Do I need a case gauge?


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Baron
January 2, 2012, 08:29 PM
Hey all - I hate trimming brass more than I can express politely, so I'm using the x-die. I have a lingering fear that some cases might still be a bit long and thus get bulged during resizing. Is a case gauge what I think it is - basically another chamber that I can drop rounds in to confirm they will chamber easily?

Many thanks.

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Walkalong
January 2, 2012, 08:40 PM
A case gauge like Wilson makes will check headspace, but also shows if the case is too long. You do not need a case gauge to see if the cases are too long, just a dial caliper, but the case gauge will let you size to SAMMI specs, ensuring your brass will fit any properly machined chamber.

http://www.thehighroad.org/showpost.php?p=5816665&postcount=16

Hondo 60
January 2, 2012, 08:45 PM
Need???
no - you can always use your barrel.
If it gives you any resistance, use a magic marker & try again.
The places where it rubbed off will show you if there are any problems.

Would it help? Yes, those case gauges are usually manufactured to SAAMI minimums.
So if it fits in a case gauge, it'll fit in almost any firearm of that caliber.

Metal Tiger
January 2, 2012, 08:52 PM
I like them little handy tools. Dillon makes a very fine set. Final step before loading mags for me is to run the cartridges through the case gauge it's easier than taking the barrel out and checking that way. Just makes it quick and easy.

rfwobbly
January 2, 2012, 08:55 PM
Baron -
Most reloaders simply use a 6" caliper for this task. If you are using a digital caliper, then you can run the jaws out to the perfect case length and then press the "Zero" button. From then on the reading is the amount longer or shorter than optimal.

For instance, the "trim length" on Rem 223 is 1.750". You can set your digital caliper to an opening of 1.750 and then re-zero. If the case you measure is +.002, then the case is 1.752" long. You would not accept cases with negative numbers (shorter) or those with readings above +.010" (1.760", the SAAMI max case length).

Although you can use a case gauge for length measurements, it is extremely hard to feel dimensions as small as .002" over or under. You'd probably pass more out-of-spec brass by feel than by direct reading.


A case gauge's main use is measuring roundness and shoulder distances. Roundness is literally impossible to measure with a 2-jaw caliper. Shoulder distances are also difficult due to the absence of any hard feature to measure from. A case gauge or cartridge gauge can also check finished rounds more rapidly than taking 3 or 4 independent measurements with a caliper.

So if you want consistently good ammo, you need both a caliper and a case gauge, but for case length the caliper is the way to proceed.

cfullgraf
January 2, 2012, 09:12 PM
Rifle case gauges, particularly Dillon and Wilson, check over all case length and shoulder position. They are cut generously in the diameter dimensions.

Cases can fit into a rifle case gauge and still not fit the chamber. Read the manufacturer's description on what the gauges measure and don't measure.

Pistol case gauges are a different story.

Both are useful for what they check, but there are alternate ways to make the same measurements.

As already said, I would get a calipers before, or instead of, buying a case gauge.

gamestalker
January 2, 2012, 09:13 PM
A case that is long enough to cause pinching when the round is discharged, isn't likely to show resistence during chambering. Resistence is felt primarily from shoulder location (head space), case diameter, and OAL, but not from case length unless it is well beyond the maximum SAAMI maximum for that cartridge. .010" beyond SAAMI maximum case length isn't likely to show up or be felt when chambering, but it is certainly long enough to cause pinching that can unpredictably elevate pressures.

It is common for brass that has just been resized or had the shoulder's bumped, to now need trimming even though it wasn't too long prior to such, yet it will chamber nicely.

Baron
January 2, 2012, 09:14 PM
Yeah, I'm not worried about OAL - I'm sure I don't have OAL issues. I just want to be sure the shoulder hasn't bulged at all, and the only way I can check that now is to drop each round into the chamber of a rifle, which I really don't want to do 1,000 times. There's really no other way to check that the shoulder is in spec that I know of...

Baron
January 2, 2012, 09:16 PM
Oops - started typing the reply when only one had responded - thanks for all the feedback! Yes, since I suspect that if any of my brass has bulged, it's going to be a rare exception, it really doesn't make sense to run it all through my rifle chamber. Sounds like a case gauge is exactly what I was hoping it is and I need to get one. Thanks for all the input.

Walkalong
January 2, 2012, 09:22 PM
Rifle case gauges, particularly Dillon and Wilson, check over all case length and shoulder position. They are cut generously in the diameter dimensions.

Cases can fit into a rifle case gauge and still not fit the chamber.This is true. The gauge checks the shoulder position, but unless you have a really tight chamber, if it fits the gauge it will most likely fit your rifle. You would have to have an oversized (Diameter) sizer to push the shoulder back enough and be too fat to chamber.

Baron
January 2, 2012, 10:37 PM
Yeah, that's why I'm a little worried since I'm using the X-die. Since it operates sort of differently, and if a case is too long, it bulges, I'm worried that a conventional case gauge might not pick up on that before it jams up at the wrong time in my rifle. I really need an exact replica of a rifle chamber I can try these in - I think I'm hearing that this exists - will stop by the shop tomorrow.

cfullgraf
January 3, 2012, 07:59 AM
This is true. The gauge checks the shoulder position, but unless you have a really tight chamber, if it fits the gauge it will most likely fit your rifle. You would have to have an oversized (Diameter) sizer to push the shoulder back enough and be too fat to chamber.

Not necessarily. I have a full length sizer and a 223 Remington rifle that must be at opposite extremes of the tolerance ranges.

Certain cases resized in that particular full length sizer will not chamber in that particular rifle but will chamber in other 223 Remington rifles.

But, the errant cases will slip nicely into my Dillon case gauge.

The die does not size the lower body of the case enough. It has nothing to do with upsetting the shoulder.

I have another full length sizer that i do not have the problems with. All cases resized in it fit any of my 223 Remington rifles.

Since the gauge manufacturers say their gauges are cut generously in the diameter dimensions, in my opinion, it is not reasonable to expect the gauge to simulate a chamber in the diameter dimensions. Obviously, if a case will not fit a case gauge, it will not chamber, but, in my experience, it can fit the chamber gauge and not chamber.

While this may seem like a rare occurrence and take a certain set of circumstances, I feel this kind of combination may be one of the reasons folks feel they need for small base dies with 223 Remington AR rifles. Not the only reason, but one of the reasons.

Without having several 223 Remington rifles, two full length resizers, and a small base resizer, I never would have discovered the true reason for cases not chambering in one of my rifles. I started my investigation because I was chided on one of the forums that my dies were set incorrectly which I knew was not the case. My preconceived notion was that I absolutely needed small base dies and I set out to prove that. To my surprise, that was not the case.

243winxb
January 3, 2012, 08:26 AM
Is a case gauge what I think it is - basically another chamber that I can drop rounds in to confirm they will chamber easily?
No. I really need an exact replica of a rifle chamber I can try these in - I think I'm hearing that this exists - will stop by the shop tomorrow. For this to work, the gauge would have to be cut with the same reamer that was used on the rifles barrel.

Blue68f100
January 3, 2012, 09:25 AM
You said your using the RCBS X-Die, did you do the initial trim of 0.020" below max (with all your brass) when you setup the die? If untrimmed brass gets mixed in, it can cause a problems. This must be done for the xdie to work properly. Once it's setup they tell you not to change the adj or the brass will start growing. Or you may start pushing the shoulder back with no place for it to go. This will throw something off so a test gauge will be helpful in figuring out where it's going. If you have the dies setup so your pushing the should back too far this can cause problems too.

popper
January 3, 2012, 10:44 AM
X die won't allow bulging the OUTSIDE during sizing, excess brass collects on the INSIDE of the case neck. It could cause the shoulder to collapse, like crimping too much. The case gauge will allow you to have a standard to set your die with. It is NOT a chamber checker. I assume you are shooting an AR. If oal is too long, you could get a slam fire(firing pin is floating) or jamming, too short and a FTF.

Walkalong
January 3, 2012, 10:58 AM
Not necessarily. I have a full length sizer and a 223 Remington rifle that must be at opposite extremes of the tolerance ranges.

Certain cases resized in that particular full length sizer will not chamber in that particular rifle but will chamber in other 223 Remington rifles.

But, the errant cases will slip nicely into my Dillon case gauge.

The die does not size the lower body of the case enoughI have a tight chambered EMP that needs well sized cases. Like you say, both ends of the tolerances. :)

jmorris
January 3, 2012, 02:44 PM
Not necessarily. I have a full length sizer and a 223 Remington rifle that must be at opposite extremes of the tolerance ranges.

I don't keep size dies or case gauges that are on the loose size (the best case gauges are made not ordered out of a catalog). Also, if a chamber won't run factory ammo I have it reamed to proper specification or sell it (if its chromed). I have no need for a rifle that has to be fed anything special, like must use undersize dies.

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