.300 WSM or .300 Win Mag

You can build it on a normal WSM size actions . You can get the 2900-2950 velocity range easy enough .

Doing a short mag in a long action allows you to max out the amount of case capacity you can use by allowing a longer OAL so you don't loose as much by having to seat the bullet deeper in the case .

The issue right now with the SAUM and WSM is brass availability . Remington hasn't had reloading brass in damn near a decade now and the Winchester stuff is just starting to show up again . So the only readily available stuff is expensive shitty Nosler brass .

The long action RM and WM brass from Winchester is back in stock at Powder Valley last time I checked , which is cheaper and a harder alloy than the Nosler / Norma junk .

For that reason I'd go long action because without brass you aren't shooting . If I was building a 7 now it would be a long action in 7/300 WM . Same case as the RM but 1/10th of an inch longer for more case capacity and built around the 180 ELDM . That combo easily makes 3000 fps and the Hornady bullets are cheaper and more readily available than the Berger 190s .

Have been shooting the ELDM's in 6.5 and 338 for a year now and they work well .

The thing with the 230 / 240 GR 30 cal bullets in a win mag chamber is without a custom chamber with the throat pushed way out they are 2600-2650 ish fps .

The military load with the 230s IIRC are stupid hot and not something I'd want to have to support on my own dime .

The 300 WM is probably best used with something in the 200-210 GR range to balance usable velocity and bullet performance .

Quote:

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Originally Posted by C Ward

The thing with the 230 / 240 GR 30 cal bullets in a win mag chamber is without a custom chamber with the throat pushed way out they are 2600-2650 ish fps .

The military load with the 230s IIRC are stupid hot and not something I'd want to have to support on my own dime .

The 300 WM is probably best used with something in the 200-210 GR range to balance usable velocity and bullet performance .

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I'm sorry, don't know what you mean "is without a custom chamber"? If one caliber I choose is Win Mag I would probably lean towards the 215's. One of my others I used to run the 208's and I liked the way it performed.

7SAUM will do 2900-3000fps with a 180 out of either a short or long action. Long action makes things easier because of magazine length. I got a new 29" barrel, bolt-head and magazines for my Bighorn and screwed it on last week. Not quite as fast as XC's 7/300 WSM, or as sexy looking, but should deliver the mail out to a mile or so. I know Mark Chanlynn has chambered a couple 7SAUM's recently if you need a smith, I can also put you in touch with another is you decide to go that way.

Whichever you decide on, you better come down and shoot that sucker.

Quote:

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Originally Posted by Delfuego

7SAUM will do 2900-3000fps with a 180 out of either a short or long action. Long action makes things easier because of magazine length. I got a new 29" barrel, bolt-head and magazines for my Bighorn and screwed it on last week. Not quite as fast as XC's 7/300 WSM, or as sexy looking, but should deliver the mail out to a mile or so. I know Mark Chanlynn has chambered a couple 7SAUM's recently if you need a smith, I can also put you in touch with another is you decide to go that way.

Whichever you decide on, you better come down and shoot that sucker.

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I'm planning on it for sure. I just had a second surgery on my back (cervical fusion) with screws and rods. So while I'm down I want to build another to shoot. I guess my plan right now is to build a switch barrel in 7mm SAUM and .300 Win mag, give me a chance to play with both. I'll build it on a Surgeon LA most likely. Might just have Bugholes chamber me two barrels with the bugnut and call it a day!
What do you recommend for a twist rate for the 180's in 7mm?

8.5 twist

I too am in the 7 camp. Just had a 2nd 7saum built on a short action, 30" barrel. Intended purpose ELR matches. Just started working up a load, up against 3000fps/180 Hybrids. Elrod chambered it.

1st 7saum a few years back, also on a short action. 2950/180 Hybrids 27" was the sweet spot with it. pulled the barrel with 1600rds.

Previous to that had a straight 284 on a long action. Shot the Sierra 175 SMK's, Berger 180 Hybrids just came out when I pulled the barrel at 2500rds. Depending how far you are going to shoot, the 284 is a sweet caliber. Very easy to tune, easy neck up Lapua 6.5x284 brass. Clearly see why the 284 is the darling of the 1000yd F-Class Open. It will drop anything at a realistic hunting distance.

The 300 WM with the 230 / 240 s will need a chamber cut with a longer than SAMMI spec throat because of the extra bullet length .

Look at the research Litz is doing about twist rates and BC , the old consensus of just use the bare minimum twist is been been pretty much disproven and there is a benefit to over stabilization especially at long range .

Buddy just finished his 7RM and is running the 180 ELDM and the twist is 7.5 ,IIRC , I'll have to check . The thing is a hammer and the 5 rds I shot out of it without adjusting it to me went in to about 2 1/2 inches at 640 yds prone with a bipod and bag . Just checked and the rifle is an 8 twist

He built the gun heavy with a 28" barrel on a Defiance action with 30 moa built in to the receiver , my first choice for actions now . Rifle weighs in at 20 - 21 lbs and recoils about like a 308 with no can on it .

With having a jacked up back a 7 will be easier to shoot , the 300 WM with 230 / 240 s has probably 30-40 % more recoil than a 7 with 180 s all else being equal .

Quote:

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Originally Posted by C Ward

Look at the research Litz is doing about twist rates and BC , the old consensus of just use the bare minimum twist is been been pretty much disproven and there is a benefit to over stabilization especially at long range .

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Good point, reason I went with a 8.5 twist on the new one, distances I plan on shooting......

My plan was to use a 1:8 twist at 22"-24" for a hunting rifle. Now I'm just thinking of using a Remington short action with a proof barrel and running it lighter than normal.