Most people in the precision rifle game have owned a 308 Winchester rifle at some point in their life. If those same people are reloaders, they have gone through the process of finding a load that works for their rifle.
My particular 308 has been a bit of a headache to reload for. I have tried multiple different projectile weights, multiple different manufactures and always run into some accuracy issues.
This time I did some reading and watching YouTube for different methods of finding that optimal load. What I have come up with here is nothing new; however, it has been tweaked to fit my needs and available range space etc.
Step 1: Choosing and prepping brass
For this load I am basing it on OSA brass. This was once fired brass fired from an AR10 variant made here in Australia (The WT25 by Wedgetail Industries). The brass was decapped, wet stainless tumbled, full length resized and trimmed to spec using my Worlds Finest Trimmer (review on this later).
Step 2: Consult a reputable reloading manual
As I use ADI Powders here in Australia I used the ADI Handloaders guide. I have a hard copy; however, a downloadable copy is available here: ADI Handloaders Guide 9th Edition.
Step 3: Loading
I chose to load in 0.2gr increments from the minimum charge weight up to just past the maximum listed charge. From experience I have learned reloading manuals are often conservative in nature.
I chose to prime the brass with Federal GM210 primers as they have always been reliable for me. Cases charged and projectile seated.
When doing a test like this i like to write the charge weight on the side of the cases for ease of reference later.
Step 4: Shooting and Velocity Testing
Next I headed out to the range with one of my mates and setup. Due to the layout at my local range I was restricted to shooting off the bench. That isn’t exactly a problem for this kind of test, even though I prefer shooting prone for load development. I set the Magnetospeed up on the end of the barrel and went to work.
Please Note: Before I commenced the test I fired 5 rounds down the barrel of another load to warm the barrel and myself slightly so as not to induce any shooter or cold bore errors.
Below are my observations from the test. All of the below charge weights were fired at a single aiming point.
Step 5: Analysis
As you can see above, I have identified two possible nodes indicated by the Red and Orange texts. These will warrant further investigation. Although my bet is 43.6gr will be on the money +/- 0.1gr and maybe 44.5gr as a backup for slightly more velocity.
I also found it quite interesting to see that all 17 rounds went into a 1.23″ group with a velocity spread of 167 fps for the different charges. This indicates to me this particular projectile suits my rifle.
Part 2 of this test will see me load up two or more groups of 5 for each of the charge weights I have identified and fire them over 100 meters/yards as well as 300 meters / yards. I’ll measure velocity as well as group sizes and make a decision from there.
Until then it is back to the reloading bench.
Cheers,
Craig
Precision Rifle Guy
Disclaimer:
Reloading can be dangerous even when following published load data. All reloading and firing of reloaded ammunition is done at your own risk. The load data published by this website is intended for discussion purposes only and for use by experienced reloaders only.
Do not attempt to reload until you have read and understand at least one printed reloading manual. Always wear safety glasses when reloading. Do not smoke while reloading. Keep primers and powder away from heat and open flames. Keep primers and powder where they cannot be accessed by children. Work up your loads following the standard procedures described in printed load manuals.
All reloading and firing of reloaded ammunition is done at your own risk, the author(s) assume no liability for death, injuries, or damage due to the use of this, or any other load data.
Precision Rifle Guy 