Discussion Forums

Scott Struif

I frequently run across the claim that such-and-such a cartridge is “inherently accurate.” This implies that its SAAMI specs - the design of the cartridge coupled with that of its chamber - is an infallible combination that, absent shooter and gun variables, results in groups that are better than other cartridges. A recent gun-rag article states that two recent cartridges are inherently accurate because “freebore slop” is minimized. Freebore is commonly-defined as the area between the end of the cartridge-neck and the beginning of the leade, while “throat” refers to the area between the end of the cartridge-neck and the point where the leade tapers to the diameter of the rest of the bore. The article suggests that minimizing freebore diameter somehow aligns the bullet with the leade, and thus the bore, giving accuracy superior to cartridges of yore. I’m skeptical of the claim because, as its name implies, “freebore” is an area which the bullet shouldn’t touch. The bullet should be driven into the leade, and thus the lands, while exiting the neck, without contacting the freebore area. I suppose if you have a bullet that “space-walks” in a long throat, tight freebore diameter might come into play. But that would assume the concentricity of the bullet was cattywampus.