Are Headspace Gauges Necessary?

[Innovative]

Consider Measuring ....

Case gauges are very useful - assuming your chamber (and the gauge) are both within specifications. At least you know for sure that your handloads will fit in the gauge.

However, it's always best to measure how YOUR handloads fit in YOUR particular chamber.

.

 

[fguffey]

“Case gauges are very useful - assuming your chamber (and the gauge) are both within specifications”

I am sure everyone understands what all of that means, well? Almost. First, it must be understood “Visit our website at WWW.LARRYWILLIS.COM it's devoted to helping shooters make the best handloads possible” is trying to sell something. The Wilson case gage is ‘IN SPECIFICATION’ the Wilson case gage is a datum based tool, I know all of you have heard the term ‘DUMMY ROUND’, like the Wilson case gage, it depends on who is using it.

“ However, it's always best to measure how YOUR handloads fit in YOUR particular chamber” Back to ‘SPECIFICATIONS’ AND CONFUSION. LARRY WILLIS MAKES A TOOL HE REFERS TO AS BEING A DIGITAL HEAD SPACE GAGE, in all appearance it looks like a comparator, as in measure before and again after then compare the difference, and then? (Along came John) measure again after sizing to determine the effect sizing had on the case length from the shoulder to the head of the case.

Back to 'ASSUMING’ The L.E. Wilson case gage is in specification, it has a datum (measured from), when a case (30/06) is placed into the Wilson case gage the case sits on on a datum/round hole of .375”, again, there is no shoulder in the gage for the shoulder to sit on, there is only the datum/round hole with a radius. The distance from the datum to the head of the case is minimum length when measured to the bottom of the low deck, the distance from the datum to the high deck is is go-gage length.

That leaves the other measurement as in ‘specifications’, from the datum to the mouth of the case (At this point I am beginning to believe no one understands the opening statement). There are case trimmers that are set up to trim off of the shoulder of the case, meaning case length is not part of the specifications and it is assumed a reloader understands there are two length of the chamber, one from the datum/shoulder to the bolt face of the chamber and the other from the datum/shoulder to the mouth of the chamber.

again, I have an Eddystone M1917 that has a long chamber, it has .016” added between the shoulder and bolt face, problem? No, I add .014” to the length of the case between the shoulder and head of the case, ‘And then’ I add .014” to the length of the case for trimming.

What does all of this mean when checking my cases for the Eddystone M1917? The case will protrude from the Wilson case gage .014” above the low deck of the Wilson case gage and .009” above the high deck.

And then? I ask about the case mouth at the opposite end of the gage?

For those with dial calipers, measure the length of the Wilson case gage, THEN!? compare the length of the gage with case length specifications.

F. Guffey

 

[popper]

Measure a fired case from YOUR gun in a case gauge & feeler gauge, case head end. Set your die to push the shoulder back 0.002-4 ( for tolerance). Measure in case gauge again and WRITE the numbers down. Check to see if they need the mouth trimmed. You DON"T want to lock up a 308 AR. You don't want a slam fire. Yes, makers & builders set HS but there are tolerances and who knows if it was a 3 armed monkey that did it. Unless your are makeing a scatch build or have a real problem gun, you don't need the fancy stuff.

 

[MEHavey]

This is the only "headspace" gauge I trust to give me precise information of the exact
case fit to my chamber's actual headspace (i.e., the bolt will just close).
I can then (and forevermore) size to any dimension just short of that -- regardless of
brass type, make, condition, or cartridge.


http://www.midwayusa.com/product/47...-headspace-gage-5-bushing-set-with-comparator

 

[Walkalong]

I make my own.

 

[Clark]

Like Walkalong, I made one a month a go, after getting flames about my using brass as a headspace gauge for chambering rifles. I wanted to quantity the error in my process.

 

[hentown]

I by no means claim to be a reloading expert, but to this date I have been just fine by trimming to minimum case length after sizing. My understanding is that a headspace gauge is great if you have reason to believe that your headspace is off, but since headspacing is done by the manufacturer at the time of assembly(hopefully), the only real need for one is if you are barreling your own action and need to specifically know headspace as part of rebarreling.
I am more than likely wrong though.

Yep, your last sentence pretty much sums up your post. You apparently don't have any idea why some of us choose to use case gages. (They're not chamber-prooving gages) I use them for setting up my sizing die, as do most people who use them and understand why they're using them.

 

[MEHavey]

No.... Rather than "no idea," it was the age-old problem of potAAto vs potaHto definitions.

A chamber headspace gauge is that solid piece of metal that measures internal chamber dimension -- bolt face to shoulder.

A case headspace gauge measures the external dimension of the cartridge case -- bolt face to shoulder again -- and is the
one used by handloaders to ensure precise case fit within any given chamber.

 

[ranger335v]

"Drop-in" gages only tell you if a loaded cartridge should reliably fit any chamber ever made for that cartidge IF the chamber itself is still in specs, but it won't tell you much else. Any of the adjustable "comparitor" type gages from RCBS, Hornady. Sinclair, Innovative Technoligies (or a home-made approximation) will tell you exactly what you're doing with your sizer.

Everyone knows reading anything from Guffy will tell you nothing.

 

[Hondo 60]

G11354 - Ya see, here you went & used the term "Necessary"

That right there just gums up the whole scenario.

Is it "Necessary" - no.
But if you're lookin for uber accuracy, any step designed to minimize "play" helps.

 

[fguffey]

“No.... Rather than "no idea," it was the age-old problem of potAAto vs potaHto definitions.

A chamber headspace gauge is that solid piece of metal that measures internal chamber dimension -- bolt face to shoulder.

A case headspace gauge measures the external dimension of the cartridge case -- bolt face to shoulder again -- and is the
one used by handloaders to ensure precise case fit within any given chamber”

Mehavey, A head space gage does not measure chamber dimensions, the head space gage is used to measure the length of the chamber from the shoulder/datum to the bolt face. For all but a very few reloaders the head space gage is a fixed gage described by all but a few as go, no-go and field reject.

The case length gage (not a case head space gage) measures the length of a case from the shoulder/datum to the head of the case, and, the case does not have a head space designation, the case has a case length designation.

Then there is that part where some are led to believe the case dimensions are measured with a case length gage, again, a case length gage measures the length of the case from the shoulder/datum to the head of the case if the rleoader understands the difference between drop-in and a datum based tool.

F. Guffey

 

[fguffey]

"Drop-in" gages only tell you if a loaded cartridge should reliably fit any chamber ever made for that cartidge IF the chamber itself is still in specs, but it won't tell you much else. Any of the adjustable "comparitor" type gages from RCBS, Hornady. Sinclair, Innovative Technoligies (or a home-made approximation) will tell you exactly what you're doing with your sizer.

Everyone knows reading anything from Guffy will tell you nothing.

Unread Yesterday, 06:48 PM #34
ranger335v
Member



There are very simple tools a reloader can make, there are simple tools beyond bushings with round holes in them a reloader can use, with all the information available about the Wilson case gage there is no excuse for a reloader to refer to it as a drop-in gage. The instructions that has been included with the L.E. Wilson case gage go back to the day when the pocket rule had a prominent place in the pocket of the skilled trade. The instructions referred to the steel pocket rule as a straight edge, then there is the feeler gage, the feeler gage/straight edge goes back further than the Wilson case gage instructions. For some it is a natural transition, I do not place limits on others, they set their own limits.

F. Guffey

 

[mljdeckard]

I use one for .45, but it's mostly because I have one very finicky .45. For 9mm, I don't use one, I've never had a problem.

 

[JGalt]

Fine tune the sizing die

I prefer to use the gauge to fine-tune the resizing die setting on my Dillon 550. After setting up my .223 sizing die according to Dillon's DVD instructions, I ended up with die almost touching the shell plate. When checking with case headspace gauge, it was still a scoche high (case shoulder just a hair forward). Due to the forgiving nature of an AR chamber, they worked fine, but I didn't like it. That caused me to do more research - which lead me to a memo on Dillon's site explaining in depth the appropriate way to set sizing die. You can not only contact the shell plate, but you have 1/4 - 1/2 of a turn you can go after contact due to spring allowing some give on the plate. I was then able to get the headspace perfect between the min and max of the gauge.

 

[Innovative]

JGalt .....

Assuming that your chamber is somewhere within specifications and your gauge is correctly made .... you're good to go. Your handloads fit in your gauge.

However, exactly how do they fit in your chamber?

.

 

[ranger335v]

"However, exactly how do they fit in your chamber? "

I can answer that Larry; excessive resizing equals a sloppy fit and unneccessary case stretch when fired! It's better to make ammo that actually fits your chamber than to make ammo that fits your gage!

(But you know that too! )

 

[fguffey]

JGalt, thanks for sharing, notice the first response from WWW.LARRYWILLIS.COM starts out with “Assuming that your chamber is somewhere within specifications and your gauge is correctly made .... you're good to go. Your handloads fit in your gauge”.

Question: Why would anyone with all the talent WWW.LARRYWILLIS.COM claims he has ‘ASSUME’ anything? I do not assume my Wilson case gage is is within specifications, I measure the gage with a standard. I do not assume my dies are within specifications, I measure my dies with a standard. I measure shell holders for ‘in specification’, I measure the deck height, there was a time when reloaders thought all that was required when sizing a case correctly was to match the brand of the die with the brand of shell holder, some still do.

Chambers: I measure chamber lengths in thousandths with or without a conventional head space gage, the advantage goes to the non conventional method, rational: Non conventional methods give a reading in thousandths, conventional offers 3 choices as in go, no-go and beyond.

The Dillon 550B uses a 4 position shell plate, it is possible to have a shell plate that has different deck heights, for most the difference goes unnoticed because of the 1/4, 1/2 etc., additional turn of the die after contact.

Stick with the material you have from Dillon and welcome.

F. Guffey

 

[fguffey]

JGalt,Then there is the “exactly”. If they understood transfers, standards and the art of verifying they could answer their own question, it is possible to correlate the chamber, with the gage with the case.

F. Guffey

 

[fguffey]

then there is the “assuming”, why would WWW.LARRYWILLIS.COMWWW.LARRYWILLIS.COM assume, why would he expect you to assume anything.

http://www.saami.org/PubResources/CC_Drawings/Rifle/223 Remington.pdf

assuming and specifications when applied to the 223 Remington, SAAMI says there could be .010” difference in the length of the chamber from the shoulder/datum to the bolt face. AND as it applies to the head space gage called ‘go’ we all know the go-gage will go, we all know the no go-gage will go if the chamber is on the long side. With unconventional methods the length of the chamber can be known in thousandths.

F. Guffey