Wilson Case Gauge measurement questions

[JCSC]

Question regarding the Wilson Gauge.

I picked one up for my 6.5 Gr and it is the first one I have owned, but I plan to get them for the reast of my dies. I checked some of the new Hornady black ammo I have and it all seemed to be right at the low end on case mouth length and high end for base length. It appears to be pretty consitent ammo, with the exception of OAL, which I have not checked at the OGIVE yet.

The gauge measures 1.520" OAL, which corresponds to the SAAMI OAL length in my books. The undercut areas measure 1.505", but I am not sure how the .015" is split between the two ends, as I didn't have my depth mic handy. I am speculating -.010" on the mouth and -.005" on the base.

I have not checked my own fired ammo yet, but I have 200 pcs of brass I got at the range from a nice looking precision RPR style rifle with a Vortex Razor ( not that it matters).

If I drop those Hornady casings in the gauge they show that the case had stretched .010" from shoulder to base. Consistently 2.529 / 2.530". These were once fired Hornady American gunner, so I would have expected the brass to be consistent with my Black ammo from the factory.

What does this tell me about the rifle, or any rifle for that matter? I have no reasoning except for gut, but I expected to see the brass stretch .002-.004"? so, my gut was telling me that the gun had a headspace issue? I would like to get some thoughts on this.

Lastly, When I shoot and measure my own brass, do I aim to adjust the FL sizing die to push the case -.002/-.003" from the fired reading I get? I initially purchased a RCBS small base die, because they are 7$ for a set on the PSA website! Can I still adjust to bump a shoulder back on the small base style dies? Until this year, I was unaware that people adjust the dies to the gun, rather than tightening them down to get a slight cam over on the press. I am sure I would have learned this, but my reloading mentor passed away long before he got to teach me 1/4 of what he knew.

I appreciate some thoughts and info on this! Thanks!

 

[Walkalong]

I have not checked my own fired ammo yet, but I have 200 pcs of brass I got at the range from a nice looking precision RPR style rifle with a Vortex Razor ( not that it matters).

If I drop those Hornady casings in the gauge they show that the case had stretched .010" from shoulder to base.

Since it was fired in another rifle, and you did not measure those cases in the gauge prior to firing it tells you nothing at all.

but I expected to see the brass stretch .002-.004"? so, my gut was telling me that the gun had a headspace issue? I would like to get some thoughts on this.

.002 to .004? Yes, that would be more common and infinitely better than .010. Headspace issue? Perhaps, but since you did not measure that particular brass/ammo in the gauge, you don't know.

When I shoot and measure my own brass, do I aim to adjust the FL sizing die to push the case -.002/-.003" from the fired reading I get?

Basically yes, although for once fired brass in your chamber I would go for .001 to .002. It already sprung back enough to eject and re-chamber freely. You can always go another .001 if needed. And you'll need to keep an eye on this as you continue to use the cases, as they will work harden and start to resist sizing. You'll either need to anneal after awhile (2 to three firings) or adjust the sizer down one or two thousandths as this happens.

Can I still adjust to bump a shoulder back on the small base style dies?

Yes, any full length die can be adjusted to move the shoulder the amount you want.

Until this year, I was unaware that people adjust the dies to the gun, rather than tightening them down to get a slight cam over on the press.

Welcome to the next level of sizing.


Sorry to hear about your mentor.

 

[JFrank]

Question regarding the Wilson Gauge.

I picked one up for my 6.5 Gr and it is the first one I have owned, but I plan to get them for the reast of my dies. I checked some of the new Hornady black ammo I have and it all seemed to be right at the low end on case mouth length and high end for base length. It appears to be pretty consitent ammo, with the exception of OAL, which I have not checked at the OGIVE yet.

The gauge measures 1.520" OAL, which corresponds to the SAAMI OAL length in my books. The undercut areas measure 1.505", but I am not sure how the .015" is split between the two ends, as I didn't have my depth mic handy. I am speculating -.010" on the mouth and -.005" on the base.

I have not checked my own fired ammo yet, but I have 200 pcs of brass I got at the range from a nice looking precision RPR style rifle with a Vortex Razor ( not that it matters).

If I drop those Hornady casings in the gauge they show that the case had stretched .010" from shoulder to base. Consistently 2.529 / 2.530". These were once fired Hornady American gunner, so I would have expected the brass to be consistent with my Black ammo from the factory.

What does this tell me about the rifle, or any rifle for that matter? I have no reasoning except for gut, but I expected to see the brass stretch .002-.004"? so, my gut was telling me that the gun had a headspace issue? I would like to get some thoughts on this.

Lastly, When I shoot and measure my own brass, do I aim to adjust the FL sizing die to push the case -.002/-.003" from the fired reading I get? I initially purchased a RCBS small base die, because they are 7$ for a set on the PSA website! Can I still adjust to bump a shoulder back on the small base style dies? Until this year, I was unaware that people adjust the dies to the gun, rather than tightening them down to get a slight cam over on the press. I am sure I would have learned this, but my reloading mentor passed away long before he got to teach me 1/4 of what he knew.

I appreciate some thoughts and info on this! Thanks!

Wilson case gages are a sammi based tool to be used for comparison purposes, your chamber may have slight differences in shoulder angle so always keep that in mind.
No need to bump shoulders ( headspace) a cartridge until it’s fully fire formed. Stiff bolt lift at about 3-4 firings is a typical indicator. Until then just size enough to chamber .
J

 

[1KPerDay]

Wilson case gages are a sammi based tool to be used for comparison purposes, your chamber may have slight differences in shoulder angle so always keep that in mind.
J

to be clear, Wilson gauges do NOT check chamber/sidewall dimensions. Just OAL and case headspace. There are other gauges that are actually sized to match a SAAMI spec chamber.

 

[JFrank]

Yes
Lots of other gages, your chamber is the best one and as a friend always said, it’s free and always accurate.
J

 

[JCSC]

Can I get some more clarification on the Wilson gauge.

1- Although new ammunition measure between the min max on the CG, sized brass from my press does not fall between those parameters. After sizing, my brass is probably .003 over the max from base to throat. This was with the case properly lubed and even a second run across the press. I worked the brass a bit sizing, so they need trimmed as well. My fired brass is also longer than the Wilson CG min max, so what is this dang thing supposed to be telling me?




2- Do many people even bother adjusting shoulders in AR platform rifles, or just FL size and move forward? I really wanted the most accurate load possible, so the plan was to bump them into the proper headspace clearance for my chamber.

3- is this a good tool for establishing my shoulder datum, or better off with a hornady type case headspace caliper attachment?

 

[JFrank]

Your chamber is over max.
If the case mouth protrudes , trimm
If the case head protrudes measure how much. You may have an over spec chamber or you may need more headspace
I have one rifle that the case head protruded .004 it was snug chambering a resized case so I bumped a couple more thousand checked again and everything Chambers freely and my case just sits .002 proud. Where? Probably the shoulder angle isn’t a perfect match.

I have no experience with AR or the Hornday Tool but the Wilson is very good

 

[Walkalong]

After sizing, my brass is probably .003 over the max

You may not have the sizer screwed down enough, how do the fired/unsized cases look in the gauge, that is a better reference to your chamber. You can actually push the shoulder on the brass forward with a sizer if not properly adjusted.

Assuming the diameter will let it slip into the gauge, we need to know how the brass sits in the gauge before sizing. If it will not, something like this simple CTS tool can get you a reference number to where the shoulder is after firing and before sizing, then use it after sizing to see what you did to the shoulder.

A home made one.

 

[JFrank]

It sounds like your using a Die with an expander ball also, be advised those can stretch the case at the neck shoulder junction skewing your measurement

 

[Blue68f100]

2- Do many people even bother adjusting shoulders in AR platform rifles, or just FL size and move forward? I really wanted the most accurate load possible, so the plan was to bump them into the proper headspace clearance for my chamber.

3- is this a good tool for establishing my shoulder datum, or better off with a hornady type case headspace caliper attachment?

AR's can really stretch the brass pretty bad, if their over gassed. The bolt also has enough energy to move the shoulder back several 1/1000's too on closing. For simi-autos you need to size the brass for it's to have 0.002-0.003" clearance in your chamber. Assuming most AR chambers are in spec, which means fitting the test gauge. I have min spec chambers on my AR's and if the rounds does not fit the gauge it will hold the bolt open. You can check them in your chamber if your remove the ejector and see of the bolt will close easily by hand.

I agree that your not moving your shoulder back enough which requires you to adj the sizing die down some more.

You can use 9mm brass over the neck to get a reference like the comparator, remember this is just a reference. Then size the brass and measure again. This will tell you how much you moved the shoulder. Then adjust your dies accordingly.

 

[1KPerDay]

Adjusting the die down more isn't going to help your OAL if that's what you're thinking. Brass stretches and you need to trim it. The Wilson is usually close to the max OAL for case length. If it protrudes out the end, you need to trim. Trim after sizing. Confirm with calipers.

 

[JCSC]

I think I may have made this confusing.

First let me say that my question is not relating to neck length. I am familiar with trimming those areas.

The Wilson CG measure 1.520.

My fired brass measured 1.529/1.530 from the case gauge to the case base. I measured slightly off to the side, as to not have the primer or neck length interfere. The primer is protruding a tiny bit.

My die, when set to cam over and lubed properly, is only capable of reducing a case to 1.525.

Knowing the above, I am more than likely in perfect shape, relative to my chamber. I can easily back the die off a smidge and have a good headspace.

My concern:
My dies, nor my chamber, appear to be in spec against the CG?
If I had a tight chamber, my current set up would not work.

Lastly, I guess a CG is only a reference, whereas I thought it was a go no-go. Obviously, neither Odin works or RCBS produce a product that meets the CG specification in my case.

 

[JFrank]

Perhaps a sharpie to add color at the neck shoulder junction and the Datum line would expose a spot where the case is rubbing

 

[Walkalong]

Use the depth gauge part of the calipers to see where the base of the case is in relation to the gauge when a case is inserted. A pic of the case in the gauge might help. Even though the gauge is cut generously in the body it may be scrubbing there and not going in all the way.

Check out this thread.

https://www.thehighroad.org/index.php?threads/case-gauges.759018/

 

[JCSC]

Fired brass contacts on both edges of the case should.

Sized brass only contacts the transition from neck to shoulder.

 

[JFrank]

So it appears that it’s just a slight difference between the reamer and the gage.
What if anything will you do

 

[JFrank]

Just to put things into perspective.003 is about 2 human hairs

 

[JCSC]

Thanks for the comments.

I agree it looks fine and my fired shoulder is a good fit to the gauge.

I was under the assumption that even fired brass would still fall within the .010” marks on the case gauge shoulder to base length.

RCBS also told me that the dies will not adjust back to original mfg size, as it would work the brass excessively.

 

[Blue68f100]

If spring back is the issue anneal the brass and it should size on down.

The base of the gauge is whats used to measure the head spacing, should land between the cutout and top. The slot should only be 0.003"-0.006" depending on caliber. When you set the case gauge down on the base the top part will indicate if it's need trimming. If above the top edge, trimming is needed.