338 Win Mag vs 338 Lapua: Loaded for Bear
Sam Jacobs 
Website: Ammo.com
Blog: The Resistance Library
Date: 05-20-2024
Subject: Gun Rights

With an effective range of over half a mile, the 338 Lapua Magnum and 338 Winchester Magnum are two centerfire rifle cartridges that excel at long range shooting.

The 338 Lapua Mag is the rifle cartridge of choice for military snipers as it was developed to punch through body armor at 1,000 yards and bridges the gap between the 300 Win Mag and the 50 BMG.

The 338 Win Mag was part of the belted-magnum cartridge craze in the late 50's and early 60's and has been the go-to ammo of choice for dangerous game hunters across North America. Capable of ethically harvesting any thin-skinned game animal on the planet, it is the preferred cartridge in Alaksa to protect yourself against belligerent grizzly bears or other large game. But which of these two magnum cartridges is the best option for your new medium bore bolt-action rifle?

For most non-competitive shooters, the 338 Win Mag will be more than enough cartridge to suit your needs while the 338 Lapua is most at home on the firing line for 1,000+ yard shooting competitions.

In this article, we will examine the advantages and disadvantages of the 338 Lapua and 338 Win Mag to help you understand which will work best for your needs.

What's the Difference Between 338 Lapua and 338 Win Mag?

The 338 Lapua and 338 Win Mag are two centerfire magnum rifle cartridges that fire the same 0.338" diameter bullets. Although both rifle cartridges fire the same caliber bullets, this is where the similarities between the two ends.

One major difference between the two is the design of the cartridge case. The 338 Win Mag utilizes a belted-magnum design that became popular during the magnum era of the late 1950's and was marketed for big game hunters while the 338 Lapua uses a non-belted case and was designed specifically for military use.

The 338 Win Mag was also designed to fit into a long action like a 30-06 Springfield, while the 338 Lapua requires a magnum action as it is a longer, beefier round.

Both 338 magnum cartridges excel at long range accuracy and precision, you will not find the 338 Win Mag on the firing line of a 1,000-yard competition that is dominated by 6.5 Creedmoor, 300 Win Mag, and 338 Lapua.

But why is that?

The reason is because the 338 Win Mag is primarily a sporting cartridge while the 338 Lapua is long range precision cartridge. Each have their own roles that they fill admirably and understanding the difference is critical to making the right choice for your next rifle.

In the following sections, we will break down the differences between these 338-caliber magnums so that you can more clearly understand the advantages and disadvantages of each.

Cartridge Specs

When evaluating two big game hunting cartridges, it's a good idea to analyze the cartridge specs to gain more knowledge of each. The first, and most obvious, similarity is that both the 338 Lapua Magnum and 338 Winchester Magnum fire the same 0.338" diameter projectiles. However, this is where the similarities end.

One major difference is the case length of both rifle cartridges. The 338 Lapua Magnum has a case length of 2.724" and overall length of 3.681" compared to 2.50" and 3.34", respectively, for the 338 Win Mag. This difference in case length directly affects case capacity.

The 338 Lapua is well-known for having a cavernous cartridge case. With a case capacity of 114.2 gr, the 338 Lapua can hold over 30% more powder than the 338 Win Mag at 86 gr. This added powder capacity is what allows the 338 Lapua to fire heavier bullets with a higher ballistic coefficient than the 338 Win Mag.

Another difference is the type of rifle action that both cartridges are fired from. With its longer overall length, the 338 Lapua sits firmly in a heavier and stronger magnum action, while the 338 Win Mag is short enough to fit into a long action rifle like the 30-06 Springfield and 300 Win Mag.

At the time of writing, SAAMI has not proofed the 338 Lapua and does not have an established max pressure for the round. To complicate matters, Lapua and the CIP have been somewhat ambivalent about the max pressure for the cartridge.

There is some scholarly debate as to the max pressure for the 338 Lapua, but the lower limits (and therefore safer) suggest 420 MPa (60,916 PSI).The max pressure for 338 Winchester Magnum is 64,000 PSI.

The 338 Lapua is an overall larger case and can fire heavier bullets, and although those projectiles perform extremely well at long distance shooting, there is a price to be paid for this enhanced downrange performance.

The additional case capacity afforded to the 338 Lapua has a negative effect on felt recoil and barrel life when compared to the 338 Win Mag.

Continue reading the full analysis of 338 Win Mag vs 338 Lapua here.