Re: “My 7 twist LWRC keyholes 55gr stuff. So I’d say that’s pretty bad for accuracy. Try a box out of your gun, yourself.” Over-stabilization is definitely a possibility, but it may not be the only explanation for what the owner of that LWRC is seeing. Jacketed projectiles, such as full-metal jacket military-specification bullets with a lead core surrounded by a copper alloy (gilded metal) jacket, are generally stoutly-constructed enough to stand up to the very high rpms generated by a faster twist rate barrel such as a 1:7 RHT. On the other hand, some hunting and varmint loads, as well as some match-grade OTM loads, may not stand up well to the centrifugal force of extremely high rates of spin – and may disintegrate and fly apart during flight, or become unstable and key-hole on the target. It isn’t simply bullet weight which determines the rate of optimum twist, but the length of the projectile as well as its design. Since nearly all bullets are designed in such a way as to be tail-heavy, i.e., have their centers of gravity behind the midline, sufficient spin is required to keep the projectile in the proper orientation in flight. Varmint bullets, in particular, are designed to fragment easily when encountering a small game (varmint-sized) animal, rather than for the deep penetration required of some hunting bullets for larger prey species. Since varmint bullets are often hollow and have thin walls, they are more-prone to disintegrating in flight due to excessive spin. OTM-style match bullets are made by drawing up petals of gilding metal (copper alloy) to surround and enclose a lead or other core, coming together at the pointed tip or metplat. Although more-stoutly constructed than varmint loads, it is possible to cause an OTM design to disintegrate in flight via over-stabilization. This effect has become rarer in recent years because of advances in ammunition design and greater attention by ammunition manufacturers to the use of strict QC manufacturing measures as well as high-quality starting materials. Bonded or solid-metal bullets, on the other hand, which are designed to be extremely tough for enhanced penetration against large and/or dangerous game, after firing at high velocity from magnum or other long-action cartridge cases – are very hard to damage via over-spinning them. As previously mentioned, over-stabilization may not be the only factor in play with the specific user in question. The barrel may be damaged in some manner. For some reason – manufacturing defect, abuse by a previous owner or a retailer, etc. – the barrel may be damaged internally. Some of the rifling may be missing or worn-away, or perhaps the manufacturer did not cut the correct rate of twist into the barrel. Seasoned reloaders know to slug their bores to check manufacturer specs for twist rates; it is not at all uncommon for stated rates to be markedly different from those actually found on the rifle. You may think you have a 1:7 but actually have a 1:8 or 1:9, and… Read more »