Headspace & Accuracy

[rammac]

Depending on neck tension, what makes you think you have any headspace after the firing pin pushes the case up?
I know years ago I read on BRC a guy did some testing with dead primers measuring how much the firing pin pushes the cases up on jammed bullets. It was more than you would think. I am not sure the results would be quite the same if the case actually fired.
I kinda think that is why jumped bullets can be so accurate. When the firing pin shoves the case up the shoulder centers the cartridge. But then what the hell do I know.

OK, I've got to ask, just where do you think headspace is and what is the reason for it?

I don't intend to take this off topic but I'm curious how someone could think that headspace disappears when the cartridge case is pushed forward.

 

[johnnyi]

I’m a fan of this process that Wheeler posted on YouTube...

I have had much more consistent results with this process vs simply pushing the shoulder back .002 based on the caliper measurement alone.

 

[Dusty Stevens]

All new brass needs to be fl sized to properly fit your chamber before they are ever loaded. They are all over the place

 

[swd]

No less then .002" and no more then .003" is what I get best results from in my 1000-BR rifles.

Listen to Donovan. You'll never have to worry about your cases being a problem with these clearances.

 

[KenOath]

No less then .002" and no more then .003" is what I get best results from in my 1000-BR rifles.

Dmoran,
Have you found this clearance to be ok with straight BR? I never tried anymore clearance than .001” so just curious..

Cheers Rushty

 

[dmoran]

@Rushty

I don't have a straight 6BR, but if I did that is what I would use for it as well. That is the amount I like and use in 6Dasher, 6PPC, 243, 243-Ack, 300-WSM, to name a few.

 

[moondog]

So, it wasn't shooting until you bumped shoulders a bunch? How much of a change did you see?

This subject of bumping shoulders and seeing results on paper is very interesting.

All of this was from 2x fired Lapua brass. I'm not sayin it's right, but it is what it is. I was getting ready to pull the barrel till I stumbled on it. I know I'm not the only one who has run into this on the BRA.
I do have another Reamer coming.

 

[Stan Taylor]

We'll I am going to put my 2 cents in here if I don't get chastised buy someone I always encourage my gunsmith to cut a stub off the end of barrel and chamber deep enough for a shoulder measurement with a set of calibers or a dial indicator on a stand it works perfectly for shoulder bump.

 

[rwj]

We'll I am going to put my 2 cents in here if I don't get chastised buy someone I always encourage my gunsmith to cut a stub off the end of barrel and chamber deep enough for a shoulder measurement with a set of calibers or a dial indicator on a stand it works perfectly for shoulder bump.

Good idea for measuring! Do you notice any case wall bulging when used to bump shoulders?

 

[Stan Taylor]

Good idea for measuring! Do you notice any case wall bulging when used to bump shoulders?

The good thing about a stub is it is off your chamber reamer and on a fresh barrel you can locate a good measures for the lead in your throat for seating depths answer to your question no I haven't had a problem with bulge a lot more accurate than buying a comparator the gunsmith that does your work can provide this to for probably less tha ordering a comparator.