need help with head spacing an m48

mauser/m48 · October 16, 2009, 03:59 PM

I am rebarreling a mauser m48 Yugo to 257 roberts. i am using a short chambered by Shilen. this barrel has a flat breech end. the original barrel has a shoulder turned on it that recesses into the receiver that mates to the bolt face. I need to know if I should turn a step into the breech of the barrel to match the oringinal barrel or can I just clear the slot for the extracter and have proper head space.

mapsjanhere · October 16, 2009, 05:04 PM

Hmm, unless I misunderstood the process, short chambered barrels need a finish reaming to set the head space after you got the bolt in place. So which ever method you use, you will still have to move the shoulder to the right distance from your bolt face.

Harry Bonar · October 16, 2009, 05:34 PM

Sir;
I think the M48 has a clearance cut at the breech face for the extractor to clear and it must clear! After you get that done then strip the bolt and adjust your headspace with a finish reamer. There is a little more to it than that but that will get you started - the bolt MUST close of the "go" guage and NOT close on the "no-go" guage!
Harry B.

mauser/m48 · October 16, 2009, 05:45 PM

yes sir I am aware that there must be a clerance slot and that short chambered barrels must be finish reamed, and the go/no go gages must be used to set the proper head spacing. However the original barrel had a .047 thousandths step (or lip) turned on the breech end of the barrel that protuded into the receiver to meet the bolt face. I need to know if cutting this step is a necessary step of the process or if I can have the correct head spacing without having to make this cut.

Harry Bonar · October 17, 2009, 09:57 AM

Sir;
Yes, the new barrel should match the original.
Harry B.

October 16, 2009, 03:59 PM	#1
mauser/m48 Junior Member Join Date: October 11, 2009 Posts: 4	need help with head spacing an m48 I am rebarreling a mauser m48 Yugo to 257 roberts. i am using a short chambered by Shilen. this barrel has a flat breech end. the original barrel has a shoulder turned on it that recesses into the receiver that mates to the bolt face. I need to know if I should turn a step into the breech of the barrel to match the oringinal barrel or can I just clear the slot for the extracter and have proper head space.

October 16, 2009, 05:04 PM	#2
mapsjanhere Senior Member Join Date: August 6, 2009 Location: Albuquerque Posts: 2,832	Hmm, unless I misunderstood the process, short chambered barrels need a finish reaming to set the head space after you got the bolt in place. So which ever method you use, you will still have to move the shoulder to the right distance from your bolt face. __________________ I used to love being able to hit hard at 1000 yards. As I get older I find hitting a mini ram at 200 yards with the 22 oddly more satisfying.

October 16, 2009, 05:34 PM	#3
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	headspace Sir; I think the M48 has a clearance cut at the breech face for the extractor to clear and it must clear! After you get that done then strip the bolt and adjust your headspace with a finish reamer. There is a little more to it than that but that will get you started - the bolt MUST close of the "go" guage and NOT close on the "no-go" guage! Harry B.

October 16, 2009, 05:45 PM	#4
mauser/m48 Junior Member Join Date: October 11, 2009 Posts: 4	yes sir I am aware that there must be a clerance slot and that short chambered barrels must be finish reamed, and the go/no go gages must be used to set the proper head spacing. However the original barrel had a .047 thousandths step (or lip) turned on the breech end of the barrel that protuded into the receiver to meet the bolt face. I need to know if cutting this step is a necessary step of the process or if I can have the correct head spacing without having to make this cut. Last edited by mauser/m48; October 16, 2009 at 05:58 PM.

October 17, 2009, 09:57 AM	#5
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	M48a Sir; Yes, the new barrel should match the original. Harry B.