300 Win Mag -VS- 300 PRC

[Steel head]

So silly question from someone who wants to do something rather impractical:

Context: I have a switch lug MPA rifle in 6.5 CM built on a Curtis Axiom short action. Shoots very well! Don’t want to build a completely new rifle and buy another $2K scope, kid-at-college situation. Objective is “ELR-on-a-tight budget”.

It is really very easy to change barrels at the range, takes only 30 seconds, and my zero moves two clicks. Want to shoot heavy 30 cal mono bullets at ELR distances (2,500 is my new personal goal), and i like the 241 gn Seneca bullet from Patriot Valley Arms. Bullet length is 2.050”!! Claimed G7 BC is 0.55... but even of the BC turns out to be 0.49 i am still in! Hoewer, it needs a 7 twist barrel.

Would a 300 PRC “work” on this SHORT action Curtis Axiom action in the MPA BA chassis?? I realize it will be single feed only, and a new magnum bolt will be needed ($400, ouch!), and extracting an unfired round will require the bolt to be removed. I am ok with these leas than nice inconveniences, tolerable.

Or should i stick with the 300 WSM case and give up 100-150 fps in speed? Will likely get a 28” or 29” barrel (an extra $50) to compensate for the less than ideal speed, and probably HBN coat the bullets. COAL is 3.60”:


View attachment 7608413

View attachment 7608414

A Seneca round loaded in a 300 PRC case would likely be closer to 4” long.

I shoot this out of a short action Nuke

Magnum boltface and 4.25” long.

 

[NamibHunter]

I shoot this out of a short action Nuke
View attachment 7608433
Magnum boltface and 4.25” long.

Neatly done Mr. Steel! What bullet is that? Presume that is a 300 PRC case.

Like the fat cigar in the pic.

Do you have to remove the bolt to extract a loaded round? Any other impracticalities?

 

[Steel head]

285 badlands
To drop a loaded round I just drop the magazine.
It runs pretty well.
No issues.
13ish mils to 1800 and 33ish to 2980 is nothing to sneeze at.

You may want to compare the performance of the lighter solids as well as with the additional speed it could be a better option.

 

[NamibHunter]

285 badlands
To drop a loaded round I just drop the magazine.
It runs pretty well.
No issues.
13ish mils to 1800 and 33ish to 2980 is nothing to sneeze at.

You may want to compare the performance of the lighter solids as well as with the additional speed it could be a better option.

Ahh... So a 285 gn 338 bullet, with a G1 BC of 1.01. [... hard to make out the scale from the photos.] Thanks for sharing.

It seems we are in the middle of a technology race. Fascinating to watch, but soon we will all need new barrels with faster twist rate.

I noticed their heaviest 416 “ICBM” bullet has a BC of 1.2... Wow!!

 

[Kickin45]

It depends on what 300 wm you’re comparing the PRC to. If it’s a winmag that’s been throated for heavies, the two cartridges are virtually identical. If you have a standard winmag chamber, and that puts 225/230 class bullets way down Into the case, the PRC will likely outperform it. The PRC is merely a blown out AND shortened winmag. The resulting capacity is the same, but in a shorter overall length.

No it’s really not

 

[Steel head]

No it’s really not
View attachment 7771612

Mark and Sam in Australia actually found that they could get better speeds in a properly throated 300WM than a 300 prc with 230+ class bullets

 

[Supersubes]

No it’s really not
View attachment 7771612

Would you say that picture is an apples to apples comparison?

 

[Steel head]

Would you say that picture is an apples to apples comparison?

I laughed when he posted that pic because it directly illustrated your point

 

[Lost_Phil]

No it’s really not

Wrong!

This is what my COAL is with my 0.050" throated Win Mag (3.600" chamber), and I would say that my 300 Win Mag is pretty much a belted PRC now that I have a throated match barrel.

I will add, that if I did not have dies and brass already for the 300WM, I would have gone the 300 PRC route. 300 PRC is nothing more than a modern version of 300WM, like the 375 Ruger is to the 375 H&H (Which sadly never took off). But unlike the 375 Ruger, it is here to stay. I also think that as more modern powders come out from the manufactures, the faster you will see them go with heaver bullets.

One last thing, if you are going to build a modern 300WM, I would go with a 3.600" chamber minimum. It will let you load the 208's to 245's long, which is fine for most people. If you're going to shoot the monolithic style of bullets, I would go with a 3.700" chamber minimum so you can run them long as possible and get the most out of them. I would also go with a CIP (3.850") length magazine minimum, as it will let run them out as fer as posable, and this also applies to 300 PRC as well for magazine length. For twist rate, I went with a 1:9 since I am only looking at shooting the 208 to 220 bullets, but I would not hesitate to go the same twist as 300 PRC, winch is 1:8.

Bottom line, you cannot go wrong with ether choice.

 

[Steel head]

Wrong!

This is what my COAL is with my 0.050" throated Win Mag (3.600" chamber), and I would say that my 300 Win Mag is pretty much a belted PRC now that I have a throated match barrel.

View attachment 7773079

I will add, that if I did not have dies and brass already for the 300WM, I would have gone the 300 PRC route. 300 PRC is nothing more than a modern version of 300WM, like the 375 Ruger is to the 375 H&H (Which sadly never took off). But unlike the 375 Ruger, it is here to stay. I also think that as more modern powders come out from the manufactures, the faster you will see them go with heaver bullets.

One last thing, if you are going to build a modern 300WM, I would go with a 3.600" chamber minimum. It will let you load the 208's to 245's long, which is fine for most people. If you're going to shoot the monolithic style of bullets, I would go with a 3.700" chamber minimum so you can run them long as possible and get the most out of them. I would also go with a CIP (3.850") length magazine minimum, as it will let run them out as fer as posable, and this also applies to 300 PRC as well for magazine length. For twist rate, I went with a 1:9 since I am only looking at shooting the 208 to 220 bullets, but I would not hesitate to go the same twist as 300 PRC, winch is 1:8.

Bottom line, you cannot go wrong with ether choice.

Factory Saami freebore on 300 win mag is basically 0 burying any bullets well into the case


Match chambers vary but the .140 freebore was pretty common before the super heavies became popular but that one would be excellent with 190-240 class solids

The other more modern 300WM chamber is a .230 freebore similar to PRC and Norma magnum for 215+ cup/core bullets and it will do everything the prc will do but at a longer OAL

 

[PBWalsh]

Resurrecting an older thread due to relevance of my question.

The range I go to is moving and is slated to expand to have a 1600 yard range area. I’m very slightly considering building a 300 magnum based rifle to use.

If a person was starting with no reloading supplies, doesn’t want to reload (BTDT), and wants decent factory or semi-factory options off the shelf, which of the two chamberings are better suited for the task?

At most, this rifle would see 3-4 range sessions per year, or probably 300 rounds per year. Not to concerned with barrel life considering each trigger pull will cost $2-3.

Again, this is theoretical as I’d probably spend a year or two maxing out the distance of my 556 gasser first.

 

[Supersubes]

Not even close, 300 PRC.

 

[PBWalsh]

Not even close, 300 PRC.

Can you or another go into specifics as the why?

 

[Bandit320]

I have both, and given the qualifier that I shoot both single shot only, they both preform almost the same. I load the WM with 225 ELDMs at 2960 at almost 3.7”. I load the PRC with 230 A-Tips at around 2950.

The reason I built the PRC was to get a faster twist so I could shoot the 250 A-Tips. I ended up using the 230 because I’m just not getting the velocity with the 250s to make a difference.

I’ve shot the WM to 2,000 and the PRC to 2,500. With the WM loaded long they are very close in performance.

Some people don’t like the belt on the WM. Doesn’t bother me.

 

[rustyinbend]

Not sure, but I'm gonna find out. Been shooting a MPA-300WMBA to a mile with good results, factory Hornady 195 ELDM's. Recently started handloading for it. Just got a 300-PRC barrel for my Barrett MRAD and shooting factory ammo to zero, break-in, and generate brass to handload. Got Berger 220's for the 300-PRC and in the early stages of using QuickLoad to generate the first ladder test. I'll let you guys know if the PRC is same, better, or worse than my very accurate 300-WM. The journey is just beginning.

That was me, back in 2021. I've been shooting both my MPA 300-WM and my Barrett MRAD 300-PRC since then, and I can tell you that for me, they both shoot straight and true, and I can hit a 2'x2' one mile steel plate with either one. By my experiences, hand-loading and shooting, the results are VERY similar and both give me long-range accuracy and single-digit SD's. Here are my two best recipe's for each. Retumbo works best, but I have used H1000 as well with solid results

 

[Supersubes]

Can you or another go into specifics as the why?

Its all been laid out in this thread. As soon as you specify long range and factory ammo, these two cartridges aren't very comparable. Only reason anyone should ever pick a 300 WinMag for long range is if they are already invested in the cartridge.

 

[PBWalsh]

Its all been laid out in this thread. As soon as you specify long range and factory ammo, these two cartridges aren't very comparable. Only reason anyone should ever pick a 300 WinMag for long range is if they are already invested in the cartridge.

Thanks, thats what I was figuring after reading everything. I assumed the WM factory loading were geared more towards hunting and the PRC loaded to the target end of things.

 

[Supersubes]

Thanks, thats what I was figuring after reading everything. I assumed the WM factory loading were geared more towards hunting and the PRC loaded to the target end of things.

Look into the berger 300 PRC offerings. They load the 205 and 245(.413 G7) elite hunters.

 

[PBWalsh]

Thanks for the lead @Supersubes

It’ll be a year or three (if ever) before this project can take off due to other more practical needs. But its nice to see direction my thoughts should go once I do.

Big issue is these rifles are not cheap once you factor in rifle, optic, ammo, mags, and associated periphery equipment.