Accuracy doesn’t always fade with time—it can disappear halfway through your first range trip. You’ve probably seen it yourself: the first few groups look great, then things start to open up, and by the end of the box, your shots are walking all over the target. Sometimes it’s heat, sometimes it’s barrel wear, and sometimes the caliber just wasn’t built for sustained precision. These are the rounds that might look impressive on paper but fall apart once they’ve been through twenty or thirty rounds. If you’ve spent more time chasing flyers than tightening groups, you’ve probably met a few of these.
.17 HMR
The .17 HMR might print tiny groups early on, but it’s quick to remind you it’s a rimfire. Once the barrel starts heating, consistency goes out the window. The lightweight bullets are hypersensitive to barrel fouling and even small shifts in velocity. You’ll see your first magazine stack tight, and then suddenly those neat clusters start drifting. Most shooters clean after every 20 rounds or risk flyers. It’s fun, accurate, and flat-shooting—until you try to run a full box and end up chasing your point of impact all over the paper.
.22 Hornet
The .22 Hornet is a charming round with a history that outlives its consistency. It’s accurate for a short stretch, but carbon fouling and temperature shifts send it off track fast. The thin brass and odd case shape make pressure inconsistent across reloads, which translates into wandering groups after a few strings. Even with factory loads, once your barrel warms, you’ll notice the Hornet printing high or wide. It’s one of those calibers that demands constant cleaning and load tweaking to stay sharp—and few shooters have that kind of patience anymore.
.243 Winchester
The .243 Winchester starts strong. It’s fast, flat, and light-kicking, which makes it a favorite for new hunters and precision beginners. But those high velocities burn barrels faster than most realize. A hot barrel and light-for-caliber bullets don’t mix. Accuracy tends to degrade after a box or two, especially in factory sporter barrels. You’ll start with sub-MOA groups and end up wondering if you bumped your scope. It’s not a bad round—it’s just one that punishes extended strings and long-range work unless you keep it clean and cool.
.300 Weatherby Magnum
Few cartridges show off speed like the .300 Weatherby Magnum. Unfortunately, that speed comes at the cost of consistency. The powder charges are massive, the recoil punishing, and the heat builds quickly. After twenty rounds, your barrel’s sizzling and your groups are widening by inches. It’s a round that delivers raw power but not sustained precision. Great for a single cold-bore hunting shot, terrible for range work. The throat erosion also sets in fast, which means accuracy fades with use far sooner than you’d expect from a rifle that costs that much to feed.
6.5 PRC
The 6.5 PRC promised to be the “long-range upgrade” to the Creedmoor, but in reality, it’s a barrel-eater that loses its sweet spot quickly. The high powder volume in a relatively small bore accelerates wear, especially in factory barrels. It starts tight—sub-MOA all day—and then suddenly your groups start spreading once the barrel warms. Consistency becomes harder to hold past that first box. It’s a great hunting caliber when you’re firing a few rounds, but it’s not built for long range sessions or sustained precision. The PRC shows its best side only when you baby it.
.204 Ruger
The .204 Ruger is blazing fast, but that’s part of its problem. It’s so hot that it cooks its barrel and carbon-bakes the throat within a single range session. Those little 32-grain bullets hit over 4,000 fps, which means accuracy falls apart fast once temperatures climb. After the first 20–30 rounds, you’ll see vertical stringing and wild flyers. It’s a fun varmint round, no doubt, but it’s one you have to treat like fine china—clean it often, shoot it slow, and never expect the same accuracy across an entire box of ammo.
.257 Weatherby Magnum
The .257 Weatherby Magnum is a deer-slayer’s dream for the first few shots, but it’s a barrel’s worst nightmare. The throat erosion is brutal, and accuracy loss comes sooner than most magnums. It’s a laser beam for maybe 20 rounds—then it turns unpredictable. Once the barrel heats, those tight groups start walking up and right, and even quality glass can’t keep up. It’s meant for one-shot precision in the field, not long bench sessions. You might love it for its speed and flat trajectory, but if you shoot it often, you’ll see it fade before the first box is gone.
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Here’s more from us:
Calibers That Shouldn’t Even Be On the Shelf Anymore
Rifles That Shouldn’t Be Trusted Past 100 Yards
*This article was developed with AI-powered tools and has been carefully reviewed by our editors.
