Decided to pull this out of another thread to make it a separate topic...

Did a little research on the short mags lastnight. My conclusion.....

The offerings: 243 WSSM, 270 wsm, 7mm wsm, 300 wsm    270 rsum, 7mm rsum and the 300 rsum. Based on case design, the cartridges are almost identical so I doubt you can really find any real difference in performance. The Win cartridges seem to be a hair longer though. Overall market offerings indicate that Winchester won hands down but not all the cartridges won. 300 wsm and 270 wsm seem to be the only two that really caught on. 7mm might be holding on by a thread. Some threads on the subjects were dated around 2010 so it's been over a decade the market has had a long time to shake out.

Kind of disappointed that 7mm is dying, think that is the one I would have interested me. I saw some models that were offered by Tikka and Savage but it looks like they out of stock and not listed on the manufacturers pages.

Blah.  So much wonder that never really did much differently than other existing cartridges as judged by the market apparently.

I’d be looking hard at 6.5 SAUM.

New too

With all the new heavy bullets in the 30 cal, be hard to pick the much harder on barrels 7mm or smaller cals for me..especially on anything with good case capacity...

I mean you have the new Bergers in 200/205/208/210/220/230/245 the new hornadays in what 208/212/225/230/250 and others I am sure I am forgetting...

What are the prc chamberings?

Forgive the wall of text that follows.  I always thought the short magnums were just a craze - something invented by marketing people to sell more rifles.  I still hold that view.  

In theory, a short, fat case should have an advantage, higher velocity in a stiffer, shorter action with greater potential for accuracy.  In practice it has not proved to be the case.  To get the higher velocity, you usually have to increase barrel length.  Unless you increase the diameter of the barrel, it’s not as stiff, sometime offsetting some of the claimed accuracy advantage.

And, short actions have not really proven themselves to be enough more accurate or lighter enough to be of benefit.  The straighter sides and sharper angle of the case shoulder can actually make the baby magnums harder to chamber smoothly.

I will focus on the 7mm chamberings as an example. All said and done, in 7mm the short magnums offer no clear benefit for the same barrel length over their longer cased predecessors.

7mm-08 and 7mm Rem Magnum (for a bit more reach, but burning more powder, with sharper recoil, requiring a long action) remains popular for a reason - they work and the new chamberings really don’t do anything demonstrably better.

The 7mm, in its various iterations, is a great bullet for both hunting and long range shooting where high energy down range is needed.

Honestly, this brings me to my favorite 7 - the shamefully neglected .280 Remington, based on the ‘06 case.  It was and still remains perhaps the best non-magnum hunting cartridge ever created.  Remington neglected it in favor of the 7mm Rem. Mag and failed to promote it against the slightly smaller bore .270 Win.  (.284, true 7mm, against odd-ball, even to this day .277).

If you handload, it can be safely loaded to within 100 fps of the 7mm Rem Magnum with typical hunting weight bullets.  The 7mm Rem Mag does not show a benefit until you start pushing heavier, longer, higher BC bullets out beyond 400 yards in a longer barrel. The factory .280 is a bit downloaded by Remington to make it a bit easier on some of the early semi-auto 742 rifles.  It can easily improve on factory velocity with safe handloads.  It can easily push a 139-140 grain bullet to 3150 fps when hand loaded, fired through a 24” barrel.  Another benefit, is that because of concerns about stupid people accidentally loading a .280 round into a .270, the .280 shoulder was pushed forward .050”, preventing a round from chambering in a .270.  This produced two additional benefits — greater powder capacity than its .270 and .30-06 siblings (case dimensions are otherwise identical except for this pushing out of the shoulder and case mouth diameter), and it means that bullets can often be seated further out, closer to the rifling lands for potentially improved accuracy in a barrel that will permit this.  

A popular and easy “upgrade” bringing it even closer to magnum performance is the .280 AI or Ackley Improved chamber.  Any decent gunsmith can ream any existing .280 Rem for the AI chamber, further increasing powder capacity while remaining backward compatible with all standard .280 ammo.

The variety of 7mm bullets available is astounding, ranging from light, thin jacketed 120 grain varmint, or lighter, to VLD 195 grains, including monolithic and solids, even including a 203 grain long range target bullet for those with fast enough twist, while .270 bullets are usually limited to 130 and 150 grains.

I have three .280 Rem rifles, two 7mm Rem Magnum rifles.  Ain’t selling any of them.  I have offloaded all the short magnum rifles.  Been there, done that, not impressed.  Frankly, the .280 remain my favorite, popularity notwithstanding, because of its versatility, efficiency and lower recoil.  The 120 grain Barnes all copper TSX or TTSX can safely reach a blistering 3300 fps from a 24” .280 barrel with devastating terminal performance on deer.  That has become my favorite deer load.

Those who handload continue to enjoy the advantages of the .280.  Those who handload, love the variety and efficiency of 7mm bullets and don’t own at least one .280 are missing out on a truly great 7mm, perhaps the best of them all.

Sorry if I somewhat derailed the thread, I just never saw a clear benefit to the short magnums and wanted to share my reasoning  . . .

The only one I have is the 7mm WSM. I wanted a 243 Win, but Winchester only was chambering them in WSM at the time. I am a PA deer hunter.

OK.  Everyone has their opinion.  I have an opinion because I have a real rifle.  In 300 WSM.  I reload.  From 110 to 220 gr.  It shoots great.  I like it.  

I have a safe full of guns and if I had to grab a rifle and run, it would be a Win 308 because everyone has one.  But if I had one rifle to use for every purpose and could reload for it, it would be my 300 WSM.

One problem the short magnums have is increased bolt thrust due to the case body having less contact with the chamber walls.

With the early short magnums, they had a problem with the headspace increasing. I don't remember what the fix was, better heat treating or stronger steels.

Bottom line, the older belted magnums have longer cases and more surface area to grip the chamber walls.

i have a 270 wsm in Remington 700 sps.. Its accurate and "it kills"

I have taken 3 deer with it so everyone have been 1 shot kills DRT...

very little recoil love it..

I don't think its a popular as in the past.. Ammo seems not stocked like it was years ago.. I mean the last two years ammo not the panic now..

I'm going to disagree with the case grip theory.  In that theory you are saying a cylinder of brass only a few thousands thick is holding enough force that the bolt steel isn't deformed.  I doubt it.  The short magnums have a much larger base diameter which gives a lot more surface area for those PSI to push on thereby increasing bolt thrust.

Winchester Short Magnum (WSM) Cartridges
https://www.eabco.com/WSM01.htm

(Update 11/30/05 - Apparently there ARE problems with some of the original turn-bolt guns. Some manufacturers have now introduced special guns or revised designs for the short magnums... Savage, CZ, and Browning, to name three).