I own one of the few 277 AM's out there right now. The 277 AM ballistics are absolutely awesome. The problem is: to get the most out of the Allen Magnums that are based on the 338 Lapua case, you need to shoot heavy-for-caliber bullets. The 277 AM really shines with the 195 grain and 169.5 grain bullets from Wildcat Bullets. The 277 AM will launch the 195 grain (BC = .8 to .9) around 3100 to 3200 fps. The 169.5 grain (BC = .7+) leaves the barrel at approx 3400 fps.
Problem is, there aren't any of those bullets to be had right now and it has been that for nearly a year. Its like having a race car, but no gas. The sole source of the heavy bullets in .277 was Wildcat Bullets. The company was sold a while back, but the new owner hasn't yet got the fed go-ahead to start production. The heaviest bullets available in .277 caliber from the better-known bullet makers are only 150 grains. Given the short barrel life of the 277 AM, it seems a shame to shoot the 150 grainers (velocity 3500 fps or more?).
Even though the 277 AM is a great round, its weakness is the limited number of companies that make the heavy-for-caliber .277 bullets. Instead, I would recommend either the 7mm AM or the 300 AM. Besides Wildcat Bullets, you have Berger, Nosler, Sierra and a few others that make heavier bullets in the .284 and .308 caliber. If one bullet gets discontinued, you still have other to choose from. Just my two cents.
