Which short action magnum?

Here is a visual example of why the SAUM is better suited to a short action than a WSM.

Left to right - 300 SAUM, 6.5 SAUM Improved necked up to 30 cal and 300WSM.

COAL on the SAUM cartridges is 2.950 with a Berger 185 Juggernaut with the bearing surface above the neck/shoulder junction. The WSM is seated at 2.980 and the bearing surface is slightly below the neck/shoulder junction. This is really of no importance if you are shooting one and done and not reloading.

Another thing to note, the improved version of the SAUM cade actually has higher powder capacity than the WSM.

EDIT: I’ll post the picture with the bullets seated tomorrow. I thought I had it on my phone but I don’t.
One thing about a longer action is that it allows for the use of longer ogive bullets and longer overall lengths. Very familiar with the 185 Juggernaut as it was the standard that we used to test profile changes that would allow improvements in BCs. Interesting that an AI modification of the SAUM case increases capacity beyond the WSM.
 
One thing about a longer action is that it allows for the use of longer ogive bullets and longer overall lengths. Very familiar with the 185 Juggernaut as it was the standard that we used to test profile changes that would allow improvements in BCs. Interesting that an AI modification of the SAUM case increases capacity beyond the WSM.
No doubt. The SAUM/WSM/6.5PRC definitely benefit the most from a medium or long action but if you don’t have that option the SAUM is the best option for a short action IMO. And it’s best used with either the Hawkins Hunter DBM or a 3” Wyatt’s center feed box. It is sad that the 300 SAUM never caught on like it should have for those that prefer 30 caliber. It seems to be seeing a resurgence in the competitive shooting world.

In the pic below there’s hardly any visual difference but it shows the minuscule measurements we are talking about but how it can make a big difference.
 

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Not sure if you have noticed, but there is a distinct lack of WSM brass. You might be better getting a 7 SAUM. Seems like that one has some people interested.

or 6.5 PRC.

Whatever you do, please take some time to complain to Lapua, Peterson, Alpha and ADG about the lack of available WSM brass right now. I’ve been on a 2yr hold basically due to lack of quality brass.
 
Not sure if you have noticed, but there is a distinct lack of WSM brass. You might be better getting a 7 SAUM. Seems like that one has some people interested.

or 6.5 PRC.

Whatever you do, please take some time to complain to Lapua, Peterson, Alpha and ADG about the lack of available WSM brass right now. I’ve been on a 2yr hold basically due to lack of quality brass.
Can’t find any 6.5 PRC or 6.8 Western brass. Much harder to find that stuff than it would to rebarrel a 270win with an 8 twist barrel and use the high BC .277 cal bullets. Might even do a 270Win AI.
 
You will be happy with the 7 WSM. I have a browning Abolt loaner rifle that friends and family use. Loaded with 168 Bergers an RL23 it is devastating on game. It’s killed elk, coues, blacktail, antelope and hogs.
150 rounds of brass should last you awhile. I have some of the Hornady that I haven’t tried yet. Interested to see how it does.
 
Can’t find any 6.5 PRC or 6.8 Western brass. Much harder to find that stuff than it would to rebarrel a 270win with an 8 twist barrel and use the high BC .277 cal bullets. Might even do a 270Win AI.

Here's some brand new ADG right here:



I see it for sale on the Hide quite regularly.



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For what it is worth, I see loaded 270, 7, and 300 WSM on store shelves far more often than SAUM. I bought Winchester silvertip for 29 a box at the height of pandemic panic, and saw more 300WSM than 308 in some stores at that time as well- and NO SAUM, not even a space for it.

To the best of my understanding, while the WSM cartridges do leave more on the table when constrained to a short action, in a short action they are capable of higher velocity with a given bullet than anything else. That may have changed with the Sherman designs and exceptionally long bullets... But if chasing fps is your jam, I do think WSM is the way to go. Efficiency and unobtained potential are also important considerations. I do like my 7WSM, but for my needs it doesn't do anything a SAUM or even my new 7-08AI can't do.

I think you will be very happy with your choice.
 
Here is a visual example of why the SAUM is better suited to a short action than a WSM.

Left to right - 300 SAUM, 6.5 SAUM Improved necked up to 30 cal and 300WSM.

COAL on the SAUM cartridges is 2.950 with a Berger 185 Juggernaut with the bearing surface above the neck/shoulder junction. The WSM is seated at 2.980 and the bearing surface is slightly below the neck/shoulder junction. This is really of no importance if you are shooting one and done and not reloading.

Another thing to note, the improved version of the SAUM cade actually has higher powder capacity than the WSM.

EDIT: I’ll post the picture with the bullets seated tomorrow. I thought I had it on my phone but I don’t.
What powder do you shoot out of that 300 saum imp mike? Also what barrel length? I have h4350, 5lbs of rl16, but also wonder about vhit 555 with that 185 juggernaut. thanks
 
What powder do you shoot out of that 300 saum imp mike? Also what barrel length? I have h4350, 5lbs of rl16, but also wonder about vhit 555 with that 185 juggernaut. thanks
I tried N555 in my 300 WSM and got pressure at lower velocity than N560 shooting 168 grain ELD-M. Not sure if that helps you or not. Rifle is a Christensen Ridgeline.
 
I tried N555 in my 300 WSM and got pressure at lower velocity than N560 shooting 168 grain ELD-M. Not sure if that helps you or not. Rifle is a Christensen Ridgeline.
I had a custom Borden done in 300 WSM. My first powder I tried with Norma brass, as my other commercial 300 WSM rifles love that brass. I found such extreme pressure with even the lowest powder charges that it literally locked the bolt shut. I could not open it at all. Frustrated, I packed up my junk and went home. I called Mr. Borden to discuss. He asked, "what brass are you using?" When I told him, Norma, he started laughing. He went on to inform me of the different ductility properties of market brass & that Norma was the softest of all. He asked if I got the bolt open yet & told me to get a hammer handle or a substantial piece of wood and literally beat the bolt open. He said he'd done it many times. He suggested I try a different brass mf'r & start with the highest charge & that the first two shots would tell me everything I would need to know. So, I loaded 5 R-P brass with 64gr VV 550, 155 Scenar's & fired the first two rounds of five. Those two went into the same hole & all of them printed 1/2 moa @ 3285 fps & ZERO pressure signs. Bolt lift was normal. That is my hunting load for that rifle now. And this all started with my first load development work with a brand new gun. It went from unusable to dialed in after 12 rounds fired.
 
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