There have been volumes written on this subject. I don’t pretend to have anything new to add except my recent experience testing a couple of my pet loads. Sometimes anecdotal evidence is a valuable aid in understanding things. I hope my findings and thoughts on the subject will at least provoke some discussion that ends up helping someone. We all want our load development to answer the same basic questions:
• Is my load accurate?
• Will it perform adequately for its intended application?
I’ve been thinking about those two questions a lot lately regarding some loads I’ve worked up. They inspired another important question:
• How do I define accuracy?
How one answers that question has implications for almost every other part of their handloading and testing routine. Different applications have different accuracy requirements. Each shooter determines for himself what “accuracy” means for his or her intended use. “Good enough” for hunting is usually going to be considered horrible by a benchrest shooter. A guy with a $6000 custom rig will have different expectations than the guy with an entry level scoped combo. Accuracy is defined relative to the purpose and sometimes the budget of the shooter.
My personal goal was to be able to find a load for each of my stock Savage barrels (.308 and .223) that would be capable of .5” five-shot groups @ 100 yards. They must always print less than 1” for 5 rounds in calm conditions.
I have worked up a load in each caliber that I thought would meet those requirements. Both printed half MOA 5-shot groups during load development. Both showed more than adequate muzzle velocities and boast single-digit standard deviations. I was proud of them and had confidence that my goal was successfully realized.....Until I shot multiple 5 round groups with them.
Suddenly, my sub MOA awesome creations (with target pics to prove it) were averaging 1.14” and 1.15” respectively over 8-10 five round groups. Each load had a group that measured 1.5”!
What happened to my loads? Did I just get lucky during load development? Was it shooter error? Did I get sloppy during brass prep or while assembling the rounds? All of these things are possible I guess but not likely. I was shooting pretty much the same as I always do. My reloading process didn’t change. What happened then?
Math happened. Probability happened. Reality happened.
When I chose the best powder charge for each of these loads, I picked the smallest 5 shot group. I checked the standard deviation. I eliminated charges with high SDs or excessive vertical stringing. The subsequent assembled rounds with the winning charge and COL from my ladder tests still have small SDs. The groups just got bigger. Sometimes. At least it happened often enough to change what I had thought of as a .5” inch load into a 1.15” inch load.
In reality, I don’t believe anything changed but the sample size. I believe I got excited about a couple of tight groups and declared them sub moa. I now believe I need to reevaluate what “sub moa” means.
Are my loads CAPABLE of printing tight groups? Absolutely. Will they do it every time? Apparently not.
My OCD kicked in hard enough to order a new Select Match barrel for one of these guns. My accuracy standards haven’t changed. How I define and evaluate accuracy has changed.
So, the next time you see a picture of someone’s “one ragged hole” 3 or 5 round group, congratulate them. Then ask ‘em if they can repeat that group 10 times in a row. If they can, they have something. I bet that 98% of those pics represent the smallest group that combo was capable of. I know I am guilty of doing the same thing. I bet that if enough rounds were fired to let math really happen to that load test the resulting targets would tell a different, more honest story.
Just my two cents. Does anyone want to tell me where I’m wrong?
