Where can I send a Mauser 98 bolt for Rockwell hardness testing? I have a commercial Mauser receiver by Voere and the bolt got lost a long time ago (probably during the 3 times that I have moved). A few years back, I obtained a brand new unused military 98 bolt from Sarco. The bolt fits the receiver perfectly and I gave the lugs the file test and it seems to be OK. Still, I am curious about how hard this bolt really is in the locking lug area. I imagine anything between 30 and 45 Rockwell C would be good?
Rockwell hardness test 98 bolt
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rcmodel
Member in memoriam
I'm not too sure you could tell anything much by RW testing it.
The reason I say this is, nobody knows what steel your replacement bolt was made from, so nobody knows what the proper RW should be for it.
Between 30 and 45 HRC is a heck of a lot of differance!
98 Mauser receivers were made from relatively mild steel, and case-hardened. So the receiver would be soft on the inside, and very hard on the outside.
98 Bolts were thought to be made from better steel, but what it is exactly on your surplus bolt, nobody knows, because we apparently don't know who made your bolt.
So what should the Rockwell hardness be?
I think the thing to do would be to get a GO headspace guage and check it, then shim the guage with steel shims until you know exactly what the headspace is.
Then run 50 rounds of ammo through it with it tied to a tire.
Now check the headspace again and see if it has changed any by measurable amount more then normal lug seating would account for. (perhaps .001" - .002")
If it has, your bolt is soft and the lugs are stretching.
If it hasn't, you should be fine.
rcmodel
The reason I say this is, nobody knows what steel your replacement bolt was made from, so nobody knows what the proper RW should be for it.
Between 30 and 45 HRC is a heck of a lot of differance!
98 Mauser receivers were made from relatively mild steel, and case-hardened. So the receiver would be soft on the inside, and very hard on the outside.
98 Bolts were thought to be made from better steel, but what it is exactly on your surplus bolt, nobody knows, because we apparently don't know who made your bolt.
So what should the Rockwell hardness be?
I think the thing to do would be to get a GO headspace guage and check it, then shim the guage with steel shims until you know exactly what the headspace is.
Then run 50 rounds of ammo through it with it tied to a tire.
Now check the headspace again and see if it has changed any by measurable amount more then normal lug seating would account for. (perhaps .001" - .002")
If it has, your bolt is soft and the lugs are stretching.
If it hasn't, you should be fine.
rcmodel
frogomatic
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the reciever should be between 30 and 40 on the rockwell C scale. The bolt should be a point or two harder than the reciever. This is a standard among rifles. The hardness needed on the bolt is relative to the hardness of the reciever. this is important to the life of the locking lugs, they must be harder than the reciever.
With a new bolt, you should lap the lugs untill you get 85% or more contact on the bearing surface. Use a lapping compound, I use clover paste, it works pretty well and can be had in several different grits. Apply a little paste to the back of the lugs, insert the bolt and push it all the way forward and close it with farward pressure applied. With the bolt closed, pull back on the bolt(or use a rubberband to generate a little pressure, and rotate the bolt handle up and down no more than 10 degrees(you don't want to lap the camming surface). Do this for 2-3 minutes. Remove the bolt, clean off the compound, then using a lighter, candle, or lamp, carburize the bearing surface on the lugs. Then put the bolt back it, push forward and close, then rotate the bolt handle up and down about 10 degrees, a couple of times and remove the bolt(push forward, open, remove, so you don't disturb the marks you left in the carbon) look at the lugs, wherever the carbon is removed is where you are making contact. Repeat the process untill you have 85% or more contact on both lugs. NEVER EVER TRY TO SEAT LUGS BY FIRING THE GUN! This is a good way to shear the lugs, which at best will destroy the rife, and at worst can kill you. The critical factor here is the distibution of recoil forces, and if you have only 40% contact in the locking engagments, then ALL the recoil forces are applied to the smaller engagment surface...more force on less area, guess what can happen.
On the subject of headspace, you should be able to close the bolt fully on a go gauge, and you should NOT be able to close the bolt completely on a no-go gauge. I you can close the bolt on a no-go, the gun has excessive headspace and is potentially dangerous.
hope this helps. If you happen to be in the Denver area, I can do a rockwell test for you.
PS. not all mausers are the same. Many, many, many countries make, and have made the mauser. not all of them used the same processes, or used the same materials. If can tell me the country of origin, and the year of manufacture, I can tell you alot more about the possibilities.
With a new bolt, you should lap the lugs untill you get 85% or more contact on the bearing surface. Use a lapping compound, I use clover paste, it works pretty well and can be had in several different grits. Apply a little paste to the back of the lugs, insert the bolt and push it all the way forward and close it with farward pressure applied. With the bolt closed, pull back on the bolt(or use a rubberband to generate a little pressure, and rotate the bolt handle up and down no more than 10 degrees(you don't want to lap the camming surface). Do this for 2-3 minutes. Remove the bolt, clean off the compound, then using a lighter, candle, or lamp, carburize the bearing surface on the lugs. Then put the bolt back it, push forward and close, then rotate the bolt handle up and down about 10 degrees, a couple of times and remove the bolt(push forward, open, remove, so you don't disturb the marks you left in the carbon) look at the lugs, wherever the carbon is removed is where you are making contact. Repeat the process untill you have 85% or more contact on both lugs. NEVER EVER TRY TO SEAT LUGS BY FIRING THE GUN! This is a good way to shear the lugs, which at best will destroy the rife, and at worst can kill you. The critical factor here is the distibution of recoil forces, and if you have only 40% contact in the locking engagments, then ALL the recoil forces are applied to the smaller engagment surface...more force on less area, guess what can happen.
On the subject of headspace, you should be able to close the bolt fully on a go gauge, and you should NOT be able to close the bolt completely on a no-go gauge. I you can close the bolt on a no-go, the gun has excessive headspace and is potentially dangerous.
hope this helps. If you happen to be in the Denver area, I can do a rockwell test for you.
PS. not all mausers are the same. Many, many, many countries make, and have made the mauser. not all of them used the same processes, or used the same materials. If can tell me the country of origin, and the year of manufacture, I can tell you alot more about the possibilities.
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rcmodel
Member in memoriam
The question I would ask is, how much lapping can you do on a 98 reciever before you cut through the case hardening? Kind of hard to say I would think.
Lapping is fine on a modern reciever like a Remington 700 that is hardened the same clear through.
I question the practice on an old Mauser 98.
rcmodel
Lapping is fine on a modern reciever like a Remington 700 that is hardened the same clear through.
I question the practice on an old Mauser 98.
rcmodel
frogomatic
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As I said before, there are millions of Mausers out there and many of them were fabricated with different methods. Many mausers were not case hardend. Even if he has a gun that's been case hardend, lapping the lugs will only remove .001-.002", and what material is removed is split between the bolt and the reciever. Typical case hardening is around .005" thick.
mrmeval
Member
Look for a local heat treatment place. They have the tools to check hardness. The test does leave a dimple as any Buck double tested knife will show so you'll need to find an area where that is acceptable.
Clark
Member
I have got lots of 98 bolts from Sarco and I never worry about heat treat.
There are calculated risks and perceived risks.
I have been doing destructive tests on guns for 10 years, so I have fewer unknowns.
M98 is the safest action out there, with the best safety features and design margin.
The worst out there....
If you want a big boost in personal safety, don't stand to the right of anyone shooting a CZ52 pistol at the range. The barrels are .060" thick, vary in hardness from RC25 to RC47 and the surplus ammo averages 42,000 c.u.p. The chambers are tight and the extractor pieces could be lethal.
There are calculated risks and perceived risks.
I have been doing destructive tests on guns for 10 years, so I have fewer unknowns.
M98 is the safest action out there, with the best safety features and design margin.
The worst out there....
If you want a big boost in personal safety, don't stand to the right of anyone shooting a CZ52 pistol at the range. The barrels are .060" thick, vary in hardness from RC25 to RC47 and the surplus ammo averages 42,000 c.u.p. The chambers are tight and the extractor pieces could be lethal.
Why should BobSmith lap the bolt? Lapping is fine if you are building a rifle and can adjust the headspace later, but lapping can also create excess headspace.
If the bolt fits OK now, and headspaces OK, I strongly recommend not lapping anything.
As to Rockwell testing, check with a local machine shop or a largish welding shop. If they don't do it, they probably know who will. Most gunsmiths don't have the equipment.
Jim
If the bolt fits OK now, and headspaces OK, I strongly recommend not lapping anything.
As to Rockwell testing, check with a local machine shop or a largish welding shop. If they don't do it, they probably know who will. Most gunsmiths don't have the equipment.
Jim
dirtyjim
Member
i don't lap any of my bolts unless i'm going to send the receiver & bolt to be re-heat treated. the hardness layer on the receiver averages about .010, if you only remove .001 your still removing 10% of the layer
if you want to have it reheat treated stick with someone who is familiar with guns or your receiver & bolt can come out looking like a bannana. blanchards metal processing in salt lake city specializes in mausers, i'd call them before i trusted it to one of the local heat treaters
if you want to have it reheat treated stick with someone who is familiar with guns or your receiver & bolt can come out looking like a bannana. blanchards metal processing in salt lake city specializes in mausers, i'd call them before i trusted it to one of the local heat treaters
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