Home Forums Hunting & Shooting Long Range Hunting 7mm Wby and LRAB results...........

I used the Hornaday load data sir. It worked as shown. I went by the book.

So far the Bee has been sweet and easy to use.

I learned that I would not be shooting your load in a Mashburn.

Where this train ran off the tracks.

4700 BAR converts to 68167.736733202 psi

Yes, and the 30-338 Lapua still has a CIP rating of 4700 Bar.

I used the Hornaday load data sir. It worked as shown. I went by the book.

So far the Bee has been sweet and easy to use.

.300 lapua mag isn't saami'd?

The .300 Lapua Magnum

The 300 Lapua Magnum was developed concurrently with the 338 Lapua Magnum, but didn�t receive the public notoriety of its more famous stable mate. In fact, few shooters were aware of this cartridge until it appeared in the Lapua and Vihtavuori Reloading Manuals in the 1990s. Both the 300 and 338 Lapua Magnums were formally approved by CIP in 1989. During its development, the round was originally called the 30 Lapua Magnum. It wasn�t until it was finalized that it became known as the 300 Lapua Magnum. The 300 Lapua Magnum is a purely Finnish design, the brainchild of Juha Evasoja. Juha was Lapua�s head engineer from the 1970s into the early 2000�s.

The 300 Lapua can be considered a spin-off of the original development process of the 338 Lapua Magnum. It remains a true wildcat, as no factory rifles have been chambered for it, nor has ammunition ever been commercially loaded. Lapua produced a single test lot of 300 Lapua Magnum cases bearing that headstamp, but it has not been produced since. Cases used in the existing rifles chambered for the 300 Lapua Magnum are normally formed from 338 Lapua Magnum brass, necked down to accept a 30 caliber bullet.

The basic idea behind the 300 Lapua Magnum was to create a high velocity, flat-shooting 30 caliber cartridge, based on the existing 338 Lapua Magnum case. The 300 Lapua Magnum shares the same basic case dimensions as the 338 Lapua Magnum, differing mainly in the neck and shoulder areas. Case volume remains the same as the parent 338 Lapua Magnum.

The 300 Lapua Magnum is one of the first 30 caliber Magnums to reach the magical 1000/mps (3300 fps) threshold with heavy weight bullets. Actually, the new Lapua development was the first of the 30 caliber �super magnums�, when the 300 Weatherby Magnum was generally considered to be the upper limit where 30 caliber rounds were concerned. The 30-378 Weatherby (based on the necked down 378 Wby Mag case), was still an experimental wildcat cartridge and not yet fully standardized by SAAMI or CIP. It was originally proposed that the hypothetical 300 Lapua Magnum military sniper round be loaded with a 12.6 g (194 grain) B406 FMJBT. Early research indicated that this combination would deliver a muzzle velocity of 1000/mps (3300 fps) from a 27 inch barrel.

The 300 Lapua Magnum has not become a production item, yet it still exists as a long-range target cartridge. It has a loyal following for this demanding game, which is not at all surprising. Delivering ballistic performance similar to the 30-378, it does not display the sensitivity to load variations common to the Weatherby. Being a standardized CIP cartridge, several gunsmiths have built long-range rifles around this impressive round.

The 300 Lapua Magnum is at its best with very slow burning powders like Vihtavuori N170 or 24N41. Like other very large magnum cases, the 300 Lapua needs a Magnum primer for reliable ignition.

No factory made rifles for the .300 Lapua Magnum have ever existed, but several gunsmiths have built rifles for this caliber. The main application of the .300 Lapua Magnum is long range target shooting.

Yes, but it was standardized by CIP, even though no rifles were commercially chambered in it.

If read what I posted from Laupa;s web site above it does not mention that the 300 was ever CIP'd

No, we wouldn't. The case capacity is too similar between the Weatherby and Mashburn to get even close to another 100 fps at the same pressures.