Mauser 98 Barrel (Sight) Alignment

[Denny Gibson]

Hi! Back after two year absence … question:

How are Mauser 98 sights aligned with their receiver? I’m rebarreling a German M98 … I don’t see any alignment marks on the barrel or the receiver.

Apparently, the end of the barrel is against the adjacent face in the receiver which would leave the sight position (angular) depending on the precision of the angular relationship of the threads to the sight base positioning holes on both pieces. Do I have that right or is there more to it than that?

This is my first Mauser build … built from parts that I procure, refinish as necessary, and combine to build a “nice shooter” … kind of my “hobby.”

 

[Big Bore 44]

Mauser rear sights were soldered in place.

 

[Denny Gibson]

I understand. My concern is with the alignment of the barrel (hence the sights). Apparently the sights will line up when the barrel is torqued I have lot's of experience with machining precision parts. Combining the tolerances of angularly aligning the thread to another feature (a little round hole on the od of the barrel in this case) can be tricky. I'm impressed! Other manufacturer's typically align the barrel with the receiver by way of a notch (or other mark) on both parts (torque it 'til it lines up). Definitely a less expensive approach.

 

[BBBBill]

How close is it to being aligned now (angular offset)? Barrel turned up hand tight or torqued into place? If it is just snugged up and not torqued and the angle off only around 10 degrees then you have a near perfect setup for final torque. With a 12 TPI, 10 degrees is just a hair over .002". Thats what folks generally shoot for.
If you've got something else going on then that probably won't work.

 

[stillquietvoice]

@Denny Gibson welcome back. Pictures will help us better see what your issue is. I've done 2 m98 sporter rifles, well I'm working on 2 anyway. But would like to restore a few more to original configuration as well.

 

[Denny Gibson]

Thanks guys!

I haven’t run the barrel down all the way yet … waiting for a tap to chase the threads first. Of course I tried to screw it together but it’s resisting enough that I couldn’t by hand.… hopefully in the next week I’ll have the tool and can check it out.

I’ll definitely put pictures up as this goes together.

It’s great to be back on The High Road again … I’ve gotten lots of help and had great conversations here!

 

[Slamfire]

Thanks guys!

I haven’t run the barrel down all the way yet … waiting for a tap to chase the threads first. Of course I tried to screw it together but it’s resisting enough that I couldn’t by hand.… hopefully in the next week I’ll have the tool and can check it out.

I’ll definitely put pictures up as this goes together.

It’s great to be back on The High Road again … I’ve gotten lots of help and had great conversations here!

As stated by @Big Bore 44 bore the front and rear sight bases on a Mauser service rifle were lead soldered into place after the barrel was installed on the receiver. So take into account the proper amount of taper needed for the bases before you lathe turn any blank.

I installed a surplus barrel, used the bottom of the receiver as a reference flat. Bases were aligned with parallel rulers. I was surprised to see with very long rulers, just how the smallest bit of misalignment was clearly visible between rulers. Much better than a bubble level. I used a blow torch and soft lead, making sure to heat only enough to melt the lead solder.

I recall both of the bases had pins which were installed after the bases were soldered on. Took a drill and ran it through the holes to create passages on the barrel for the pins.

 

[Denny Gibson]

Interesting Slamfire ... I had a new, short-chambered, military contour barrel (in the white) without alignment holes. I decided not to use it since I had no way of aligning the holes to machine them with respect to the threads. You've given me an approach that woill work. Thanks!

 

[Denny Gibson]

Actually ... it could have been done in production that way with a fixture to hold the sights in place while they're soldered.

 

[Slamfire]

Actually ... it could have been done in production that way with a fixture to hold the sights in place while they're soldered.

Probably. A factory will have a lot more equipment than I have in my garage. Like hundreds of millions of dollars more fixtures and machines than I have.

I make do.

 

[Denny Gibson]

No doubt about that! Same here.