Why Are There Not More Magnum Semi-Auto Rifles For Hunters?

The Browning BAR Mk. III

 The title of this post is derived from an article at The Truth About Guns, "Ask Josh: Why Aren’t There More Magnum Semi-Auto Rifles for the Modern Hunter?" by Josh Wayner. The question put to Wayner was: "Why are the majority of semi-auto hunting rifles chambered for weak rounds or small calibers? I want to go hunting with a magnum rifle, but there are only one or two companies that make a semiautomatic rifle in magnum calibers. Why is this and will that ever change?"

    Unfortunately, Wayner doesn't answer the man's question. Instead, he makes what come across as ad hominem attacks on the questioner about the man being caught up in the "bigger-is-better" crowd, wanting to use .338 Lapua for hunting, and basically discussing why he thinks long-range hunting is unethical. The problem is, the question (at least the part provided) doesn't raise anything about .338 Lapua or long range hunting.

    Before answering the question on why there are not more magnum rifles in the market, I do briefly want to discuss why someone might want to use a magnum rifle. Basically, it comes down to two factors: velocity and penetration. 

    Thirty caliber and smaller magnums have higher muzzle velocities than standard calibers using the same bullets (e.g., .308 versus a .300 Win. Mag.) and, therefore, have more velocity at longer ranges. That means not only less bullet drop at a given distance for the same bullet design and weight, but also reliable expansion at longer ranges. For instance, Terminal Ballistics Research has this to say about standard soft-point ammo in .308 (emphasis added):

Loaded with conventional soft point bullets, many bullet brands lose the ability to produce hydrostatic shock at impact velocities below 2600fps and in such cases, dead running game can be a common occurrence when using the .308 at ranges beyond 50 yards. In fact with some bullet brands, its as if a magic button has been switched off right at the 2600fps mark. Several bullet brands do however have the ability to produce hydrostatic shock (instant collapse) of game down to velocities as low as 2400fps, depending on target resistance and relevant factors. Regardless, hunters can manipulate speed of killing by matching bullet construction to the job at hand and in this caliber, there are some excellent options, capable of extremely fast killing via wide wounding. The 2600fps parameter and the gradual reduction in shock with conventional SP bullets below this velocity is common throughout the small bores, up to the .338 caliber.

Conversely, Terminal Ballistics Research indicates that .300 Win. Mag. provides good expansion to ranges of 300 yards or more. Newer (and more expensive) bullet designs that have improved expansion at lower velocities and new cartridges have been developed that are better at retaining velocity (e.g., the 6.5 Creedmore), but if you need good expansion out at 200+ yards, you could probably benefit from using a magnum cartridge. And while someone in Eastern woodlands might rarely need to shoot at distances over 100 yards, such shots are more common on open ground or in the mountains of the West.

    The other issue is penetration. When using .30 caliber or larger projectiles, the magnums tend to be able to shoot heavier bullets at greater velocities. Yes, this might be wasted against a deer, but larger or tougher skinned animals such as bear or moose are generally better hunted with heavy, deep penetrating bullets that can break bone and reach vitals. In fact, many brown bear and grizzly bear hunting guides require hunters to use at least a .338 Magnum for this very reason.

    For the person that wants to use a semi-automatic rifle for hunting--and there is nothing wrong with that--there are only two companies that I know of off the top of my head that produce semi-autos using magnums: the Browning BAR which offerings have included some of the sub-thirty caliber Winchester Short Magnums as well as the .300 Win. Mag. and the .338 Win. Mag.; and the Benelli R1 which offerings include .300 Win. Mag. and .338 Win. Mag. In doing some quick research for this article, I came across a third company--Noreen--that has produced a larger AR style rifles designed for long action cartridges, including offerings in .300 Win. Mag. and 7 mm Rem. Mag. (They also have a .338 Lapua Magnum semi-auto).

    The reasons for the dearth of semi-auto magnums is probably two-fold. First is the lack of demand. Relatively few hunters use magnums to begin with, and the number demanding a semi-auto over a bolt-action is going to be smaller still. Thus, there simply is not going to be the market to support more than a few makers.

    Second is the difficulty and expense of designing and manufacturing a rifle able to handle the recoil and chamber pressure of the magnums and still operate reliably in field conditions (remember, that these rifles are going to mostly be used by hunters in Alaska or high mountain hunters in the West in rough conditions for one or more weeks at a time). An expensive proposition when there is only a limited market.