start establishing a baseline for your own handloads. Shoot a variety of loads and bullet weights to find out which performs best in your rifle and start loading your own based off of this data.

When selecting the proper bullet, keep your barrel twist in mind. We've written in the past on the importance of barrel twist rate with regards to bullet weight or, more accurately, bullet length. For any given caliber of ammunition, the heaver the bullet is the longer it will generally be. Longer bullets require a faster twist rate to get them spinning at a high enough speed for effective stabilization in flight. If there is a specific load you just have to run, consider rebarreling your rifle with a barrel with a more appropriate twist rate.

The first barrels produced by Colt for the AR-15 had a slow 1:14 twist rate, which was adequate for 55 grain bullets under normal circumstances. However when air density increased due to lower temperatures, the 55 grain became unstable. This prompted the Army to switch to a faster 1:12 rate barrel, and later an even faster 1:7 rate barrel to accommodate heavier 62 grain M855 bullets. Most modern rifles have a 1:9 twist rate, which has been found to be a healthy compromise that is able to stabilize bullets weighing from 50 grains on up to some 69 grain bullets.

Varminters often use very light weight bullets such as the 40 grain Sierra Hornet. Such bullets are exceptionally accurate in order to hit small targets, lightly constructed to provide explosive expansion while minimizing ricochets, and lightweight to obtain high velocities with flat trajectories. The extremely flat shooting varmint round is perfect for taking small game at unknown distances. Competitive shooters on the other hand tend to favor longer and heavier bullets with an aerodynamic boat tail design. These long bullets have a superior ballistic coefficient which allows them to maintain a high velocity for a longer distance, thus making them less prone to wind drift at extended ranges.

One concern when loading heavier longer bullets for your AR is the overall cartridge length. Heavier bullets are longer, and there is a limit to how far back they can be seated. Standard AR-15 magazines can hold cartridges up to 2.275 inches long. If you are loading rounds with heavy 79 grain or heavier bullets, such as 90 grain Sierra MatchKings favored by long range target shooters, the overall cartridge length will likely exceed 2.275 inches, requiring you to load and fire these handloads one at a time. If you are preparing a load that is over-length, it is important to make sure that your barrel is designed to handle it. A barrel with a 1:7 twist is generally not sufficient to stabilize bullets weighing over 77 grains (however some shooters claim to be able to stabilize 90 grain bullets in a 1:7 barrel), but more importantly, in longer handloaded cartridges the bullet could be swaged up against the lands of the rifling and cause overpressure in the case. Barrels for the longest of these loads will usually be custom made with a 1:6 or 1:6.5 twist rate and have a longer leade (the unrifled portion of the bore just past the chamber) to fit the longer bullet.

Depending on the weight of the bullet you are pushing, you will need different powders. Faster burning powders are more effective for propelling relatively light weight bullets. Slower burning powders in general should be used with heavier bullets. For our purposes here, powders such as Reloader 7, Reloader 10X, Accurate 2015, IMR4198 or Hodgdon H322 are excellent choices for accurate varmint loads topped with light 40 grain to 55 grain bullets. Reloader 15, H4895, IMR4064 or Varget are all good choices used for accurate match loads that propel heavier bullets weighing 60 grains and more.

When developing a load, always start at 75% of the manual recommended max load and work your way up, checking for signs of overpressure as you gradually increase the powder charge. If you don't have enough powder of one type or another, get more: never mix powders! Mixing powders can result in unpredictable burn rates and could cause a case rupture or detonation.

When choosing a primer for your match loads, stay away from hard military style primers. Most match triggers will not generate primer strikes hard enough to reliably shoot hard primers. Instead, stick with high quality standard small rifle primers such as CCI 400 or Winchester WSR primers for most loads, and Federal Gold Medal 205M for heavier match loads using slower powders.

Brass for match grade or varmint loads should always be cleaned and polished. This not only makes it chamber better, but it removes any carbon or debris from the case resulting in better more consistent powder burn. When resizing, don't rely on just a neck resize. For the most accurate loads your brass should be fully resized to ensure a consistent case capacity. Fully resized cases also fit the chamber better. What brand of brass you use isn't particularly important, but some shooters prefer Winchester or .223 Remington brass due to the consistent case weight and wall thickness.

When trying to wring every bit of accuracy from a handload, the devil is in the details. Turning the neck of your brass will help to ensure that your case mouth is perfectly round and concentric with the case body, giving you a consistent crimp and seal all the way around your bullet and positioning it perfectly concentric with the bore. RCBS makes a case neck turner and .223 pilot to help you turn the perfect case neck. Necks that are out-of-round can have gas escape around the bullet prior to the bullet entering the bore and result in an uneven bullet release. A perfectly even bullet release helps to ensure that it swages onto the rifling evenly.

Handloading Procedure
One of the primary reasons for handloading is that it gives you the ability to ensure absolute consistency among all of the rounds. Handloads that are quickly and carelessly assembled may be great for plinking and making a bunch of noise, but they are useless for precision shooting. Additionally, carelessly assembling your rounds can be dangerous! Double charged or poorly measured loads can destroy your expensive rifle and kill or seriously injure you. When sitting down to reload, get rid of all possible distractions. Never watch TV or have a conversation while reloading. Dividing your attention between the task at hand and something else can result in a mistake that could prove deadly. Remember that the more attention you give to the quality and consistency of your loads, the more accurate they will be.

See our article on reloading necked rifle ammunition for more details on the reloading process.

Example Loads

BulletBullet WeightPowderPrimerOverall LengthCharge (grains)Velocity (FPS)
Hornady V-Max35 grAccurate 5744CCI 4002.1321.13602
Speer SP40 grReloder 7CCI 4002.0620.53011
Speer SP40 grReloder 10XCCI 4002.0624.53481
Nosler BT40 grAccurate 2015CCI 4002.26025.43671
Speer SP45 grReloder 7CCI 4002.155203059
Speer SP45 grReloder 10XCCI 4002.155243292
Nosler BT50 grReloder 10XWSR2.224.23389
Nosler BT50 grReloder 15WSR2.2283356
Speer HP52 grReloder 7CCI 4002.220.52931
Speer HP52 grReloder 10XCCI 4002.222.53179
Nosler BT55 grAccurate 2015CCI 4002.23024.03215
Speer SP55 grReloder 10XCCI 4002.175233159
Hornady V-Max55 grVargetWSR2.24027.03344
Speer FMJ62 grReloder 15CCI 4002.25525.02832
Sierra HPBT69 grReloder 15Fed 205M2.2625.52956
Hornady A-Max75 grH4895Fed 205M2.27324.52861
Swift Scirocco75 grVargetFed 205M2.27023.02714
Sierra HPBT77 grReloder 15Fed 205M2.2624.12783
Sierra MatchKing90 grH4895Fed 205M2.55021.72600
Sierra MatchKing90 grIMR-4064Fed 205M2.55022.42600

All load data presented here should be used with caution. Consult a reloading manual and always begin with a reduced load to ensure that they are safe in your particular rifle before proceeding to full power loads. Cheaper Than Dirt! has no control over the quality of the components that you choose, the condition of your rifle, or the actual loadings you use, and therefore assumes no responsibility for your use of data presented here.

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