Solving Unusual Accuracy and Reliability Issues

I was sitting on the shooting bench with a shiny new (new for me, anyway) Winchester Model 70 when I became frustrated. I bought the best mounts and scope I could afford. They were not impressive, but they were reliable. The rifle is chambered in.375 Holland & Holland magnum, which can take any game animal, but doesn’t crush your shoulder. The rifle, scope, and mounts are capable of fine accuracy, and the recoil is not as severe with the larger bores. I also purchased the best ammunition and did my best in zeroing the rifle. I sat down to evaluate the group size once the gun had printed on the bull’s eye. The rifle would–routinely–print the first shot in the 1-inch bull’s-eye, the second shot 2 to 3 inches up and to the right and the third shot within 3/4 inch of the first. I was convinced that my shooting was the problem, so I asked dad to send down some lead to prove me incorrect. After blaming the ammunition for the problem, I ordered some reloading components and dies, and began to handload and develop loads for the rifle. Photo: Massaro Media Group. In fact, some of the load got worse. I tried changing primers, bullets, powder, the charge and seating depth, but nothing worked. It took me swallowing pride to call a professional, who diagnosed the problem over the phone. It was a common problem with the Model 70 of my era, but I would have never known this without consulting a gunsmith. It was a great learning experience that I will never forget. Photo: Massaro Media Group. Sometimes firearms do things that they shouldn’t or at least seem unexplainable. My Winchester’s action was moving between two spots in the stock every time it recoiled, but the bedding job fixed that, and it became a 1-MOA-adjustable rifle after surgery. Rifles are not just a bunch of components that have been slapped on. A friend has a 7mm Remington Magnum and he bought a few different premium brands for it. He called me and asked what was wrong with his rifle. He couldn’t keep 3 shots within 5 inches. Action screws were properly tightened, scope and mounts were also, and he had a couple of other rifles at the range that day printing impressive groups, so it–apparently–wasn’t the shooter.He abandoned the rifle that weekend and went back the following weekend with a well-known but “lesser” brand of ammo. “I don’t understand. The author with his Winchester Model 70 in.375 H&H, which was a bit temperamental before it was properly bed. Photo: Massaro Media Group.I own another Winchester Model 70 from the same era, but it is chambered in.300 Holland & Holland. It has a strong dislike for the 180 grain bullets that I have used in other.300 H&Hs for many years. I almost sent the rifle to be exorcised. It was a Nosler box of ammunition loaded with their AccuBond 200-grain boat-tail bullets that turned the rifle into a hero, consistently printing under 3/4-MOA. The issue with both rifles is barrel harmonics. It will seem that the rifle is invincible when you find the right harmonics for the barrel. When the harmonics don’t match the barrel, everything seems to go wrong. When I began to develop the most accurate handloads for my rifles, a difference of 0.2 grains of powder can have a dramatic effect on group size. The bearing surface can play a significant role. I’ve had rifles prefer bullets with a lot of bearing surface, like my.300 H&H, and others that prefer bullets with less bearing surface. My Ruger.308 Winchester is a clear preference for bullets weighing 150 and 165 grains, while the Winchester 70 Classic Stainless.300 Winchester Magnum is able to handle anything. It’s impossible to tell by looking at a barrel what kind of harmonics it will like. Sometimes, it takes some experimenting to find the best performance. In the case of the 7mm Remington Magnum mentioned above, the premium ammo was not at fault. The most expensive ammunition does not guarantee optimal performance. The smooth boat-tail bullets like the Hornady ELDX shown here might need some time to settle. As ammunition supplies improve, I recommend stocking up on the ammo that your rifle prefers. You might find the perfect combination by trying something new. A friend bought a new autoloading pistol and proudly brought it to the range along with two boxes of ammunition that the gunshop recommended. Within an hour, the man had declared that his new purchase had been a “pile” of crap. It had jammed, failed feeding and frustrated him. You’ll notice an immediate improvement if you polish the feed ramp. It wasn’t the gun that was bad, but the feed ramp of the pistol. When loading a cartridge into a rifle or pistol, a smooth ramp is needed at the right angle for the cartridge. Sometimes a flat-pointed bullet won’t work but a round-nosed one will. When a gunsmith takes the time to hand-polish the feed ramp, it is noticeable. I’ve seen a finicky gun that had trouble feeding wadcutters feed flat-points after the feed ramp was “tuned.” Your handgun, especially your defensive handgun, needs to feed reliably every time. Two days before the opening of deer season, when everyone is sighting in their rifles, I had a friend stop by my home in a panic. His Savage rifle would not chamber a cartridge correctly: He couldn’t shut the bolt and had no clue why. I took a look at the rifle and noticed that it was relatively new, and that a lot of the rust preventative goo around the receiver was still visible. He admitted that he had not cleaned the rifle properly, so I grabbed a jar of Hoppe’s No. I grabbed the Hoppe’s No. 9, a cleaning rod, and a nylon brush. After a bit of elbow grease, I cleaned the chamber with some dirty patches. Then I worked on the barrel. I was reminded of how dirty barrels, actions, chambers, and chambers have been an issue for years. A dirty bore or chamber will affect accuracy and make you wonder what happened to your favorite handgun or rifle. You’ll be a happier shooter if you keep things clean enough but not too clean. Photo: Massaro Media Group. The traditional jacketed cartridge is the cleanest bullet design, but it can still deposit enough copper jacket to affect accuracy. If you let it go too far, you will see a decrease in accuracy and an increase in pressures. Lead bullets are inexpensive and easy to use, but they can foul a barrel, causing it to malfunction. Lead-free monometal ammunition can deposit enough copper in the bore that it will cause accuracy and pressure problems. I admit to not cleaning my handguns and rifles as often as I should. While I don’t recommend scrubbing your barrel every time you fire the gun, it can cause a lot of performance issues. I’ve seen a bullet fly 6 inches in the air when an overly-oiled bore is used. I was on a hunting safari in Zimbabwe with my Heym Model 89B Double Rifle in.470 Nitro Express. I spent a lot of time developing a handload and the gun was printing two shots (one each from each barrel) at 100 yards in a group that was just under 2 inches. The author checking zero on the Heym 89B.470NE in Zimbabwe. The oil in bore caused the shots print higher than desired. Photo: Massaro Media Group.We inspected the rifles the morning of the hunt. I was shocked to hear my professional hunter say that the two shots were equally high and 5 inches apart. I realized that I had cleaned and oiled both the barrels and bore for the trip over the pond. This resulted in higher accuracy and pressures. After I shot the oil from the bore, the next two shots performed as they did at home. Cleanliness is important but it can be overdone. I clean my rifle during the off-season, and then shoot it right before the hunt. This leaves a little fouling in the bore to ensure optimum performance in the field. Another question I am often asked is why boat-tails do not give the same accuracy as flat base bullets. Boat-tail bullets are more accurate outside of 250 and 300 yards. Assuming the rifle is in good condition, they will take longer to settle down than flat-base bullets. Imagine a spinning top. You start it spinning, and it wobbles a little. Then it settles down into a near-perfectly concentric rotation. Boat-tail bullets are not as effective at close ranges. However, they do show a slight advantage within 250 yards. As some bullet companies will tell you, flat-base ammunition is a great choice for most hunting distances. The author’s Ruger77.22250 Remington shows a strong preference for flat-base Bullets like the Sierra 52 grain MatchKing. If the crown on your rifle’s barrel has even the slightest imperfection you may find that the rifle prefers flat-base bullets. I have a.22250 Remington in a Ruger Model 77 which could benefit from a re-crowned barrel. The rifle loves the Sierra MatchKing 53-grain flat-base bullet but struggles with boat-tail bullets. The gun is perfect with the Sierra bullet, even though I should have had the barrel’s crowned reworked. If you have problems with boat-tails, ask your gunsmith to take a look at the crown of your rifle. I’ve seen shooters constantly adjust their riflescopes as the point of impacts moved up and down, right and left, with little or no success. Most commonly, the adjustment will say “one click at 1/4-MOA”, or “one click at 100 yards”, but in reality this is not true. I’ve had scopes that moved closer to 1/2 MOA, while others moved closer to 1/8. A Leupold VX-6HD calibrated to the trajectory of the 6.8 Western bullet. The turret wouldn’t work if this scope didn’t have such precise adjustments. Photo: Massaro Media Group. The savings from a cheaper scope that has weaker springs are quickly offset by the ammunition costs spent trying to find zero. I have personally switched to a more reliable optic, which generally means spending more. For target shooters who like to shoot at long distances, and for hunters who prefer dialing in their elevation adjustments, a reliable reticle is essential. I recommend that you buy the best riflescope that you can afford. The best riflescopes will save you ammunition and give you confidence when adjusting them. The target grids and bullseyes are in MOA. Subscribe to the Gun Digest newsletter and we will send you your print-at home target pack immediately. Enter your email below.