On the fence on 338LM or 300 Win Mag

FirearmsEnthusiast said:
OP - I wonder if the source you refer to is Bryan Litz at Applied Ballistics.

He wrote a very interesting paper in 2021 entitled "Weapon Employment Zone (WEZ) Analysis of the Optimized 300 Winchester Magnum vs 338 Lapua Magnum With Various Ammunition Types"

Spoiler alert:
- Litz concluded that using certain projectiles can enable the 300WM to outperform the 338LM

It certainly opened my eyes - I have an excellent rifle in 300WM that performs incredibly well - I'm considering a 338LM (now that my 50 BMGs are prohibited since May 1 2020).

Handloading the 300WM is best accomplished by abandoning the idea of headspacing on the belt of the cartridge (it's a belted magnum after all) and simply focusing on headspacing off the shoulder.

Please keep us posted on your thoughts on whether you will go for the 300WM, 338LM or the other cartridges that other firearm enthusiasts have mentioned in this thread!
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I wouldn't think it is controversial at all that 'some' 300wm loaded ammo can outperform 'some' 338LM ammo.

Ultimately I'm guessing the intended target is a huge factor in determining which calibre should be used for the specific job at hand.
 
Bfranklin said:
I wouldn't think it is controversial at all that 'some' 300wm loaded ammo can outperform 'some' 338LM ammo.

Ultimately I'm guessing the intended target is a huge factor in determining which calibre should be used for the specific job at hand.
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I remember reading Litz' paper and although quite interesting it's more applicable to military rifles in that it was comparing the newer .300WM load the US military was starting to use (can't remember the designation) that is basically set up as "one-time use brass" to an older issued .338 Lapua load. So not exactly apples to apples for civilian reloaders. Still, no question that you can really push a 300WM but there are better options now that were designed for the task from the ground up.

Fast forward to now and there really isn't much of a justification for going with a 300WM over a 300PRC if buying a factory rifle as it's both easier to find quality precision rifles chambered in 300PRC that have a barrel with a tight enough twist to stabilize the heavy for caliber bullets and easier to find quality match ammo in 300PRC. The only real reason I could see for going with the 300WM is that you already have dies and a supply of quality brass (using range pickup or random brass for an ELR rifle is counterproductive as you'll end up with terrible ES/SD).

If you're building a custom rifle from scratch, there's no good reason to not build a 300NM for both performance inside 2000 yards as well as the lower cost of components. You also get the added benefit of having an action and bolt face sized so that if you decide the Norma isn't quite enough boom for you, your next barrel can be a 338 Lapua or better yet a 338 Norma Mag, 33 XC, etc.
 
Macman12 said:
Good thread discussions, I am leaning 300 over 338 based on ammo availability.
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I also think that the availability of dies, reloading components, and resale value of the rifle are important factors.

The more specialized cartridges mentioned in this thread have some great ballistic advantages, but are obscure enough that the resale market for the complete rifle is fairly narrow in my view.
 
FirearmsEnthusiast said:
I also think that the availability of dies, reloading components, and resale value of the rifle are important factors.

The more specialized cartridges mentioned in this thread have some great ballistic advantages, but are obscure enough that the resale market for the complete rifle is fairly narrow in my view.
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The resale market for anything that’s not a factory rifle is very limited. Most “long range shooters” are following fads and not investing enough for the game they say they want to play. It is far more expensive than many realize.
 
FirearmsEnthusiast said:
I also think that the availability of dies, reloading components, and resale value of the rifle are important factors.

The more specialized cartridges mentioned in this thread have some great ballistic advantages, but are obscure enough that the resale market for the complete rifle is fairly narrow in my view.
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I've never sold a rifle and I don't plan to as long as I'm alive so that has no bearing on my decision making.
The availability on components isn't that bad for 338LM.

There was someone selling factory 338 Lapua ammo on the EE for $4.00 a round during the scamdemic.
There were also great deals on 338 Lapua chambered rifles around the same time.
 
Vote for .338lm
Its a fun round, you can reload for around $2.50 a shot which is cheaper then .300 wm factory ammo.
Ive owned .300 wm, .300wsm and .338lm .338lm was the only one i could get doped to hit at 1600m first round every range trip. The other two were way to enviromental sensitive. I never could get the .300wsm doped past 1200m, it was spend 30 rounds figuring out the days conditions to make hits past 1200 and even them it lacked steam for consistency
 
Timely argument over the 300 PRC vs. 300 Wind Bag.

https://www.fieldandstream.com/guns/300-prc-vs-300-win-mag/


There’s no real definition as to what “magnum” means when it comes to rifle cartridges, but as far as .30-calibers are concerned, “magnum” generally means a cartridge that’s more powerful than the 30-06 Springfield. That means there are 11 popular .30-caliber magnum cartridges to choose from. The most popular is the 300 Winchester Magnum. It’s one of the best long-range hunting cartridges and a great rifle cartridge for elk hunting. But a lot of shooters are becoming interested in the 300 PRC and are wondering if it might be a better option. Before we get into the differences between the 300 PRC vs 300 Win Mag, let’s look at how they stack up against the other nine .30-caliber magnums, in terms of their best-recognized muzzle velocities with a 200-grain bullet.

With all these offerings shooters can have a magnum 30 that’s short and fat, long and slender, or somewhere in between. Ballistically, the 300 Winchester Magnum and the 300 PRC are very similar and just slightly north of average, so, if you’re struggling with which one to get, what things should you take into consideration?

300 PRC vs 300 Win Mag: man shooting a long range rifle
If long-range precision shooting at paper or steel is your primary interest, the 300 PRC is a better option than the 300 Winchester Magnum. Richard Mann
The Most Important Considerations When Deciding Between a 300 PRC vs 300 Win Mag
Rifle and Ammo Cost/Availability
I believe the first thing to consider is whether you’re going to handload for your new magnum. Currently, a major online retailer—MidwayUSA—lists 80 factory loads for the 300 Winchester Magnum and only six for the 300 PRC. That’s a tremendous difference and matters when you’re trying to find the load your rifle likes. On the other hand, if you’re going to reload your own ammunition it’s not that big of a deal until you’re on an elk hunt in New Mexico and the airline loses your handloaded ammunition. You’ll also find that 300 PRC brass will cost about 3% to 4% more than 300 Winchester Magnum brass.

Ballistic Coefficient
Because SAAMI specifies a rifling twist rate of 1 in 8.5, the 300 PRC can handle—better stabilize—bullets that are longer and have a higher ballistic coefficient. This is where the 300 PRC has a distinct advantage over the 300 Winchester Magnum, which has a SAAMI specified rifling twist rate of 1 in 10. It’s something to keep in mind, if you purchase factory 300 Winchester Magnum ammunition, it will be designed to work with a 1 in 10 twist, and if you handload for a factory 300 Winchester Magnum rifle, you’ll have to use bullets that are designed to work with a 1 in 10 twist.


However, if you have a custom rifle built for either cartridge, you can specify the rifling twist rate you want, and then you can handload whatever bullet you want. This sort of levels the playing field, but because of the 300 PRC’s larger powder capacity it will be able to push those heavier, higher BC bullets a little bit faster. This means at extreme distance you’ll see less drop and less wind drift, and both are important when shooting into the next zip code.

300 PRC vs 300 Win Mag for Big Game Hunting
If you’re looking for a magnum 30 for big game hunting, there are some other things you need to consider. Those ultra-high BC bullets that the 300 PRC can handle are mostly match or target bullets. With a good big game bullet, like the mono-metal 190-grain Hornady CX, you can expect a muzzle velocity of about 3000 fps out of the 300 PRC and about 2900 fps out of a 300 Winchester Magnum. At practical shooting distances, I don’t know how you’d tell any difference in terminal performance between the two. However, if you want to reach way the hell out there to whack your mule deer or elk, the 300 PRC is going to have a slight advantage.

If you strive for a bullet impact velocity of 2000 fps, the 300 PRC will take you to about 650 yards with the 190 CX bullet. Out of the 300 Winchester Magnum, the same bullet will drop to a speed of 2000 fps at around 600 yards, so the 300 PRC gives you about 50 yards more reach. The reason the 2000 fps impact velocity is important is because that’s the velocity mono-metal bullets like the Hornady CX need to show measurable bullet upset. Similarly, this 50- to 75-yard velocity advantage the 300 PRC has vs the 300 Win Mag will apply to almost any good big game bullet.

Cartridge/Action Length and Recoil

The 300 Winchester Magnum cartridge is loaded to a SAAMI-specified maximum overall length of 3.34 inches. This means it will fit in standard-length rifle actions—the same size rifle action that works with the 30-06 Springfield. The 300 PRC on the other hand is loaded to a specified maximum overall length of 3.7 inches. It is a long cartridge, and it requires a longer action and magazine.

When it comes to rifle cartridges, everything is a tradeoff. You can design a cartridge that’s more powerful and that will work with heavier, longer, and higher BC bullets, but with that will come extra recoil. Out of a rifle of the same weight, the 300 PRC will recoil with around 6% to 7% more force. However, because the 300 PRC needs a longer action, a 300 PRC rifle will likely weigh a bit more and the recoil impulse will most likely be very similar.

Man with a rifle next to a dead deer.
Most big game hunters would probably be better served with the 300 Winchester Magnum as opposed to the 300 PRC. Richard Mann
300 PRC vs 300 Win Mag: Which Way to Go?
When the totality of the differences is considered, I’m of the opinion that if big game hunting is your primary consideration, the 300 Winchester Magnum is a better choice. Even if you’re a big game hunter that wants to dabble in long range precision – target – shooting, I still think the 300 Winchester Magnum is the better option. At sensible shooting distances the 300 Winchester Magnum will kill big game just as well as the 300 PRC. And, for recreational long range shooting, there’s not enough difference to justify being regulated to a cartridge for which there is limited ammunition options available. Also, there are more 300 Winchester Magnum rifles, in more different styles to choose from.

However, if you want a rifle that will allow you to perform as well as possible at extreme long range, when ringing steel or punching paper like you might do in competition, then the 300 PRC is one of the best rifles you can choose. Partly because it has a slight ballistic advantage over the 300 Winchester Magnum, partly because if you’re serious about long-range shooting, you’ll probably be handloading and the limited factory ammunition issue will not matter. And finally, it’s also partly because many of the factory-made 300 PRC rifles are ideally configured for precision long-range shooting.
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No question that a 300 PRC is better suited for long range precision than the 300 win mag.
That being said, a custom chamber/throat for the win mag can get you most of the way to a PRC. The shorter neck and longer case will work against you for concentricity and seating above the NSJ and fitting CIP mags though.
IMO, the only real 30 cal players are 300 PRC and 300 Norma. You can still spin up a big 338 barrel for both actions later on, the 338 edge is effectively equivalent to the 338 Lapua. But if you want a 338 lapua/improved or 33xc later on you'll want to start with the Norma.
 
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My friend, all this talk about availability, cost, and such is really going nowhere. You know you want the 338 LM. When you pull the trigger on the 300 WM, are you going to think, gee, I'm glad I spent 50¢ less on that shot? No. You're gonna think why am I shooting such a piddly little cartridge!

You've got the little calibers for cheap fun that can also reach out far. Now it's time to go for something big, so get the one that will put a smile on your face. It's what I got, and it's great. With a decent brake it's honestly not bad too shoot, but the satisfaction level is off the charts.

Listen to your heart.
 
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