I'm thinking of building a 375wsm on the new win short 300 mag brass,wiyh a 21" barrel built around 6.5lbs,especially for sheep and goat in griz country,as I don't enjoy any calibers of .308 or under ,can't see the point in them for up here.Has anyone tried such a caliber,if what kind of performance with 235gr-270gr bullets

I have a Lazzeroni HellCat which is a .375 based on his short-Patriot case. The .30 Patriot will shoot 180gr bullets about 100fps faster than either the WSM or SAUM.

I haven't shot anything lighter than 300gr Noslers but in a 23" barrel I get 2550 fps without any real problems...that's 4330ftlbs of muzzle energy. I would think you should be able to reach 2550 fps with a 260gr Nosler..that's 3750 ftlbs of energy.

In a rifle as light as you describe I would guess the recoil will be "interesting".

Why not use .350 Rem Mag or 35 Whelen?

I would humbly suggest 376 steyr, in the same action, or 338 wsm. But, the WSm's runum HIGH pressure
jeffe

The Steyr won't fit into the short-action!

We may be splitting hairs here but I think if it won't fit into a Remington 700 or 7 short-action, and at 3.1" it won't, then it doesn't qualify as a short-action round. I would guess if you ask 100 shooters you would get a very large majority that agreed with me

Gents,

Anyone done this in a 416 or 458? I have a left handed 700 short action I would like to re-do.

Roger QSL

roger, i looked into the 416 wsm quite a bit. it seemed a reasonable wildcat as there is nothing for big bore shorts without a belt or very expensive brass involved. i was told the 416 is as big as you can go due to headspace issues.
the best route i came up with was a rebore. buy a .30 wsm and ship it to cliff labounty. he told me he would rebore, run a 416 neck reamer in it so as to keep the 300 case dim the same. recrown and bed it for me for $285. what a deal!
cheapest wildcat rifle i think you could want. you wont have an expensive barrel/gunsmith costs involved if you are not hapy with the cartridge. put a take-off back on it and off you go.
you will need to neck size and fireform. let me know if you do it as a divorce is pending for me so that idea is out for a while.
you can find cliff's number by doing a search under his name. he is a nice guy that will answer your questions with patience.
adios
woofer

458 jamison 500 gr horn 2067fps 90gr water
458 jamison 400 gr sper 2460fps 90gr water

416 jamison 400 gr horn 2264fps 87gr water

375 jamison 300 gr horn 2578fps 85gr water

While these are not exactly xbywsm, they are fairly close. Interesting note, the 376 steyr holds 82gr.

jeffe

Jeffe, Woffer

Thanks for your info.

Jeffe,
Looking at the load data from your post, I am a little confused at the 458 and 416 loads.

The 400 gr. 458 Jamison is a little faster than the 416. If a fellow could achieve 2400+ in a 458, than why not get 2400+ in the 416. Either of these loads should get you to 416 Remington ft/lb levels. Should make a very handy, heavy gun.

One more question for ya, will the Remington Short Action Bolt face work with the 300 WSM case?

My little lefty is currently chambered for the 308 Winchester.

Thanks,
Roger QSL

Roger,
I was confused too, and since you called me on it, I went back and reran it, in quickload. I think they might be a problem with it, on the speer 400s, as it also said you can get more than 2500 from a 458 winnie. The load I posted is what it SAYS the 458 jamison can do...
remmington is making their model 7 in rsm, so I think the answer is yep, it can get there, but I haven't done it.
interesting thoughts.
jeffe

roger,
yes your rem 7 will work. when i spoke to lazzeroni he told me that his 416 short will work in a remington length magazine. 2.8 oal.
also, it's about $100 to open your bolt face and install a mauser extractor. you will have to do some work on the rails and feed ramp although the guys at the remington custom shop told me they dont touch the action and use a standard follower! when i built my 284 on a model 7 there was no way i was going to have a functioning rifle without this work.
i hope you do it as i think it would be a very viable do-all rifle. the recoil might be a bit on the harsh side but it's not like your firing a 100 rounds a day!
adios
woofer

Roger....the reason you would get a higher velocity from a 400gr .458 bullet using the .300WSM case as opposed to a 400gr .416 bullet from the same case is from the what I think is called the "bore/pressure" ratio. The .458 has a bigger hole in the barrel for the pressure to work against and so will propel the bullet faster...assuming equal weight bullets from the same parent case.

Take a look in a reloading manual for something like the .338 WinMag and see how fast it will drive a 200gr bullet...much faster than a .338 necked down to .308 can (look at the .300 WinMag as it's a close cousin to the .30/.338).

Bill,

Interesting term, "Bore Pressure/Ratio". Never seen it before. This is the exact reason I like this site. Always learning something here.

If we could have seen the loads that generated the data, then it probably would have helped to understand the results that were achieved. I do understand his thinking in not giving out load data.

Here are some loads that I worked with while loading for the 450 Alaskan. These were all fired over a chrono, and they were 5 shot strings averaged. Notice the small increases between the various slugs used.

All the loads were the same as far as powder thrown. 67 grains, 3031 and new cases from Buffalo Arms.

300 gr Sierra 2178 fps
350 gr Hornady 2168 fps
400 gr Speer 2153 fps

Don't know how the Bore Pressure/Ratio works here, but I thought these small increases in velocity were normal. By the way, these are not max loads for this powder.

Roger QSL

Expansion ratio, is what I know it to be called.
A larger bore begats more push on a bullet then a smaller bore. Take the 338-06 and 35 Whn, both using the same bullet/weight, for example. The 35 Whn will push the bullet faster (although not by much).
I believe expansion ratio refers to how many inches a bullet needs to travel to double the case capacity. A 45-70 bullet needs to travel less then two inches to double it's capacity, thus has a very high expansion ratio. A 460 Wby needs more distance (not comparing speeds here, just ratios), thus it has less of a ratio. ~~~Suluuq

Rusty...you're right! I must have been having a "senior moment" when I coined a phrase that sounded good......my explanation was right on however.

With respect to using a Remington action "opened up" to take the Lazzeroni case with the 0.578" head, don't do it. Read the article about bolt-thrust on Dan Lilha's (barrel maker supereme) web-site....the safety margin becomes way to small. There are some 'smiths who do the conversion but why take the risk...especially in a DGR?

If you want the Lazzeron case go to the same action they use....the McMillan MCRT with Sunny Hill bottom metal.....plenty strong and will feed perfectly. Not cheap!

With respect to reboring....probably not enough meat in the 300WSM barrel and you wouldn't be saving that much over a custom barrel. Might need to think about the stock as the forend is pretty thin on most of them except the Coyote.
If I wanted to keep the cost down I would buy a new Model 70 in .300WSM....sell the barrel and stock if I could....then have the action squared up and rebarreled to .416 WSM and install the stock of my choice. Won't quite get you to 2400 fps with a 400gr bullet but you should get 2300 fps and perhaps a bit more if you go to a longer barrel.