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Best tool to measure base to ogive
- Thread starter Poconolg
- Start date
Both the Hornady and the Sinclair units are comparitors They allow comparisons between like bullets for consistency and seating depth adjustments.
The Hornady and Sinclair are nothing fancier than metal with holes slightly smaller than the caliber and deep enough so the meplat does not bottom out. It allows you to take a micrometer reading from either the base of the bullet or the head of the case and compare them to similar bullets and similar bullets seated. The method works great and not much that can go wrong with either one. I use Hornady but they both use the same principle
The Hornady and Sinclair are nothing fancier than metal with holes slightly smaller than the caliber and deep enough so the meplat does not bottom out. It allows you to take a micrometer reading from either the base of the bullet or the head of the case and compare them to similar bullets and similar bullets seated. The method works great and not much that can go wrong with either one. I use Hornady but they both use the same principle
Best tool to measure base to ogive
The chamber, problem: There is nothing in the vocabulary of the reloaders that covers it.
I use transfers, I transfer the dimensions of the chamber to the seating die. No Hornady/Sinclair comparator, no attachments for the dial indicator etc..
it only involves manual dexterity.
And then there is that other thing about tension, I use bullet hold, I want all the bullet hold I can get. I can measure bullet hold. I would measure neck tension but none of my tension gages measure tension. All of my tension gages measure hold in pounds.
F. Guffey
And then there is my deflection gage, it measures deflection in inches and as always there are pounds/weight.
I use transfers, I transfer the dimensions of the chamber to the seating die. No Hornady/Sinclair comparator, no attachments for the dial indicator etc..
it only involves manual dexterity.
and down the guffy rabbit hole again, tell us once again no one does it right except you
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and down the guffy rabbit hole again, tell us once again no one does it right except you
hounddawg, again, it is about the best tool; I make tools. I am not competing for attention. I do not need a stack of tools, that seems to threaten reloaders in the world of social media, and that causes me to wonder what you are afraid of. Transfers have been with us forever, I did not invent the ideal or the concept.
F. Guffey
so tell me how your hole in a piece of metal is better than the store bought one. Anyone with a six inch long piece of 1 x 1 aluminum and six numbered drill bits - #93, 91, 89, 87, 85, and 84 and make a tool to do base to ogive comparisons on everything from 20 cal through 30 cal. It's just cheaper and less hassle for most of us to buy the ones by Hornady and Sinclair.
stop trying to over complicate simple concepts
stop trying to over complicate simple concepts
Guffey, I do believe it's pretty obvious that the OP is asking about a tool that he can buy. So, unless yours is for sale, you're unnecessarily clouding the issue at hand.
Poconolg,
I agree with others that if you want absolute measurements, the RCBS Precision Mic is good. For comparative measurements, I like the Hornady and Sinclair comparator sets, but the Sinclair nut may be just as good, I can't say.
Poconolg,
I agree with others that if you want absolute measurements, the RCBS Precision Mic is good. For comparative measurements, I like the Hornady and Sinclair comparator sets, but the Sinclair nut may be just as good, I can't say.
My COAL for case check is acualy a converted Ogive adapter from the Hornady set.
Its totally non spec, I just drilled out a .22 to just under 30 caliber size (I didn't use a transfer by the way).
So its a one off that will never be close to anyone elses.
But it works and me thinks that is what counts.
Its totally non spec, I just drilled out a .22 to just under 30 caliber size (I didn't use a transfer by the way).
So its a one off that will never be close to anyone elses.
But it works and me thinks that is what counts.
IT really gets into the term best, means different things to people, its a concept and not data.
Ergo, for me the modified Hornady was best. It was there, I never plan to load .22 caliber stuff and it works (for my bullets, too long and there is an issue)
Also some satisfaction in making your own tools (cost vs benefit ratio of course) - often it can be done but at extended hours to do so and you think, hmm, what is my time worth?.
Ergo, for me the modified Hornady was best. It was there, I never plan to load .22 caliber stuff and it works (for my bullets, too long and there is an issue)
Also some satisfaction in making your own tools (cost vs benefit ratio of course) - often it can be done but at extended hours to do so and you think, hmm, what is my time worth?.
Poconolog,
I own a couple of the RCBS Precision Mic's I acquired 25 or 30 years ago. Measuring a good quality Headspace GO gauge with the case datum thimble, I see around ±0.002" absolute error among my units, so you really need to have a good quality GO gauge to determine the offset correction needed to get absolute measurements of cases (usually a fire-formed case used to transfer measurement of the chamber headspace). That's really only more accurate than using a GO gauge with a caliper adapter and case insert by the amount lower the repeatability error in the PM is. Half a thousandth to a thousandth. If you have a hard-extracting gun that bends case rims, neither system is remarkable accurate before you get the bend out.
For measuring the case-head-to-bullet-ogive of a loaded cartridge, your hex tool is one of the better ones. This is because the holes are finished with chamber reamers so they tend to settle where your barrel throat will make contact if your chamber was cut with a reamer that matches the SAAMI standard. Other reamer designs can have different throat angles, so they won't contact your bullet at the exact same point. If you want exact, you need to keep the ends of your barrel blanks and to ream a throat into one of the ends with the same reamer you used to cut the chamber, then let that stub become your gauge.
The aluminum Hornady inserts for their bullet comparator adapter contacts bullet ogives higher up. It picked up the ogive of those 308 match bullets 0.380" above the base, where the Hornady insert's narrower hole picked them up 0.524" above the bullet base. I've measured that the higher contact point introduces a little bit of added length measurement variation because all the bullets in a box don't come off the same set of tooling and often have slightly different ogive shapes. (That ogive varation introduces about 3% variation in ballistic coefficient within a box of match bullets, according to Bryan Litz.) But the difference I measured between a reamer-made hole and the Hornady aluminum insert's smaller hole was only about half a thousandth increase in standard deviation.
Most people don't mind that the ogive location is a little arbitrary. You are just looking for a comparison to a bullet set out to touch the lands to learn how much jump to those lands your loaded bullets are making, and as long as you use the same tool for both measurements, you will be duplicating it within half a thousandth.
I believe Mr. Guffey's underlying point is that if you have basic measuring tools and know how to use them, you don't need to go to the expense of accumulating a lot of specialized tools. However, I think folks who don't understand how to drill down to first principles of measurement or those who do, but who have more money than time and are willing to pay for the convenience of a dedicated tool will still buy the commercial tools.
I get bit by curiosity about a tool's design, so I've wound up owning some things I don't really use and should probably sell. For ogive location measurements I have a tool of own design that reads bullet jump directly in thousands with respect to the case shoulder and not from the base. This is because most of my rifles use rimless cartridges and they headspace on the chamber shoulder. I've observed a couple of thousandths variation in base-to-shoulder sizing of some case lots as they come out of the sizing die. While I can fix them easily enough, I find it faster to sort cartridges by bullet jump as referenced off the case shoulder and then use the seating die's micrometer adjustment to correct them all to match the shortest one. You don't need my gauge to do this, however. I just made it as an experiment. You can also use any case comparator to sort your resized brass from shortest to longest, and then raise the seating die height by the amount a particular case is longer than the shortest case was. Just two or three settings usually covers a resized lot.
I own a couple of the RCBS Precision Mic's I acquired 25 or 30 years ago. Measuring a good quality Headspace GO gauge with the case datum thimble, I see around ±0.002" absolute error among my units, so you really need to have a good quality GO gauge to determine the offset correction needed to get absolute measurements of cases (usually a fire-formed case used to transfer measurement of the chamber headspace). That's really only more accurate than using a GO gauge with a caliper adapter and case insert by the amount lower the repeatability error in the PM is. Half a thousandth to a thousandth. If you have a hard-extracting gun that bends case rims, neither system is remarkable accurate before you get the bend out.
For measuring the case-head-to-bullet-ogive of a loaded cartridge, your hex tool is one of the better ones. This is because the holes are finished with chamber reamers so they tend to settle where your barrel throat will make contact if your chamber was cut with a reamer that matches the SAAMI standard. Other reamer designs can have different throat angles, so they won't contact your bullet at the exact same point. If you want exact, you need to keep the ends of your barrel blanks and to ream a throat into one of the ends with the same reamer you used to cut the chamber, then let that stub become your gauge.
The aluminum Hornady inserts for their bullet comparator adapter contacts bullet ogives higher up. It picked up the ogive of those 308 match bullets 0.380" above the base, where the Hornady insert's narrower hole picked them up 0.524" above the bullet base. I've measured that the higher contact point introduces a little bit of added length measurement variation because all the bullets in a box don't come off the same set of tooling and often have slightly different ogive shapes. (That ogive varation introduces about 3% variation in ballistic coefficient within a box of match bullets, according to Bryan Litz.) But the difference I measured between a reamer-made hole and the Hornady aluminum insert's smaller hole was only about half a thousandth increase in standard deviation.
Most people don't mind that the ogive location is a little arbitrary. You are just looking for a comparison to a bullet set out to touch the lands to learn how much jump to those lands your loaded bullets are making, and as long as you use the same tool for both measurements, you will be duplicating it within half a thousandth.
I believe Mr. Guffey's underlying point is that if you have basic measuring tools and know how to use them, you don't need to go to the expense of accumulating a lot of specialized tools. However, I think folks who don't understand how to drill down to first principles of measurement or those who do, but who have more money than time and are willing to pay for the convenience of a dedicated tool will still buy the commercial tools.
I get bit by curiosity about a tool's design, so I've wound up owning some things I don't really use and should probably sell. For ogive location measurements I have a tool of own design that reads bullet jump directly in thousands with respect to the case shoulder and not from the base. This is because most of my rifles use rimless cartridges and they headspace on the chamber shoulder. I've observed a couple of thousandths variation in base-to-shoulder sizing of some case lots as they come out of the sizing die. While I can fix them easily enough, I find it faster to sort cartridges by bullet jump as referenced off the case shoulder and then use the seating die's micrometer adjustment to correct them all to match the shortest one. You don't need my gauge to do this, however. I just made it as an experiment. You can also use any case comparator to sort your resized brass from shortest to longest, and then raise the seating die height by the amount a particular case is longer than the shortest case was. Just two or three settings usually covers a resized lot.
Unclenick
The problem I had with fired formed cases . My cases were getting shorter do to expansion , I ordered a Go Gage for my 308 1.630 to measure my chamber , my chamber measures 1.632 , even though my mic zero is off I can adjust knowing where my 1.632 zero is on the mic. Being I'm loading a mild reload is most of the problem with fire forming for me , knowing chamber size is the only way I could size to .015 case headspace. Thank you , I value your advise.
Chris
The problem I had with fired formed cases . My cases were getting shorter do to expansion , I ordered a Go Gage for my 308 1.630 to measure my chamber , my chamber measures 1.632 , even though my mic zero is off I can adjust knowing where my 1.632 zero is on the mic. Being I'm loading a mild reload is most of the problem with fire forming for me , knowing chamber size is the only way I could size to .015 case headspace. Thank you , I value your advise.
Chris
This is good post on best way to measure base to ogive.
http://bulletin.accurateshooter.com/tag/base-to-ogive/
http://bulletin.accurateshooter.com/tag/base-to-ogive/
This is good post on best way to measure base to ogive.
Datum dial systems by Forster.
Replace a Bin Full of Comparator Inserts
For $157.00, the $157.00 is the price reloaders pay when they do not understand datums, can not make datums and for not recognizing a datum when they see it.
F. Guffey