300 Win Mag and Mauser 98

J

Joe Portale

New member
Hello folks,

I decided it was time to push ahead with another Mauser project... can't let the bank account get too full...;)

I am planning on barreling a BRNO VZ 24 action to 300 Win Mag. I need a couple of tips or cheats to get me through this.

I see that the bolt face needs to altered to accept the base of the 300 WM cartridge. Am I right in the assumption that the lip that acts as the case retaining ring and extractor claw needs to be dressed back by .059" to accept the larger 300 WM case?

Does the bolt face need to be set back a couple of thousanths also?

And, when dressing the rails to accept the fatter cartridge, is all that is needed is to set them back or do they need to be beveled or reconfigured to a different angle?

Many thanks.
 
Joe ... I was surprised by my 300WinMag Turkington ... one major piece of artillery, kicks like a mule (my brake is half done and rifle is out of service until I finish it) but it IS a lot of fun :eek:

The bolt face needs to be opened up, but it doesn't need to be set back unless you are trying to clean it up. Now that I re-read your question, I'm not sure what you are asking about the bolt face. The rim that protrudes forward from the face of the bolt needs to be made thinner (radially) so that the larger cartridge base can sit squarely against the bolt face. The Extractor needs to have some material removed so that it allows the cartridge to sit in place ...

The rails, I have found, are a mixed bag. Some of them require almost NO work at all and some require extensive filing. A group of us built a group of these and what we did was to open up the mag well (a mill works much better than a Dremel for this!) to accept the longer round and then redo the feed ramp to allow us to utilize the new longer mag well. Then you start finding out what is getting in the way and removing it. A lot of trial and error here, but mine now feeds 300WM better than it ever fed 8x57!

Here is a hint on improving the feeding: After finishing the chamber, you will have two sharp edges ... one at the very back of the chamber and one about 60 mils ahead of that (where the belt seats) ... if either of these are sharp, they will shave your brass on the bottom as it feeds causing all kinds of feed problems and trashing your brass to boot :eek: I was looking out for the rearmost one as all calibers present this issue, but the extra one caused by the belt caught me off guard ... somehow it didn't make it into Kuhnhausen's book ... probably because the book is about Mausers and not about belted magnums ;)

Good Luck,
Saands
 
Saands wrote:

"The bolt face needs to be opened up, but it doesn't need to be set back unless you are trying to clean it up. Now that I re-read your question, I'm not sure what you are asking about the bolt face. The rim that protrudes forward from the face
of the bolt needs to be made thinner (radially) so that the larger cartridge base can sit squarely against the bolt face. The Extractor needs to have some material removed so that it allows the cartridge to sit in place ... "

Yes, you hit it right on the head. That was what I was refering to. (was sneaking in the post while at work: was typing fast and think slow). I was asking about the rim. Turning the bolt face down a bit was more of a cleanance question. Now that I found a drawing of the thickness of the cartridge rim, I see that the bolt face question was un-necessary.

Thanks for the pointers about the rails and the chamber edges. I learned about a sharp back of the chamber when I built my .243. The from one where the belt sits would have caught me by surprise also.

Joe
 
Thoughts on the process...

First off, I am lucky with my project (35 Whelen- VZ 24 Mauser) in that I didn't have to do a thing to the feed rails on my action. This rifle fed both 30-06 and 35 Whelen rounds without a fault, so I didn't have to mess with the rails.

My thoughts about the rails are this. If you were to take a 8mm round and sit it next to a 300 WinMag shell to compare their differences (or likenesses) you will be given some insight on where you might have to remove material from the feed rails on your action.

Filling the magazine with 300 WinMag rounds will show you how they sit in the mag when you look down into the action. This, with the insight gained from comparing the two cartridges, will perhaps give you an idea are to where any potential hangups might occur. Putting Prussian blue on the bottom side of the feed rails and cycling a couple rounds through the action might show you where the majority of friction is happening - thereby showing you where you need to remove metal for better feeding.

I'd take it slow, removing just a bit here, and there, until I was just satisfied with the feeding (but not completely satisfied!) and move on from there. I say this because I've tried to please the inner child more than a few times, and the usual end result is that something is ruined in my childish search for perfection. ;)

At any rate, this is how I'd go about it. Please do let us know how you fare!

Unkel Gilbey
 
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