This year's project caliber

[Hoot]

Well, 2010 was the year of the 450b. Though I'm not done with it, my sights this year are on a .300 WSSM semi-wildcat. I say semi because HSM does produce the ammunition and it is submitted for SAAMI registration, but to the best of my knowledge has not been approved. It is based upon a necked up .25 WSSM case and with IMR 8208XBR, can push a 150gr bullet out at around 3100fps from an AR15 platform!

Not much in the way of load recipes yet, so lots of opportunity to contribute to a really nice and informed group of enthusiasts. Right now, Mike Milli of Dtech makes them as well as Olympic Arms. I have their Game Stalker with its 22 inch barrel, topped off with one of Ross' brakes. Their WSSM production line actually produces a quality product at an affordable price and I'm spending a lot of time over at oa2.org lately. It uses a special BCG to accommodate the fat case, as well as a special upper receiver modified to fit the beefier barrel extension and high pressure. Like the 450b, it is constrained by the length of the AR magazine though.

If you think the Hornady 450b ammo is expensive, count your blessings. The HSM 150gr runs around $50.00 per box of 20. I already have the Hornady custom dies and resized 25 WSSM brass ready to go. Unfortunately, comfortable shooting weather is still a couple of months away, I'll be miserably doing my barrel break-in shots in less than optimum weather (0 to +20f). Here's a picture of the upper on my RRA NM lower I also use for the 450b. I may be getting QL to aid in load design for the larger weight 30 cal bullets. Lots of folks over at The WSSM zone who are QuickLoad gurus as well as a few at oa2.org, So' I'll get help picking up the process of using it. Nopoint working up too much while the air temps are so low, but I look forward to hours of fun experimentation, which I truly enjoy.





You'd think the necked down 450b to .308 (Remington AR) round would deliver similar performance, but it doesn't.

Hoot

[bushmeister]

Very nice. You can tell by the pic there is a little more diameter in the base of the necked down cartridge. Should hold more powder. I discussed this round with my brother. We both are holding out to see if they will come out with a carbine length version.

[wildcatter]

See what Happens when I open the can of worms. Before my work the 223 and the 6mm/223 were all that was available, now the sky's the limit. In the early days, I was chastised for making the statements we all now know to be true. Even Jim Sullivan (the actual man behind the M-16), joined a group of engineers, from Wayne State University, and they proved, beyond a shadow of doubt, that the 450 Bushmaster (the 45 pro then) was NOT possible. By the end of the Study, they all asked me to build them a weapon. Now many of the original Nay-Sayers are making their version of my "Not-Possible", work. I for one welcome the developments, the science is way too important. A-Square is about to release a .510 cal monster AR, and, as is in this 30cal that hoot is working on, will require a totally different upper, to accommodate the larger barrel extension and larger bolt.

Way to go Hoot, can't wait to read your experiences with that 30 cal.

Ps..Who is it, that is submitting it to SAMMI?

..t

[Hoot]

Ps..Who is it, that is submitting it to SAMMI?

..t

From what I can tell and they sometimes hold their cards close to their vest, Olympic Arms through the manufacturer HSM, or so that's what they say.

Again, from what I read, there is a fellow who sues anyone who uses the term "WSSM" in their cartridge name, so it is being submitted as the .300 OSSM. The O being for Olympic. Mike Milli's is called the .30-25 WSSM and is a true wildcat at this point, so no problem using the term WSSM. It's as bad as the front and back room dealings in Washington, to try to follow and understand. Definitely a lot of jockeying going on. HSM appears to have some profits to spare as there is talk of Olympic building some Counter Sniper, AR based rifle with HSM's name on it, that uses the .300 OSSM. It will have a proprietary upper receiver that accommodates a deeper magazine to allow loading the .300 OSSM with high BC bullets and still fit in the magazine. I'm glad my livelihood doesn't depend upon all these pipe dreams that get batted about at get-togethers. Too hard to keep track of it all. Seems to me that the 30 caliber market is already well represented. I'm surprised they couldn't do more balistically with the 30 RAR. We've seen the energy you can get out of the 450b parent case.

Lots of conversations to snoop on over at oa2.org if you're interested.

Hoot

[Hoot]

Very nice. You can tell by the pic there is a little more diameter in the base of the necked down cartridge. Should hold more powder. I discussed this round with my brother. We both are holding out to see if they will come out with a carbine length version.

Yeah, imagine of you blew that case out and necked it back to .44 or .45. Quite the Thumpette given it's tolerance for high pressure.

Hoot

[wildcatter]

Very nice. You can tell by the pic there is a little more diameter in the base of the necked down cartridge. Should hold more powder. I discussed this round with my brother. We both are holding out to see if they will come out with a carbine length version.

Yeah, imagine of you blew that case out and necked it back to .44 or .45. Quite the Thumpette given it's tolerance for high pressure.

Hoot

Hoot my-man, how much pressure is it operating at? ..t

[BayouBob]

Very nice. You can tell by the pic there is a little more diameter in the base of the necked down cartridge. Should hold more powder. I discussed this round with my brother. We both are holding out to see if they will come out with a carbine length version.

Yeah, imagine of you blew that case out and necked it back to .44 or .45. Quite the Thumpette given it's tolerance for high pressure.

Hoot

Imagine the possibilities if you could blow that case out and end up with a Thumper with a shoulder to headspace on. All the woes of crimping and working around the case mouth diameter would go away. If I had an AR-EG (AR Elephant Gun) I could get rid of the 375 Weatherby and the 458 Winchester!

[Hoot]

Hoot my-man, how much pressure is it operating at?

..t

They were running the 110gr Vmax at 3,500 fps up to 62.2k psi, 180gr PSPCL at 2850fps at 60k psi, but they hold the commercial 150gr stuff back to 3050 fps at 56k psi. They're getting more than 15 reload cycles from the brass. The powder of choice (until I can find something better ) is IMR 8208XBR with good ole H4895 close behind. The issue, as you might expect, with the heavier bullets is fitting them in the AR magazine without having the ogive below the case mouth.

Last year it was agonizing in the spring waiting for the upper to arrive. This year it is agonizing with an upper waiting for spring to arrive.

Hoot

[wildcatter]

Hoot, who is this manufacturer "HSM", it escapes me.

Ok, guys, this really isn't as big of a deal as we think it is, other than our Hoot-Man is building one for us and of course we'll be pestering him, to death for data.

The reason I say no big deal is that as long as you are going to increase the size of the upper, the sky is the limit.. Did Cobb Manufacturing make one shoot the 30-06, 300 win mag, 338-Lapua and look at all the 50BMG's you can get for the AR lower, AND, Anzio Iron Works (see below), replaced the AR-mag well with a bigger one to house a magazine, for a cartridge that shoots a 1600gr bullet at 3300fps, called the 20mm Cannon.

Now, Hoot is fooling you, he's just warming up, cause the "Rumor on the Street", is that his next project is the 155mm Howitzer round with an AR lower, wink..Huummm. ..t

[Hoot]

Hoot, who is this manufacturer "HSM", it escapes me...snip

Here's a link to them. A lot of foks trying to stretch their ammo budget buy from them. I won some of their 5.56 stuff at a gun show. It's ok for trigger time practice. About like the QA rejects For Practice Only that Lake City gives to LEOs and non-profits.

When I said the some of the .300 OSSM upper receiver dimensions were slightly larger than the mil spec receivers, I didn't mean unusually so. Looks like a regular A3 flat top with the port enlarged and no dust cover from the outside. Aside from the enlarged opening for the oversized barrel extension and the beefed up BCG, it's pretty much mil spec otherwise.

Hoot