Max head space?

[500Stroker]

On a quality built custom bench gun with a BAT B action what is the max head space that is allowed?
6BRX. lapua fire formed brass, 108 Berger bullet.
Thanks in advance

 

[4xforfun]

Are you asking how much you should bump the shoulders back?

 

[500Stroker]

Are you asking how much you should bump the shoulders back?

No
What is the max allowed before you will see issues.
I normally bump .002

 

[DRNewcomb]

Help me out here. If you are resizing to just bump the shoulder back, wouldn't headspace (in the normal usage of the word) become irrelevant? In this case, "excessive" headspace just becomes your own personal wildcat?

 

[Joe Salt]

Watch one of Gordy Gritters Videos he explains the way he does it.

Joe Salt

 

[Eddie Harren]

No
What is the max allowed before you will see issues.
I normally bump .002

Are you asking how far you can bump the shoulders before you have issues?

 

[NorCalMikie]

The less you bump the shoulders back, the less chance you have of causing headspace issues. .002 or less would be a good starting point.
YOU will determine the "brass headspace" as you resize your brass. Bump the shoulders back "too far" as you size your brass and you end up with excessive headspace.
And, right or wrong, anything is allowed. Depends on who built the rig and set the "barrels" inital headspace.
Keep pushing the shoulders back on each resize and you run the chance of case head separation over time, besides overworking the brass.

 

[Lapua40X]

Sroker, I have a bug hole shooting 6BR - originally a bench gun that is now set up for tactical competition. I don't like the unreliable readings that can occur when trying to measure headspace with those headspace gauges (e.g. Hornady) where the slightest variation in the position of the case in the caliper or some other factor can cause doubt. I simply remove the firing pin and ejector from the bolt and use the Redding progressive competition case holders (https://ads.midwayusa.com/product/525874/redding-competition-shellholder-set-1-308-winchester-30-06-springfield-45-acp?cm_mmc=pf_ci_google-_-Reloading+-+Dies+&+Shellholders-_-Redding-_-525874&gclid=CKbsnLLAiNMCFRBEfgodsE8ElA) to push the shoulder back just far enough so that the bolt handle falls unassisted when I close the bolt on the resized case. Never had any headspace problems using that method and I'm always sure of consistency.

 

[butchlambert]

Sroker, I have a bug hole shooting 6BR - originally a bench gun that is now set up for tactical competition. I don't like the unreliable readings that can occur when trying to measure headspace with those headspace gauges (e.g. Hornady) where the slightest variation in the position of the case in the caliper or some other factor can cause doubt. I simply remove the firing pin and ejector from the bolt and use the Redding progressive competition case holders (https://ads.midwayusa.com/product/525874/redding-competition-shellholder-set-1-308-winchester-30-06-springfield-45-acp?cm_mmc=pf_ci_google-_-Reloading+-+Dies+&+Shellholders-_-Redding-_-525874&gclid=CKbsnLLAiNMCFRBEfgodsE8ElA) to push the shoulder back just far enough so that the bolt handle falls unassisted when I close the bolt on the resized case. Never had any headspace problems using that method and I'm always sure of consistency.

So what if your headspace is good, unbeknownst to you, but closing the bolt is still hard? Bunch of folks, including me, have continued to use the Redding shell holders or screwed the die further in to allow the bolt to close. This will eventually allow the bolt to feel good as you have sized the base further, but you have really created a head space problem in doing this.

 

[NorCalMikie]

Bunch of folks, including me, have continued to use the Redding shell holders or screwed the die further in to allow the bolt to close.

Could it be that the case body got fat and the headspace was still good? One trip thru a body die will answer that question and solve that problem. We've seen the questions and answers to "shoulder bumping" rolleyes but if you only bump, you need to body size once in a while.

 

[butchlambert]

Could it be that the case body got fat and the headspace was still good? One trip thru a body die will answer that question and solve that problem. We've seen the questions and answers to "shoulder bumping" rolleyes but if you only bump, you need to body size once in a while.

Could it be??

 

[savagedasher]

Could it be that the case body got fat and the headspace was still good? One trip thru a body die will answer that question and solve that problem. We've seen the questions and answers to "shoulder bumping" rolleyes but if you only bump, you need to body size once in a while.

Why not do it every time ?. Smile Larry

 

[BoydAllen]

To the OP, I think that we need more information. Did you bump some cases more than you intended? Are you having bolt closing issues even though your shoulder bump is what it is supposed to be? Tell us more.

 

[500Stroker]

To the OP, I think that we need more information. Did you bump some cases more than you intended? Are you having bolt closing issues even though your shoulder bump is what it is supposed to be? Tell us more.

It's pretty simple, I am trying to use some brass that came out of another rifle that was cut with the same reamer. To make a long story short I have two rifles cambered with the same reamer, by two different gunsmiths. Two sets of brass, when I measure a fire formed case from each set, one set is .004 shorter. Apparently? one of the smiths ran the reamer in .004 deeper creating two different chamber lengths. I am measuring from the shoulder datum point to the base of the brass.
Can I safely shot the shorter brass in the longer chambered rifle without creating problems.

 

[fguffey]

On a quality built custom bench gun with a BAT B action what is the max head space that is allowed?

It is not going to happen on this forum but I wonder if you are talking about the maximum length of the chamber from the shoulder of the chamber to the bolt face. My cases do not have head space. If there was an intent to cut a short chamber the length of the chamber must be determined from the shoulder/datum to the bolt face. If two rifles were chambered with the same reamer and chamber is .004" longer from the shoulder to the bolt face than the other you can use a comparator to determine the differences in length.

Back to your original question and maximum head space/chamber length from the shoulder to the bolt face; most reloaders are lock onto the ideal there are three different length chambers starting with go-gage length and then they move to the no go-gage length chamber and finishing up with the field reject length chamber. I measure all chamber lengths in thousandths. If a reloader has a go-gage length chamber and they choose to reduce clearance they have to increase the length of the case from the shoulder to the case head. I have one rifle hat has a field reject length chamber +.002". It is not necessary for me to fire form cases, it is not necessary for me to form a false shoulder; all that is required when sizing cases for that chamber is to adjust the sizing doe off the shell holder .014" when sizing 280 Remington cases. I know, everyone is 'SOOOO' confused but when I finish sizing the case I have the magic .002" clearance between the shoulder of the chamber and shoulder of the case.

F. Guffey

 

[BoydAllen]

It's pretty simple, I am trying to use some brass that came out of another rifle that was cut with the same reamer. To make a long story short I have two rifles cambered with the same reamer, by two different gunsmiths. Two sets of brass, when I measure a fire formed case from each set, one set is .004 shorter. Apparently? one of the smiths ran the reamer in .004 deeper creating two different chamber lengths. I am measuring from the shoulder datum point to the base of the brass.
Can I safely shot the shorter brass in the longer chambered rifle without creating problems.

Now that is a well written question I would not switch them back and forth, but if you are talking about a one time thing, I think that you can get away with it. The best way to find out would be to do the old paperclip test to see if you can feel a groove on the inside of the case near the head after firing one of the shorter cases in the longer chamber.

There is something else that you might want to think about, that could help minimize the issue if you are working with fired cases from the shorter chamber sizing them for use in the longer chamber. As as you adjust a typical FL die down to the point where it will bump, if you start far enough back, you will see the case "headspace" actually increase slightly from what it was after firing, and then as the die is screwed down from that point cases will start to make contact with the die's shoulder the case's headspace will gradually decrease with each adjustment. You can use this to actually set your shoulders forward a bit, and that should have you in fine shape, but even so, I would keep the brass for each rifle separate. When requested to do so, smiths can usually manage to set headspace to within a thousandth of an existing chamber.

 

[butchlambert]

Brass ain't that expensive. I do not mix brass in different chambers even if "I" chamber them and use the same reamer. I can hit the headspace dimension, but the base of the case may not machine the same.
Just designate brass for each chamber.

 

[mmcu]

Now I understand the question you were asking.

Dedicate brass to the specific rifle; don't mix 'em up!

 

[Lapua40X]

So what if your headspace is good, unbeknownst to you, but closing the bolt is still hard? Bunch of folks, including me, have continued to use the Redding shell holders or screwed the die further in to allow the bolt to close. This will eventually allow the bolt to feel good as you have sized the base further, but you have really created a head space problem in doing this.

"if your headspace is good, ... but closing the bolt is still hard" then the problem you were working on was not headspace. Case length? Neck sizing? Web dimensions? Improperly sized case? As a side note, adjusting your full length sizing die to decrease shoulder set back defeats the purpose of full length resizing. Use a small body instead.

 

[500Stroker]

"if your headspace is good, ... but closing the bolt is still hard" then the problem you were working on was not headspace. Case length? Neck sizing? Web dimensions? Improperly sized case? As a side note, adjusting your full length sizing die to decrease shoulder set back defeats the purpose of full length resizing. Use a small body instead.

Bolt closure is right on.