Hi Guys,

Mods, if this is the wrong forum, please feel free to move it.

I've always had an itch for a 358 Norma as I really like 35 caliber rifles.

I have a question for the gurus of AR, and need your knowledge and advice.

I have a Ruger Hawkeye SS/syn 338WM that I am thinking should be able to be converted to 358 Norma. It seems this should be fairly easy to do, but that is why I am asking. I am hoping to rebore the barrel.

What do you think? Is this an easy conversion? Anything I should consider or be worried about? Anything else that needs to be done besides reboring the barrel?

Thanks in advance for your time and knowledge.

I think you are asking for problems, but if the barrel-rebore is perfect and you have the room it might be worth a try.

I'd talk to the rebore folks.

The 358Norma is slightly long for your action but I think it would be do-able. I would seek out an experienced smith to seek advise on this issue. He will probably say "lets do it" but I don't know for sure.

It principally depends upon your actual .338 WinMag chamber dimensions... If oversize then not a good idea. If at specification or perhaps slightly tight then it's doable.

The .338 WinMag is a 2.50" case length with a loaded 3.340" COAL. The .358 Norma Mag is a 2.52" case length with a 3.346" COAL. Both cartridges are belted and designed to function from a 3.4" magazine length. Your Ruger M77 likely has 3.42" magazine length so again your good to go.

Your limiting factor is your barrel wall thickness at the muzzle.

As a rule of thumb, you would want a minimum barrel diameter at the muzzle of .558, but I personally would not sweat it if it is at least .550 at the muzzle. By the way, the .358 Norma is a great cartridge that is generally underrated.

Kinda like painting a tin barn IMO...You gain nada balistically..but to each his own.

Ray,

I hear you, and basically, I think you're probably right.

However, I already own six 338 WMs, and I won't miss one of them. I do not own a 358 NM. And personally, I just like 35 calibers more than 33s.

Besides, as someone on this forum keeps saying, it's all supposed to be fun. And to me, it is!

Thanks for your response!

quote:

I won't miss one of them

Sell one and buy a rifle in 358 Norma

Different sources may have slightly different numbers but book I'm looking at tells me the 338 has a shoulder diameter of .491" measured 2.040" from the case head. The 358 Norma has a shoulder diam of .490" measured 2.084" from the case head. IF you have a tight chambered 338 a 358 N may clean up the chamber without setting the barrel back. In real life that is not likely going to happen. I would seriously consider a new barrel. If things don't work out you could always put your 338 take off barrel back on. That will not likely happen because when loaded with good bullets the 358 Norma is quite a killer.

I had a Ruger 77 in 7mm Remington Magnum rebored to .358 Norma Magnum, and aside from the barrel heating up pretty significantly with prolonged firing, I had no problems whatsoever.

Prolonged firing with the NM is not something I would expect you to do anyway. I was training myself to shoot instinctively left handed, due to a problem with my right eye, and to operate the bolt effectively with my left hand. I shot up a lot of .358" jacketed pistol bullets in the process.

This was the last rebore job done for me by Delta Gunshop/Clearwater Reboring before Jim Dubell died, and I don't know if the business is continuing without him or not.

Surefire,
Well I can't argue your point, its as good a reason that I can think off..In fact its hard to really justify most any change of rifle caliber other than "want to"...and with six 338s, of course you need a 358 Norma..I would have high plains reboring do the work, I have had half a dozen jobs from him and they all shot great.

I'd do it. I don't think from a feeding stand point you would have any problems. The 358 Norma is a very serious cartridge. When Kile cut his back from 24-22" he didn't loose squat in velo ~
40fps. I kinda got disenchanted with the 35 Wln but I'd do a 358 Norma in a heartbeat. It's got great horsepower.

I'd do it just because I like being different and I am a huge fan of the .358 win.

The 35 calibers get no love in the United States. Ironically the 358 Norma was the first commercial 35 caliber offered in the US after the 35 Newton but it never caught on. The 358 Norma is more popular in Canada and Europe. I could like the 358 win and 358 Norma but the 35 Whelen is just bores me to death after owning one.