Gunsmithing Head space question r700

[dmdakota]

I recently had my factory barrel set back and re chambered. I have fired 50 rounds and have noticed flat primers with mild loads and had a case head separation on a factory .308 round.
So this got me to thinking and I measured a factory winchester piece of brass against a fired piece of brass from my chamber and using a hornaday gauge the difference was +.025. Could this be a problem? I think that this is way excessive but I could be wrong please educate me.

 

[eddieharren]

Re: Head space question r700

If your measurements are true and accurate you have a serious excessive headspace problem.

 

[LRI]

Re: Head space question r700

If your H/S is off by .025" then you certainly have an issue.

Ditch the brass and get a gauge. That's step one.

Step two: If the H/S is out by more than .006" then it's time to rattle the cage of whoever did the work for you.

A H/S issue will certainly replicate most of the issues you've experienced. Most the case head split on a new cartridge. The brass is trying like hell to inflate (fireform) to your chamber. You can't rob Pete without also paying Paul. Meaning that material has to come from somplace in order to fill the gap.

In this situation its at the web of the case. It pulls it like taffy until it splits. Then "poof" you have a mess.

Get it fixed before you go on shooting. It's not worth an eyeball.

Good luck,

C.

 

[dmdakota]

Re: Head space question r700

Chad the gauge you are talking about which one?
I thought something was off when I lost about 80fps with the same load.

 

[colchester]

Re: Head space question r700

DM the gauge he is referring to is a headspace gauge. They are available as a GO or NO-GO. These can be purchased from Brownell Midway or PTG as well as other sources

 

[JFComfort]

Re: Head space question r700

+1 get a go gauge and find out what the new head space is or call him up and see if the smith recalls what he did.

 

[aj_brown]

Re: Head space question r700

A Go gauge will not tell you if you have an excessive headspace problem. You will need No Go or Feild gauge. A Go gauge is for min. headspace, Field is max. head space, and No Go is about half way between them.

Alan

 

[GasLight]

Re: Head space question r700

go-gauge is a great start, you can then shim the rear of the die in .001 or .002" increments until it won't close, then you know exactly what your headspace is, with a no-go or field gauge you can't tell where it is, only if it is within spec or not

 

[aj_brown]

Re: Head space question r700

If it does not close on a NO GO it is fine. If it does not close on a Field it is still safe to shoot.

Alan

 

[x ring accuracy]

Re: Head space question r700

And forget the idea of a go guage and scotch tape on the back side as a no go guage. Bad juju

 

[LRI]

Re: Head space question r700

A GO gauge is quite capable of telling you what your exact headspace is.

Here's how. Tear the bolt apart so that nothing spring loaded is installed.

Drop the gauge in the chamber.

Cut a snip of soft, small diameter solder and stick it to the bolt face with a dab of grease.

Close the bolt.

Pull it all apart and measure how much the solder squished. Anyone who's built an engine knows where I ginned this up.

Plastigauge. . .

Now you KNOW where your H/S is. The value will be expressed as GO+.003" etc. . . If your past .006" then I'd be talkin to the smith that fitted it because this is where/how a go/nogo gauge is set up.

We do it on every barreled action we fit. This method qualifies the chamber depth to a dimension that can be recorded. Better imo because I know where its at prior to delivery and in the event of a big sneeze we can see if lugs got peened back.

Nogo gauges become rather obsolete.

C.

 

[LRI]

Re: Head space question r700

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AJ Brown</div><div class="ubbcode-body">If it does not close on a NO GO it is fine. If it does not close on a Field it is still safe to shoot.

Alan </div></div>

If your a fire and forget kind of shooter sure. If your a handloader you'll likely split a case on about reload number 4.

These dimensions exist for a reason.

 

[GasLight]

Re: Head space question r700

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: X Ring Accuracy</div><div class="ubbcode-body">And forget the idea of a go guage and scotch tape on the back side as a no go guage. Bad juju</div></div>

I didn't say scotch tape, I use shim stalk like from a feeler gauge. Chad's solder idea is also a solid one. I think to make sure you are within .002" the scotch tape idea does have merit, but not to determine exact headspace.

 

[M.rolen]

Re: Head space question r700

if the gunsmith is local you should clean the rifle, disassemble the bolt and take it down there to him and have him check the head space. dont wast your money on gauges if you can just take it to the smith who did the work and possibly caused the problem

 

[aj_brown]

Re: Head space question r700

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AJ Brown</div><div class="ubbcode-body">If it does not close on a NO GO it is fine. If it does not close on a Field it is still safe to shoot.

Alan </div></div>

If your a fire and forget kind of shooter sure. If your a handloader you'll likely split a case on about reload number 4.

These dimensions exist for a reason. </div></div>

If your a handloader you should not be bumping the shoulder ever time you load.

alan

 

[LRI]

Re: Head space question r700

Regardless, it doesn't change the fact that your stretching the brass and everytime you resize it the web is being worked. Shoulder bump or not.

The reamer that cuts the chamber is tapered. A 308 win will measure in the vicinity of .4712" at its widest point. The reamer is larger in size as it moves towards the shank of the tool. Cutting a chamber .025 too deep (op's estimate) is going to result in an oversize chamer at the breech. Given that many brass manufacturers are mysteriously fixated with manufacturing brass several .001's undersize, its not unreasonable to expect accelerated fatigue/failure.

the focus here being the dimensions exist for a reason. They aren't conjured from thin air. Sure, there are band aid fixes, but in this case .025 too deep H/S requires a big ass bandage. Nevermind now that primers are going to push out of the cups with std loads, the ignition issues that can surface while fireforming, and the accelerated wear/tear on brass.

Fixing the problem is the solution. Partial F/L sizing isn't.

C.

 

[Tac284]

Re: Head space question r700

Please enlighten me on the go-gauge + tape and why it seems to be a no-go (no pun intended) issue?

 

[aj_brown]

Re: Head space question r700

Chad

If the chamber is .025 too deep it would close on the field gauge and would not be safe to shoot once. I understand how reamers work I have cut a few chambers over the years. In the common calibers I have gauge sets by the thousands from the Go to the Field.

Alan

 

[krlemas]

Re: Head space question r700

I would make it simple buy a no go gauge if the bolt closes on it take it back to the smith, with your gauge, show him and tell him to correct his mistake and then never go to him again because he should never have sent it out like that, keep or sell gauge.

 

[GasLight]

Re: Head space question r700

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tac284</div><div class="ubbcode-body">Please enlighten me on the go-gauge + tape and why it seems to be a no-go (no pun intended) issue? </div></div>

While the tape is approximately .002" unless it was measured, it isn't necessarily a fixed value, or an exact measurement of the headspace. If you chamber a rifle, and it will close on the go, and not on the go with a piece of scotch tape on the back of it, you are well under the no-go gauge.

My point in my posts is that unless you have an entire set of gauges by the thou, from go to field like AJ (read very expensive), then it makes more financial sense to buy just a go gauge and determine the exact headspace instead of just knowing it is good enough with a no-go or field. That is just my opinion, and you would spend the same money buying a go as you will a no-go. I haven't heard anything here that won't work, but knowing the exact for the same money seems to make more sense to me.

I would go the go-gauge route instead of just bringing it back to the smith first, because if he did that poor of a job to start with, who knows what line of BS he will feed you when you bring it back in...

This is all just my $.02

Dave

 

[eddieharren]

Re: Head space question r700

In case any of you hard hitters needs some lead squirts, from making bullet cores (these work like Chad's solder pieces),I have plenty available. I use them on the bolt face when checking final headspace cuts as well as cone depth on the breech.

 

[x ring accuracy]

Re: Head space question r700

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GasLight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tac284</div><div class="ubbcode-body">Please enlighten me on the go-gauge + tape and why it seems to be a no-go (no pun intended) issue? </div></div>

While the tape is approximately .002" unless it was measured, it isn't necessarily a fixed value, or an exact measurement of the headspace. If you chamber a rifle, and it will close on the go, and not on the go with a piece of scotch tape on the back of it, you are well under the no-go gauge.

My point in my posts is that unless you have an entire set of gauges by the thou, from go to field like AJ (read very expensive), then it makes more financial sense to buy just a go gauge and determine the exact headspace instead of just knowing it is good enough with a no-go or field. That is just my opinion, and you would spend the same money buying a go as you will a no-go. I haven't heard anything here that won't work, but knowing the exact for the same money seems to make more sense to me.

I would go the go-gauge route instead of just bringing it back to the smith first, because if he did that poor of a job to start with, who knows what line of BS he will feed you when you bring it back in...

This is all just my $.02

Dave
</div></div>
Amen

 

[9H_Cracka]

Re: Head space question r700

Excessive headspace will allow the primer to flow and make the primer at first glance be giving you "pressure signs". I have experienced and repeated this first hand.

In the process of doing this, I also had premature insipient head separation.

The bottom line is your brass is being oversized, the shoulder pushed back too far, for the chamber in the rifle. WHY that is happening can be easily diagnosed with a Wilson Case Gauge.

No matter what the cause (die set to over size or long headspace in the chamber), the problem can be remedied by adjusting your sizer.

 

[wnroscoe]

Re: Head space question r700

Dakota,

Call PTG and order Go & No Gauge gauges. I have incremental gauges from zero headspace to the no go from JGS, about 7 gauges in all. The PTG Go Gauges are +.002" from my JGS zero and is what I use 99% of the time.

Strip the bolt of the fire control and ejector for an accurate feel/reading. I've seen WW brass so far under normal headspace it was almost funny, I own some BTW.

Like Alan said, if the bolt closes on a go and doesn’t close on the no go your good to go

Just so you'll know who AJ Brown is, when he speaks, William Roscoe listen's, I cant say that about too many people

Good luck.

 

[dmdakota]

Re: Head space question r700

Well I took the rifle to a different Smith and he is going to measure and let me know what he finds. I don't want to be THAT guy that starts talking smack about someone if my way of measuring was wrong. Thanks for all of the input. I will post results.

 

[dmdakota]

Re: Head space question r700

Well I just got the call My rifle swallowed the no-go gauge with no resistance closing the bolt.

 

[jeepwilson]

Re: Head space question r700

I hate that for you but you didnn`t get hurt.And should be a fairly easy fix.Good luck.