The .338 win mag has a longer neck by a couple of though, for the rest, the rechamber looks like it would work. Is if possible to rechamber with having the extra neck spacE?

The neck length is not the issue. The longer tapered neck on the 338 Norma will not clean up the shoulder area of the 338 wmag.

Looking at the cases, it looks like the shoulder should clear, or am I looking at it the wrong way?

http://www.cip-bobp.org/homolo...iiical-en-page22.pdf

http://www.cip-bobp.org/homolo...bical-en-page133.pdf

The body of the 300 win case is longer than the Norma. compare the two here:

http://ammoguide.com/cgi-bin/a...er.cgi?sn=ViVZqmVhXW

Simply rechamber and set the barrel back a thread or two if/as needed. No biggie

quote:

Looking at the cases, it looks like the shoulder should clear, or am I looking at it the wrong way?

I think you are looking at it backwards. For the 338 Norma to clean up a 338wmag chamber the distance from the base to the start of the shoulder on the 338Norma must be longer than the 338wmag. The 338 Norma per your link is 47.78 the 338wmag is 51.82.

I'm way too lazy to draw it up and calculate just how many threads you would need to set it back. If you could set it back then you have the issue of the barrel no longer fitting the inletting.

While it can be done by setting back the barrel a bit and rechambering, I'm not sure WHY...???

From my perspective there aren't many positives and a ton of negatives...most obvious is going from a standard to a wildcat without any gain in case volume, the Norma and Win case volume being almost identical, ~86 gr H2O, and neck length not really being an issue except MAYBE on paper, plus custom dies and custom reamer etc.

If you want more performance I would go with the standard, relatively available cartridges that should work through an action that the 338 Win works through...like a 340 Weatherby, 338 RUM, or a 338/375 Ruger (an already available wildcat but very easy to accomplish and you can use 375 Ruger bushing dies).

If you just want something called a "338 Norma Magnum" then go for it.

I'm a wildcatter from way back so I'm NOT adverse to 'catting per se, but I have to see more gain then loss and it's getting harder and harder to see that in todays world with todays standard cartridges...and/or the "justforkicks" kinda thing.

Where I am the Norma brass is easy to come by, and it is not a small increase in performance as you seem to believe. 82 win mag vs 105 grains H2o Norma mag.

It's a standard long action case that stacks up to the .338 Lapua.

The real problem is that the rifle in question is a Blaser, so setting the threads back is not an option.

I was mistaken in thinking it could be done, I somehow ignored the body length of the win mag, whihc is now glaringly incompatable.

Ahhhhh...I see the one you are talking about...I was thinking 358 NM necked down.

So why not just go with the Lapua if you can get Norma brass. Any problem going with the longer case in your Blaster? There are several 2.85" cased calibers listed for the R8 in the Safari.

If I had a choice I would go with the longer case...you can always download.

The 338 Blaser would almost do it if you could fudge the barrel a bit or not worry about the 0.016" neck diferencee once the brass was formed and the dies were adjusted.

Have you talked with Blaser about this conversion? Probably the better people to ask.

Interesting problem!!!

Luck

Its easyer to get a .338 Blaser barrel norma makes ammo for what one too.

An even better alternative...I don't know much about Blaser's so not certain about rechambering problems or barrel swaps, I need to peruse this a bit more...

I compared(overlays) the WM and NM prints from my QL and it looked like the NM would just clean up if done very carefully especially in this type of "non-adjustable" barrel, but I would definitely consult with Blaser USA for their input of actual reamer specs, and go with a 'smith that knew R8's...this is just like doing break action or R#1 falling block rifles, there AIN'T NO WIGGLE ROOM.

An alternative would be a maximum SAMMI spec reamer which might make the clearances at the shoulder and still not have an "oversize" chamber.


I'm guessing you know a bit about this sport and mucking about with conversions, EXPRESS, but here goes how I would do this thing anyway...

I would do a chamber cast to see just exactly where the neck/shoulder junction is in YOUR 338 WM chamber...drawings are not always reliable...then contact Blaser for there 338 WM SAMMI min/max specs and a reamer maker for their 338 NM reamer specs.

Unless you already have a 'smith with a 338NM reamer, you cal always have a reamer AND dies made to YOUR specs that would also let you shoot factory ammo along with reloads.

My drawings give 2.17" for the WM and 2.15" for the NM and those numbers may or may not mean much, there are many ways around a 0.020" "maybe", it just depends on HOW you go about doing this type of conversion and how "picky" you are about keeping exactly to those measurements. Splitting the difference and allowing for a 0.010" "overage" and just might get you your 338 NM, but it is YOUR rifle and your dollar and I'm very good at spending other peoples money.

If I was totally committed to doing this project...and it is a good one...I would do a lot of homework and talk to knowledgeable people, NOT on the web.

If it were me and saw all the possible problem I would just go with the Lapua...should be relatively quick and easy, you can use NM brass and you can down load to NM numbers.

I like my 338 Lapua but I also have a 338-06 that pretty much is the equal of a 338 WM, so I only use the Lapua for long range stuff, 250-300 gr bullet weights and the Lapua takes roughly 30 gr more powder just to equal the 338-06 velocities with my "normal" 225 gr Hornady SP.

Luck EXPRESS...you have presented a very interesting problem.

Thanks for taking the time to look so far into the problem NONAG, at this moment, I'm waiting on a .338 win mag barrel, and plan on shooting quite a bit of steel and game with it, and possible ordering another down the line, in the match profile, in one of the 338 calibers offered, and reaming it out to the Norma for LR shooting. But now I have a better idea of how to go about it.
BTW, I learned you need a carbide reamer to work o the blaser barrels because the steel they use is so hard.

Cheers.