Kinda torn!!! Build advice

The 300 PRC is a much better design than the 300 WM.

Just because you can make a 300 WM shoot, or find more ammo on the shelf, or because it has been around longer, doesn't make it a better design, just useable.

Go with the 300 PRC and don't look back!
Hornady factory ammo will shoot well, and reloading will go easier and and be every bit as accurate as the WM.

That being said, personally I would go for the 300 Norma if I were doing a 30 cal. Magnum. But it would not shoot any better than the PRC, and would cost more. However, my 338 LM bolt face is the same, so it makes sense for me.
Much better design based on what criteria?
 
Much better design based on what criteria?
Here's a link to a LRP podcast in which this is discussed - you can decide whether or not the 300 PRC is an improvement over earlier 30 cal cartridge designs. Agree or not, I think the facts are well discussed when dealing with an apples to apples comparison of SAMMI spec chambers. If going custom - this is of no value then.

 
Much better design based on what criteria?
The design being based around current long high bc bullets makes the PRC a better choice for precision shooting.
Shorter case with a better shoulder angle and no belt reduce case growth, feed better and resize easier.
Factory match grade and hunting ammo available.
 
The design being based around current long high bc bullets makes the PRC a better choice for precision shooting.
Shorter case with a better shoulder angle and no belt reduce case growth, feed better and resize easier.
Factory match grade and hunting ammo available.
Your points about factory Ammo are somewhat valid as long as your primary goal is match type shooting but your choices on manufacture are very limited. Hunting Ammo is much more limited for the PRC.

The remaining items are debatable. While I do agree on the case stretch issue with the 300 WM, that is really a moot point after the first firing and Peterson is addressing the brass issue with their long brass for the 300 WM.
 
If we assume the max hunting distance will be 700 or less, this discussion is academic. Any of the 30 cal mags will have ample energy to kill elk and deer and whatever.
Clearly the WM has a component advantage, but after that its all personal preference.
The cartridge case holds powder and a bullet. Design of the case is the proverbial Ford, Chevy, Dodge conversation.
I own a 300wm and wouldn't feel slighted by any of the other mags. My only disqualifier is case capacity. No substitute for displacement.

OP: What bullet weight are you looking to shoot? This might help in the decision process.
 
If we assume the max hunting distance will be 700 or less, this discussion is academic. Any of the 30 cal mags will have ample energy to kill elk and deer and whatever.
Clearly the WM has a component advantage, but after that its all personal preference.
The cartridge case holds powder and a bullet. Design of the case is the proverbial Ford, Chevy, Dodge conversation.
I own a 300wm and wouldn't feel slighted by any of the other mags. My only disqualifier is case capacity. No substitute for displacement.

OP: What bullet weight are you looking to shoot? This might help in the decision process.
Does it really matter how much powder you stuff in a case if the bullet weight and pressure is the same?

Serious question because I'm becoming more convinced pressure is the factor that determines how fast a bullet is pushed down range.
 
Does it really matter how much powder you stuff in a case if the bullet weight and pressure is the same?

Serious question because I'm becoming more convinced pressure is the factor that determines how fast a bullet is pushed down range.
It absolutely is the pressure.
Compress a load of super slow 50 bmg powder that is way too slow in a 22-250 and see what happens. (Please don't do this)
But, you are correct, it is pressure that dictates velocity!
 
I'd have to agree with build whichever you can find components for. Personally I lean towards 300 Win Mag because I have brass and still see dies on the market. But at this point whichever you can you can get components or ammo for is the one to build.
 
Here's some hands on live comparison of the 300 PRC and the 300 Win Mag. Ladd did a great job comparing the two while developing loads for them.

 
Does it really matter how much powder you stuff in a case if the bullet weight and pressure is the same?

Serious question because I'm becoming more convinced pressure is the factor that determines how fast a bullet is pushed down range.

The short answer is "yes". This is a physics question that is fortunately easier to explain. There are 2 main factors that come into play here. The first basic premise is smokeless powders turn into a gas and become a propellant, not and explosive like black powder. The gas pressure pushes the bullet down the bore. But it takes a certain amount of PSI(some reference 15K or more) to actually move the bullet. This is because of the interference caused by the bullet being forced down the bore.
Now to answer the question:
There is peak pressure and AUC (area under the curve). For optimal performance we need to be at safe peak pressure while having the gas volume to keep the pressure behind the bullet at 15K+PSI
Screenshot_20211215-072320_DuckDuckGo.jpg
. There are a number of powders that can generate peak pressure for most rifle cartridges, but only a certain burn rate will allow enough powder burned to achieve the gas volume necessary for peak velocities. With a larger case capacity, you can use slower burning powders that generate the same peak pressure and maintain 15K+ PSI longer. Also keep in mind that peak pressure is relative to burn rate and case capacity.
Example 308W vs 300wm. If loaded to the same pressure, the 300 wm wins by a mile. Only real difference is case capacity.
I'm attaching a chart which illustrates what I'm attempting to example. Compare lines 1 and 3.
Screenshot_20211215-072320_DuckDuckGo.jpg
 
It absolutely is the pressure.
Compress a load of super slow 50 bmg powder that is way too slow in a 22-250 and see what happens. (Please don't do this)
But, you are correct, it is pressure that dictates velocity!

Its the combination of peak pressure and the duration above a certain threshold pressure that dictates velocity.
 
I know you said 300 PRC or 300 WM but for components and performance 30-06 AI will do the job on elk and deer. Load with 180 grain bullets. and in a pinch off the shelf 30-06 ammo works. I built Rem 700 with X caliber 20 inch 9.5 twist barrel and it shot amazing, wish I had never sold it. Fixing to build another.
 
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