300 WSM VS 300 WIN MAG Cartridge

[ernierod]

It is said that because of the cartridge dimensions-the 308 Winchester is inherently more accurate than the 30-06. Is this true about the 300 WSM VS the 300 Winchester Magnum?? Opinion plse.

[Mike in tx]

308 Norma Mag beats both of them. My old gun can still put 2 bullets through 1 hole and the next 3 are touching. It is a shame that it never took off. 180 at 3000 with a 1 in 9 1/2 twist.

[versifier]

"Inherently more accurate" is one of those terms that amuses me. Inherently more efficient I can buy. Statisticians aside, I don't think there is a practical difference in accuracy between either of those rounds in a factory action.

Absolute comparative accuracy potentials of the rounds themselves? Quality of the barrel, skill of the smith who chambers and installs it in a carefully inspected and if needed trued action, and most importantly the person working the trigger can make any one of those cartridges appear to be way more accurate than any other. If you built a matched pair of heavy BR rifles in each chambering, which one would be more accurate? And what would that prove? Two rifles would not be a significant statistical sample. Have the same smith build a hundred of each, as alike as he could make them (he has kids to put through school too after all) and then you could begin to see some general statistical trends regarding inherency. But I'm still betting if the smith is good, as far as pure accuracy and no other factor is considered, they'd all shoot one hole groups at impressively long ranges regardless of which chambering you picked.

The .300mag was once a popular BR round, so we know it is potentially a very accurate round. Inherent? I don't know, but certainly proven over time. I haven't followed recent trends so I don't know what the accuracy kings are playing with these days, but if people are wildcatting off the WSM case, it's a good indication of the cartridge's efficiency. I know my friend's factory .270WSM keeps five rounds in 2" at 300yds if you let the barrel cool after each shot, first two shots from a cold barrel at that range are usually touching. What more could you ever ask of a big game rifle, really? (And he doesn't hand load, that's factory ammo. Damned impressive.) Same parent case as the .300, so I know the potential is there.

Maybe there are other valid considerations though, beyond "inherency". The WSM is provably more efficient of powder, but damnably hard and getting harder to find cases for, where there is literally tons of .300mag brass available. For the handloader though, one also has to figure the non-belted WSM cases (if not maxed to the point their primer pockets loosen) will likely last for many more loadings (maybe dozens versus a mere three or four times) and don't have to be carefully checked for incipient head separation after every firing like any belted magnum. You may or may not get away with neck sizing hunting ammo, depends on the loading dies and how closely they match the exact interior dimensions of the chamber.

But will this be a BR, target, or hunting rifle? How much is it going to get shot, at what, and at what ranges?

I like shortfat cartridges as long as the action is designed to feed them properly. The .284 in an old Win m88 or m100. The 7.5 Swiss in a K31 or an Encore (I figure if you want to talk about an "inherently accurate" .30cal cartridge, few are more so than the 7.5 Swiss). Not that the .308 or -06 are any slouches in the accuracy department when the gunsmith building the rifles is competent, but both those rounds have more conventionally proportioned long thin cases. The point is that the WSM was not the first of the shortfat .30's and the impressive results of testing 7.5's certainly make me more positively disposed towards the WSM versus the belted mag, at least efficiency-wise. Not to ignore the proven BR track record of the .300mag in actual competition, but rather to not dismiss the WSM from consideration simply because it's a much more recent invention and doesn't have the better part of a century of existence and experience.


In a double or a single shot break action, the belted case has the advantage of easier extraction and faster reloading over any rimless case. That is irrelevant to inherency, but still an important matter of practicality, for the .30cals are important for both their hunting and their target capabilities.

Thanks for posting the question. You got me thinking before noon.