headspace?

[Axis II]

thanks Ron. when I meant sloppy chamber I remember the heavy barrel brass that was new from BB after I sized it would fit without resistance in the regular barrel but tight in the heavy barrel so I figured it was just longer or sloppy seeing how its a $275 sport barrel.

I wanted to make sure the putting the case in the comparator and tightening the calipers then zeroing it and sizing and checking was correct. I tried zeroing the calipers on the comparator and then put the case in but I kept dropping everything. thanks again now I can load some ammo without worrying about it.

 

[Bart B.]

I don't care where the shell holder is relative to the die bottom when shoulder setback is what you want it to be. Correct amount is what leaves about .002" to .003" head clearance in your rifle. Head Clearance = space between case head and bolt face when the round fires.

Setback varies with the spring of the press, lubricant type and how much is used plus how long one leaves the press ram all the way up.

Best consistency on setting shoulders back so all resized case have the same headspace (+/- .001") is a set of Redding competition shell holders. They're made in .002" heights above the standard .125" for shell holders. If you get the right setback with one of them, doing all with the shell holder stopping against the die bottom will give the smallest spread in case headspace.

 

[RussellC]

I don't care where the shell holder is relative to the die bottom when shoulder setback is what you want it to be. Correct amount is what leaves about .002" to .003" head clearance in your rifle. Head Clearance = space between case head and bolt face when the round fires.

Setback varies with the spring of the press, lubricant type and how much is used plus how long one leaves the press ram all the way up.

Best consistency on setting shoulders back so all resized case have the same headspace (+/- .001") is a set of Redding competition shell holders. They're made in .002" heights above the standard .125" for shell holders. If you get the right setback with one of them, doing all with the shell holder stopping against the die bottom will give the smallest spread in case headspace.

Thankyou Bart and Walkalong! This is starting to make sense now, another good thread. I have one question and I think it will be as clear as it is going to get for me:

OK, this is for semiautomatic, .223 so as you guys have stated, shoulder is bumped back a little more than Bolt guns, 3 or 4 thousandths, right?

If I take a piece of once fired that I have de primed and put in the RCBS headspace comparator, I see
1.461 inches. I size it and get 1.454 (which is what a commercial winchester I had on hand measured and I set my die for). This is 7 thousandths, which appears to much right?

If I deprime a piece I have reloaded and fired I get a thousandth or so less, but I am still bumping 5 thousandths...a bit much right?

If I am measure 1.461, I should set the die to result in 1.458ish? I have no Go headspace guage or I guess I might answer my own question, and I am getting ready to order one, any suggestions? Is the winchester ammo a little short?

Thanks

Russellc

 

[Walkalong]

Factory ammo has to fit any SAMMI spec chamber out here, including those with minimum headspace. They tend to be smaller than most guns need.

Yes, if your fired brass measures 1.461 with the comparator, then you need to be at an average of 1.458. I always get an average of several fired cases and then set up the sizer to get an average .002 or .003 below that, depending on what I am loading. I do .003 for 300 BLK in my AR and it has worked fine.

You might find you have a couple of very tough cases which resist sizing. You can scrap them, or adjust your sizer down until it responds, but then you have to re-set the sizer. I generally just scrap those.

 

[RussellC]

Factory ammo has to fit any SAMMI spec chamber out here, including those with minimum headspace. They tend to be smaller than most guns need.

Yes, if your fired brass measures 1.461 with the comparator, then you need to be at an average of 1.458. I always get an average of several fired cases and then set up the sizer to get an average .002 or .003 below that, depending on what I am loading. I do .003 for 300 BLK in my AR and it has worked fine.

You might find you have a couple of very tough cases which resist sizing. You can scrap them, or adjust your sizer down until it responds, but then you have to re-set the sizer. I generally just scrap those.

Thanks, that's what I figured. I have several 100 that are at 1.454, I will know better next time. Checking ones I have "refired" that were sized that way shows them blown back out to 1.461-1,459...

Russellc

 

[RussellC]

Factory ammo has to fit any SAMMI spec chamber out here, including those with minimum headspace. They tend to be smaller than most guns need.

Yes, if your fired brass measures 1.461 with the comparator, then you need to be at an average of 1.458. I always get an average of several fired cases and then set up the sizer to get an average .002 or .003 below that, depending on what I am loading. I do .003 for 300 BLK in my AR and it has worked fine.

You might find you have a couple of very tough cases which resist sizing. You can scrap them, or adjust your sizer down until it responds, but then you have to re-set the sizer. I generally just scrap those.

Small problem with 1.458, it wont pass guage test with either my sheridan or Wilson. With the Wilson case gauge depth micrometer on top, it shows about 4 one thousandths too long. I guess 1.454 wasn't so far off? By tuesday I should have the RCBS case micrometer, but if it doesn't pass the others....confused... if 1.461, it appears I must push shoulder 7 thousandths? Or should I try one at 1.458 with no primer or powder, measure before and after bolt closes on it? assuming it will close? Then back twist die in until it will?

Russellc

 

[Walkalong]

Are you sure it isn't something else holding the sized case up in the gauge, not the shoulder?

What do you get when you put a fired case in the Wilson?

How does the "commercial winchester" case sit in the gauge?

 

[RussellC]

The fired case doesn't go all the way in.
Case and gauge both cleaned. The Winchester round fits as it should, with the depth micrometer on top it shows 2 thousandths under max.

Russellc

 

[RussellC]

I am firing up computer, and will post some pics, this is by phone

 

[RussellC]

I am firing up computer, and will post some pics, this is by phone

These pics are of the winchester round in the Hornady Comparator, winchester round in the Wilson gauge with wilson depth micrometer on it, and of a unfired LC brass in the Wilson gauge.

Russellc

 

[Blue68f100]

Just a though....

Are these new dies, been cleaned? The reason I ask I have received new sets where the sizing die body and bullet seating die body were assembled wrong. Seating die in the sizing die. If this is the case the sizing die (seating body) will not move the shoulder in the correct areas. Take a quick look at the markings and confirm they are correct. If correct you may just need to turn the sizing die down more till it fits your chamber.

If you have away to anneal the brass, it would make it easier to push the shoulder back if spring back is causing the problem.

 

[RussellC]

Here the Wilson Gauge and micrometer with its zero slug in place

 

[RussellC]

No, not new dies, I have been using them for some while, a Lee full length sizer die

 

[RussellC]

I will disassemble the die if this will help...it says LEE-223 F3 on the side, and has a depriming pin.

The seating die says LEE-223-13 on the side, the sizing die has flats on it to use to tighten the decapping pin, while seater die has round textured area, no flats, so unless I misunderstand, I think they are right.

 

[Blue68f100]

Have you marked up the round and checked to see where it's binding in the gauge? May trying using a thick film lube too. This will change the dimensions some.

 

[RussellC]

It goes almost all the way in, just the rim is taller than the "Safe" edges. I dont understand how this will help, whatever the gauge is measuring is still showing up on the RCBS comparator, right?

I tried it, nothing. It goes in easy, just stops before the rim seats in far enough...no marks
All lube wiped clean...

 

[RussellC]

Here is a pic of the one I just marked up, (unsized of course) now put in the comparator

 

[RussellC]

I am looking for a thread where I first heard of this RCBS Headspace comparator, if I recall correctly the poster showed his round in the comparator that was also at 1.454, not that is unequivocally proved correct by that...

Russellc

 

[RussellC]

My 1.454 cases previously sized pass the "feel test" in the Wilson gauge w/o the micrometer, as well as the sinclair gauge. As they get around 1.452, they "feel" on the short side.

I know these Comparators like my commercial unit, or the DIY version Walkalong has are just a reference number, but for what its worth, the insert and its holder are 2" before zeroing. The RCBS unit allegedly rests on the datum line, I dont know about the diy versions

It may be I havent done as Walkalong suggested, measure a bunch and take an average...some of these I have fired are 1.457-8, and minus 3 thousandths wouldnt be so far off where I am.

I think I will try the other thing Walkalong said, slowly turn the die in until it passes tests with gauge's "feel" test. and confirm with the comparator, and the RCBS precision thing that is on the way.

Russellc

 

[RussellC]

I am looking for a thread where I first heard of this RCBS Headspace comparator, if I recall correctly the poster showed his round in the comparator that was also at 1.454, not that is unequivocally proved correct by that...

Russellc

I keep calling it "RCBS comparator" it is Hornady...I think the take away here is that with the variations in the brass, one can only strike a middle ground. As such, any setting close will result in some that are on the money, some over, some under. At least the majority will be worked a minimal amount. As long as nothing is seriously over or short, of course!

Russellc

 

[Walkalong]

Something is weird. You didn't get hold of a partially sized case where the shoulder was moved forward did you? Does that "long" case chamber?

 

[RussellC]

Something is weird. You didn't get hold of a partially sized case where the shoulder was moved forward did you? Does that "long" case chamber?

Not sure which one you are referring to? The unsized LC brass that was 1.460 was from Brass bombers, still had crimped in primers. One piece, that I sized down to 1.458 was the result of slowly screwing down the die until I hit that. Oddly, the first "sizing" with the die too far out resulted in it growing a few thousandths, then as I turned it in I eventually got 1.458...that was the one that was "beyond max" in the Wilson gauge, was in the pics.

Looking at several pieces of brass, I am finding them from 1.458 to 1.461, with one odd ball that measured 1.465!...this is as they came from BrassBombers, deprimed and cleaned by me, but not sized.

I will make some more with 3-4 thousandths and see how they fit. If they don't, will slowly screw it down until it does. As previously stated, 1.454 ( on the Hornady Head space comparator measures perfectly "feel" wise in both the Sheridan, and the Wilson gauge. With the Wilson case depth micrometer, it shows 2.5 or so thousands below the Max (zero) line.

I was going to buy a really nice set of 11 .223 case gauges, ranging a thousandth larger as they go up, from minimum to "No go", but it was 200 bucks and change. This would provide the proof I suppose.

Russellc

 

[Blue68f100]

With the painted brass put it in the case gauge and see where it's rubbing, or chamber and look. This will tell you if the round has expanded at the base to a point causing problems, and/or where it's rubbing.

 

[RussellC]

With the painted brass put it in the case gauge and see where it's rubbing, or chamber and look. This will tell you if the round has expanded at the base to a point causing problems, and/or where it's rubbing.

I did, see post #66....it's just beyond SAMMI max.

 

[Walkalong]

with one odd ball that measured 1.465!...this is as they came from BrassBombers,

So the ones that were so long and stuck out of the gauge weren't fired in your gun? Maybe I missed something.

Size five of those BB cases you bought to fit the Wilson gauge. (Headspace) Then measure where they sit in the Wilson gauge. (Using a depth gauge or the piece on the end of a dial caliper). Then fire them in your gun and get measurements with the Gauge, as well as with your comparator.