throat erosion. Throat erosion is greater in higher chamber pressure overbore cartridges. This was particularly true in the 1950s to early 1960s, with the chrome moly steels almost universally used for barrels then. But recent advances with stainless steel barrels, especially with cryogenic treatment, have extended barrel life considerably with the .264 Win. Mag. and many other cartridges. While very few production line riflemakers currently offer the .264 Win. Mag. as a factory chambering, the caliber remains popular with some enthusiasts using custom built rifles and handloading their own ammunition, as an internet search shows. As of 2018 and 2019, Winchester is once again producing its M70 bolt-action rifle in .264 Winchester Magnum. The introduction of Remington's 7 mm Magnum in 1962 almost immediately eclipsed the .264 Win. Mag., even though the 264 Win. Mag. uses an identical brass cartridge case (the neck diameter of either cartridge case can easily be modified to accept the others' bullets by the handloader), it never fully recovered from the competition of the slightly larger-bore cartridge. The fact that the 7 mm Rem. Mag. thoroughly eclipsed its popularity has been attributed to many causes, the premature "burning out" of barrels as compared to the Remington cartridge often cited. More likely is the fact that hunters had more confidence in the game-getting ability of heavier 7 mm (.284") 150 to 175 grain spitzer-shaped projectiles on big game, as compared to 140 grains being the upper end of pointed .264 bullets. Conversely, Winchester marketed the .264 as a long range, combination varmint and deer round, although suited for harvesting elk or moose. Unfortunately, the recoil it generates, plus the expense of the sheer quantity of ammo that may be used to shoot pests at long range (compared to pure varmint cartridges like the .222 Remington and the .220 Swift, or the smaller varmint / deer rounds, like the .243 Winchester) inhibited its popularity further. The result was more sportsmen opting for the bigger Remington 7 mm round because it was seen as more effective on a wider variety of big game; rather than a compromise round that could be used for varmints, worked well on whitetail and mule deer, but was borderline for the largest North American big game when the need arose. In Europe, two of the .264 Win. Mag.'s champions were George Swenson of John Wilkes gunmakers, London, and David Lloyd of Northampton, England.