I have my 300 win mag PSS sitting here and was wondering, what would happen if i put one of those m852 from the shelf into the chamber and fired.  It is the same size bullet (.308) is the pressure going to be too low or would it work?  

You want to chamber a .308 in your .300WM???

PUT THE RIFLE DOWN AND MOVE AWAY FROM THE LOADING BENCH.
A quick and easy simulation of your questions outcome can be had by having your largest neighbor crack you over the head with a shovel. Then have the neighbor mail the rifle to my FFL.
It's just better that way for all concerned.

I'll echo the sentiments of the others, but here is the reason why.

Every time you touch off a high-velocity centerfire cartridge, the chamber pressure will peak around 50,000 PSI IIRC.  At that kind of pressure, your tolerances must be pretty tight.  Although the diameter is the same, the case length and the head diameter are much smaller.  Since the case will not be supported in at least two directions by the chamber and/or boltface, the case will fail.  Depending upon the manufacturer and construction of your rifle, that hot gas (plasma) will be directed in another direction.  At the least you'll have a mess, at the worst your rifle will be destroyed and you will be injured.

However, I believe it would be difficult to fire the rifle as the cartridge would PROBABLY slide forward enough that the firing pin would not contact the primer.  If you elect to try it, please warn me in advance so I can be long gone.

SRM

Just to Clarify;
The idea itself warranted the shovel.
The outcome would probably have been benign due the case length and bolt face differences. I still think I should get the rifle.

It was just an idea, I have plenty of black hills 190gr to last me a while, I didnt think about the length of the casing, that would seriously cause a problem because of the much longer case of the win mag.

Just for kicks... and to keep this thread alive... how about .308 in a .300 WSM (Winchester Short Magnum)?

Are the cases not roughly the same? It is just a belted .308. Or are they also very much different?

Just wondering. I will not however be trying to fire .300WSM out of my beatiful .308 Bolt Gun.

Holy Smokes.

Quoted: Just for kicks... and to keep this thread alive... how about .308 in a .300 WSM (Winchester Short Magnum)? Are the cases not roughly the same? It is just a belted .308. Or are they also very much different? Just wondering. I will not however be trying to fire .300WSM out of my beatiful .308 Bolt Gun.

The case diameter on the WSM is larger than a .308. The shoulder angle might be different, along with the neck length. And I thought the WSM is beltless, but maybe I'm wrong. If it is belted then it headspaces on the belt, instead of the shoulder like a .308, which makes it even more incompatible.
I can't believe you guys.

next time you think about life insurance keep my name in mind as benificary!

why use 308 just use 7mm mag the cases are closer to the same size and the bullit is so much smaller it goes out of the long thing what ever you call  oh a barrel thats right with out ever touching the side as it's a smaller diameter than the 30 cal.
(IHOPE YOU WERE NOT SERIOUS AS I'AM NOT)

KABOOOOOOOOOOM!


If you're that short of cash to get REAL 300WM then i'll send you some of mine. I'd hate to hear about your untimely demise.......


now, should you insist on persuing this experiment be sure to add me to you insurance as a benificiary.

I don't recommend you try it.  There was, however, an article about just this type of thing in one of the gun rags a few years ago.  Essentially, cartridges that were too short and still managed to be supported enough by the extractor to fire ended up as pretty strange looking things. They had the neck blown out to chamber diameter.  The author did not report any damage to himself or the guns.  The point of the article was to NOT do such a thing, though.

Quoted: I have my 300 win mag PSS sitting here and was wondering, what would happen if i put one of those m852 from the shelf into the chamber and fired.  It is the same size bullet (.308) is the pressure going to be too low or would it work?

Ideal situation for an instant KB!  If you're going to do it, buy two more rifles that match the first.  That way you can verify your test results.  (NOT!)

Well hopefull the round will not chamber correctly and float away from the bolt saving your face from certain catastrophe. The .300winmag's case is larger in diameter at .513 base to shoulder .491 vs. .470 to .454 and much longer than the .308.

Someone post that picture of what happens when you fire the wrong caliber in a rifle. A picture is worth a thousand warnings.

Please have a close relative videotape you in the act, then have them post the file under your login, posthumously.

I smell a Darwin Award in the work!

Everyone should look on the bright side. At least he thought to inquire about it before doing it. Just think about how many people own firearms but don't know about critical dimensions and headspacing.

"I bought a big gun, put big bullets in it, and pull the trigger. It goes 'bang,' right?"

It's scary but a lot of people barely understand the difference between single and double action, let alone this sort of thing.