Load Development Brian Pearce In I 1964 the U.S. military adopted a new service cartridge known as the 5.56mm Ball Cartridge M193, while Remington announced the.223 Remington cartridge, a commercial version, at essentially the same time as the military s official adoption. Like most previous military cartridges, its success among civilians was inevitable, and today its popularity continues to grow. It has been chambered in a variety of rifles ranging from bolt, lever and single shot, but the M-16/AR-15 rifle s popularity among civilians has been incredible, especially in the past decade or two. Recent shortages in.223 ammunition have driven many to begin handloading, while others just want to save money. Various competitions have also driven the AR-15 popularity, but to be truly competitive one must handload to get the most from the rifle/cartridge combo. Handloading the.223 cartridge for use in AR-15 rifles is straightforward, but there are some facts that handloaders should be aware of before assembling loads. For instance, early rifles featured a onein-14-inch rifling, but that twist rate was soon discontinued in favor of a one-in-12-inch twist that better stabilized 55-grain bullets, especially at longer ranges. In conjunction with military ammunition changes (to 62-grain bullets), the rate was again 1 www.loaddata.com The AR-15 rifles have gained considerable popularity in the hands of civilians in the past decade. They offer accuracy, reliability, are incredibly fun and an excellent choice for defense.
Handloading the AR-15.223 with 1-in-12 twist Industry maximum overall cartridge length is 2.260; however, many factory loads measure 2.2045 inches. for 80- and 90-grain bullets. In two future issues of LoadData.com, we will offer handloads for AR-15s featuring one-in-9- and one-in-7-inch twist rates and tips for loading them. Today, however, it seems prudent to offer loads for barrels with the onein-12-inch twist. All.223 Remington loads were checked for velocity using an Oehler Model 35P chronograph. changed to a one-in-7-inch twist, which stabilizes heavier bullets up to 80 grains but does not generally perform well with lighter versions weighing 55 grains or less. They not only fail to properly stabilize, but also many frangible varmint bullets leave the muzzle turning around 330,000 rpm and essentially disintegrate in midair, failing to reach the target. To make this subject even more interesting, a number of AR-15s are offered with one-in-9and one-in-8-inch twist barrels. And recent select barrels feature a onein-6-inch twist, designed specifically The action and gas operation system of the AR-15 presents some additional challenges to handloading the.223 Remington that common bolt-action rifles so chambered don t face. For instance if a cartridge is not properly sized for easy drop-in chambering, the bolt closing force of the AR-15 is weak, and therefore the round will not chamber, thus tying up the rifle. Many recommend the use of a small base sizing die to assure that the case fits easily into the chamber. This approach works, especially if loads are to be used in multiple rifles, but I have also used The.223 overall cartridge length cannot exceed magazine length, or they will hang up and fail to feed correctly in the AR-15. January-February 2008 2
Load Development standard full-length sizing dies for cases that were fired from a given rifle and will be again fired in that same rifle. This approach tends to work the case less, giving longer case life and results in excellent accuracy. Regardless which approach is taken, sized cases (as well as loaded rounds) should chamber easily. A case gauge (available from Midway and Dillon) will help assure that cases are sized correctly for reliable chambering. Bullets should be crimped even those without a cannelure. The Commercial.223 Remington cases have a greater powder capacity than military versions. Military cases require the use of less powder, or pressures will rise. Load pressure was carefully gauged by measuring case head expansion. Brian used a variety of powders to develop.223 Remington loads in the AR-15. cartridge s trip from the magazine to the chamber is rather bumpy or rough, which can batter rounds, deforming bullet tips and can even seat bullets deeply into the case (on top of the powder charge) if they don t have enough pull. This is a dangerous situation, as pressures can rise significantly, which can damage the rifle and injure the shooter. For those two reasons, I suggest crimping all.223 ammunition that will be used in an AR-15 (with the exception of specialty loads that will be fed in the single-shot mode and are not today s topic). Bullets with a cannelure usually allow a fairly deep crimp. It is suggested to study the crimp on factory loads from Federal and Winchester and try to duplicate them. Bullets without a cannelure cannot receive as great a crimp, but crimp as much as they will allow without deforming or buckling the case and without damaging the bullet. Another tip to prevent bullets from seating deeply during the cycling process includes using an expander ball that measures.215 inch, which will offer a tighter pull on the bullet in addition to the crimp. The AR-15 gas system thrives on powders that produce enough pressure and gases to reliably operate the action but does not like being overworked from the use of a too slow burning powder. A too fast burning powder might produce enough pressure and velocity but might fail to cycle the action reliably. For example 22.0 grains of IMR-4198 powder behind most 55-grain bullets is a safe, maximum load in a bolt-action.223, but it won t cycle the action of many AR-15s. In this respect medium burn rate.223 powders have proven the most reliable. Examples include Winchester 748, Hodgdon H-335, BL-C(2), H-4985 and others with a similar burn rate. Too slow burning powders can overwork the gas system, so choose carefully. Before choosing a powder, I might point out some other factors that may help in assembling first-rate ammunition. The.223 is probably the most popular bottleneck rifle cartridge reloaded on progressive presses. In this application a powder that meters uniformly becomes somewhat crucial. For instance longer cylindrical powders tend to fluctuate charge weight when thrown from a powder measure. Considering that most loads for the.223 only call for 21.0 to 28.0 grains of powder, a one-grain variance is too much, producing greater extreme velocity spreads and pressures than wanted. (With many powders, changing the charge one grain resulted in a 150 to 180 fps change.) Another issue includes bridging wherein the powder hangs up in the.22 caliber (or less) powder through system, which means that a case fails to get its Overall case length should not exceed 1.760 inches. Cases should be trimmed to 1.750 inches as needed. 3 www.loaddata.com
Bullets should be crimped in place to prevent their movement during the AR-15 feeding and cycling process. The Hornady SP bullet is available with a cannelure for proper crimp placement. full powder charge, while the next case may get more than desired. Powders that meter accurately will prove top choices for those loading progressively or choosing to throw charges rather than weighing them. In this respect, spherical powders are difficult to beat. Every load listed functioned flawlessly in the AR-15. AR-15 extractors are comparatively weak, which means that if a load is producing even slightly excess pressure, the case may stick in the chamber. Thus the extractor slips over the rim, leaving the case in the chamber. (This leaves the rifle inoperable until the case is somehow cleared.) The point is, AR-15 rifles are not generally the best vehicle for.223 loads that approach maximum. This can be done but requires special attention in case preparation, selection of components and a carefully chambered rifle. AR-15 rifles fitted with a onein-12-inch rifling will generally Either Small Base or Full-Length sizing dies may be used to size cases. Be certain that re-sized cases chamber correctly. January-February 2008 4
Load Development Loaded cartridges should easily drop into the chamber of the rifle. stabilize and shoot accurately bullets ranging in weight from 40 to 55 grains, but some rifles shoot fine with 60-grain bullets. Although load data is offered with 40-, 45-, 50-, 52-, 55- and 60-grain bullets, surveys indicate that the most popular bullet weight is generally the 55-grain version among handloaders, therefore bullets in this category received the most load data in the accompanying table. Commercial.223 Remington cases have a greater powder capacity than military cases. Commercial cases from Winchester, Federal and PMC were used to develop the accompanying load data. If using military cases, the powder charge should be reduced 5 percent from those listed. Military cases feature crimped-in primers and must first be decapped, then the primer pocket swaged or reamed to remove the crimp before a fresh primer can be seated. All previously fired cases should be carefully inspected for defects and trimmed if necessary, as excessively long cases can cause pressure to jump significantly. For greatest uniformity and accuracy, use cases of one manufacturer and even of the same lot number. Mixed cases will result in a decrease in accuracy and overall load uniformity. Special for all LoadData.com Members! Varmint and Small Game Rifles and Cartridges $10. 00 (ppd USA only) This book covers varmint and small game loads. Call 1-800-899-7810 to Order! 5 www.loaddata.com
Remington 7½ Small Rifle Bench Rest primers were used exclusively in the accompanying data. This is not a magnum primer and contains essentially the same mix as the 6½ primer, but the cup is 25 percent thicker to withstand.223 loads that generate up to 52,000 CUP. With select powders, such as Winchester 748 and Hodgdon H-335, some report best results with a Small Rifle Magnum primer. In studying the chronograph tape and extreme spreads, both of the above powders were giving excel- Hornady One Shot case lubricant is great aid for the high-volume handloader. lent results with this combination and were accurate. If you experience greater extreme spreads than desired, it might prove worthy to try the Federal 205 or CCI 450 Small Rifle Magnum primers. Considering the small charges of powder associated with the.223, it is doubtful that a magnum primer would be required with any of the other powders. The.223 Remington is a welldesigned and splendidly accurate cartridge. With the correct selection of components, and reasonable care in assembling handloads, satisfying results are almost guaranteed. January-February 2008 6