Chamber depth

RCP Fab · May 6, 2013, 10:35 AM

Toward the end of this year I am planning on making my first barrel. I've done a ton of reading and watching videos, but right now I am getting hung up on chamber depth.

I understand the headspace aspect of it, but what I do not understand is how much of the brass should stick out from then end of the barrel.

I have read a various amount of things from "as little as possible" to probably way more than I would feel safe about.

The only numbers I found were to measure the depth of the bolt face and add .004-.006" to that, and not to exceed .010", which makes sense, keeping the cartridge in the barrel as much as possible. Then use the go gauge and ream until that much of the go gauge is sticking out. (I'm sure there are better ways to check that too.)

Currently, my rifle leaves the cartridge hanging out .255", the bolt face is recessed .125", leaving .130" of space. This makes me question the information that I found above, but it could be that there is a very loose tolerance on this in production rifles.

Thanks

kraigwy · May 6, 2013, 10:54 AM

In setting headspace on a barrel.

Measure from the face of the action to the bolt face.

Measure the shank.

Subtract the shank length from the measurement you get from the measuring to the bolt face.

That is how much of the brass or headspace gage that should stick out.

You're suppose to make this about .004 longer to make up for the torqueing the barrel onto the action. I don't do that, I make it to fit as above which wont allow the "go" gage to work. I then hand turn the reamer one turn at a time until the bolt closes on the "go" gage.

Dixie Gunsmithing · May 6, 2013, 01:37 PM

I do it the same as Kraig. You want to hand fit the headspace, by getting it close, and trying to close the action on a go gauge a little at a time, while hand reaming it, until it finally closes.

RCP Fab · May 6, 2013, 02:44 PM

My concern is, that with a barrel with a barrel nut, I could end up with a rifle that chambers correctly, but leaves too much of the cartridge hanging out. I feel that my rifle as it sits leaves too much hanging out...

Dixie Gunsmithing · May 6, 2013, 08:13 PM

I would have to look at the setup you have, more, but you'll most likely have to take a dimension from a shoulder on the barrel to its breech end, to see how much goes inside the receiver, then a measurement where it abuts the frame to the face of the bolt when closed, to calculate it.

There will generally not be very much clearance at all from the bolt face, or edge of the bolt when its face is recessed, to the breech end of the barrel. Just enough for the bolt to freely turn so there's a minimum gap between the two. In a recessed bolt face, like on the 700 Remingtons, the cartridge sticks out of the end of the barrel, and into the recess to where the extractor can go into the extractor groove. If I recall, there's not very much of a gap between the two, and only the solid brass surrounding the primer sticking out of the barrel, with all of the cartridges tubular portion in the chamber. Really, the stick out should be just enough for the extractor to reach the groove when closed. If any of the wall of the cartridge is exposed, its the same as too much headspace, and would rupture.

**4V50 Gary** · May 6, 2013, 08:49 PM

What Kraigway says

RCP Fab · May 8, 2013, 07:13 AM

Thanks. I am sure to be back with more questions as I get started with this process.

May 6, 2013, 10:35 AM	#1
RCP Fab Senior Member Join Date: February 22, 2013 Posts: 113	Chamber depth Toward the end of this year I am planning on making my first barrel. I've done a ton of reading and watching videos, but right now I am getting hung up on chamber depth. I understand the headspace aspect of it, but what I do not understand is how much of the brass should stick out from then end of the barrel. I have read a various amount of things from "as little as possible" to probably way more than I would feel safe about. The only numbers I found were to measure the depth of the bolt face and add .004-.006" to that, and not to exceed .010", which makes sense, keeping the cartridge in the barrel as much as possible. Then use the go gauge and ream until that much of the go gauge is sticking out. (I'm sure there are better ways to check that too.) Currently, my rifle leaves the cartridge hanging out .255", the bolt face is recessed .125", leaving .130" of space. This makes me question the information that I found above, but it could be that there is a very loose tolerance on this in production rifles. Thanks

May 6, 2013, 10:54 AM	#2
kraigwy Senior Member Join Date: June 16, 2008 Location: Wyoming Posts: 11,061	In setting headspace on a barrel. Measure from the face of the action to the bolt face. Measure the shank. Subtract the shank length from the measurement you get from the measuring to the bolt face. That is how much of the brass or headspace gage that should stick out. You're suppose to make this about .004 longer to make up for the torqueing the barrel onto the action. I don't do that, I make it to fit as above which wont allow the "go" gage to work. I then hand turn the reamer one turn at a time until the bolt closes on the "go" gage. __________________ Kraig Stuart CPT USAR Ret USAMU Sniper School Distinguished Rifle Badge 1071

May 6, 2013, 08:49 PM	#6
4V50 Gary Staff Join Date: November 2, 1998 Location: Colorado Posts: 21,831	What Kraigway says __________________ Vigilantibus et non dormientibus jura subveniunt. *Molon Labe!*

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May 6, 2013, 01:37 PM	#3
Dixie Gunsmithing Moderator Emeritus Join Date: April 27, 2013 Location: Ohio Posts: 1,923	I do it the same as Kraig. You want to hand fit the headspace, by getting it close, and trying to close the action on a go gauge a little at a time, while hand reaming it, until it finally closes.

May 6, 2013, 02:44 PM	#4
RCP Fab Senior Member Join Date: February 22, 2013 Posts: 113	My concern is, that with a barrel with a barrel nut, I could end up with a rifle that chambers correctly, but leaves too much of the cartridge hanging out. I feel that my rifle as it sits leaves too much hanging out...

May 6, 2013, 08:13 PM	#5
Dixie Gunsmithing Moderator Emeritus Join Date: April 27, 2013 Location: Ohio Posts: 1,923	I would have to look at the setup you have, more, but you'll most likely have to take a dimension from a shoulder on the barrel to its breech end, to see how much goes inside the receiver, then a measurement where it abuts the frame to the face of the bolt when closed, to calculate it. There will generally not be very much clearance at all from the bolt face, or edge of the bolt when its face is recessed, to the breech end of the barrel. Just enough for the bolt to freely turn so there's a minimum gap between the two. In a recessed bolt face, like on the 700 Remingtons, the cartridge sticks out of the end of the barrel, and into the recess to where the extractor can go into the extractor groove. If I recall, there's not very much of a gap between the two, and only the solid brass surrounding the primer sticking out of the barrel, with all of the cartridges tubular portion in the chamber. Really, the stick out should be just enough for the extractor to reach the groove when closed. If any of the wall of the cartridge is exposed, its the same as too much headspace, and would rupture.

May 8, 2013, 07:13 AM	#7
RCP Fab Senior Member Join Date: February 22, 2013 Posts: 113	Thanks. I am sure to be back with more questions as I get started with this process.