Switch barrel problem

[Nude nut]

Gday,
I have an issue that I think I have worked out myself but still would like to hear others thoughts.
I was at my club match saturday and my load did not perform as usual shooting at 600yrds I did expect some change due to bumping the shoulder back as this was 6x fired lapua brass neck sized brass in 308.
Now my tools will read different to others I dont have a .400 bush for my headspace guage so I used a .410 bush in my oal guage this not about comparing numbers but more the varibles in mine.
So 6x fired case base to shoulder-1.614.5
bumped back to 1.613
Now fired after shoulder bump 1.608.
Now im no expert but this leads me to the conclusion that switching barrels from week to week that im putting them on tighter than usual.
Do yoous agree or have other thoughts .

Cheers Trev.

 

[TAJ45]

I was in a bud's shop and I THINKI remember him saying that he could get abt .0005", maybe a bit more with a good honk down.

However, with the same pc of brass, have you tried it with ea bbl to see if one was looser, bolt close differences? Maybe not quite chambered to the same depth?

 

[jonbearman]

Was the bolt closing a bit stiff. That is a lot of crush if your original measurement is correct .

 

[Nude nut]

The barrels are different calibers so no can do.
Cheers Trev.

 

[Nude nut]

No bolt wasnt hard to close I thats whats got me confused as you say thats a big difference.
I will go and measure again just to make sure.
Yes measurements are correct.
Cheers Trev.

 

[Dans40X]

Switch Bbl set up on a Salvage action?
If you are measuring w/vernier,dial or electronic calipers the industry standard is .003000000000000000000000000000000000000000000000000000000000000"
3 one thousandths of an inch.

Micrometers,dial indicators,height stands on a granite or iron surface plate will reveal true dimensions.

 

[Nude nut]

Switch Bbl set up on a Salvage action?
If you are measuring w/vernier,dial or electronic calipers the industry standard is .003000000000000000000000000000000000000000000000000000000000000"
3 one thousandths of an inch.

Micrometers,dial indicators,height stands on a granite or iron surface plate will reveal true dimensions.

Confimed with Innovative Tecnoligies headspace digital indicator.
The action is a stiller viper ss.
First checked with vernier then checked sized brass to fired with digital indictor it indicates 5 thou shorter than the szed brass from base to datum on shoulder.
Cheers Trev

 

[expiper]

Trev,,,,go by feel ,,,spend less time measuring and more time shooting,,,Roger

 

[Nude nut]

Trev,,,,go by feel ,,,spend less time measuring and more time shooting,,,Roger

I shoot plenty but shoulders are moving backwards insted of forward after firing I want to know why as I said I think I screwed the barrel on a wee bit tighter saturday I took it off tonight and put it back on hand tight as I have in the past saturday I used the action wrench.

Cheers Trev.

 

[Ggmac]

If it true you will not compress the shoulder a measurable amount

 

[rain164845]

Is it a savage with a nut that can cause variable headspace, or a shouldered barrel?

 

[Dans40X]

rain164845-
post #7(lower RH corner to left of Like Reply) by the OP states-

The action is a stiller viper ss.

 

[Nude nut]

Is it a savage with a nut that can cause variable headspace, or a shouldered barrel?

No savage its a stiller viper ss rblp with truflite barrel I have swapped between 308 and 6.5x47 several times now and both loads have shot very well the last shoot with the 308 went awol.
As I took the barrel off yesterday and put it back on as hard as I could by hand I will shoot same ammo and measure base to shoulder again and see what I get.
Think I will put an index mark on action and barrel for further reference,I was going to load up some palma brass for next match but in virgin state they are longer base to shoulder than the fired brass is will see what happens after I shoot ammo nxt weekend and go from there.
Oh and no barrel nut just screws up to the action.

Cheers Trev.