Case head protrusion 98 Mauser question?

[Clayton]

...Glad you’re back.

Thanks. I'll never be "all back" but what's left of me is good to be here. I'm operating under my own steam and am told I'm doing terrific. God's been good to me.

I was glad to see you're still working on this one.

 

[Shawn.54]

Slowly plugging away held off on reamer I going to lap the lugs this weekend.
Shawn

 

[John P.]

 

[John P.]

Lapping Lugs

 

[John P.]

These are handy. One is for 55 degree mauser threads the others for 60 degree threads.

And thread gauges:

You need a good depth micrometer and a 0-1" and a 0-2" micrometer

 

[John P.]

Another way to set the tool bit:

 

[John P.]

Did I say tool bits?

 

[John P.]

Everything you need to know is in the books:

 

[John P.]

Make a cheat sheet. This one is for a M70.

 

[John P.]

Important to know is "Bolt Float". In the photos I am measuring prior to torquing the barrel. A case, or the go gauge, is in the chamber. Receiver screwed on hand tight.

Bolt pushed in:

Bolt against lugs: 0.005". When the barrel is torqued, you will lose 0.002" to 0.003", leaving about 0.oo2" float, OK for the average chamber. Mabe a little more for a DGR chambering so any brand cartridge will fit. Tighter for accuracey rifles.

 

[Shawn.54]

It seams like I quit the gun work but that is because I had to focus on firewood for the last couple weeks and small engine repair.
John I thank you for all the information I’m ready to do the barrel installation but holding off at the moment so I can catch up on other things that have been being ignored like keeping the family warm sighting in rifles and hunting.
As I walked past my gun cabinet I swear I heard one of them crying.
Shawn

 

[John P.]

It seams like I quit the gun work but that is because I had to focus on firewood for the last couple weeks and small engine repair.
John I thank you for all the information I’m ready to do the barrel installation but holding off at the moment so I can catch up on other things that have been being ignored like keeping the family warm sighting in rifles and hunting.
As I walked past my gun cabinet I swear I heard one of them crying.
Shawn

Yea I have been out for a long time with a MRSA infection in the lower leg and out of control high blood sugar. Now back on the mend and looking at forums again.

I will put up more chambering info later.

 

[John P.]

My pumped coolant system. Coolant is pumped through the barrel from the muzzle when chambering. flushes out chips, keeps the reamer cool, lubricates the cut, and the reamer stays sharp for many chambers. Coolant tank with pump is behind the lathe, on the floor. The pan catches the coolant and it is returned to the tank via a hose and strainer.

This method is about 10 times faster than the "Wipe & Brush" method and gives a very smooth chamber.

Muzzle end: Rotary union. Note the barrel centering "cathead".

Floating reamer holders. I use the big one on the top. Others are "So-So".

Reamers are held by this special No. 3 MT adapter I made. Bore is 7/16" to fit the reamer shank. The setscrews engage the flats on the reamer shank to prevent turning.