I am wondering about how to get your headspacing and whatever else is needed when putting a new barrel on the action. Any help is appreciated
Gunsmithing new to building rifles and need help
- Thread starter brushcountryghost
- Start date
Re: new to building rifles and need help
What action?
What action?
Re: new to building rifles and need help
Got a rem 700 action for a 6.5x284
Got a rem 700 action for a 6.5x284
Re: new to building rifles and need help
Not to sound like a dick man, but if you dont understand head spacing and how to chamber and gauge a barrel please dont do it. Send it off to have someone who knows what they are doing chamber and fit your tube to your action. At best you will ruin a good barrel. At worst you will destroy the rifle and severely hurt yourself or kill yourself in the process.
If you do understand the process and are just looking for the fine points of the art then refer you to Youtube and the plethora of videos they have on there from many people showing their processes for chambering and head spacing a barrel.
Not to sound like a dick man, but if you dont understand head spacing and how to chamber and gauge a barrel please dont do it. Send it off to have someone who knows what they are doing chamber and fit your tube to your action. At best you will ruin a good barrel. At worst you will destroy the rifle and severely hurt yourself or kill yourself in the process.
If you do understand the process and are just looking for the fine points of the art then refer you to Youtube and the plethora of videos they have on there from many people showing their processes for chambering and head spacing a barrel.
Re: new to building rifles and need help
A lot of pressure in there if you don't get it right. Is your face worth more then 250 bucks?
Seriously, I want to know how to do the same thing but I will pay someone to teach me how to do it when/if the time comes.
A lot of pressure in there if you don't get it right. Is your face worth more then 250 bucks?
Seriously, I want to know how to do the same thing but I will pay someone to teach me how to do it when/if the time comes.
Re: new to building rifles and need help
Im pretty new at this stuff and will take yalls advice and have someone who knows what they are doing do it. Thats alot of risk im just not willing to take. Thanks guys
Im pretty new at this stuff and will take yalls advice and have someone who knows what they are doing do it. Thats alot of risk im just not willing to take. Thanks guys
Re: new to building rifles and need help
Yep with a remmy you should have it done I'd say! Even with a Savage if you don't understand the process it could be tragic.
Yep with a remmy you should have it done I'd say! Even with a Savage if you don't understand the process it could be tragic.
Re: new to building rifles and need help
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brushcountryghost</div><div class="ubbcode-body">I am wondering about how to get your headspacing and whatever else is needed when putting a new barrel on the action. Any help is appreciated </div></div>
I do it on a lathe with measurements I record on this sheet:
www.700barrels.com/stuff/700dimensions.pdf
You will need to work out your measuring tools, but once you do, it's just machining...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brushcountryghost</div><div class="ubbcode-body">I am wondering about how to get your headspacing and whatever else is needed when putting a new barrel on the action. Any help is appreciated </div></div>
I do it on a lathe with measurements I record on this sheet:
www.700barrels.com/stuff/700dimensions.pdf
You will need to work out your measuring tools, but once you do, it's just machining...
Re: new to building rifles and need help
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brushcountryghost</div><div class="ubbcode-body">I am wondering about how to get your headspacing and whatever else is needed when putting a new barrel on the action. Any help is appreciated </div></div>
Since you asked. . .
There's a dozen ways to skin this cat. I'll preface this by saying its how I do it. That does not mean its the best way, most accurate way, its means its the best and most accurate for me.
So, here we go.
I'll assume you understand the fundamental operations of a lathe along with cutter geometry, tooling speeds/feeds, etc. .. If not, devote a solid years worth of your free time learning it before you waste a bunch of money scrapping a barrel/ruining tooling. Lathes are dangerous. Mills eat fingers. Lathes eat limbs!
Don't let spectators arrogance kill you. (seriously)
Set up your reamer and touch it to the back of the barrel using a .1000" thick gauge block. Now zero your carriage/tailstock so that it reads .100 from the face of your barrel.
I set my GO gauge right on the tool supported between two flutes and align it with the shoulder/body transition point. I then take a 6" scale (machinist for "ruler") and measure from the very tip of the reamer pilot screw (or nose of the tool in the case of carbide reamers) and then note the distance to the back of the GO gauge. I do this because I use a CNC lathe for all my barrel work. If I don't set it up this way its very, very, very easy for the machine to think that the tool is free and clear of the barrel when it rapids out of the way after the "roughing" cycle. This would destroy the tool and the barrel as my machine moves at over 1000 inches per minute when given a G0 (rapid) command.
From here I subtract .100" so that I have no danger of going too deep and creating a whole bunch of extra work for myself.
The prefered method these days is to use a muzzle flush system. Nothing more elaborate than pumping cutting oil through your barrel in the effort to lubricate the cutter and evacuate the chips from the gullets of the reamer.
CHIP EVACUATION IS A CRUCIAL FUNCTION TOWARDS CUTTING BEAUTIFUL CHAMBERS. This cannot be stressed enough.
So, begin your plunge. The RPM and feedrate will be determined by how rigid your setup is. I won't publish my figures only because my setup is unique. My machine weighs 9000lbs and I have a rigid tool holder. It means I can be more aggressive with feedrates than most.
The tool should develop an even, linear load. The chip formation should be forming across all the flutes. Not just one or a few. If you have this something is wrong and STOP before you ruin the barrel. Figure out what's out of whack and fix it before continuing.
Once you get to the initial depth you remove the tool, clean any remnant chips, and plop the GO gauge into the chamber. It should be sticking out of the breech ring a bit. That's OK. Now start screwing the action onto the barrel tennon as if you were putting it together. Have the bolt installed in the action with all the spring loaded doo hickies removed. Your bolt should resembled an "L" shaped lump of steel and that's it. This is so you can feel what's really going on with your chamber depth and not be confused by something loading against a spring.
Screw the thing together while wiggling the bolt handle. Once the bolt sticks you know your loaded against the GO gauge. Note the gap between the recoil lug and barrel shoulder. Measure that gap. This is your distance to GO. If your a bad ass with the scale (ruler) you'll be exactly .100" from your target depth.
How this gets measured varies, what I like to do is use a set of gauge pins. My pins are in .001 increments from .04 to .500. I grab one that I think is close and adjust/repeat until it barely slides into the gap between the lug and barrel tennon shoulder.
Lets say for sake of argument that value is .094". If my initial target depth was 2.72" I'd add .094" to that figure for a total plunge depth of 2.814". This is the # I'm shooting for.
But experience has taught me that if I did this the H/S would be too tight. It's no secret and those who chamber guns frequently are equally aware of it. You have to allow for "crush" and this is a sort of "feel-voodoo" sort of deal.
It largely depends on the quality of your thread fits. Loose sloppy threads tend to generate more crush than silky smooth ones. It's easier to predict the amount of crush if your thread fits are good. (meaning the action doesn't rattle like a marble in a can as you screw it onto the barrel tennon)
In my shop we add .004" to our final value. This allows for .002" of thread crush and puts the final headspace dimension at a value we refer to as "GO+.002". I like this because its conservative while not being so tight that shooters have issues with function while running the gun at the range. It also gives me a qualified dimension to reference to which I'll explain more later.
So, now its to depth. Next is to put a polish on the chamber. "Polish" is a relative term. It's impressive to the untrained eye to see a chamber and reflects your face back at you as you look at it. It's also a great way to accelerate brass wear.
Brass moves when you fire it in a gun. As time goes on it will flow towards the neck of the case and start to thin out the webs. Things like full length sizing helps this along. It doesn't happen overnight, but it does happen and its a well documented phenomenon within the gun world. You can help mitigate some of this by the surface finish you leave in your chamber.
A cross hatch pattern with 320 grit emery soaked in WD40 at 1500rpm will leave a finish very similar to what a freshly honed cylinder bore looks like in an engine. This finish is smooth to touch and will allow brass to extract easily. What it does for you is allow the brass to "bite" the chamber when it pressures up. This bite will resist the brass from flowing up the chamber. The nice thing is it's also smooth enough to leave a nice finish on your brass.
If you do it with a coarser grade of abrasive it can produce what's called "frosting" on the brass. The fired case will almost look sand blasted upon extraction. this is because the pressure exerted against the brass during firing causes the case to extrude into all those deep scores/scratches and it roughens the finish. Light doesn't reflect back as well and it appears dull.
Most shooters hate chambers that frost the brass. Just be aware of this if you start doing this for your buddies.
Now you clean everything out and admire your skills. Assemble the barrel and torque it up as you normally would. Now plop the GO gauge back in the chamber and see of the bolt still drops with no resistance. Assuming it does you now have qualified that your chamber meets the MINIMUM headspace distance required for the cartridge to work. That does NOT mean you did it right. It could be too deep.
Companies like Pacific Tool and Gauge sell gauges in sets. You get a GO and a NO GO. This is the tolerance variance between minimum depth and maximum. (were ignoring field gauges for this exercise)
While this works I like to know exactly where the HS is. I do this with very thin diameter lead based solder sold at Radio Shack. Cutting a sliver of it and sticking it between the bolt face/gauge will allow me to measure the gap because the solder gets smooshed and I can measure how thick it is afterward. I refer to this dimension as "GO+...."
If our numbers were spot on your chamber would measure "GO+.002". That's about perfect in my book. It's .004" under the general SAAMI specification for max HS on most cartridges. It ensures the SAAMI length cartridge case will chamber with no resistance. It's also short/tight enough to mitigate brass flowing from the web towards the shoulder/neck as it tries to inflate to the chamber dimension.
Failure to observe this often results in shooters burning through brass after the 3rd or 4th reload because the web just keeps getting thinner each time they full length resize the case.
As a general rule, ALWAYS load the brass to the gun, not to SAAMI length. This helps the brass live longer.
Hope this helped and didn't raise more questions than answers.
Good luck.
C.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brushcountryghost</div><div class="ubbcode-body">I am wondering about how to get your headspacing and whatever else is needed when putting a new barrel on the action. Any help is appreciated </div></div>
Since you asked. . .
There's a dozen ways to skin this cat. I'll preface this by saying its how I do it. That does not mean its the best way, most accurate way, its means its the best and most accurate for me.
So, here we go.
I'll assume you understand the fundamental operations of a lathe along with cutter geometry, tooling speeds/feeds, etc. .. If not, devote a solid years worth of your free time learning it before you waste a bunch of money scrapping a barrel/ruining tooling. Lathes are dangerous. Mills eat fingers. Lathes eat limbs!
Don't let spectators arrogance kill you. (seriously)
Set up your reamer and touch it to the back of the barrel using a .1000" thick gauge block. Now zero your carriage/tailstock so that it reads .100 from the face of your barrel.
I set my GO gauge right on the tool supported between two flutes and align it with the shoulder/body transition point. I then take a 6" scale (machinist for "ruler") and measure from the very tip of the reamer pilot screw (or nose of the tool in the case of carbide reamers) and then note the distance to the back of the GO gauge. I do this because I use a CNC lathe for all my barrel work. If I don't set it up this way its very, very, very easy for the machine to think that the tool is free and clear of the barrel when it rapids out of the way after the "roughing" cycle. This would destroy the tool and the barrel as my machine moves at over 1000 inches per minute when given a G0 (rapid) command.
From here I subtract .100" so that I have no danger of going too deep and creating a whole bunch of extra work for myself.
The prefered method these days is to use a muzzle flush system. Nothing more elaborate than pumping cutting oil through your barrel in the effort to lubricate the cutter and evacuate the chips from the gullets of the reamer.
CHIP EVACUATION IS A CRUCIAL FUNCTION TOWARDS CUTTING BEAUTIFUL CHAMBERS. This cannot be stressed enough.
So, begin your plunge. The RPM and feedrate will be determined by how rigid your setup is. I won't publish my figures only because my setup is unique. My machine weighs 9000lbs and I have a rigid tool holder. It means I can be more aggressive with feedrates than most.
The tool should develop an even, linear load. The chip formation should be forming across all the flutes. Not just one or a few. If you have this something is wrong and STOP before you ruin the barrel. Figure out what's out of whack and fix it before continuing.
Once you get to the initial depth you remove the tool, clean any remnant chips, and plop the GO gauge into the chamber. It should be sticking out of the breech ring a bit. That's OK. Now start screwing the action onto the barrel tennon as if you were putting it together. Have the bolt installed in the action with all the spring loaded doo hickies removed. Your bolt should resembled an "L" shaped lump of steel and that's it. This is so you can feel what's really going on with your chamber depth and not be confused by something loading against a spring.
Screw the thing together while wiggling the bolt handle. Once the bolt sticks you know your loaded against the GO gauge. Note the gap between the recoil lug and barrel shoulder. Measure that gap. This is your distance to GO. If your a bad ass with the scale (ruler) you'll be exactly .100" from your target depth.
How this gets measured varies, what I like to do is use a set of gauge pins. My pins are in .001 increments from .04 to .500. I grab one that I think is close and adjust/repeat until it barely slides into the gap between the lug and barrel tennon shoulder.
Lets say for sake of argument that value is .094". If my initial target depth was 2.72" I'd add .094" to that figure for a total plunge depth of 2.814". This is the # I'm shooting for.
But experience has taught me that if I did this the H/S would be too tight. It's no secret and those who chamber guns frequently are equally aware of it. You have to allow for "crush" and this is a sort of "feel-voodoo" sort of deal.
It largely depends on the quality of your thread fits. Loose sloppy threads tend to generate more crush than silky smooth ones. It's easier to predict the amount of crush if your thread fits are good. (meaning the action doesn't rattle like a marble in a can as you screw it onto the barrel tennon)
In my shop we add .004" to our final value. This allows for .002" of thread crush and puts the final headspace dimension at a value we refer to as "GO+.002". I like this because its conservative while not being so tight that shooters have issues with function while running the gun at the range. It also gives me a qualified dimension to reference to which I'll explain more later.
So, now its to depth. Next is to put a polish on the chamber. "Polish" is a relative term. It's impressive to the untrained eye to see a chamber and reflects your face back at you as you look at it. It's also a great way to accelerate brass wear.
Brass moves when you fire it in a gun. As time goes on it will flow towards the neck of the case and start to thin out the webs. Things like full length sizing helps this along. It doesn't happen overnight, but it does happen and its a well documented phenomenon within the gun world. You can help mitigate some of this by the surface finish you leave in your chamber.
A cross hatch pattern with 320 grit emery soaked in WD40 at 1500rpm will leave a finish very similar to what a freshly honed cylinder bore looks like in an engine. This finish is smooth to touch and will allow brass to extract easily. What it does for you is allow the brass to "bite" the chamber when it pressures up. This bite will resist the brass from flowing up the chamber. The nice thing is it's also smooth enough to leave a nice finish on your brass.
If you do it with a coarser grade of abrasive it can produce what's called "frosting" on the brass. The fired case will almost look sand blasted upon extraction. this is because the pressure exerted against the brass during firing causes the case to extrude into all those deep scores/scratches and it roughens the finish. Light doesn't reflect back as well and it appears dull.
Most shooters hate chambers that frost the brass. Just be aware of this if you start doing this for your buddies.
Now you clean everything out and admire your skills. Assemble the barrel and torque it up as you normally would. Now plop the GO gauge back in the chamber and see of the bolt still drops with no resistance. Assuming it does you now have qualified that your chamber meets the MINIMUM headspace distance required for the cartridge to work. That does NOT mean you did it right. It could be too deep.
Companies like Pacific Tool and Gauge sell gauges in sets. You get a GO and a NO GO. This is the tolerance variance between minimum depth and maximum. (were ignoring field gauges for this exercise)
While this works I like to know exactly where the HS is. I do this with very thin diameter lead based solder sold at Radio Shack. Cutting a sliver of it and sticking it between the bolt face/gauge will allow me to measure the gap because the solder gets smooshed and I can measure how thick it is afterward. I refer to this dimension as "GO+...."
If our numbers were spot on your chamber would measure "GO+.002". That's about perfect in my book. It's .004" under the general SAAMI specification for max HS on most cartridges. It ensures the SAAMI length cartridge case will chamber with no resistance. It's also short/tight enough to mitigate brass flowing from the web towards the shoulder/neck as it tries to inflate to the chamber dimension.
Failure to observe this often results in shooters burning through brass after the 3rd or 4th reload because the web just keeps getting thinner each time they full length resize the case.
As a general rule, ALWAYS load the brass to the gun, not to SAAMI length. This helps the brass live longer.
Hope this helped and didn't raise more questions than answers.
Good luck.
C.
Re: new to building rifles and need help
Wow again I'm impressed Mr Dixon! Awesome right up, but mostly in how you'll just put it out there sir. A lot of builders wouldn't do that and especially not in that detail, and for no money even.
Wow again I'm impressed Mr Dixon! Awesome right up, but mostly in how you'll just put it out there sir. A lot of builders wouldn't do that and especially not in that detail, and for no money even.
Re: new to building rifles and need help
Very nice write up Chad, very detailed.
One thing an old BR friend has taught me - use the stub of barrel you cut off, to make a chamber gauge for your brass. It does not have to be as long as the brass, unless it is a belted mag, headspaced on the belt. To make it:
Face off both ends of the stub, keeps it pretty.
Sink your reamer into the stub, as deep as possible, without allowing the bullet end of the brass to exit the stub. You want the head end of the brass out of the stub when finished.
Next, shoot the rifle, with a new batch of brass. Take the brass as removed, and measure the projection of the head end from the stub. It is easiest to do that with calipers across the head end and the opposite side of the stub. Write that number down.
Next, resize the brass, setting up the die, such that you only move the shoulder back .001". You use the guage you just made to measure that setback. Works like a champ every time, extends brass life a lot. It is not unusual for BR guys to use the same 10-20 pieces of Lapua brass for several HUNDRED reloads, by minimizing the shoulder set back. I have shot an entire weekend match ( 100 rounds, plus warmups and sighters ) with ten rounds of brass, and not had to trim case length.
Not exactly on topic, but if you are learning to chamber, it's good info.
Very nice write up Chad, very detailed.
One thing an old BR friend has taught me - use the stub of barrel you cut off, to make a chamber gauge for your brass. It does not have to be as long as the brass, unless it is a belted mag, headspaced on the belt. To make it:
Face off both ends of the stub, keeps it pretty.
Sink your reamer into the stub, as deep as possible, without allowing the bullet end of the brass to exit the stub. You want the head end of the brass out of the stub when finished.
Next, shoot the rifle, with a new batch of brass. Take the brass as removed, and measure the projection of the head end from the stub. It is easiest to do that with calipers across the head end and the opposite side of the stub. Write that number down.
Next, resize the brass, setting up the die, such that you only move the shoulder back .001". You use the guage you just made to measure that setback. Works like a champ every time, extends brass life a lot. It is not unusual for BR guys to use the same 10-20 pieces of Lapua brass for several HUNDRED reloads, by minimizing the shoulder set back. I have shot an entire weekend match ( 100 rounds, plus warmups and sighters ) with ten rounds of brass, and not had to trim case length.
Not exactly on topic, but if you are learning to chamber, it's good info.
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