Short Action Magnum Chamber Considerations

Crews

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I’m contemplating putting together a medium weight rifle for 80% hunting and 20% target shooting (just to practice for hunting.) It would most likely be something like an Origin in a Bravo and a 22” barrel, 10 pounds or so.

I’d like to chamber it in a short mag. Idea is to eliminate as much potential for bad wind calls as possible, and maximize terminal performance to a max range of 800 yards (and realistically it’s more like 600.) Factory ammo is strongly preferred. Is there anything out there that fits the bill? Up front I’d prefer milder recoil or a 6.5 or 7, but could be convinced otherwise.
 

AMG04

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6.5 PRC is the new kid on the block with factory ammo available.

7 SAUM has factory offerings from Nosler, but it's not cheap.

300 WSM likely has the most variety and offerings available.
 

Totoro

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I found myself in a similar quandry and opted to go 300WSM in BDL rather than DBM for a light(er) weight rig.

Factory match ammo in the PRC is limited to Hornady but also offerings from Nosler and Federal.

As my build is centered more around hunting with occasional rock sessions the 300WSM made more sense due to more factory loaded ammo.
 

Rkpnw

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I'm going to repeat what crews said :
Deer hunting you could go 6.5 PRC, 6 MM creedmore (small body deer)
Larger game (elk,bear,moose) I would go with a 300 WSM or 270 WSM.
You can 300 WSM in long action as well and get some extra OAL with AICS mags. I have a Tikka T3 300 WSM running in a long action with AICS mags . Seating the 178 ELDX bullets at 3.910.
 

Crews

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I guess it would help to mention target quarry is deer, no need for something capable of killing an elk at 800 yards. Also, I am not interested in a long action.
 
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wade2big

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I'm going to repeat what crews said :
Deer hunting you could go 6.5 PRC, 6 MM creedmore (small body deer)
Larger game (elk,bear,moose) I would go with a 300 WSM or 270 WSM.
You can 300 WSM in long action as well and get some extra OAL with AICS mags. I have a Tikka T3 300 WSM running in a long action with AICS mags . Seating the 178 ELDX bullets at 3.910.
I’m thinking about doing the same thing you did with the 300wsm and a Tikka except I will use factory 300wm magazines to keep everything flush for hunting. Did you have to have your chamber throated long?
 

The D

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I guess it would help to mention target quarry is deer, no need for something capable of killing an elk at 800 yards. Also, I am not interested in a long action.
Sounds like 6.5 PRC is your gal then
 

Rkpnw

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I’m thinking about doing the same thing you did with the 300wsm and a Tikka except I will use factory 300wm magazines to keep everything flush for hunting. Did you have to have your chamber throated long?
I'm running stock t3 action,barrel, and stock with an MDT bottom metal and 300WM AICS mag. Nothing custom besides the minor modification to the stock.

I'm sure you would have to run a tikka LA stock to run the LA mags , unless I'm mistaken.
 

wade2big

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I'm running stock t3 action,barrel, and stock with an MDT bottom metal and 300WM AICS mag. Nothing custom besides the minor modification to the stock.

I'm sure you would have to run a tikka LA stock to run the LA mags , unless I'm mistaken.
The actions, stocks, and factory bottom metal are all the same. The mags all have the same footprint as well. Just spacers to limit cartridge placement and of course bolt stop to limit bolt throw.

I appreciate the info.
 

Westernhntr

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I’m contemplating putting together a medium weight rifle for 80% hunting and 20% target shooting (just to practice for hunting.) It would most likely be something like an Origin in a Bravo and a 22” barrel, 10 pounds or so.

I’d like to chamber it in a short mag. Idea is to eliminate as much potential for bad wind calls as possible, and maximize terminal performance to a max range of 800 yards (and realistically it’s more like 600.) Factory ammo is strongly preferred. Is there anything out there that fits the bill? Up front I’d prefer milder recoil or a 6.5 or 7, but could be convinced otherwise.
6.5 PRC with a 142 ABLR is the best you'll do for LR deer without a doubt
 

hereinaz

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Check out the Sherman Short mags. 6.5 and 7 as true short action.

I run a 7mm Sherman Short with 180 at 3020 fps out of a 26" barrel. It burns 60.5 grains of RL 26, 8 grains less than my old 7 Rem Mag. Has more case capacity and fits a true short action with the heavies, which a 7Saum can't.
 
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wade2big

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Check out the Sherman Short mags. 6.5 and 7 as true short action.

I run a 7mm Sherman Short with 180 at 3020 fps out of a 26" barrel. It burns 60.5 grains of RL 26, 8 grains less than my old 7 Rem Mag. Has more case capacity and fits a true short action with the heavies, which a 7Saum can't.
On these cartridges that need fire forming, is the first loading just a wasted shot, time, and money. In other words my first shots to fire-form brass would be worthless? If I were to load the exact load again the second firing, would I have different results as far as the load goes? I would hate to have to load 100 rounds and shoot them in the dirt just start all over with less barrel life and basically loaded rounds that cost twice as much.

This alone would push me to a 7 SAUM over the 7ss or 7max.
 

Steel head

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For hunting and factory ammo I’d seriously consider the 270WSM
Ammo isn’t hard to find and very mild shooting with some good ompf without the stupid long OAL of the 6.5PRC.
 
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BCX

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On these cartridges that need fire forming, is the first loading just a wasted shot, time, and money. In other words my first shots to fire-form brass would be worthless? If I were to load the exact load again the second firing, would I have different results as far as the load goes? I would hate to have to load 100 rounds and shoot them in the dirt just start all over with less barrel life and basically loaded rounds that cost twice as much.

This alone would push me to a 7 SAUM over the 7ss or 7max.
First 100 rounds shouldn't be shot in the dirt. Use them to break in the barrel. Fire forming loads can be very accurate. .25-.5 moa! I even shoot 1k yards w them w good accuracy.
 

wade2big

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First 100 rounds shouldn't be shot in the dirt. Use them to break in the barrel. Fire forming loads can be very accurate. .25-.5 moa! I even shoot 1k yards w them w good accuracy.
I understand that but once I fire form wouldn't I be starting all over with load development? Or to rephrase that, wouldnt I be beginning load development as the first firing really didn’t do much if anything in that regard.
 

Steel head

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First 100 rounds shouldn't be shot in the dirt. Use them to break in the barrel. Fire forming loads can be very accurate. .25-.5 moa! I even shoot 1k yards w them w good accuracy.
Most of the first 100 rounds of my new barrel were at a mile and beyond.
They always shoot decent, you just have to account for the barrel speeding up.
 
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BCX

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I understand that but once I fire form wouldn't I be starting all over with load development? Or to rephrase that, wouldnt I be beginning load development as the first firing really didn’t do much if anything in that regard.
Yes, you will be starting over. I never work up a load till i get 100 rounds down a tube. So my method works for me. I have had barrels speed up 100-170 FPS between 100-150 rounds down a tube.
 
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wade2big

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Yes, you will be starting over. I never work up a load till i get 100 rounds down a tube. So my method works for me. I have had barrels speed up 100-170 FPS between 100-150 rounds down a tube.
I didnt give that a thought considering I am just beginning to handload for my 6.5 CM. I havent noticed a speed increase im my factory rifles but my PVA barrels sped up drastically around 60-75 rounds or so.

I have been considering a magnum cartridge build on a Tikka which is why this thread interested me.
 

BCX

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My 7 Max is doing well throated long for 190/195 Berger's. Perfect cartridge for a Tikka build.
 

Westernhntr

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I understand that but once I fire form wouldn't I be starting all over with load development? Or to rephrase that, wouldnt I be beginning load development as the first firing really didn’t do much if anything in that regard.
I just built a 30 Sherman mag and I fire formed my brass with 30 grains of unique with a shop towel stuffed down tight.

No cream of wheat etc. And the brass formed nearly perfect, just slightly rounded on the shoulder but it shoots the same as twice fired so you're basically doing load development from the first live firing.

Pretty simple you just have to let the barrel cool when forming like you would with regular loads
 

hereinaz

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Fireforming breaks in the barrel. Buy Prime 7 saum if you want.

No, they are not wasted.

And, loading for a 7 ss is super easy. Wide nodes.

Heck, the pet load of 60.5 RL 26 under a 180 vld shot .25 moa, lol. That was almost the extent of my load dev.

Its an option, man for hunting it is killer.
 

JGR1953

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The actions, stocks, and factory bottom metal are all the same. The mags all have the same footprint as well. Just spacers to limit cartridge placement and of course bolt stop to limit bolt throw.

I appreciate the info.
Have you tried putting a WSM into a 7/300 LA magazine ?
I've seen several people state that the 300 WSM won't fit the standard 7/300 magnum plastic magazines they said the case is wider and the WSM was opened up inside for it to fit and it was a no go on the standard magnums.
 

wade2big

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Have you tried putting a WSM into a 7/300 LA magazine ?
I've seen several people state that the 300 WSM won't fit the standard 7/300 magnum plastic magazines they said the case is wider and the WSM was opened up inside for it to fit and it was a no go on the standard magnums.
No I haven’t. A 6.5 PRC round fits no problem but that is all I have to check. I will look more into that.
 

Crews

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Check out the Sherman Short mags. 6.5 and 7 as true short action.

I run a 7mm Sherman Short with 180 at 3020 fps out of a 26" barrel. It burns 60.5 grains of RL 26, 8 grains less than my old 7 Rem Mag. Has more case capacity and fits a true short action with the heavies, which a 7Saum can't.
Man this sounds great, but I’m not a hand loader so I really feel like it would be a significant limitation for me. I just don’t have the time or resources to get into it. Open to suggestions though if I am missing something.
 

6brshooter

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For hunting and factory ammo I’d seriously consider the 270WSM
Ammo isn’t hard to find and very mild shooting with some good ompf without the stupid long OAL of the 6.5PRC.
Whatchu talkin bout Willis, lol20200803_101948.jpg
This mag actually has a bent in front and still has plenty of clearance, about .050. Granted these are 140eldm set for a .020jump in a .155freebore 6.5prc