A Real Head Scratcher-30-06 Headspace Issue

[skipglo]

While I'm by no means new to reloading, this one has got me scratching my head big time. I purchased a Weatherby Vanguard Range Certified (guarantee less than 1 moa) new not too long ago along with 100 new Lapua brass cases. Originally stated load development with IMR 4895 and then the powder shortage set in and I had to switch to IMR-4064 as I was able to get 14lbs of it. Throughout load development I only neck sized. Best load seems to be 49.0grs IMR-4064 with bullet seated .011 off the lands with groups 50% of the time under 1/2 inch and some 1/4 inch and the other 50% around 3/4 inch to just under. In an attempt to get more consistent groups I had already eliminated everything I could think of....EXCEPT headspace as I was only neck sizing, nonetheless I figured let me just check headspace...and man was I in for a surprise.

Of the 100 lapua cases fired out of the Weatherby the cases measure anywhere from .003 to .017 BELOW max headspace for 30-06 using Wilson case gauge along with Wilson case gauge depth micrometer. So I took 8 cases that all had the same headspace and loaded them up and shot them today. Four shot 3/4 inch group and four shot 3/8 inch group @100yds and once again noticed several primers were slightly above flush (having seated them .002 below flush with tight primer pockets. A buddy of mine at the range said you might have too much headspace so measure the case with the primers in them and then measure w/o the primer. The result are as follows: with primer .002 - .004 below max. w/o primers .004 - .012 below max. so at this point I pulled out my Hornady Headspace Gauge and cases measure 2.035 - 2.040 now If I'm reading SAMMI spec correctly max headspace is 2.052 -.007 setting minimum at 2.045. So best case I'm .005 shorter than minimum and worst case .007 shorter. How in the heck is this happening, I thought cases were supposed to stretch to eventually fit the chamber....remember I haven't FL sized any. I'm lost and would appreciate any insights. Thanks.

I will normally full length size after fire forming all the new cases....then trim all the cases to the shortest case length....this way everything has the exact same starting point and cases should now stretch uniformly!

 

[jdyoung]

While I'm by no means new to reloading, this one has got me scratching my head big time. I purchased a Weatherby Vanguard Range Certified (guarantee less than 1 moa) new not too long ago along with 100 new Lapua brass cases. Originally stated load development with IMR 4895 and then the powder shortage set in and I had to switch to IMR-4064 as I was able to get 14lbs of it. Throughout load development I only neck sized. Best load seems to be 49.0grs IMR-4064 with bullet seated .011 off the lands with groups 50% of the time under 1/2 inch and some 1/4 inch and the other 50% around 3/4 inch to just under. In an attempt to get more consistent groups I had already eliminated everything I could think of....EXCEPT headspace as I was only neck sizing, nonetheless I figured let me just check headspace...and man was I in for a surprise.

Of the 100 lapua cases fired out of the Weatherby the cases measure anywhere from .003 to .017 BELOW max headspace for 30-06 using Wilson case gauge along with Wilson case gauge depth micrometer. So I took 8 cases that all had the same headspace and loaded them up and shot them today. Four shot 3/4 inch group and four shot 3/8 inch group @100yds and once again noticed several primers were slightly above flush (having seated them .002 below flush with tight primer pockets. A buddy of mine at the range said you might have too much headspace so measure the case with the primers in them and then measure w/o the primer. The result are as follows: with primer .002 - .004 below max. w/o primers .004 - .012 below max. so at this point I pulled out my Hornady Headspace Gauge and cases measure 2.035 - 2.040 now If I'm reading SAMMI spec correctly max headspace is 2.052 -.007 setting minimum at 2.045. So best case I'm .005 shorter than minimum and worst case .007 shorter. How in the heck is this happening, I thought cases were supposed to stretch to eventually fit the chamber....remember I haven't FL sized any. I'm lost and would appreciate any insights. Thanks.

Get some Cerrosafe and cast the chamber, follow the directions as to exactly when to measure and make a diagram of your chamber . That way you will know how your chamber measures. You'll have a base line.

 

[59FLH]

If I'm reading SAMMI spec correctly max headspace is 2.052 -.007 setting minimum at 2.045.

Your not reading it correctly, head space reads from the chamber not the cartridge the correct SAAMI values for 30-06 head space are 2.0487" - 2.0587".

Assuming this is a new factory chambered rifle, I think you have an error in your measurements. Are you using the Hornady C375 bushing?
If your confident you measurements are correct and it is a factory chambered barrel I recommend you take it back to the place of purchase and have them check it. It may need a trip back to Weatherby.

 

[ThrdKllr]

If you wanted to try a little experiment, you can expand the case neck to 32 or 338 caliber and then neck size to 30 caliber in small increments until the bolt closes with slight resistance and then fire form your new brass and it should fit perfectly. This provides a false shoulder for it to headspace on. I get nervous jamming bullets in to the lands with the chamber that close to my face.

 

[Chas1]

If you wanted to try a little experiment, you can expand the case neck to 32 or 338 caliber and then neck size to 30 caliber in small increments until the bolt closes with slight resistance and then fire form your new brass and it should fit perfectly. This provides a false shoulder for it to headspace on. I get nervous jamming bullets in to the lands with the chamber that close to my face.

What charge weight would you suggest for fire forming given min max is 44.9 - 52.1 ?

 

[243winxb]

Fire some factory ammo. Measure head to datum.

 

[Chas1]

I barely started to seat 1 primer in case that was .003 below max headspace and another primer seated in case that was .017 below max and closed bolt gently on each then measured with hornady comparator with primers left in and both were 2.045 so my thinking is I could use that as baseline to compare other cases....YES ? NO ? In the meantime I'm waiting for go gauge and box of factory ammo to arrive.

 

[ThrdKllr]

Yes. 2.045 is your measurement with your comparator. Appears that your Lapua brass is a hair on the short side.

 

[59FLH]

.

Bad C&P

 

[59FLH]

I barely started to seat 1 primer in case that was .003 below max headspace and another primer seated in case that was .017 below max and closed bolt gently on each then measured with hornady comparator with primers left in and both were 2.045 so my thinking is I could use that as baseline to compare other cases....YES ? NO ? In the meantime I'm waiting for go gauge and box of factory ammo to arrive.

This reads as if one case increased in length .014" just from being chambered. Or one case decreased in length .014"

Case #1 is -.003", Case #2 is -.017", After closing the bolt they both measure the same.

Am I mistaken or are you really using your bolt face to seat primers as part of your head space measurement regiment?

I'm confused

 

[Chas1]

Am I mistaken or are you really using your bolt face to seat primers as part of your head space measurement regiment?

I'm confused

Yes, just as a test

 

[ThrdKllr]

The gauge is to compare fired brass to sized. Not chambers.

Light loads in 30-06 will do 2 things.
1. Expand the case body and make the head to datum & trim length shorter.
2. A fired case may not except a bullet or it will be very snug. The neck has not fully expanded because of low pressure.

Try f/l sizing a couple of fired cases with the f/l die backed out a half of a turn( about .035) and see what kind of measurement you come up with

 

[jdyoung]

This reads as if one case increased in length .014" just from being chambered. Or one case decreased in length .014"

Case #1 is -.003", Case #2 is -.017", After closing the bolt they both measure the same.

Am I mistaken or are you really using your bolt face to seat primers as part of your head space measurement regiment?

I'm confused

Yes, just as a test

You don't have to and shouldn't use live primers for that test. Spent primers work just as well.

 

[436]

While I'm by no means new to reloading, this one has got me scratching my head big time. I purchased a Weatherby Vanguard Range Certified (guarantee less than 1 moa) new not too long ago along with 100 new Lapua brass cases. Originally stated load development with IMR 4895 and then the powder shortage set in and I had to switch to IMR-4064 as I was able to get 14lbs of it. Throughout load development I only neck sized. Best load seems to be 49.0grs IMR-4064 with bullet seated .011 off the lands with groups 50% of the time under 1/2 inch and some 1/4 inch and the other 50% around 3/4 inch to just under. In an attempt to get more consistent groups I had already eliminated everything I could think of....EXCEPT headspace as I was only neck sizing, nonetheless I figured let me just check headspace...and man was I in for a surprise.

Of the 100 lapua cases fired out of the Weatherby the cases measure anywhere from .003 to .017 BELOW max headspace for 30-06 using Wilson case gauge along with Wilson case gauge depth micrometer. So I took 8 cases that all had the same headspace and loaded them up and shot them today. Four shot 3/4 inch group and four shot 3/8 inch group @100yds and once again noticed several primers were slightly above flush (having seated them .002 below flush with tight primer pockets. A buddy of mine at the range said you might have too much headspace so measure the case with the primers in them and then measure w/o the primer. The result are as follows: with primer .002 - .004 below max. w/o primers .004 - .012 below max. so at this point I pulled out my Hornady Headspace Gauge and cases measure 2.035 - 2.040 now If I'm reading SAMMI spec correctly max headspace is 2.052 -.007 setting minimum at 2.045. So best case I'm .005 shorter than minimum and worst case .007 shorter. How in the heck is this happening, I thought cases were supposed to stretch to eventually fit the chamber....remember I haven't FL sized any. I'm lost and would appreciate any insights. Thanks.

Why don't you try actually a fire forming load for your .30-06 case and see if that helps to form it to the chamber. How are you lubing your case, dry? or liquid? It sounds like they aren't stretching in the web of the case right? no bright ring. Just asking.