Choosing the right round for your AR build is one of the first things you should consider in your build process. With so many options ranging from .22 long to .50 BMG it is not an easy task. Several factors need to be taken into consideration, what will the rifle be used for? Plinking, home defense, large game? Does the cost per round and availability meet my needs? $3.78 a round for .50 BMG is a little expense compared to $0.48 for 22LR for frequent range trips and general plinking. Other considerations are barrel length and twist. Heavier bullets require more twists, 1:12 and longer barrels while lighter bullets can use shorter barrels with less twists, 1:7.
There are four major bullet types:
Full metal jacket (FMJ): a harder metal like copper, steel alloy, or gilding metal wrapped around a soft core usually lead. Sometime referred to as ball ammo. Inexpensive and good penetration are characteristics of this type.
Jacketed soft point (JSP): a harder metal like copper, steel alloy, or gilding metal wrapped around a soft core usually lead but with the lead tip exposed. This allows the round to expand on impact creating a larger wound.
Jacketed Hollow point (JHP): a hard metal like copper, steel alloy, or gilding metal bullet with a hollowed tip. It is designed to create a mushroom shape on impact decreasing penetration allowing for less collateral damage.
Boattail (BT): a hard metal like copper, steel alloy, or gilding metal bullet with a shape of a boat. This allows for a more stable and accurate round. Usually used in competitions.
A way to save money on the ammo mentioned above is to purchase surplus. Surplus ammo comes with other, non-monetary cost. It usually uses corrosive primers and/or has been sitting in storage for a bit collecting dust and dirt. One way to mitigate the corrosion is with ammonia, the amount in window cleaner is enough to get the job done. Just flush your upper with some cheap window cleaner when you are done shooting. Then when you are home clean and lube everything up, just like you do after every range trip. Not so much with 5.56 surplus ammo anymore but something to keep in mind with surplus ammo is that it is not marked well. You might not know what is in the projectile. It might be steel or other material that is not indoor range friendly.
The caliber and twist of your AR 15 is normally stamped on the barrel, if not, check the literature that came with your barrel or rifle. The 5.56 and .223 rounds are close, but not identical. The .223 is a civilian round and has Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) specs while the 5.56 is a military round that has their own specifications that might require higher pressure for higher velocity. As a rule of thumb, 5.56 chamber is OK to fire both 5.56 and .223 but .223 chamber is not OK to fire only .223.
Surplus ammo plays a role in the cost effectiveness of reloading. With the cheap price of surplus ammo it is not cost effective to reload those calibers. I think you start seeing a return on your investment when you start reloading “off” or custom calibers. Your presses and other equipment’s can cost a couple hundred dollars to your total cost of investment. If you are not reloading to save money but rather to get better accuracy with a better round or as a great way t relax and get more involved with your complete shooting experience, then reloading is for you.