Accurate Load Development For Your RifleDeveloping an accurate and consistent load for your rifle can be one of the most time consuming but rewarding tasks an avid shooter can undergo. Having spent most of the summer of 2009 developing loads for a semi auto and a bolt action rifle, this article has been in the works for some time!
This summer I spent a great deal of time developing loads for both a .270 Winchester Model 70 and a Rock River Arms .223 AR-15. The development process was similar for each firearm and the techniques described in this article can be used for developing a load for any type of rifle.
The following few paragraphs describe the method that I followed and that worked for me.
Since my shooting range is limited to just over 100 yards, extra case preparation steps such as neck turning or organizing cases by weight were ignored for shooting at this distance. If you are a long range shooter, then you may want to apply some of those other techniques to obtain every bit of accuracy from your particular load.
I first begin by doing research on powder and primers. I select a primer and powder first instead of trying multiple powders and primers. By doing this it helps to eliminate a couple of variables right away. Online forums are a great place to start doing research for this type of information. Another great place that I visit often is 6mmbr.com - they have info pages for a lot of different calibers with information about popular powders that most of the top shooters use along with primer and bullet weight information. Again, if you are a long range shooter, then trying different powders might be something you will want to do.
Once I have my powder and primer selected, I will begin researching what bullet weight will most likely work best with my particular barrel twist rate. Bulletsamples.com is a great place to buy samples of various types of bullets. It's much better then having to buy a box of a 100 bullets only to find your gun doesn't like them! I will purchase at least 20 of various brands of bullets in different weights. It's amazing how bullets of the same weight, but different manufacture can shoot differently in your gun. (Perhaps if manufacturers would offer powder samples, I would test more types of powder as well!) The next step is to start loading up some rounds!
Loading and testing different bullet weights and different charges is where the real work begins. It's also the most time consuming part of the process; that's why I prefer to select a powder and primer right away and use that as my starting point. I begin with the starting charge listed in my reloading manual and then load five (or ten if you are shooting an AR style semi auto) rounds. I increase the charge weight by half grain increments until I reach the maximum charge weight listed in the manual for my particular bullet weight and powder type.
Once you have some rounds loaded up, you are now ready to head out to the range. Be sure to take accurate notes and record your shots (at least save and label your targets after you fire each group). When your range session is over, you should measure your group size and look for the bullet weight and charge that gave the tightest group. Doing this, will give you a starting charge weight that is most accurate for your gun for the particular bullet you are shooting. I will adjust this load and increase the charge weight or decrease the charge weight by a fourth of a grain to see if I can squeeze a bit more accuracy out of it. By repeating this process with each bullet type and charge weight you are shooting, you will be able to determine witch bullet/powder combo works best for your rifle.
Finally, for some further tweaking if you so desire, you can experiment with using a precision mic to determine the optimal bullet seating depth for your rifle. For the AR-15, I simply loaded the rounds to fit the magazines I was using.
Good luck and happy shooting!