Case gauge question

[Reloadron]

But there is a need isn't there? Isn't that the whole purpose of the guage? I bulged some 223 by over crimping. This bulge was very small and hard to notice. If I had a gauge made with a chamber reamer, I could've spotted the problem. Pistol cases don't seem as critical to this or as subject to the bulging. I dunno maybe I'm putting too much thought into this. If it's a tube with a hole drilled in it I'm going to feel a bit silly for spending the $ on them.

The "need" depends on how we look at the purpose of the gauge. As I quoted earlier from L. E. Wilson the gauges (this type) is only used to measure two features, the case headspace and the case length. The gauges do that just fine.

Using true chamber reamers to cut gauges would prove an expensive proposition. They want to make a gauge that exceeds maximum allowable cartridge diameter so the gauge is useable over a wide range of cases for its intended use and again that use is only to measure two features.

There are bench rest and match shooters who will use a precision reamer to cut a chamber and then use that same reamer to cut a gauge and die. Just a matter of how precise or OCD we want to get about making a gauge. The average hand loader has no need to go to this extreme.

Anyway, when used correctly gauges like the case length and case headspace gauges we are discussing do fine for their intended use. No, they won't catch a slightly buckled shoulder. A good visual inspection should and if we push a little metal out the headspace dimension should come up a little short. As it pertains to bottle neck rifle like 223 or 308.

Ron

 

[Reloadron]

Reloadron, that's what I was talking about when I said they were straight-drilled. My Lyman is the same way. The headspace length would be right, but a bulged shoulder would drop right in without issue. I didn't have a chamber reamer, but I used a drill bit the same diameter as the entrance hole. It dropped right in the gage and did not stop until it hit the shoulder upset.

Yep, another way to see what's in there.
Simpler too.

Ron

 

[HJ857]

But there is a need isn't there? Isn't that the whole purpose of the guage? I bulged some 223 by over crimping. This bulge was very small and hard to notice. If I had a gauge made with a chamber reamer, I could've spotted the problem. Pistol cases don't seem as critical to this or as subject to the bulging. I dunno maybe I'm putting too much thought into this. If it's a tube with a hole drilled in it I'm going to feel a bit silly for spending the $ on them.

You're correct on all this. Reloadron has been doing a great job explaining the diiferences in the gauges.

To summarize it, there are three types of drop in gauges.

1) the Wilson, Dillon, et al are oversized and only measure length and what we generally say is headspace (really we mean matching the case sizing to fit a rifle's headspace). So it measure two things.

2) The gauges made by JP Rifles are cut to measure to SAAMI spec. So they measure three things. length, headspace and case body, compared to the SAAMI standard.

3) A true chamber gauge which would be made by whomever crafted you uber expensive match barrel, and that chamber gauge would be cut with the same tool that cut your barrel's chamber.

Personally I have no idea why one would spend pretty close to exactly the same amount of money on a gauge that only measures two things when another gauge is available that will measure three things.

Just as note. All of the gauges can be used to determine correct sizing when setting up or checking your sizing die, based on how accurately you can discern thousandths of an inch by eye. If you really want accuracy to a level of 1/1000 on an inch, you'll probably be better off with a different gauge.

Like this. http://www.midwayusa.com/product/47...hing-set-with-comparator?cm_vc=ProductFinding

Finally, while the JP product will check the integrity of your finished round, that's not to say that it is a round that's precisely matched to your chamber. What it really gives you is a completed round that will chamber in any rifle. That's certainly worth a lot if you load for competitions or defense where 100% function is critical. But it's not going to give you rounds for precise accuracy unless you use other tools along side it.

I have a Wilson, the JP and the Hornady. I use the Hornady the most by far, I use the JP to check finished rounds, but not for checking head space, I have the Wilson on my desk and it functions perfectly for holding a pencil.

 

[BluewaterLa]

If you are looking for a guage that will give you chamber spec, check out
EGW web site and the chamber checkers they have available. The company explains how they are reamed and made, also the function.
I use the one for 9mm, 38spl, 40 and 45 four hole checker and their 7 hole 223
Chamber checker guage. They are very tight specs and will catch many issues
With brass you may in counter. Some times I find rounds that will barley fail their tight spec chamber checker that will still chamber without problem in my firearm. Go check em out !

 

[fguffey]

My previous understanding of case gauge was that it was an exact shape of a Saami chamber, or maybe slightly smaller to give some wiggle room, and therefore would tell a person of their ammo was able to chamber or not?!

Paddy, the gage you are referring to is a chamber gage.


F. Guffey

 

[fguffey]

I have a Wilson, the JP and the Hornady. I use the Hornady the most by far, I use the JP to check finished rounds, but not for checking head space, I have the Wilson on my desk and it functions perfectly for holding a pencil.

Checking head space of what? I suggest you get your pencil out of your Wilson case gage, the Wilson case gage is a case gage, it is not a head space gage because the case does not have head space.

SAAMI says: Reloaders and smiths are confused and do not understand there is only one head space and one head space gage. SAAMI omitted the symbol for head space from the case drawings because the case does not have a head space, reloaders and smith believe SAAMI made a mistake.



F. Guffey

 

[Reloadron]

Checking head space of what? I suggest you get your pencil out of your Wilson case gage, the Wilson case gage is a case gage, it is not a head space gage because the case does not have head space.

SAAMI says: Reloaders and smiths are confused and do not understand there is only one head space and one head space gage. SAAMI omitted the symbol for head space from the case drawings because the case does not have a head space, reloaders and smith believe SAAMI made a mistake.



F. Guffey

Enter Mr. Guffy. I had a feeling this would happen, I thought about touching on this earlier but felt it best to let a sleeping dog lie. Mr. Guffy is correct in his assertion. I admit that I haven't a clue why so many manufacturers make case gauges they refer to as case headspace gauges. Even a Google of "Case Headspace Gauge" will yield a dozen plus hits. It must be true because it's on the Internet and they can't put stuff on the Internet unless it is true.

Looking back to the SAAMI 308 case dimensions we see that in fact while a dimension is shown for the cartridge that dimension is not labeled as a headspace dimension shown by a circle with a small x in it. However, if we look at the lower chamber dimensions the headspace dimensions are clearly shown and noted. The cartridge dimension is shown as 1.634" (the typical NoGo limit) -.007". If we look at the chamber dimensions we see an allowable tolerance of 1.630" Min to 1.640" Max. Typically a 308 Winchester chamber starts at 1.630" (Go), followed by 1.634" (NoGo) and finally 1.638" (Field) which comes in .002" below the Max.

Below is an image of 308 Winchester headspace gauges. This is a 9 gauge set ranging in .001" increments from 1.630" to 1.638" and the 3 gauges on the side are just extra Go, NoGo and Field gauges.



I can use those gauges to check my Wilson or Forster gauges but I generally use a set of RCBS Precision Mic gauges which I can also check as seen below:



Headspace gauges are used when doing the final finishing cuts on a new chamber.

Also, if we look at the SAAMI glossary, we note as Mr. Guffy points out there is no case or cartridge headspace mentioned. There is a Case Gauge defined as follows:

CASE GAGE
A fixture used to inspect cartridge case dimensions (i.e. length, diameters, thickness, etc.) to insure conformance to established tolerances.

Anyway, while Mr. Guffy is in fact spot on target correct there are countless manufacturers out there using the term Case or Cartridge Headspace. Personally I just see it as a contextual term and it really depends how pedantic we want to get over the term. I don't see it as much to worry about as long as we know what we are measuring and how we are measuring it.

Just MY Take....
Ron

 

[Walkalong]

All true, the gauges do not check the mechanical headspace of the firearms chamber. They check the sized case so that it will fit chambers with proper headspace if the brass passes the gauge checks for shoulder placement. As posted, some of these "headspace" gauges do not check case diameter. They are for setting up a sizer. If one doesn't want to set up a sizer that way, then they should use some sort of tool to measure shoulder position and set up their sizer that way. There are many ways to do this. The RCBS Precision Mic pictured is one way.

That said, it is what it is and they are marketed as headspace gauges, just like Ron posted.

 

[Zapp]

Agreed. I don't have a guage for my pistols because I use the barrels and also just run on faith that the die will shape a straight wall as well it should, and the lengths are easy to measure. However I'm trying to start up 300blk and will be making cases from 223 and I'm not sure how easy it is to use the barrel of a AR to do a plunk test. Seems hard to see and reference given the locking lugs and all the dark deep recesses involved.

I have the Sheridan gauge on the way but I opted for the non slotted because it's like 24$ more for the slot and I'm cheap. If the dillon gauge slots out okay I will just do it on the other gauges I have too, might as well use the big bad mill that sits quietly most all the time.

Paddy,

Good luck with slotting the gauges. I have seen a lot of people griping about the price difference between slotted and standard gauge. I will tell you that its not JUST as simple as throwing it on a mill and cutting the slot.

For the brands of gauges that are actually cut to the chamber spec, even a very small burr will ruin the measurement. And for the brands of gauges that are cut bigger than the chamber, there is no sense in cutting the slot so you can see how it fits, since the gauge diameters are oversized anyhow.

I have to do a lot of cleanup, including with a chamber reamer, after I slot the gauges. And if you do a cleanup like that, you should probably use the same reamer you used initially to make the gauge. Just a heads up

 

[Paddy]

Okay noted. So the Sheridan gauges are cut with a chamber reamer?

 

[Reloadron]

Okay noted. So the Sheridan gauges are cut with a chamber reamer?

The nice people at Sheridan Engineering say:

AMMUNITION GAUGES Are uniquely designed to check loaded ammunition, giving you the ability to check your factory ammunition or reloads against a spec chamber. The chamber is SAAMI spec on rounds where there is a SAAMI spec. This allows you to check brass sizing, headspace, bullet seating, and crimping all with one gauge.

Wouldn't hurt to visit their website and give them a call.

Ron

 

[Paddy]

Nice. Thx. I have limited wifi here and their website seemed kinda basic but I missed that part.

 

[CoalTrain49]

Gauging 45 ACP

I use a gauge to tell me if there is a possibility of an over sized case after I load a round.

My 1911 is a needy girl and doesn't like just any old reload. If they don't go into the gauge without pressure I shoot them in my revolver. Most of them would probably chamber in my 1911 but some of them would fail, maybe 10%.

Just my experience.

 

[mtrmn]

I use a gauge to tell me if there is a possibility of an over sized case after I load a round.

My 1911 is a needy girl and doesn't like just any old reload. If they don't go into the gauge without pressure I shoot them in my revolver. Most of them would probably chamber in my 1911 but some of them would fail, maybe 10%.

Just my experience.

I pull the barrel off my 45 and use IT for my case gage......

 

[Innovative]

There is a better way . . . .

Take a look at the Digital Headspace Gauge.

You can avoid a bunch of complicated techniques by finding just one dimension (shoulder clearance). That's exactly what this tool displays after comparing one of your fired cases to your first resized case.

In a few seconds, it shows how YOUR handloads fit in YOUR particular chamber. Then you can adjust your die height accurately. Check it out.

 

[fguffey]

Paddy,

Personally I have no idea why one would spend pretty close to exactly the same amount of money on a gauge that only measures two things when another gauge is available that will measure three things.

I do not agree, a chamber gage is not designed to measure a fired case and a minimum length/full length sized case and everything in between, a chamber gage is designed to measure a minimum length/full length sized case. I have chamber gages that match my chambers, my gages have case head protrusion because my chambers have case head protrusion.

Even on chambers that do not match my chambers I can measure the length of a chamber then transfer the measurements to the gage.

Wilson Case gages: For years I have tried to motivate reloaders to think of it as something beyond a drop-in gage, I use the Wilson case length gage as a chamber gage.

F. Guffey

 

[fguffey]

There is a better way . . . .

--------------------------------------------------------------------------------

Take a look at the Digital Headspace Gauge.

Or he can learn to use a comparator, he is also capable of making a comparator. AND? WAIT! That is not a head space gage, that is a comparator, but you know that.

F. Guffey

 

[Innovative]

It's designed for handloaders . . . .

The Digital Headspace Gauge is designed specifically for handloaders (not for the barrel swapper). There are over 2,400 shooters now using it to accurately measure chamber clearance for setting their die height.

Good luck trying to make one of these! As you probably know, this gauge has our patented adjustable v-block, and it works on ALL different calibers without needing expensive attachments, special bushings or complicated instructions.

 

[Walkalong]

I like to use home made "buttons" "gauges" or whatever you want to call them to see where the shoulder is upon firing, sizing, and subsequent firings and sizing. (Bolt guns) The brass does not fully stretch to the chambers size the first firing due to pressure, brass resistance to pressure, and spring back.My little bump gauges give me an arbitrary number, but it can show me how much I am moving the shoulder, and where it started from. I can form a case to the chamber by hammering it with three or four full power loads (To the point of chambering hard), and then size a hair at a time until it chambers freely, getting useful, if not arbitrary, numbers along the way. That way I end up with a number that just does fit the chamber without binding any when chambering. I always size a hair more to give me some wiggle room.

That said, for my ARs and Mini 14, I just adjusted my sizer using the Wilson case gauge and am getting very good case life (Less in the Mini) with no chambering problems. One exception, for my 300 BLK I am using a home made gauge to check shoulder position and set up the sizer. I am bumping .002 to .003 and getting excellent case life with zero signs of case head separation even after over a dozen firings.

.308 "gauge" Cut to shoulder angle.

.35 Remington "gauge" Cut to measure on a spot in the middle of the shoulder.

 

[Paddy]

Interesting. I like your approach. More accurate with the calipers and if you're used to using them I imagine it's even faster than a full length case gauge.

 

[fguffey]

Larry Willis head space gage is a comparator

Innovative The Digital Headspace Gauge is designed specifically for handloaders (not for the barrel swapper). There are over 2,400 shooters now using it to accurately measure chamber clearance for setting their die height.

Larry, I am the fan of transfers and standards.

Has an owner of one of your comparators discovered a way to transfer the measurement from there comparator to their press?

Good luck trying to make one of these!

As you should know the datum/measured from is a flat surface, the measure from is found with a round hole drilled through the flat surface. For years reloaders thought it was a line with an arrow. What does this mean? Anyone with the ability to drill a perpendicular hole can make a datum. Anyone that understands when using a comparator the diameter of the hole is not critical.

F. Guffey