Are the short Mags better than belted magnums?

[bearcat]

I have been considering a 7mm WSM or a 300 WSM. Are they better than the 7mm Remington Mag and the 300 Winchester Mag? They are supposed to be the equal of the belted Mags but in a short action. Ballistic charts actually show the 7mm WSM ahead of the 7mm Rem. Mag. and on par with the more powerfull 7mm Weatherby Mag. Also some loads in the 300 WSM are loaded to a higher velocity than the old 300 Win Mag. According to Ballistics the short magnums are slightly more powerful.

[AJ]

Re: Are the short Mags better than belted magnums?

The short mags are equal to or a sliver ahead of the standard length belted mags when lighter bullets are used. For example, the 300 WSM is equal with the factory ammo. Manufacturers are doing this as a sales gimic. Compare the speeds they offer in the standard magnums to that of 5 years ago. The difference is small between the WSM and standard length belted magnums. Maybe if 25 fps impresses you, it may be something, but not to me. But when comparing reloads in the Nosler 5th Edition, the 300 Win Mag is faster with all bullet weights except the 125 gr. It is 100 fps faster with 150 gr and 165 gr bullets. Its 80 fps faster with 180 gr bullets. But the big diference is the WSM is using a 26" barrel and the 300 Win Mag is using a 24" barrel. So when you equal the barrel lengths the ballistic edge still goes to the Win Mag.

Comparing reloading data from Hodgdon for the 7mm WSM and the 7mm Rem Mag you will find the two cartridges to be about equal.

The main benefit of the WSM is it allows the shooter to use a rifle with a short action. But nothing is for free, using a lighter rifle with equal speed ammo equals more recoil. The WSM cartridges are good cartridges. Will they replace the standard length magnums? Nope, not anytime soon.

[bearcat]

Re: Are the short Mags better than belted magnums?

I don't guess I'll be trading in my 7mm Remington Mag. for a 7mm WSM anytime soon. As far as the 300 magnums go, my 300 Remington Ultra Mag. beats the other two hands down anyway. AJ, any Ideas on the barrel life of the .300 Ultra Magnum if I don't overheat the barrel and keep it squeaky clean?

[AJ]

Re: Are the short Mags better than belted magnums?

I would expect it to give you good performance for the first 1500 rounds or so. This is relative to the group size. I would expect the gun to give you groups no worse than 2" at 100 yards out to 2000 rounds or so if taken care of. If you are getting 3/4" groups, that may only last 1000 rounds, maybe more, maybe less.

One thing I like to keep record of is throat erosion. You can get throat gauges from Stoney Point. Take a modified case and slip a bullet in the neck you would normally use and see how far out the lands are. The more shots, the more erosion happens. You can compensate for this by seating the bullets slightly farther out maintaining the same jump to the lands. Of course that is only until they will no longer fit in your magazine. Then you have a single shot or a gun that is not as accurate as it was before. You can also switch bullets to find another that shoots acceptably. The Barnes X-Bullets like a .050" jump to the lands. Most of my handloads with other types of bullets are less than .010" from the lands.

[bearcat]

Re: Are the short Mags better than belted magnums?

Thats good information. I think I will check into the throat gauges. I have only fired about 200 rounds through my Ultra Mag so far, so it looks like I've got a long time to enjoy this fine round. I just wish that there were more factory loads available since I don't handload. I think Remington has 3 loads and I think Federal has either 3 or 4 loads, these are the only factory loads that I can find. Hornady says that they don't have any plans to load any because there is not a big enough market for the excessively powerful Ultra Magnums. I don't understand because the .300 Ultra Mag. has basically the same ballistics as the .300 Weatherby Mag.

[AJ]

Re: Are the short Mags better than belted magnums?

Since the 300 Wby has been around since 1944 and has a big popular following, its safer for ammo makers to offer a load for it. The 300 RUM has not been around all that long and its popularity is falling. You said it yourself, its so close to the 300 Wby so why take all the extra recoil vs a 300 Wby?

The 300 RUM is a good cartridge and has its place, but there are very few hunters that can take advantage of its performance. Where the RUM shines is beyond 400 yards. It still delivers enough energy to cleanly dispatch most any big game on this continent but it still requires a lot of skill to accurately place that bullet at 400+ yards. The vast majority of hunters do not get the oppertunity to shoot on a range that far let alone at game. So, all that power is wasted.