stagpanther
New member
You can get something similar from Larry Willis at Innovative Technologies, it 's not as fast as your's but it's inexpensive and gets the job done--it's what I use.
Beginner Checking For Case Separation
- Thread starter khaines0625
- Start date
Interesting....
I was wondering how this worked for "quick" measuring and found this:
https://www.youtube.com/watch?v=gBXLHWEJluA
So keeping a 'datum' case for each rifle would seem de riguer.
I was wondering how this worked for "quick" measuring and found this:
https://www.youtube.com/watch?v=gBXLHWEJluA
So keeping a 'datum' case for each rifle would seem de riguer.
I just don’t see .006 head clearance causing case head separation.
Op can make a quick comparator using a 40s&w case to give us a before and after firing but he would have to pull a bullet from a factory round to allow the 40 case mouth to reach the shoulder . Or use some other small Tubular device like a bushing etc .
Actually, this is a 25-06 . 9 mm case might work
Op can make a quick comparator using a 40s&w case to give us a before and after firing but he would have to pull a bullet from a factory round to allow the 40 case mouth to reach the shoulder . Or use some other small Tubular device like a bushing etc .
Actually, this is a 25-06 . 9 mm case might work
stagpanther
New member
It actually works very well but has a small shortcoming in set-up IMO--it requires that the cartridge's head/rim face be as absolutely flat as can be and measured from the same position on the floor plate, having a different position can introduce a slight variation in measurement--and in this case even a .001 variance can make a difference. I just do the measurements a few times to make sure the instrument "settles" on a consistent measurement. Another thing I have to watch out for is to make sure I turn it off after each use--I've killed more than one of the tiny expensive batteries forgetting to do so.
khaines0625
New member
Okay, the Hornady headspace comparator arrived and the results are in. I had some dozen or so unfired rounds from the same lot # as the fired rounds. Tested 6 fired rounds and 7 unfired using the C gauge as instructed in the manual.
Unfired rounds averaged to basically 2.045" inches in headspace.
2.044, 2.047, 2.045 ,2.045, 2.044, 2.045, 2046
Fire rounds averaged 2.051"
2.052, 2.051, 2.051, 2.051, 2.050, 2.051
Headspace stretch of ~0.006" on average. This almost exactly what HiBC was predicting if I'm not mistaken.
It occurs to me that these fired rounds have not been de-primed. I don't have a separate de-primer tool, I only have the Full length resizing / de-primer die to do the job. Still, if I understand it all correctly... If the primer is extending that distance slightly that would mean that the fired rounds headspace length measurement I just did is actually exaggerating the stretch slightly... more indication that the headspace isn't that crazy.
I think this all makes sense to me, but please correct me if I said something stupid. My rifle appears to have acceptable headspace.
Unfired rounds averaged to basically 2.045" inches in headspace.
2.044, 2.047, 2.045 ,2.045, 2.044, 2.045, 2046
Fire rounds averaged 2.051"
2.052, 2.051, 2.051, 2.051, 2.050, 2.051
Headspace stretch of ~0.006" on average. This almost exactly what HiBC was predicting if I'm not mistaken.
It occurs to me that these fired rounds have not been de-primed. I don't have a separate de-primer tool, I only have the Full length resizing / de-primer die to do the job. Still, if I understand it all correctly... If the primer is extending that distance slightly that would mean that the fired rounds headspace length measurement I just did is actually exaggerating the stretch slightly... more indication that the headspace isn't that crazy.
I think this all makes sense to me, but please correct me if I said something stupid. My rifle appears to have acceptable headspace.
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The fired brass should have sprung back a little (0.001"). I would say the head clearance 0.007". It is on the ample side, but still not very likely to cause head separation on first firing.
It is what it is. Got to solve the issue. 0.002" head clearance for bolt gun is good, double for auto loaders.
-TL
Sent from my SM-N960U using Tapatalk
It is what it is. Got to solve the issue. 0.002" head clearance for bolt gun is good, double for auto loaders.
-TL
Sent from my SM-N960U using Tapatalk
khaines0625
New member
To be clear, I only detected bumps with the paper clip in the one with the visible crack and one other. I checked quite a bit.
Im very surprised, good call HiBC ! That seems to indicate abnormally short case or defective case . I’ve shot many 308 rounds from a AR 10 that stretch no less then .008 and never had a case head separation . Now thats on first firing , when I resize said cases I FL size them with a shoulder bump of .003 .
khaines0625
New member
The bullet is still in.
I was able to take off the C gauge portion of the comparator and set the cartridge with bullet in and see that it still had plenty of space before it would bump the end of open cavity in there. Probably even a half inch of extra space.
That being the case, I'd clean the chamber and very very lightly lube the cases before the next firings.
Allows case to slide back against the bolt face instead of sticking up front, and therefore blows the shoulder
forward instead of stretching the rear area near the web.
See https://thefiringline.com/forums/showpost.php?p=4793270&postcount=9 et al...
Allows case to slide back against the bolt face instead of sticking up front, and therefore blows the shoulder
forward instead of stretching the rear area near the web.
See https://thefiringline.com/forums/showpost.php?p=4793270&postcount=9 et al...
Hacksaw a stretched case longitudally. That will let you see what you are probing with the paper clip test. It will look almost like an o-ring groove inside the case.
My estimate of .006 isn't anything magic, I spent many years building plastic injection molds. I had to learn to think in terms of building steel components that would create a cavity /core that would mold precision parts.
A rifle chamber has some similarity. Its relatively predictable if you learn to envision what you are dealing with.
Your rifle seems to be manufactured to correct spec. No reason to think in terms of "fixing" it.
Its great you now have a tool to check your cases and die settings! Sure beats speculating in the dark!
I don't know what happened with your first firing of the factory loads. If you have any unfired ones left try measuring them. Look for short rounds.
I don't know what is best for you. I can tell you what came to be best for me.
I did not like being at the mercy of what loaded rounds are in stock on the shelf.
I sight in precisely. Buying a substitute load meant another range session to verify.
Then there was the hodge podge mix of brass. I prefer knowing my inventory .
The solution (for me) is biting the bullet and buying virgin brass. For myself, Winchester brass has proven a reliable value. There IS other good brass.
For a hunting rifle that does not run a high round count, I'd order 200 pieces.
I'd work out of 100 pieces and have 100 reserve. I'd consider 50 rounds to be a typical range session or a "using" box. The other 50 rounds would be someplace between "being processed" and "loaded and ready"
Primers and bullets come packed 100 at a time. Easy to keep notes and know the brass has been "loaded three times" You can get those nice 50 round plastic boxes.
I suggest getting a set of mechanic's feeler gauges. The little folding kit. Not expensive. Given reloading dies might take your brass back to minimum spec,(.006 stretch) try a .004 feeler gauge between your shellholder and sizing die when you set up. See if that gets you .002 head clearance. Thats good for a bolt gun.
You get the idea? Handloading has benefits.
One more concept. Tolerancing. This actually came from wartime aircraft production. Picture you are Rosie the Riveter making B-17 parts.
Imagine I am a mechanic at some forward air base patching shot up B-17s.
You send me parts held on by 1/4 in bolts. Tolerance on the holes is .257 to .281. Great! You are enamored with PRECISION so you drill the holes .261.
Quality! But there are 12 holes in the part and I have to bolt that part on the aircraft I have at a jungle air strip. The holes don' t quite line up so I have to spend an hour filing to fit,cut and try.
|
HMMM. What if you drilled the holes .279? The part still meets spec,you can control that diameter easily within the .281, and now I have no problem screwing the screws through the .279 holes. The part bolts up!.
Another bonus is ,with all the holes in a B-17,we save some weight!
The gun manufacturers have to make guns to fit the longest SAAMI ammo so the guns accept all spec rounds.
The ammo manufacturers have to make ammo to fit the tightest chambered SAAMI rifles produced.So the make them on the short side.
They might control production of guns and ammo to .001 in production today,
But the headspace will lean toward max, and the ammo will lean toward min, so every round fits every gun easy. Once.
Little concern is given to your brass life.
Point: Your rifle is not an accident on the edge of being a reject. Building to max headspace is probably production standard, as is min spec ammo.
The handloader (who can measure) can deal with it.
You will get plenty of advice to adjust a die 1/4 or 1/8 turn. Thats what I did for years.
The dies have 14 threads per inch. divide one by 14, You will get something like roughly .075 in per turn. HMMM So 1/4 turn is near .020,+ or -.
1/10 turn is .0075 . We are trying to solve a .006 problem. Would we like something more precise and repeatable? Do you think so?
Once again,the feeler gauge between the shellholder and the die
My estimate of .006 isn't anything magic, I spent many years building plastic injection molds. I had to learn to think in terms of building steel components that would create a cavity /core that would mold precision parts.
A rifle chamber has some similarity. Its relatively predictable if you learn to envision what you are dealing with.
Your rifle seems to be manufactured to correct spec. No reason to think in terms of "fixing" it.
Its great you now have a tool to check your cases and die settings! Sure beats speculating in the dark!
I don't know what happened with your first firing of the factory loads. If you have any unfired ones left try measuring them. Look for short rounds.
I don't know what is best for you. I can tell you what came to be best for me.
I did not like being at the mercy of what loaded rounds are in stock on the shelf.
I sight in precisely. Buying a substitute load meant another range session to verify.
Then there was the hodge podge mix of brass. I prefer knowing my inventory .
The solution (for me) is biting the bullet and buying virgin brass. For myself, Winchester brass has proven a reliable value. There IS other good brass.
For a hunting rifle that does not run a high round count, I'd order 200 pieces.
I'd work out of 100 pieces and have 100 reserve. I'd consider 50 rounds to be a typical range session or a "using" box. The other 50 rounds would be someplace between "being processed" and "loaded and ready"
Primers and bullets come packed 100 at a time. Easy to keep notes and know the brass has been "loaded three times" You can get those nice 50 round plastic boxes.
I suggest getting a set of mechanic's feeler gauges. The little folding kit. Not expensive. Given reloading dies might take your brass back to minimum spec,(.006 stretch) try a .004 feeler gauge between your shellholder and sizing die when you set up. See if that gets you .002 head clearance. Thats good for a bolt gun.
You get the idea? Handloading has benefits.
One more concept. Tolerancing. This actually came from wartime aircraft production. Picture you are Rosie the Riveter making B-17 parts.
Imagine I am a mechanic at some forward air base patching shot up B-17s.
You send me parts held on by 1/4 in bolts. Tolerance on the holes is .257 to .281. Great! You are enamored with PRECISION so you drill the holes .261.
Quality! But there are 12 holes in the part and I have to bolt that part on the aircraft I have at a jungle air strip. The holes don' t quite line up so I have to spend an hour filing to fit,cut and try.
|
HMMM. What if you drilled the holes .279? The part still meets spec,you can control that diameter easily within the .281, and now I have no problem screwing the screws through the .279 holes. The part bolts up!.
Another bonus is ,with all the holes in a B-17,we save some weight!
The gun manufacturers have to make guns to fit the longest SAAMI ammo so the guns accept all spec rounds.
The ammo manufacturers have to make ammo to fit the tightest chambered SAAMI rifles produced.So the make them on the short side.
They might control production of guns and ammo to .001 in production today,
But the headspace will lean toward max, and the ammo will lean toward min, so every round fits every gun easy. Once.
Little concern is given to your brass life.
Point: Your rifle is not an accident on the edge of being a reject. Building to max headspace is probably production standard, as is min spec ammo.
The handloader (who can measure) can deal with it.
You will get plenty of advice to adjust a die 1/4 or 1/8 turn. Thats what I did for years.
The dies have 14 threads per inch. divide one by 14, You will get something like roughly .075 in per turn. HMMM So 1/4 turn is near .020,+ or -.
1/10 turn is .0075 . We are trying to solve a .006 problem. Would we like something more precise and repeatable? Do you think so?
Once again,the feeler gauge between the shellholder and the die
Very nice! It does what I do,just from the other end.
Now ,if you have one of the bushing cartridge "headspace" gauges, try using your comparator stand, but set the bushing down on the plate, chamber mouth side up. Drop in a case,it rests on the datum in the bushing. Contact your indicator on the case head. No big deal,its like measuring a fish tail to head,or head to tail.
I got my granite comparator stand from some discount tool outfit,back then it may have been $60 with a Central travel indicator. Its Harbor Freight grade,not Starret! But it works!
khaines0625
New member
I just ordered this. Seems an awful lot easier than trying to twist the die 1/2929392th a turn.
In the long run I do think I'll use 100% virgin brass; it makes sense. For now, I have some fired brass to use up.
stagpanther
New member
Here's a brain-twister--how many people check the dimension differences between their go and no go gauges? You might be in for a surprise when comparing gauges from different manufacturers (and why you shouldn't mix them).
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khaines0625
New member
I want to thank you all for being so helpful in getting this figured out. It can be a bit daunting for a beginner, especially when you have never seen it done and safety is a concern.
Even this process that has yielded me 0 rounds so far has been fun to me -- I'm already hooked! I think this will be something I do for a long time.
Even this process that has yielded me 0 rounds so far has been fun to me -- I'm already hooked! I think this will be something I do for a long time.
ammo.crafter
New member
cracked up
Sounds like head space issue.
Primer pix interesting. The right pix shows high pressure and firing pin wrap around.
Are you absolutely certain you were firing new
ammo and not reloaded ammo?
Looks like cartridge loading dies were not properly adjusted and/or fired brass was not trimmed after resizing die run.
Absolutely advise Hornady of your issues.
Sounds like head space issue.
Primer pix interesting. The right pix shows high pressure and firing pin wrap around.
Are you absolutely certain you were firing new
ammo and not reloaded ammo?
Looks like cartridge loading dies were not properly adjusted and/or fired brass was not trimmed after resizing die run.
Absolutely advise Hornady of your issues.
Maybe. Depends on your end goal. Likely the brass can tolerate the differences in gauges.
If I was being sued it might matter. But I don't take on gunsmith work.
I buy and use headspace gauges. If I had one Clymer and one Forster to check my mongrel AR-15 assembly, Let me ask how many people check their new build AR's for headspace?
How many Old School Gunsmiths from the milsurp days used select fit brass and dots of tape to improvise a gauge?
Headspace and brass stretch IS important, but its not a steel on steel interference fit that must be measured to + or - .0001 .
Its a standard to meet in Gunsmithing and if you are a proper Gunsmith you meet the standard or start over.
Grand scheme of things, small variation between gauge makers is a very questionable argument.