300 WSM vs 300 Win Mag

C

CT.HNTR

Beginner
Feb 6, 2022
50
110
Happy Thanksgiving Everybody!
I currently have a 300 Ultra Mag (300 WBY) and am looking to size down a bit to a standard 300 Mag. Looking at the Tikka T3 in 300 Win Mag or 300 WSM. Ballistically, they seem the same while the 300 WSM is a shorter action. Looking for thoughts on accuracy? Will one be more accurate than the other? I have it in my head that as the 300 WSM is a newer more modern cartridge design it might be more accurate but that's just suspicion on my part. Any feedback regarding pro's and con's of each would be greatly appreciated. My plan is to stick with 165 grain and 180 grain bullets.
 
Don't believe one is more accurate than the other. The WSM is purported to have less felt recoil, though I never found the recoil on the 300 WM to be problematic. I've loaded for quite a number of each of these cartridges. Either can be a joy to own. I have owned or now own three of the WSMs, and they are an easy cartridge to load when looking for an accurate load.
 
I've owned several 300wsm and even more 300wm barrels.
They are not ballisticly the same. The WM will best the wsm by 150 to 200 fps at the same pressures. The wsm is handicapped by short action and magazine limitations with long bullets also.
I still love the wsm and my next build will be on a long action and throated for 215 gr Hybrid.
As for precision, make no mistake. Accuracy is in the barrel/ build not the cartridge.
 
The 300 Win Mag is an inherently accurate round and was commonly used for 1000 yard Wimbledon Cup matches. You also have several quality brass options available as well as factory ammo in a pinch.
Between the 300 Win Mag and the 300 WSM, I would go 300 Win Mag and never look back.

JD338
 
In my experience they are Coke and Pepsi. What one does, the other will do.

The Win Mag has the edge on case capacity and therefore can be loaded hotter. It is also easier to find brass for as well as being more ubiquitous.

The WSM does seem to kick a bit less, but the difference is negligible with loads of equal power levels.

For whatever reason, the half dozen WSMs I have shot don’t seem to require a major change of zero when changing to different bullet weights. A friend’s Browning X-bolt shoots the W-W 150 grain Powerpoint factory loads to the same zero at 100 yards as 180 grain AccuBond handloads. My Dad’s New Haven M70 shoots the Remington 150 grain Corelokt Tipped factory loads to the same zero as 180 grain AccuBond and 200 grain Partition handloads. I have never seen a .300 Win Mag do this.

Bottom line, where you have a .300 RUM, and are looking for less recoil, I personally would go with the WSM.
 
I have both, load for both, and have shot game with both.
In my opinion:
  • The accuracy is comparable between the two rounds.
  • For the same bullet, and bullet velocity, and the same powder, the WSM has less felt recoil.
  • The WM is better if looking for maximum velocity (which I do not).
  • The WM is better if using 200 grain or more bullet weights or 180 gr. or more copper bullets.
  • All things considered the same, the WSM is a shorter action and therefore a lighter rifle.
  • For 180 gr. and less lead core bullets I personally prefer the WSM.
  • I plan to keep both and use both.
  • When I went to Montana this fall, the 300 WSM was my primary rifle, and the 300 WM was my backup rifle. Both were loaded with 180 gr. AB's. I had equal confidence in both.
 
I can only comment on the .300 WSM. I have a Kimber 8400 and I love it. It’s accurate with whatever factory load and stupid accurate with 180 and 200 grain Accubonds. But the biggest reason I love it is the weight. I was toting a Winchester .338 high in the mountains and at the end of the day I swear it would gain weight. (Sorta like me on Thanksgiving day, a true mystery). With the Kimber I shaved 1 1/2 lbs off the carry weight with a very potent and capable cartridge. Could I find a .300 Win that was lighter than the WSM, probably now but back then options were not as prevelant. Tikka would be a good option today for a lighter Win Mag and compared to the WSM I doubt the weight would be much.
 
NYDAN said:
I have both, load for both, and have shot game with both.
In my opinion:
  • The accuracy is comparable between the two rounds.
  • For the same bullet, and bullet velocity, and the same powder, the WSM has less felt recoil.
  • The WM is better if looking for maximum velocity (which I do not).
  • The WM is better if using 200 grain or more bullet weights or 180 gr. or more copper bullets.
  • All things considered the same, the WSM is a shorter action and therefore a lighter rifle.
  • For 180 gr. and less lead core bullets I personally prefer the WSM.
  • I plan to keep both and use both.
  • When I went to Montana this fall, the 300 WSM was my primary rifle, and the 300 WM was my backup rifle. Both were loaded with 180 gr. AB's. I had equal confidence in both.
Click to expand...

NYDAN,
I am very curious about your comments regarding monolithic copper and lead-core bullets. Can you elaborate as to why you feel the WM is better with copper bullets and the WSM is better with lead-core bullets? The two bullets I would be testing are 180 gr Accubonds and 180 gr Barnes TTSX BT
 
CT.HNTR said:
NYDAN,
I am very curious about your comments regarding monolithic copper and lead-core bullets. Can you elaborate as to why you feel the WM is better with copper bullets and the WSM is better with lead-core bullets? The two bullets I would be testing are 180 gr Accubonds and 180 gr Barnes TTSX BT
Click to expand...
As others have stated, the 300 WM has more case capacity than the 300 WSM. Also, in my limited experience, the 300 WM tends to have a longer free bore than the 300 WSM. Both of those things allow more space for powder and bullet. Heavier lead core bullets (like 200 gr.) begin to impinge on the powder volume in the 300 WSM. Solid copper bullets are less dense than lead core bullets and therefore (for the same bullet weight) are longer and (for the same COAL) use more of the powder volume. Also, solid copper bullets tend to expand better at faster velocities.

So, the higher case capacity of the 300 WM is (in my opinion) is better suited for the heavier lead core and solid copper bullets.

Also, according to some of the reloading manuals I have read, the authors claim that the 300 WSM is easier to download to lower velocities than the 300 WM.

It all gets down to what you want to accomplish with your reloads. Up to now, I have tended toward caution and less than maximum speeds with lead core bullets. Additionally, I prefer less recoil. So, for 165 gr. BT bullets and 180 gr. AB bullets, the 300 WSM provides me with the performance I "aim for".

However, I do plan to develop a 200 gr. AB load for the 300 WM specifically for elk hunting. Also, I plan to develop a monolith bullet load for the 300 WM.

The reason for this will become evident in future posts when I discuss the elk I took this year in Montana.

I hope this helps.
 
I would choose the 300 WSM and think it's the best of the 300's myself. Easy to load it full power or load it at 308 or 30-06 speeds. In a Tikka definitely a 300 WSM, you'll have lots of room in that magazine. The 300 Win mag you'll won't have much room unless you go with new bottom metal.
With bullets up to around 180 gr the 300 WSM comes very close to the the regular 300 WM for speed.
 
Unless you don’t like that rifle I would knock a couple of grains of powder off your load and get in the 300 WSM range.
Then there is also the excuse for a new rifle😁
 
Yoteklr said:
As for precision, make no mistake. Accuracy is in the barrel/ build not the cartridge.
Click to expand...

If that were true then every winning short range benchrest caliber wouldn't be a 6ppc and almost every .30 1000yd benchrest gun wouldn't be a 300wsm. A optimal case capacity to bore size usually means the best accuracy. That is why the 6BRA is out shooting the 6 Dasher now at 600 and 1000yds.
 
A long throated 300wsm with heavy bullets, ie: 215 Bergers, and R-23 or R-26 will run 2920-2950ish with a 24" barrel or around 2960-2980fps with a 26". A long throated 300wm will run almost identical velocities with H-1000. With Retumbo it will add around 40fps and with N-570 it will add about 80fps. Bartlein barrels run a bit slower than Brux, Krieger, Benchmark, etc. There is a noticeable difference in the recoil between the 2 guns. The 300wm will run 7-8grs more powder, or roughly 10%, for the same velocity with R-23/26 versus H-1000. N-570 in the 300wm will be around 80grs versus 69grs of R-26 in the 300wm. That is closer to 15% more powder. I've built a bunch of both and anymore I run 300wsm's. They tend to shoot a bit better and have less recoil.

In a factory standard short action length the 300wsm isn't impressive with the heavy bullets. They do OK with 175-185 Bergers as they don't sacrifice case capacity like the heavies do.
 
I have owned both the WM (LH Sako Finnbear) and WSM (LH Rem 700), and now only have the WSM. For me, it has less felt recoil.
Of the two, the WSM has proven to be more accurate for me, in both factory ammo, and in handloads, whereas the 300 WM was fairly accurate, I did not handload at the time I owned it, so cannot say if it would have been more accurate with a good handload.
To date I have taken 8 animals with the WSM and 6 with the WM. Both worked just fine.
I can't ask for anything more. I must say that I prefer the WSM. But this is just my experience and preference with the 300's.
Who knows, if I had tried the H&H first, it may be my favourite... :unsure:
 
Guy Miner said:
This confuses me. The 300 Ultra Mag is a completely different cartridge than the 300 Weatherby.

Can you please clarify which you have?

Thanks, Guy
Click to expand...
Sorry for the confusion. I have a 300 WBY. I consider the WBY, RUM and 30 Nosler to be in a general category of Ultra Magnums but that might not be correct terminology.
 
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