Setting headspace with a new barrel.


November 10, 2007, 02:26 PM
I have a Savage 110 in .270 Win that I recently bought a new barrel for. The new barrel is chambered in 35 Whelen. I have a set of go/no go gauges for it, as well as a barrel nut wrench. My question is how do you use the gauges to set the headspacing? They do not come with instructions and I have never done this before. I know the general concept is that the go gauge should fit and the no go gauge should not, but that is about it.

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November 10, 2007, 02:59 PM
Take a look here for your Savage questions, good site.

November 10, 2007, 03:57 PM
If your guages are Forster, you will have to remove the extractor from the bolt assembly to obtain a reliable read.
If your guages are Clymer or Manson they have a cutout for the extractor and this won't be necessary.

Do not lubricate the guages, place them into the chamber dry.
If your guages have an extractor cutout, orient the guage so the cutout falls under the extractor claw.
Set the barrel back until the go guage allows the bolt handle to just fully close and hand tighten the barrel nut.
Recheck with the no go guage and make sure the bolt handle does not fully close down.
Torque the nut to whatever specification Savage calls for.

Lightly lubricate the guages and put them back in their storage sleeves when you are done.

Jim Watson
November 10, 2007, 07:36 PM
Helps to take out the ejector, too; so you won't be confused by spring tension against the gauge.

When I changed my barrel, I just took out the extractor and ejector, screwed the barrel most of the way in, closed the bolt on the Go gauge, and screwed the barrel in the rest of the way against the gauge. Then tightened the nut. Such material as I had read said that snugging the barrel against the Go gauge set the headspace at the very minumum but that tightening the nut stretches it out about .001" to .0015" over the minimum, which puts it in the lower 1/4 of the allowable range. Never saw the need for a No-go gauge.

November 11, 2007, 09:20 AM
I think that it is a good idea to dis-assemble the bolt while checking headspace and very gingerly close the bolt to get the proper "feel".

November 11, 2007, 12:18 PM
Strip the bolt completely or you won't be able to get a good feel of things.

The spring loaded plunger type ejectors are stiff enough to really confuse things when setting headspace.

I also agree that you don't need to buy a NO-GO gage unless you just really want too.

A sheet of .004" brass shim stock, or a dollar-two-ninety-eight feeler gage from the auto parts store will make a circular disk that can be stuck on the head of a GO gage with grease.
If that won't close, you are good to go.

Jim K
November 11, 2007, 10:14 PM
Jim Watson's method usually works fine with the Savage where you can easily screw the barrel in and out and then set it at the right place. But for other rifles, where the barrel is short chambered or unchambered and you are reaming, the GO gauge only shows that the chamber is deep enough that a "long" cartridge will be accepted, but it doesn't show by how much. The NO-GO gauge makes sure the chamber is not too deep. (A deep chamber can cause the same problems as excess headspace, since it permits a forward positioned case to back up and separate.)

So, in that special case with Savage, a GO is usually enough, but not as a general proposition in rebarrelling. Even with the Savage (or similar rifles), if the barrel is short chambered, using the GO that way could leave the barrel not screwed in far enough to properly support the rear of the case, and that could be trouble.


Jim Watson
November 11, 2007, 11:29 PM
Come on, guys, the OP has a Savage, I have a Savage and the Savage IS a "special case" when it comes to barrel changes. It is not like replacing a barrel on a Remington with a short chambered barrel, reamer, gauges, depth micrometer, etc.

Brownell's instructions, which are more elaborate than what I got off the Savage board, are at:

November 12, 2007, 10:31 AM
As I mentioned in my original post, I ALREADY HAVE a no-go gauge, which kinda makes all this argument pointless :scrutiny: All that aside, thanks for the info :)

November 14, 2007, 02:18 PM
#1). You need to understand headspace and its effects. This is the measurement that allows all commercial ammo to enter a chamber. In the "rimmed round" it is the "rim thickness" plus, that the rim occupies. Rimless goes to the shoulder or midpoint of shoulder (Uncle Sam was trying to cheat Mr. Mauser who sued and Uncle Sam lost and paid royalties on the 03 until WW I started...) It is supposed to be made smaller than any commercial/standard chamber, the ammo. BUT if you get too far off "too much headspace", then the pressure in the case can cause it to "pull apart" and release hot powder gases into the gun. These gases are at many times the temperature of a cutting torch and if they hit the right parts and the action "lets go" you could go to the cemetary or use a white cane the rest of your life or ??? This needs to be taken seriously and work with CAREFULLY and... make sure your insurance is up to date too...

#2). "Go" guage. This is a manufacturer's tool to be sure that any chamber is cut big enough and the measurements set "big enough" to allow any commercial cartridge to chamber and fire and...
"No-go" guage. This is a manufacturer's tool that tells that something is wrong. If the action accepts this, it is over sized and firing a cartridge is likely to cause separation and problems, injuries, BIG no-no... Many, many "used" guns will swallow a no-go guage without any problems. Being fired a few times "loosened them up" enough... Not enough to cause problems with a once/first fire of a factory round, new case, but ... And if the reloader does not understand and full length resizes every time... You lose cases when they separate and hopefully that is all you lose.

Military likes to use a "field guage." Since /'06 and .270 are same case, an /'06 field guage would work in a .270... (.27/'06 really...) Interestingly, if the gun takes this, most likely the measurements are so far off, TOO LONG, that a normal firing pin will not reach the primer and fire the cartridge. Not too big a deal to most hunters... deer run off. Now if the enemy is shooting back... !!! Disappointing?

As said, the extractor/ejector tends to ruin feel. You want to strip your bolt head. Then you want the barrel screwed in so that you can close on the "go" guage. [And if you are keeping it simple, not close on the "no-go" guage.] And you can adjust for more headspace by sticking spacers... you can buy "shim stock" and cut it with scissors or use scotch tape or ???... stick them to the "go" guage... "No-go" is already too long... to get the headspace you think you want.

At the same time, when you go to reload the cartridge, again, you have the option of setting headspace by not full length resizing. If the bolt closes tight, (not for pumps, semi autos or levers... usually) then you have the case filling the chamber, minimum headspace whatever you have the barrel set at, and maximum case life.

If you need pictures, please find some. It is not complicated once you understand (and don't screw it up like old farts are inclined to do, I speak from experience...) but if you get very far offfffff... Cemetary or white cane or ??? Don't forget that. The rest of us will have a black eye, too... luck.

November 14, 2007, 10:11 PM
If at any time I am uneasy about what I'm doing, I'll take it to a smith to get it checked. I may do that anyway once I'm done just to make sure :)

Jim K
November 15, 2007, 04:47 PM
Hi, iiranger,

Sorry, but a NO-GO gauge does NOT indicate "something is wrong." It is simply the other half of a check to ensure that the rifle chamber is "in spec." Just about all mass produced goods are made to a specification with tolerances, and the GO/NO-GO gauges are made to check those tolerances in a rifle chamber. Ammunition is also made to specs with tolerances, so there will be cartridges that are "long" but within specs, and cartridges that are "short" but within specs.

The GO is used just as you describe, to ensure that a cartridge that is within specs on the long side is not too long to chamber. The NO-GO ensures that a cartridge that is within specs but on the short side cannot stretch far enough that there will be a case separation. So both are needed and used in gun manufacture and in gunsmithing work involving rebarrelling or replacing parts like bolts.

But as a rifle is used, headspace increases, due to wear and setback of the locking lugs and lug seats. The Field gauge is used to determine if the wear has progressed to the point of possible trouble. ("Field" simply means anywhere outside the factory - it doesn't mean that someone ran around the battlefield checking rifles.)


November 15, 2007, 07:47 PM
I do what Watson does. If it closes on the go, and won't close on the no-go, you're golden. Check it after you tighten the nut to make sure they didn't move too much. It's really no big deal, 30 minutes your first time, 15 the second. I was torn between the 35 Whelen and the 338-06 on one of my Savages, went with the 338. Battenfield used to have a good web page on their A&B barrel page.

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