Rifle Accuracy: The Group Of Ten
July 10, 2018
The modern standard of rifle accuracy is the three-shot group at 100 yards. Fifty years ago, it was the five-shot group, and a century before that it was 10 shots. Are we now getting a better picture of a rifle's capabilities, or is this merely grade inflation, making rifles and ammunition look better than they really are?
This three-shot business generally applies to hunting rifles, and it's rationalized on the grounds that you rarely fire more than three shots at a big-game animal. Well, maybe so. But the odd time that you do- and believe me, I know- you'll be grateful for every bit of accuracy you can get.
In fairness, we have also become much more severe in our definition of accuracy. Fifty years ago, a group of 1.5 inches was good. Then, one inch. Now, the benchmark seems to be a half-inch, or 1/2 MOA.
No matter how good, a single three-shot group proves absolutely nothing. I once put three shots with a new, custom Weatherby bolt-action rifle, using factory-loaded .270 Weatherby Magnum ammunition, into a group that measured 0.249 inch. While the rifle always shot well, it never approached that rarified level again. It was simply a good 1-MOA rifle.
Sometimes you see a figure for an average of three, three-shot groups. If you're going to fire nine shots, why not put them all into one group and really find out something? And if you're going to fire nine, why not 10? Ten shots will tell you a lot more about a rifle than whether it can fluke out one or two tiny groups. In fact, it will tell you everything you need to know about that particular rifle with that particular load.
A Case Study
Recently, I got to try out a new Mauser 98. It's an 8x57 JS, which is a great cartridge, but there was one difficulty. There was no top-notch factory ammunition available and shooting ho-hum stuff would tell me nothing.
To get around this, I loaded some of my most meticulous handloads, using the best bullets from Nosler, Hornady, and Sierra. I took "accuracy" loads from three different loading manuals using four different powders and started with brand-new Nosler and Hornady brass. I did everything in my power to give the rifle a chance to shine, just like I would if using gilt-edged factory-loaded match ammunition. But my handloads were generic loads, not worked up just for this rifle.
I then shot a 10-shot group with each load. I took my time and fired a few at a time into each group so there would be no advantage or disadvantage from barrel heating.
What I learned from all this shooting is this is one very accurate hunting rifle. In three trips to the range, for sighting-in and so on, the first shots from a cold, clean barrel all went into the center of the group that followed. The best 10-shot group was 1.37 inches, using Nosler 180-grain Ballistic Tips. Another group using Hornady brass and Hornady 196-grain match bullets delivered a group that was exactly 1.00 inch for nine shots- the 10th shot (a flyer) expanded group size to 2.00 inches. The worst group of the four was also with Ballistic Tips and measured an evenly spread out 2.70 inches. Working up and down, I would expect that last group to tighten up considerably.
Since this is a hunting rifle, I'll start work using hunting bullets, with the knowledge that the rifle is capable of delivering every bit of accuracy that I, as a hunter, am capable of using.
Those 10-shot groups told me everything I need to know about the rifle and gave me several real starting points to develop some tackdrivers with no worries about whether a particularly good group is merely a fluke. All too often, that's exactly what they are.