Mauser 98 Barrel Thread Relief

[Dave in WI]

Please school me on the relief cut on the breech end of a 98 Mauser barrel.
I normally cut a 45° chamfer to thread depth to start thread.

 

[Sniperhandle]

Just release the half nut at the end of the thread, It will make it's own thread relief. Yes chamfer the starting end.

I wouldn't put a very wide thread relief on the mauser, Thread tenon is already short.

 

[Dave in WI]

Just release the half nut at the end of the thread,

Thanks for the reply, but I'm talking about the chamber end, not the shoulder.

 

[jackieschmidt]

On my Mauser project, I set it up to seat on the action face and the ring inside, so I had to cut a little wider thread relief. But it worked fine and shoots great.

By the way, you do know that is a 55 degree thread, 12 tpi, not 60.

 

[Sniperhandle]

Yes, Knew it was 55 degree, I thread mine 55 degrees with my Hartwana 55 degree inserts and tool holder as designed.

 

[Dave in WI]

I use the Arthur Warner kit Arthur Warner #18
Are there inserts available with the 55°?

 

[Sniperhandle]

I use the Arthur Warner kit Arthur Warner #18
Are there inserts available with the 55°?

Yes,

Here is what I use,

Lathe Thread Cutting Tool Vertical Indexable Thread Inserts For 55 Degree AG55 | eBay

For external thread turning tools, 55 degree thread turning tool. This threaded insert is a vertical 55 degree insert. It is used for external threads from 0.5 mm to 3.0 mm pitch. Material is carbide. Surface is coated. Can be used on steel and stainless steel. Item includes 16verag55 10pcs...

www.ebay.com

 

[Sniperhandle]

The insert may fit the Warner tool?

 

[jackieschmidt]

Since it was kind of a one time thing, I just ground one out of a piece of Rex 95 HHS.

 

[Sniperhandle]

I use the Arthur Warner kit Arthur Warner #18
Are there inserts available with the 55°?

Dave,

The pre-fit barrels sold by Shilen, Shaw etc. were all threaded with 60 degree threads and they will work fine. I don't know if Shilen still does them or not anymore, But if you threaded it 60 degrees, It will work. I just prefer to build them with the proper thread pitch.

Another thing you need to decide on is, Whether you want to bottom out on the C-ring, Or the shoulder, Or both.

They were originally designed to crush on both surfaces. Pre-fits were machined to crush on the outer face. I choose to do it this way also. Although some of my older builds had crush on inner and outer rings.

 

[Dave in WI]

Dave,

The pre-fit barrels sold by Shilen, Shaw etc. were all threaded with 60 degree threads and they will work fine. I don't know if Shilen still does them or not anymore, But if you threaded it 60 degrees, It will work. I just prefer to build them with the proper thread pitch.

Another thing you need to decide on is, Whether you want to bottom out on the C-ring, Or the shoulder, Or both.

They were originally designed to crush on both surfaces. Pre-fits were machined to crush on the outer face. I choose to do it this way also. Although some of my older builds had crush on inner and outer rings.

Thanks!
I will be threading it myself. I was taught to have both rings touch equally. But i understand that you can ask 5 gunsmiths and get 5 different answers and I believe all 5 smiths would still be correct.
So, back to my original question, is that a relief at chamber end where the red arrow is on my diagram or just the way it comes out after it is threaded?

 

[Sniperhandle]

No that is a small thread relief just like on the SMLE. I wish I had a good drawing of it, But you have those barrels in front of you to measure. You don't have to do it that way, Just put a heavy chamfer on the end of the tenon before you start your thread, That is how I do it and it has worked well for me.

 

[Sniperhandle]

Here is a barrel for an M-98 I did a a bit ago, It has a safety breech, So ignore that, But you can see my chamfer if you look close.

 

[jackieschmidt]

If you do decide to have both surfaces contact, be sure that they are true with each other.

since I trued my action, I did seat the barrel against both the action face and the C ring. It takes some careful measuring, but I think it makes for a more stable joint.

 

[gunsandgunsmithing]

Here is a barrel for an M-98 I did a a bit ago, It has a safety breech, So ignore that, But you can see my chamfer if you look close.

View attachment 1537254

That's interesting. Never heard of it. Less unsupported case that way? It's been a while so I don't remember the numbers but was thinking that there wasn't a lot left unsupported. I'm probably wrong if that's what a Safety breech" is for. Details please. I've got one I plan to barrel for a hunting rifle laying around collecting dust and curious. Thanks

 

[Sniperhandle]

That's interesting. Never heard of it. Less unsupported case that way? It's been a while so I don't remember the numbers but was thinking that there wasn't a lot left unsupported. I'm probably wrong if that's what a Safety breech" is for. Details please. I've got one I plan to barrel for a hunting rifle laying around collecting dust and curious. Thanks

This barrel was for a Model 98 Mauser I built. Yugo M48 Mauser actions came with the safety breech from the factory, I had not yet cut the extractor cut in that barrel when I took the pic.

But I used the safety breech design to build my 7.62x54R on the model 98. The brass is weak even Lapua towards the rim. Which I do use Lapua for that caliber. It needs to be supported all the way to the rim. It is a rimmed cartridge also not rimless. So that is the way I went about building that one.

The safety breech comes through the C-ring and is flush with it against the barrel. The bolt has to be modified also. M48 bolt noses are a little different than the M-98 in that the nubs that hold the cartridge have been almost removed.

So yes, Much less unsupported brass case that way.

 

[gunsandgunsmithing]

This barrel was for a Model 98 Mauser I built. Yugo M48 Mauser actions came with the safety breech from the factory, I had not yet cut the extractor cut in that barrel when I took the pic.

But I used the safety breech design to build my 7.62x54R on the model 98. The brass is weak even Lapua towards the rim. Which I do use Lapua for that caliber. It needs to be supported all the way to the rim. It is a rimmed cartridge also not rimless. So that is the way I went about building that one.

The safety breech comes through the C-ring and is flush with it against the barrel. The bolt has to be modified also. M48 bolt noses are a little different than the M-98 in that the nubs that hold the cartridge have been almost removed.

So yes, Much less unsupported brass case that way.

Ok, that makes sense. Thanks!

 

[Sniperhandle]

You don't need to go to all that trouble on a standard 98 Mauser if you are going to build one though. I just did it to handle the rimmed cartridge.

Please share your Mauser project when you build it.

 

[hoz53]

Please school me on the relief cut on the breech end of a 98 Mauser barrel.
I normally cut a 45° chamfer to thread depth to start thread.
View attachment 1537087

thanks for all the info guys