Sinclair bump gauge/insert , am I missing something here ???

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Metal god

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I've been using the Hornady LnL case headspace gage with what I believe to be great success . I have noticed how ever over time I believe the leading edge that makes contact with the case shoulder has rounded a little . This has changed the measurements over time . Not much really but some . I think my fired cases now show they are .002 shorter then when I first started using it 4 years ago .

So my thought was to buy the sinclair inserts because they where stainless steel rather then alloy like the Hornady inserts . My thinking is/was the alloy was soft and is why the edges have rounded a tad over time . The Sinclair inserts should hold up better so I bought some .

The issue is they don't seem to be accurate or at least not when comparing something . First thing I do is measure a GO GAGE and the Sinclair insert shows the gage to be .035 to long . Hmm that's odd you'd think this thing would have been at least close by at least a few thousandths .

I happened to have just finished prepping some cases so I measured one of those . Holy cow it's WAY longer then what my GO GAGE measured . OK lets measure a NO-GO GAGE . The NO-GO GAGE measures .0015 "shorter" then the cases I just finished prepping . :confused: Did I just prep 250 cases that will not chamber in my rifle ?? First I try the case that measures longer then the NO-GO GAGE , it chambers nice and smooth . OK lets try the NO GO gage . It does what is expected and I'm unable to close the bolt .

So what gives here ? Anyone use these inserts , if so how do they work ? I've seen the Sinclair video showing you how to set up your die to bump the shoulder back . I just can't believe how inaccurate these inserts are when measuring a known size .

FWIW when I use the Hornady insert it shows the same case is .001 longer then the GO GAGE and way shorter then the NO-GO GAGE
 
The gauge is a comparitor. Its to compare fired brass to sized brass, by measureing head to datum length. Different cartridges have different datum diameters, as seen in the SAAMI drawings. http://www.saami.org/specifications_and_information/index.cfm?page=CC Note that a case should be neck sized and fired at least 3 times to allow the brass to expand to the rifle chamber. Some light loads will produce a shorter head to datum measurement than what you started with, as the case body expands outward, pulling the shoulder back.
Casegage012Aa.jpg
My photo.
 
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I am not infatuated with reloading and gages. If ever there was a place KISS should be applied here it is.

I am the fan of transfers and standards, if I do not have a standard I will make it. The most complicated aspect of transfers for a reloader to understand is the part about not needing all of the tools they have surrounded themselves with.

Am I missing something? Does it appear reloaders are trying to reinvent reloading everyday?

F. Guffey
 
Different cartridges have different datum diameters, as seen in the SAAMI drawings.
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If the reloader understood the tool they were using was a comparator they would not need to worry about the diameter of the datum. If I want to measure the length of a case from the datum to the case head in thoudandths and then compare the measurement to SAAMI I use the correct datum. But from the beginning reloaders purchased pieces if metal with rounds holes thinking they were datum tools. After that they went to complaining about the spread between what they measured and what it should be not knowing the tools they purchased had radius. I make datums, my datums are not case friendly because my datums have sharp edges.

And then reloaders believe everthing is a head space gage and everthing has head space. My cases do not have head space.

F. Guffey
 
So what gives here ? Anyone use these inserts , if so how do they work ? I've seen the Sinclair video showing you how to set up your die to bump the shoulder back . I just can't believe how inaccurate these inserts are when measuring a known size .
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You could start by explaining what you mean by bumping. My dies have case body support; that makes it impossible to bump the shoulder. Many times I have said my shoulders do not move and then one day someone said I should call one of the die makers to get straigntened out. So; I did, we decided it was impossible to bump the shoulder and there could be no such thing as a body die, We decided there was something about dies and and sizing reloaders did not understand.

F. Guffey
 
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Why should I explain what Sinclair means by bump gauge . It's there tool and they made up the name . I'm asking here how it works . I thought I was clear but maybe not . How can I trust the gauge if it does not measure or compare known sizes correctly .

Maybe you missed the part the said it measures a FL sized case longer in comparison then a NO-Go gauge . How ever the case chambers in my rifle but the no go gauge does not
 
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Again and again and again etc, I am the fan of transfers and standards. I do not care what readings are obtained by the tool; I am the fan of the concept of ‘ZERO’. I measure from zero. The concept of zero and the datum is lost on reloaders; if the reloader did not use a datum with radiuses they could simply close the tool to read zero.

Back to Jimmy Dean and the chicken crossing the road; he said the chicken crossed the road to show the opossum it could be done. It was easier to show the opossum than is to show reloaders.

F. Guffey
 
Metal,

The answer is in where the gauge actually touches the case.

In order to accurately measure, in relation to the headspace standard, a "Go" or "No Go" gauge, the Comparator would have to be the same diameter as the SAAMI specified datum.

It is not. As per the Sinclair description:

Rather than measuring to the datum line, these gages indicate off of the shoulder of the case to get a better, more easily assessable measurement of how much you are actually sizing your cases.
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http://www.sinclairintl.com/reloadi...tors/sinclair-bump-gage-insert-prod35265.aspx


The gauge does not, and is not designed to, touch at the datum diameter. It doesn't matter, it only matters that it's CONSISTENT. You're measuring a CHANGE, not an absolute.
 
Rather than measuring to the datum line, these gages indicate off of the shoulder of the case to get a better, more easily assessable measurement of how much you are actually sizing your cases.
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And for years upon years I have said there is no line; the datum is a round hole and in all descriptions I have said datum/shoulder as in either and reloaders have responded with; "I am so confused:

When cutting a chamber I measure from the shoulder of the chamber to the protruding case head, I verify with a go-gage. How do I verity the go-gage? I use a datum of 3/8" or .375".

It is not up to me to be happy with Sinclair’s rational. They are not fans of transfers and standards. Why not make an attempt to get your money back?

F. Guffey
 
I had the same initial confusion from the verbal description, as the datum diameter location is measured with respect to its diameter on the shoulder and you can't measure it without making a measurement against the shoulder, so I wondered, what was the difference? However, I followed the link and read a little more, and it turns out what Sinclair is doing is machining the mouth of the comparator insert to match at least a portion of a chamber shoulder. I suspect the idea is to avoid the problem a truly sharp absolute datum diameter hole has with biting into a brass case shoulder a little. A radiused datum diameter hole doesn't do that, but it measures the absolute number slightly short. But it does just fine when you are using it to transfer your measurement from the case to other cases you are resizing or from a headspace gauge to a case.

I guess this Sinclair idea is OK. My only reservation is that the shoulder angles in chambers and dies and reamers all have a tolerance, so you will find instances in which the comparator shoulder inner edge touches slightly before the rest, and vice versa. Mostly, though, I don't think you'll notice.

The way to get an accurate absolute measurement with this tool is exactly the same thing you have to do with a radiused comparator insert, and that is zero your caliper while measuring a good quality, accurate headspace GO gauge with the insert, and then measure your fired case afterward to see how much above (or below, if your chamber is short compared to the SAAMI standard) the GO gauge it is. This number is a transfer measurement of the chamber, and will mirror your chamber's headspace length less a thousandth of spring-back or so. You then repeat this after your sizing operation so see what the sized number is. But the absolute measurement is only needed if you have to load the same round to fit any of several guns, in which case you size it for the shortest chamber among them, or for personal curiosity about your chamber and whether it is growing any over time or not.

If how much difference your resizing makes is all you want to know, as is usually the case with bumping the shoulder, then just zero on the fired case and see how much shorter than that the sizing operation makes it. That's the comparative (rather than absolute) measurement, and it's actually all you need to know if the brass lot is married to the particular gun.
 
Thanks Brian & UN , I went ahead and did some comparisons between the two gauges ( LnL & Sinclair ) . They both do transfer measurements equally well with only a .0005 difference . My calipers aren't that good so I'd say they work the same . How ever as you guys have pointed out the Sinclair insert can't be used as a comparator . The Sinclair gauge when used as a comparator indicates my sized brass is longer then a NO-GO gauge . My Hornady gauge indicates the sized case falls in between the GO & NO-GO gauges right where it should .

An interesting note and I'm still trying to understand . When using my Hornady gauge it indicates I'm bumping my shoulders .002 . How ever The Sinclair gauge when sizing from the same brass lot & die setting indicates I'm only bumping them .001 . So even when comparing apples to apples the two don't indicate the same measurement/bump . Although my calipers could be off by .0005 so the difference may not be as different as it appears .

I have so many 250ct brass lots that are used for specific loads and or rifles . It may take 10+ years before I know if either measurement is reducing case life .
 
How ever as you guys have pointed out the Sinclair insert can't be used as a comparator
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If that is what they pointed out we. Wait; allow me to correct that: I have found the source of the confusion. I insist on adjusting to zero before measuring, but when I am using a comparator all I am doing is comparing two different lengths I place no demand on the tool. All I need is a hole that is larger in diameter than the neck of the case and smaller in diameter than the case body juncture.

There are reloaders that believe the datum is located halfway between the two shoulder junctures; I could never understand that kind of thinking when the 25/06, 270 and 30/06 all use the same datum and the same shoulder angle.

F. Guffey

And then there is verify; I am the fan of verifying and I am the fan of transfers and standards.
 
Am I missing something? Does it appear reloaders are trying to reinvent reloading everyday?
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Guffey please stop posting in this thread

Thank you metal
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I refuse to believe reloaders on the Internet invented/discovered reloading. It is thought some reloaders believe no one existed before them. I am not that vain.

F. Guffey
 
Mr goofy has now personally disrespected me twice in forums . Once with an unwarranted personal attack in which I asked for an apology that never came . Now this time when I asked him nicely to no longer post in my thread and he continued to post at least three more times . He clearly has issues , I'm just glad I'm not one of his kids . At least I'm able to put him on my ignore list .
 
Mr goofy has now personally disrespected me twice in forums .
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If you want respect; earn it.

I am not an enabler, if you act like a child on the Internet; I treat you like a child.

F. Guffey
 
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