The verbiage below is pulled directly from the Oly homepage.  Unfortunately, they do not yet offer many details.  Does anyone have any inside skinny on this new round?

Ever think your AR-15 could have as much punch as an 30-06 well now it can.

The .300 OSSM has been put through the testing stage by a major powder manufacturer, and has shown that is it not only out runs .308 but also out runs 30-06!  30-06 with a 150 grain bullet runs 2792 fps, but the .300 OSSM (.300 Olympic Super Short Mag) is running 3040 fps with the same bullet.  The proof they say is in the pudding, below is a link to the Data Sheets from the company that tested the .300 OSSM, the same sheets SAMMI is going to use to standardize the cartridge,  also a link to some ballistic tests of 30-06 for comparison, you be the judge.

Why do i see some of these in the future:

I noticed on there data sheet that they had written "COAL=2.350" .  That'll make it a little hard to fit in a standard magwell...

True enough, but seating the bullet .09" deeper would get it there.  Might have to back off a little on the powder, but less than a tenth of an inch in seating isn't much.

Mike Milli (DTECH) has made several of these.

As I understand it, it's a .243 WSSM necked up to .30 caliber, and gives the ballistics of a .30-06 on the AR platform.

The smaller caliber WSSM's are standard catalog items for Olympic Arms, the .300 is a new proprietary cartridge for them.

I usually hang out at OA2.org but thought I would drop by and see if the .300 OSSM (Olympic Super Short magnum) was generating any excitement over here on ARFCOM.
Dtech (Mike Milli) has been chambering it for awhile but it looks like OLY has finally committed to building 100 Gamestalkers chambered for the new cartridge.
I was hoping to get one for Elk season this year but I doubt they’ll be done by then.
Initially there were concerns that using 180gr bullets would require such deep seating that substantial powder capacity would be lost. This may not be the case since Mike Milli has a customer up in Alaska loading 180gr bullets at near 300 Win Mag velocities without pressure signs. When I first read that I couldn’t believe it but Mike confirmed it later on at OA2.org.
They had one to shoot at last week’s customer appreciation day at the range.

http://img.photobucket.com/albums/v236/killforfood/AR15/IMG_8230.jpg


Recoil was very manageable. Even the kids liked it.


http://img.photobucket.com/albums/v236/killforfood/AR15/IMG_8240.jpg

http://img.photobucket.com/albums/v236/killforfood/AR15/IMG_8241.jpg


Everybody wanted to shoot and it never had a chance to cool down.


http://img.photobucket.com/albums/v236/killforfood/AR15/IMG_8243.jpg

http://img.photobucket.com/albums/v236/killforfood/AR15/IMG_8262.jpg

http://img.photobucket.com/albums/v236/killforfood/AR15/IMG_8253.jpg

If anybody is interested I can provide links for more specific information.

Thanks, Joel.

killforfood

Please give us links for more specific information.  It looks like the new 30RAR has some competition

This is the thread that really got things exciting

300 olympic thread

Here’s an excerpt that I posted;

I dug up Mike Milli’s post about his Alaska customer’s 300 results and they’re just amazing.

“I also have a .300 version, and my customer from Alaska is getting velocities that are matching, and exceeding the .30-06. One load that he used produced a 20-shot average of 2780 FPS with a 180 grain bullet. It was only a "lukewarm" load so he went up in his powder charge and got velocities of 2925 FPS.”    


Not only is this customer loading 180gr bullets, but was able to attain nearly unbelievable 300 Win Mag velocities.
I guess that answers my question about heavier bullets.  

Again I have to ask;

RATTLER, HOW DO I GET ON THE LIST?  

I’m going to give Mike a call but I’m willing to bet that the chances of getting one done by Elk season are slim to none.  



Here’s Mike Millis response;


The rifle I was refering to in Alaska is indeed an AR-15. I just got an email from another .300 WSSM customer that posted these results:

Hello Mike

I had the opportunity to go fire off a few rounds last weekend with my 300 WSSM and thought that you may be interested in an update. My Chrono came back with these numbers.

Hodgdon H4895 180gr. Remington PSPCL

46 grs. 2800 fps
47 grs. 2849 fps.

Taking a short look at the reloading manual. A 30-06 is around 2600-2800 fps. and a 300 WIN. is 2800-3000 fps. these are rough numbers. It appears that these loads are shooting right in the middle of the two. I am planing on trying more powders, but its hard to get what you want these days.

Anything on barrel life?  Sounds like a throat burner.

The 243 WSSM and 25WSSM have been out for years and are loaded to similar pressures. Neither of those is considered to be a barrel burner. I would expect the Barrel life for the 300 Olympic to be comparable.

simply awesome!

Man I want one of these.  May have to place an order with Dtech!!!!!

That's right!  Winchester chrome lined the bores on the 223 and 243 WSSM just for the hell of it.   They were funny that way.


My experience - in just shy of 500 rounds of 223 WSSM, 1/9 twist stainless, the throat lengthened .037", compared to less than half of that in 220 Swift and 22-250's.  


Figure there is a reason Olympic stuck with advertising (30-06 Ballistics) in their ad instead of going for the gusto?

I imagine it would be called "good sense".

I was really interested in one of these many years ago.  I held out hope for a long time, and now, 7 years later, after I'd given up, they finally get it done.  Here's the thread I started over there in 2002. http://www.oa2.org/forums/viewtopic.php?t=1576  

If anyone sees these come out, post up and let us know.  I'd like to buy the upper only if they offer that option when the time comes.

I ordered up my Olympic Arms™ GameStalker® "Upper Receiver” back on September 15th, and hopefully I should be receiving a call from the Factory sometime soon? they stated at that time … two months for delivery.

OA told us they would be shipping their own new production magazines for their pistol caliber uppers at the last SHOT Show.  Just to give you an example of how long "two months" is in WA.

oh! … you must mean these Magazines in the link; yeah, I’m still waiting on them too! and if it takes them six to ten months for the UR, then I’ll wait it out!


Link: OA2.org weblink >>> Posted: Fri Nov 21, 2008 4:29 pm    Post subject: EXCLUSIVE!! OLY'S NEW PISTOL CALIBER MAGAZINES

where did you get that magazine???

nevermind. i thought that was a high cap mag for the 300 OSSM

it’s a Oly-Arms pistol caliber magazine; one of the guy’s from the factory, posted an image of it earlier today!

.30 caliber short magnum in a 6 lb AR-15 platform or a fat 7.62 x 39 AK round?  I thought we just did that with the .30 R AR....?

Somewhere in there, one has to be running out of bolt face and chamber wall thickness.  Also, this is going to be another special magazine.  
This OSSM makes the RAR look tame in comparison.

the bolts are unique for the WSSM caliber line; it’s not a modified 5.54 bolt, if that what you were thinking?

this image was borrowed from Dtech’s web-site.





the .300-OSSM® will utilize the same type/style of modified magazine that the WSSM-line uses … here’s my modified 20-round magazine w/ Magpul Gen II follower, that has been ‘end milled cut’ to remove the follower, in order to accommodate the fat 25WSSM cartridge.  




big-time!

I think this is a big idea

Uppers based on chamberings using the WSSM case would make the AR-15 platform relevant to a much  larger segment of the hunting community.  Many hunters who 5 years ago wouldn't think of owning a "black rifke" are starting to ask "What is all this about?" and an AR-15 upper that could shoot 6mm, .250, 7mm and .308 bullets offering comparable performance to 243 Winchester, 25-06, 7mm-08, .308 Winchester and 30-06 could really increase the use of the AR15 platform in the field.

Now this assumes that the ballistics pan out, the rounds will feed reliably, and the larger diameter bullets coming out the tube at lower velocitiies won't burn barrels like the 223 WSSM –– but if the manufacturers get past these hurdles, demand will be there, which means more companies loading ammunition, which brings down the price of ammo, which creates more demand for WSSM AR-15 uppers, and the cycle continues.

I can't wait!!!!  I wonder if this is what it was like when American hunters began to shift from lever-actions to bolt-actions in the hunting fields and forests starting 70-80 years ago?

This does not seem like a high round count weapon, just from a look at the bolt, and the mag.



Lots of room for rounds to move about in the mag and the bolt does not inspire confidence...

300OSM should have barrel life some where between a 308Win and 30-06 as if has the case capacity of the former and the performance of the later.

Well, its an Oly...

Cool.

any updates on this?

Olympic Arms® will be doing a ‘First Run of 50 Rifles’ before they do any uppers only ... still no definite timeline.

Can I just swap out the barrels on my 243WSSM upper?

you can certainly swap out ‘uppers’ when they become available … but this .300-OSSM ‘barrel’ will not be available by itself for some time to come; as they (Oly-Arms) are only selling complete units at this time; and the first 50 GameStalkers™ will be complete rifles, and offered in this dipped (water immersion graphics application) camouflage pattern.

Globemaster––so despite your pre-order, you have to wait until the complete rifles are finished, and THEN you get in the queue? Bummer.

I'm antsy just waiting for your own personal range report!