Help me understand what I am seeing.

[Pirate69]

I need to tap into the knowledge of this Forum. I recently returned to Savage, an Axis rifle chambered in 223 Remington. It appeared to have an undersized chamber as determined by the case diameter at the 0.200” datum. The rifle was serviced and returned to me. The invoice indicated that the tight chamber was reamed and the chamber polished. It was indicated that the headspace is good.

Prior to loading some rounds, to see the results, I decided to check the distance to the ogive since the chamber had been reamed. Prior to shipping the rifle to Savage, the distance to the ogive measured 1.9460” for a 69 grain Nosler BTHP CC. After the chamber reaming, the distance to the ogive, from five measurements, averaged 2.0297”. The distance has increased by 0.0837”.

I wondered how the freebore could increase by 0.0837” and not affect the headspace. After loading as firing some rounds, I marked and measured the shoulder datum on five fired cases. The datum averaged 1.4615” (0.0006” SD). I full length resized the five fired cases. The average of the resized cases’ shoulder datum measured 1.4504” (0.0005” SD); a difference of 0.0111”. I assume that this represents the current headspace.

I would prefer that the headspace be much closer to 0.0000” rather than 0.0111”. The invoice stated that the headspace was good. Am I wrong in my assumption that this measurement represents headspace?

I can still seat a 69 grain Nosler HPBT against the lands and still have one bullet diameter of bullet seated depth. I am concerned that the lighter bullets, 55 grains and less, will have a long bullet jump when seated. Do you see this as a concern?

Before I contact Savage, I want to make sure that I have issues that need to be discussed. I would greatly appreciate your comments and recommendations.

Thanks

 

[L1986]

A little hard to follow what you’re asking here but it sounds like you are bumping your shoulders too far and need to screw your die out a bit to get the desired shoulder bump of around .002. If your original chamber was too tight at the base it probably was throwing measurements off so I would throw your original numbers out the window.
As far as jumping light bullets I have always found a depth that gave great accuracy far from the lands so you should be fine there.

 

[SKWERLZ]

I have no issues with lots of jump with most bullets.

Just back off your sizing die approximately 8-9 thou to get your shoulder bump in a happy place.

 

[Pirate69]

If I were to purchase a box of commercial rounds that were loaded to SAAMI specs, I would have a headspace of 0.0111". Would you be happy with that?

 

[geo.ulrich]

perhaps the reamer that was used to open the chamber had a longer free bore

 

[Pirate69]

To be clear about what I am asking comments on. Do I have an acceptable headspace issue? Since I like to load rounds at or into the lands, has the repair affected the ability to seat lighter bullet weights at or into the lands. Would you be satisfied with that situation overall if it were your rifle.

Lastly, I was asking if anyone saw any errors in my analysis. I think the potential range of bullet weights and seating depths has been negatively impacted by the repair. Just want to make sure that I am accurate in my discussions with Savage.

Yes, I realize that there are ways of addressing the issues within limitations. But again, I will potentially be giving up some flexibility.

 

[Pirate69]

perhaps the reamer that was used to open the chamber had a longer free bore

That sounds like a possible reason. I think Savage should be able to provide the data on their current freebore cuts.

 

[Jeff Porter]

Seating light bullets into the lands is a different measure than head space. Case head to shoulder datum line determines headspace. From that datum line forward to the rifling is the seating depth. Typically measured as base of case to bullet ogive and called “jump” sounds like the new reamer had a longer free bore.

Edit to add. You said that in the first post. You cannot ad steel back once it has been cut out.

 

[DShortt]

To be clear about what I am asking comments on. Do I have an acceptable headspace issue? Since I like to load rounds at or into the lands, has the repair affected the ability to seat lighter bullet weights at or into the lands. Would you be satisfied with that situation overall if it were your rifle.

A quick Google search shows the headspace dimension for .223 Rem is 1.467.

You reported a measurement of 1.4615.

So either your headspace dimension is actually short by about .005", your tooling you are measuring with is not in spec, or your cases have not completely fire-formed to the chamber.

 

[tobnpr]

I'm confoozed...
It's a nutted barrel, so you can set headspace (defined as clearance between boltface and casehead) wherever you choose.

Freebore is a completely separate element.

In order for Savage to deepen the chamber, they would have needed to face the barrel breech by the same amount to maintain the same (roughly .125) casehead protrusion.

Relying on sized cases for chamber datum measurements is not correct- only a go gauge can be used for this.

 

[urbanrifleman]

I'm confoozed...
It's a nutted barrel, so you can set headspace (defined as clearance between boltface and casehead) wherever you choose.

Freebore is a completely separate element.

In order for Savage to deepen the chamber, they would have needed to face the barrel breech by the same amount to maintain the same (roughly .125) casehead protrusion.

Relying on sized cases for chamber datum measurements is not correct- only a go gauge can be used for this.

2nded

 

[Webster]

To be clear about what I am asking comments on. Do I have an acceptable headspace issue? Since I like to load rounds at or into the lands, has the repair affected the ability to seat lighter bullet weights at or into the lands. Would you be satisfied with that situation overall if it were your rifle.

Lastly, I was asking if anyone saw any errors in my analysis. I think the potential range of bullet weights and seating depths has been negatively impacted by the repair. Just want to make sure that I am accurate in my discussions with Savage.

Yes, I realize that there are ways of addressing the issues within limitations. But again, I will potentially be giving up some flexibility.

Why do you like to load touching or jam? Shoot whatever is the most accurate. I like to be about 0.010" off touch so if I extract a loaded round I don't leave the bullet in the barrel and dump powder into the action. What is the rifle used for? Forty years of reloading never measured anything but overall length. Last 10 years I measured bump. I set it at .002". Both my rifles can shoot under .400" for GH hunting.

Sounds like a lot of guys don't think they have a problem until they start measuring things.

 

[DR_2297]

COL has nothing to do with headspace on a bottleneck cartridge. In this case I assume the reamer used has a different throat geometry than what chambered it originally.

Secondly - how did you measure HS? Measured a fired cartridge with a comparator? Some other way? You have the ability to set HS wherever you wish simply by turning the die out a fraction of a turn. If you are truly concerned and want to know if the barrel is set, within spec then get a set of HS gauges. I always use a Go gauge to zero my comparator because the numbers they give you never really align to anything on a drawing and seldom are 2 the same.

 

[L1986]

If I were to purchase a box of commercial rounds that were loaded to SAAMI specs, I would have a headspace of 0.0111". Would you be happy with that?

This isn’t exactly what you said in your op…you said the difference between a fired case in your new chamber and a case resized with your die is .0111. If your die is set up according to the instructions in the box a lot of them will severely oversized the case. You need to measure the difference between a fired case and a factory case to tell if your internal firing is stretching them excessively. If the difference between new and fired is excessive then you have too much headspace and it needs to be addressed (most likely you can loosen the barrel nut and reset headspace). This would also change where your bullets are contacting the lands.

 

[6MMsteve]

Just Take a pc of brass new you like to shoot put one pc of tape on it reheadspace your rifle to that brass, then shoot measure and run through press//and all will be good

 

[jsn]

OP,

Your comparitor will probably have a slight radius on the surface that contacts the brass shoulder, it will not be a perfect match to the SAAMI drawing or the Go and No-Go gauges.

Here is an older chart showing the differences in chamber dimensions, probably from when Sierra 77 and 80 grain bullets and the Hornady 75's were the only common heavies:

http://www.ar15barrels.com/data/223-556.pdf

 

[tobnpr]

Your comparitor will probably have a slight radius on the surface that contacts the brass shoulder, it will not be a perfect match to the SAAMI drawing or the Go and No-Go gauges.

Exactly.
That's precisely why it's called a "comparator"- it is ONLY a reference, not a standard.

 

[Webster]

COL has nothing to do with headspace on a bottleneck cartridge. In this case I assume the reamer used has a different throat geometry than what chambered it originally.

Secondly - how did you measure HS? Measured a fired cartridge with a comparator? Some other way? You have the ability to set HS wherever you wish simply by turning the die out a fraction of a turn. If you are truly concerned and want to know if the barrel is set, within spec then get a set of HS gauges. I always use a Go gauge to zero my comparator because the numbers they give you never really align to anything on a drawing and seldom are 2 the same.

Never had to measure headspace on any rifle I ever owned. Is it a form of OCD?

 

[DShortt]

Never had to measure headspace on any rifle I ever owned. Is it a form of OCD?

I presume the OP is being cautious because the original chamber/barrel was out of spec.

Can't say as I blame him for that. Assumption is the Mother of all screw-ups.

 

[DShortt]

I'm confoozed...
It's a nutted barrel, so you can set headspace (defined as clearance between boltface and casehead) wherever you choose.

Freebore is a completely separate element.

In order for Savage to deepen the chamber, they would have needed to face the barrel breech by the same amount to maintain the same (roughly .125) casehead protrusion.

Relying on sized cases for chamber datum measurements is not correct- only a go gauge can be used for this.

I would bet Savage replaced the barrel if indeed it was out of spec.

And I agree, headspace needs to be checked with GO and NO GO gauges. Many use a fired case but that's not what I was taught.