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Location: CA Central Coast
Joined: 12/01/2005
Posts: 151
rifle caliber conversion?

Hi, all -

I'm not saying that I'm going to do this, but I did get to wondering how involved it might be.

I'm bidding on a used Sako rifle in .338 on gunbroker. In my Barnes reloading manual, it says the "parent" case for this caliber is the .458, and indeed, several of the dimensions are identical. So...what would it take to convert this rifle to .458, should I get the crazy idea to do so?

I know nothing about this process, so I'm wondering simple questions like: could the action remain untouched? Could I use the same magazine? Etc.

Thanks for any insights or opinions...

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Joined: 12/03/2005
Posts: 1691
rifle caliber conversion?

If the cases are the same, same magazine would work. But that is it for my wisdom. Re-barreling is one thing, blowing a rifle bolt back through your head is quite another.
I'd be contacting Sako on this one for sure.

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Location: CA Central Coast
Joined: 12/01/2005
Posts: 151
rifle caliber conversion?

That's good advice, and before I have anything done to the rifle, I'll get the process OK'd by someone who I trust. It might not be Sako, since I suspect communications with them might be a little difficult. I'll find a good, reliable gunsmith before proceeding.

The .458 is the "parent" case for the .338. Several dimensions are the same; the only difference I can find is that the .458 case is cylindrical, while the .338 case is necked for the smaller bullet. To this tyro, it would seem a relatively straight-forward (notice I didn't use the word "simple") procedure, but...that's why I asked.

bitmasher's picture
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Location: Colorado
Joined: 02/27/2002
Posts: 2973
rifle caliber conversion?

If the overall loaded cartridge length is the same it would probably just be a rebarrel job.

If the overall loaded cartridge length is greater than the magazine well, you could still do a rebarrel; however it would effectively make the gun a single shot.

There should be no need to change out the bolt face.

I've never seen a sako in anything larger than 375H&H, this doesn't mean they don't exist; however it may suggest that the action may not be designed for the stress of the 458 win mag. I could be completely wrong though. A gunsmith who has worked with sako actions would know more....

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Joined: 12/03/2005
Posts: 1691
rifle caliber conversion?

I beleive you are absolutely correct, Bitmasher. 375 is as big as it gets according to the link below:
http://www.sako.fi/pdf/specs/75Hunter.pdf

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Location: Wa.
Joined: 03/31/2004
Posts: 1300
rifle caliber conversion?

The 264 wm, 7mm Rem mag, 300wm, 338wm, 358 Norma mag, 458wm, 257wby, 270wby, 7mmwby all utilize the same action and bolt face.
The conversion from 338wm to 458wm is as simple as a barrel change.
You pick a barrel with a 458 bore and twist. Have a gunsmith bore a chamber, blue and fit to stock.
The price of a barrel and some labor and you have a 458wm.

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Location: CA Central Coast
Joined: 12/01/2005
Posts: 151
rifle caliber conversion?

Cool...thanks, fuzz. I had suspected that it was that simple, but it's good to hear corroboration. Now, I just have to decide what that used L691 is worth to me...

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