Do I understand this? — Headspace Qs

[Chiquita]

I just changed my RPR 6.5 barrel and my understanding of the head spacing is the following.

>I use the go gauge and the bolt close feels OK to me (Not too tight and not too loose). The ejector pin is removed.
>Then I use scotch tape about .004" thick on the back of the "go-gauge" to simulate no-go gauge (the "no-go" gauge is on back order)
>this sets my head space to .004".
>when I resize I can bump shoulders back .002"
> then the subsequent firing will only move the shoulder .002". Another words the shoulder only expands .002"
Correct?

Now,
If I set the head space to .002 instead of .004 then there is a chance that may be a too tight. Correct?

Do I have this correct?



BTW, shout out to LRI barrel nut wrench and wheeler action wrench. It was VERY easy removing the barrel nut by using these two tools. VERY easy!!

 

[Doug Beach]

From a safety / function perspective, your bolt should close on your go gauge. It should not close on your go gauge w/ tape on it. By “close”, in both instances, I mean easily, without forcing. Then go shoot, and size your brass back .002”, from it’s fired dimension.
Like everything, you can make it much more complicated than the above, but you don’t actually need to.

 

[Chiquita]

From a safety / function perspective, your bolt should close on your go gauge. It should not close on your go gauge w/ tape on it. By “close”, in both instances, I mean easily, without forcing. Then go shoot, and size your brass back .002”, from it’s fired dimension.
Like everything, you can make it much more complicated than the above, but you don’t actually need to.

OK. Thanks. Sounds like I "may" be on the right track.

 

[tobnpr]

You don't need to (and shouldn't) add any tape to the back of the go gage to establish your headspace.
The gage itself is sized to minimum headspace, and all factory ammunition will (at least, should) chamber with it.

It won't be detrimental as long as you bump your shoulders to correspond, but why do it in the first place?

 

[Dusty Stevens]

You don't need to (and shouldn't) add any tape to the back of the go gage to establish your headspace.
The gage itself is sized to minimum headspace, and all factory ammunition will (at least, should) chamber with it.

It won't be detrimental as long as you bump your shoulders to correspond, but why do it in the first place?

He said it shouldnt close with tape on the back. Thats SOP for gunsmiths. Most dont even own a no-go gage

 

[tobnpr]

Then I use scotch tape about .004" thick on the back of the "go-gauge" to simulate no-go gauge (the "no-go" gauge is on back order)
>this sets my head space to .004".

Seems to me he said he was going to add the tape to set his hs at go + .004

Maybe he misspoke.

 

[Chiquita]

You don't need to (and shouldn't) add any tape to the back of the go gage to establish your headspace.
The gage itself is sized to minimum headspace, and all factory ammunition will (at least, should) chamber with it.

It won't be detrimental as long as you bump your shoulders to correspond, but why do it in the first place?

I am adding the tape so it acts like a "No-Go" gauge.

I finished it today and I have a final measurement of .003 headspace.

 

[Chiquita]

He said it shouldnt close with tape on the back. Thats SOP for gunsmiths. Most dont even own a no-go gage

what is SOP?

 

[SEGARE]

Standard Operating Procedure

 

[Davester]

I don't piss about with tape. I get the right tools for the job. Too much at stake to get it wrong. For example, I always thought "tape" (Selotape?) was 0.002" thick not the 0.004" mentioned here. IIRC the delta between go / no-go was circa 0.004 - 0.006 depending on calibre. Imagine someone having an accident and having to explain to your insurers - "Nah, didn't bother with correct gauges, I just used a bit of sticky"

 

[carlsbad]

I don't know what the terminology is but I would say your headspace is set at 0 if you can just barely close the go gauge. Put the tape on and if it just closes, that would be .004 to me. recognize that anywhere in between is considered acceptable but I like to set it always at one end or the other, generally at the go gauge end, so that all barrels in the same chamber are the same and you don't have to adjust the shoulder bump on your die.

 

[jelenko]

First, I have both go and no go gauges and always use them.
I've put scotch transparent tape on the back of my go gauge - it adds just over 1 thousandths to the headspace as measured by inserting the go gauge with the tap on the back into both Widden's and Mo's headspace gauges.

It is no where near 4 thousandths.

 

[Dusty Stevens]

The tape i use is plain packing tape. Its exactly .004. I guess you gotta know which tape to use. Doesnt really matter if its .001 or even .0005 if it closes on a go gage but not on a taped gage i can tell you thats exactly where your headspace is. If you use .001 thick tape youre hitting headspace real close and can repeat that easily on another barrel. If its .007 and still works that way your headspace is somewhere between.

 

[Will Henry]

I just cut the chamber so the chamber is +.002 on the "go" gauge. When the barrel is tightened up, it is usually right at zero. If I'm installing a barrel with a nut, I set it with a go gauge and one layer of Scotch tape. WH