I was at a local gun shop when a guy came up to me. “Aren’t you the guy who writes about shooting in the paper?” I replied that I was. “Well, I’ve got a question,” he said, and then he went to length explaining how he’d bought a quality .243 rifle and it wouldn’t shoot better than one minute of angle, or MOA, a rifleman’s description for one inch groups at 100 yards. He said he’d tried a dozen different loads and brands of ammunition and that was all he could get.
I told him one MOA was great accuracy from a hunting rifle and I’d be happy with that. He looked at me as if I was just trying to get rid of him. “You really think so? I read about guys who shoot half-inch groups all the time, why can’t I shoot groups like that?”
Great groups happen. I have two or three hanging around in my office. I have even more targets I shot in matches, past, or practice sessions that were impressive; I keep them around because they make me feel good. They make me feel good because I don’t shoot that way all the time. For some reason, I never save the bad groups or targets and I don’t show them off to my friends, it’s human nature.
All this being said, how can I say that testing multiple loads to see which shoots better in your rifle isn’t productive? I can say it because most people simply don’t have the time or resources to test extensively enough. A better way to approach it is to test loads to find the ones your rifle doesn’t like. Not long ago, I had several different loads of .223 to test. I had a few different rifles including one belonging to a friend, Dave, who was helping me in the testing. There was a specific .223 load that I won’t mention by name because to do so might prejudice someone against perfectly good ammunition, something that happens all the time, anyway.
We fired the specialty ammunition in a couple of my rifles and it did fine, not exceptionally good or bad. It shot about the average group size of the rifle. Then we shot it in Dave’s rifle. The first shot, we checked the scope to see if it was loose. The shot was five inches from where a similar bullet weight had impacted. The next shot was at least six inches from the first shot, closer to the rifle’s zero but still not a good shot. We shot five shots and the group wasn’t within eight inches. We went back to the ammunition Dave normally shoots and the rifle was fine. Back to the specialty ammunition and you couldn’t hit a ball cap. The rifle just wouldn’t shoot that ammunition for some unexplained reason.
I’ve never seen a case so extreme but I’ve seen similar situations over and over. For some reason, some rifles don’t like some ammunition. The kind of testing most shooters do will determine if their rifle simply won’t shoot a specific ammunition but finding which ammunition really is best is much more complicated. OK, I still haven’t explained why I’m saying most testing is not effective other than to say we don’t test enough.
When I ran the state rifle team, I needed a way to test a lot of M14 rifles. M14s are hard to scope and neither I nor any of my team members were good enough to simply shoot the guns with iron sights to determine accuracy. Shooter fatigue would have killed anyone trying to do so: all, we had 26 M14s and a dozen or so privately-owned M1As and all needed at least 20 rounds through them to test. Remember, the rifles had iron sights and we were looking for MOA accuracy so bench rest testing would have been tough. I built a test cradle that held the gun and recoiled on tracks and could be pushed back to the exact same place. The good rifles would shoot ten shots from the magazine, rapid fire, and put all ten shots in less than two inches at 200 yards, quite a feat for a semiautomatic service rifle. The main purpose of the testing was to put the very best rifles in the hands of the very best shooters. I was only determining the inferior rifles, not determining which was the very best rifle.
If we had a rifle that was really exceptional, we’d shoot some extra groups to be sure. Sometimes a rifle would shoot an incredible group, maybe ten shots in less than an inch. Remember, these are ten-shot groups, not the three- or five-shot groups most shooters use as a test. The next group, the rifle might print the same ammunition, just a minute or so later, into a four-inch group. That rifle was no better than a rifle that shot four inches all the time. It was eliminated from the better rifles. You can get fluke groups even when they are ten shots.
If you think you can find the best load for your rifle by shooting ten rounds, try this experiment. Shoot ten five-shot groups with the same rifle using the same ammunition on the same day. I’ll wager you get some groups that are markedly better than others. Now imagine if you were just shooting two five-shot groups with five brands of .22 ammunition. If you consider groups one and two one brand, groups three and four another brand and so on, you’ll find a pair of groups that’s markedly better and one that’s worse, all shot with identical ammunition. The fact is that bad ammunition will occasionally shoot a great five-shot group and to determine which is best you need to shoot a whole lot of shots over and over and keep very good records.
So, how much do you have to shoot to really tell if one load shoots better than another? At least five ten-shot groups to determine a statistical trend. Allowing ten minutes to cool the barrel of a lightweight hunting rifle between each ten shots (and you have to shoot each group with consistent conditions to have an effective test), it will take almost an hour for each load you check. Further, if you’re shooting a high-velocity magnum caliber like a 7mm Remington Magnum, you will have used up 25% of the rifle’s barrel life before you find the best of just five loadings. For twenty loadings, you’d use up the barrel completely and have to begin again.
For hunting rifles, the best thing is to first determine the bullet weight range that matches the twist rate of your barrel and choose a few loads that have a good reputation. Test with a minimum of twenty shots with each load and be scientific about barrel heat and cleaning consistency. Four- and five-shot groups aren’t definitive but it will give you an idea. Use the load that performs best, but realize there is probably a better load out there if you had the time and money to pursue it. If you have unlimited finances and time, you could find a loading that really does shoot better, but finding out could take days and weeks of testing with more than twenty shots per load and cost thousands of dollars. A more realistic approach is to find a load that shoots well and will perform and have faith in it. Faith is a good thing when accuracy counts.
Image courtesy Dick Jones