I think I would like my rum better if it was a .358. Anyone have any tech data and or experience? The rifle is a factory stock CDL. Would I be better off starting with a .338rum? What kind of performance can I expect? I'm hoping to gain a little more eficiency powderwise and pretty much have a 1 gun arsenal for whitetail on up. Share your wisdom and thanks in advance. By the way, great forum!

300 RUM will take anything on this continent and most things on others. I would stick with what I had but thats just me.

I'm a huge fan of the 35 bore, so understand the enticement <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> You're looking at a round that will slightly better the 358 STA, and I'd expect it would be capable of driving the Northfork 270 gr to 3000 fps. That makes it a combo that shoots as flat as a 270, and hits harder than a 375 H&H.

The only downside is you'll get some serious recoil. I'm content to drive 250's 2700 from my 350 Rigby, and if I need more, I move up to the 458 Lott.

There are some folks that have built 358 ultra mags, and they are definately capable of serious performance.

Just check your magazine length isnt a limiting factor. Wasn't the 338RUM shortened because of the magazine length in the Rem700 and relatively long .338 projectiles? A full-length 300RUM necked up and using a long spitzer like the 225gr BT may require you to seat deep and lose some of that powder space ... not sure. A 358STA may be an easier option.
Cheers...
Con

BamaHunter, you are correct but it's not based on need. It's more the fact that I'm burning all this powder and to my way of thinking I might as well push something bigger with it and I've been wanting a .358 anyway. It really matters not to me if I lose some speed as it might open up some bullet selection. I will check out the length thing or maybe someone already knows as the heavier bullets are where my interests lie. Thanks

John Ricks built a few rifles in that chambering a while back and did some load testing. John's no longer in the rifle business (AFAIK), but you should be able to dig up some of his results.

From what I remember, the results were predictably impressive. Had I found the right action, my 358 Norma may have been of the RUM variety.

CAS,

I'm pretty sure that John is out of the rifle business due to some personal issues. The guy definately could cut a chamber though, he chambered my 350 Rigby, 458 Lott and 500 Jeffrey.

I did discuss the 358 Ultra with John, and he did comment that it had ferocious recoil. My thinking is, in a rifle light enough for me to take into the woods, I wouldn't want that level of recoil, and if I had to deel with that level of recoil, I'd want to be pushing a larger dia heavier bullet.

I'm actually planning on going the opposite direction, getting a Ruger 350 rem mag as a lighter weight replacement for my 350 Rigby. For longer range stuff, 300 mag is the biggest round I'd be willing to drop the pin on in a hunting weight rifle, ie 7-8 pounds. For me, big recoil calls for a 10# rifle, but I spent a week lugging one in my arms, and it was definately too heavy for that sort of hunting.

For John to say that something had ferocious recoil, considering some of the chamberings that he built, tells me that I'd want no part of touching that thing off.

I'd heard that John was building houses not too far from my digs about this time last year. No sure if it was true or not, but the industry lost a talented guy when his luck took a bad turn. Too bad for him, and for his customers.

Mtn Hunter built a light 350 Rem Mag not too long ago. You should pick his brain about the project, as his turned out nice.

I've got an 8lb 358 Norma, and while it definitely gets your attention, it is a managable rifle to shoot. 250gr bullets really make her jump, but nothing that can't be mastered. It's harder on the critters on the other end!

I will do a search on John Ricks and see what I come up with. I don't consider myself recoil sensitive but your description (ferocious) is something I will have to research a little more. In its current config recoil seems minimal even at the range but I think it's attributable to the stock fit and R3 pad. Thanks

Sounds like good advice CAS. Their must be a calculator I could get close with. The question is if the paper numbers looked acceptable would real world experience equate. I would hate to ruin this thing by turning it into something unusable but on the other hand I don't want to not do it if it's managable afterall. Thanks

I sold my first 458 lott to fund the 500 Jeffrey, and also ended up having a replacment 458 Lott built. I don't consider myself recoil shy either. That said, the fast medium bores are known to provide a fast, hard jabbing recoil. I'm sure a 358 ultra could be made shootable by either making it heavy, or adding a muzzlebrake, but those aren't options to me for a hunting rifle.

Me thinks 358 norma mag is the practical largest sized case for 35 bore. If 225's @ 3000, or 250's @ 2800 aren't enough, get closer or get a 416 <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

If I understood what you meant by a calculator....here is a recoil calculator:

http://sst.benchrest.com/recoil.html

Thanks everyone, much appreciated. Now to find the right gunsmith.

IIRC, Mark Bansner built a 358 based on the 338RUM for Bryce Towsley. There was an article written about it also. I don't know for sure but I think it was only about 75 fps faster than my STA.

Try contacting Clay or Mark at Bansners to get more info.

I think Z-HAT made reamers in about everything you could make a RUM into. Do an internet search, and you`ll find them.

You have all been most helpful, this will get me started. Thanks again and Merry Christmas!

John Ricks built my 358-404 Imp woldcat a few years ago. It's on a M70 originally in 30-06. He did a fine job. The COL is 3.6" and nothing more. Don't worry about COL limiting you when it's a wildcat; it's a reload-only proposition. This thing has about the capacity of a 358 RUM, the latter being a bit bigger at the bottom and smaller at the top, and I've gotten 280g A-Frames into the 2900's before backing down. It just gets silly at some point. Definitely wouldn't want this case in anything smaller myself. Design intent was a severe elk thumper, throat cut for the 280g A-Frame in particular, seated to 3.6" but it does well with Nosler and Barnes 250's as well.
He and I split the cost of the reamer (as he always offers) so he still has the thing. If he ever comes back around I would certainly consider using him again.
Otherwise, Fred at Z-Hat has experience getting these Ultra rounds to feed; he'd be worth a call.