What makes a rifle cartridge “inherently accurate”? I often see this phrase in the literature, but in the same piece there is never a discussion as to what attributes actually make a rifle cartridge inherently accurate.
Do the following generalities make a cartridge inherently accurate? I am not advocating any of these as gospel, rather want to see what others have to say about this. Neither is this meant to be a cartridge superiority pi$$ing contest!
1.) Given the same case volume, a shorter cartridge is more accurate due to more consistent powder ignition. TRUE or FALSE?
2.) On rimless cases, a sharp shoulder angle gives better headspace uniformity when the charge is ignited. TRUE or FALSE?
3.) A longer case neck results in more constant bullet seating tension. TRUE or FALSE?
4.) Others?
Is “inherent accuracy” just marketing hype?
Ahhh shiiite….. after writing the above I found the following.
https://www.fieldandstream.com/the-worlds-most-accurate-cartridge/I suppose if I look there are many discussions and/or published books on the subject….. just want to get other’s opinions.
Flame away.
Petzal left out some reasons for the 6mm PPC's accuracy:
1) Its 30-degree shoulder is pretty much accepted as the angle that results in the finest accuracy. Just about every "accuracy" cartridge since it appeared features a 30-degree shoulder. A few have slightly steeper shoulders, but I have been informed by the top guys at a couple of pressure laboratories that right around 30 degrees normally results in the most consistent pressures and hence velocities. Which is why, after considerable experimentation, Palmisano and Pendell chose 30 degrees.
2) Generally a shorter powder column does result in finer accuracy. The most accurate cartridges in just about any caliber are fatter and wider. One of the major bullet companies used to do all its accuracy testing (on an indoor range) with .30-caliber bullets with the .308 Winchester, .30-06 and .300 Winchester Magnum, depending on the bullet weight. When the .300 WSM appeared they found it shot just as well, and often better, with the same range of bullets.
3) Neck length has something to do with accuracy--but not so much consistent bullet seating tension, which is mostly a matter of consistent neck thickness. But the present trend is toward seating bullets so they don't encounter the potential "donut" (thicker brass) at the neck-shoulder junction. The 6mm PPC avoids this easily, due to using lighter, shorter bullets--but some newer accuracy cartridges (such as David Tubb's 6XC) are designed to avoid it even with very long, heavy, high-BC bullets.
4) Some cartridges that don't follow all these "rules" also shoot very well in many rifles, perhaps due to some happy accident. Among them are the .308 Winchester--and the 9.3x62 Mauser, as luv2safari mentioned, which was designed around 1905.
In fact, the 9.3x62 has a relatively long body, almost no shoulder, and a standard chamber throat that's very long and TAPERED--common back when it was introduced, to accommodate bullets or widely differing weights and lengths. All modern "accuracy" throats are parallel-sided. Yet it's rare to find either an old or new 9,3x62 that doesn't group three shots into less than an inch with almost any ammo, whether factory or handloads. That won't win any benchrest matches, but it's plenty accurate for a "medium bore" big game round!
