Anyone use a Dial Indicator Gauge for measuring OAL?

[johara1]

I have used the set up i made from a extra BSC from Tubb, only mod. was to bore out the part that attaches to the indicator to allow the the bullet to enter up instead of down and attached it to the indicator and use the granite base to set the rounds on. This gives you a direct reading and it does not need to be supported on the bottom. Once set up for my loaded round, i have no trouble holding a .0005 in seating depth. I made this a lot of years ago and it has served me well, a direct reading with out any variance from operator induced pressure. …….. James O'Hara

 

[dannyjbiggs]

Here's some shots of my home-made adaptation to a Sinclair Arbor Press (see photo #1). Photo #2 shows the Tubb comparator on the right with a 180 Hybrid inserted and a comparator that I had John Whidden make for me on the left also with 180 Hybrid inserted. John's is nothing more than the muzzle off a 7mm barrel that has been drilled for a LOT of free bore. Other gunsmiths have made these for folks for years, just by reversing the reamer; but IMO that's just too shallow to contain vertical bullet wobble contributing to inconsistency/inaccuracy. Photo #3 shows John's device under the pointer gauge. The pointer tip is also a "cup" that he made to just contact the pressure ring.

Since the bullet is snugly contained in John's bullet holder, there is no need to index position, as some have done for the Tubb bullet holder, to help contain vertical bullet wobble. (David might improve his devise by drilling deeper--I might improve mine by making it longer?)

As you might guess, I have used both, and I prefer John's device for repeatability in sorting by bullet "bearing surface" and bullet "BTO" (with flat pointer tip). I had John to convert one of his aluminum bullet holders used with his bullet trimming adaptation to the Wilson Trimmer to a cylinder to contain the bullet in order to sort bullet "OAL" off the arbor press base with a flat pointer tip.

Dan

 

[dannyjbiggs]

Shucks...looks like I've got a file size issue; here's Photo #2, anyway.

Dan

 

[johara1]

Danny, do you have any trouble with fat bullets if it fits that tight? I know the fat Hybrids, Spencers and Vaper trails fit very snug in Tubbs ……. jim

 

[dannyjbiggs]

Danny, do you have any trouble with fat bullets if it fits that tight? I know the fat Hybrids, Spencers and Vaper trails fit very snug in Tubbs ……. jim

Now that you mention it, :-[ Yes! I use only the Bergers...180's, so that's my primary sort. To your point, sometimes there will be a constriction noticed--sometimes a too easy drop down into the bullet holder, too. For the former, I wipe the bullet with a cloth and push a Sinclair case neck brush through the holder (something I so anyway about every 8-10 bullets). Try the bullet again. If still not a smooth fit, I lay that bullet aside as possibly out-of-round, or oversized. Too loose fit gets that bullet a "finger wobble test" while in the holder, and maybe set aside for possibly undersized. I have very few culls though, maybe 3-4 out of 1,000 bullets processed.

Recently, one of my Team Berger team mates reported to us that one of his Berger Lot #'s turned out suspiciously tight? The next thing we heard from him was that they were shooting up a storm, and he was wondering if any of us had that Lot # to give up!! :-*

Dan

 

[johara1]

Danny, You had better luck than me with Bergers in 6mm Hybrids .2428 - .2441 you must get better bullets than i did……. jim

 

[Brians356]

snowpro440

I don't find what you pictured on that web site, all I find is his "Bullet Comparator" w/ indicator attached. Similar, but that's got a lot shorter barrel and seems to be only for what it says, comparing bullets, not checking loaded round seating depths, or possibly also checking case headspace.

???

 

[snowpro440]

snowpro440

I don't find what you pictured on that web site, all I find is his "Bullet Comparator" w/ indicator attached. Similar, but that's got a lot shorter barrel and seems to be only for what it says, comparing bullets, not checking loaded round seating depths, or possibly also checking case headspace.

???

Did you take notice to the caliper tool pictured at the bottom for loaded round seating depth ?

 

[Brians356]

snowpro440

I don't find what you pictured on that web site, all I find is his "Bullet Comparator" w/ indicator attached. Similar, but that's got a lot shorter barrel and seems to be only for what it says, comparing bullets, not checking loaded round seating depths, or possibly also checking case headspace.

???

Did you take notice to the caliper tool pictured at the bottom for loaded round seating depth ?

Yes, but what's your point?

Let's back up here. You pictured a couple of devices, tall ones w/ dial indicators on top, and told Jay they were just like his, and you got them from Bob Green's site. But I don't find any such product there, there are two other products:

1. A bullet comparator w/ top-mounted indicator.
2. A bullet comparator which requires a caliper, which can also be used as a CBTO gauge.

Neither are what you pictured (no?) and neither are like Jay's. They are much shorter than what Jay showed.

Where did I go wrong?

 

[Jay Christopherson]

Here's how I measure seating depth/COAL consistency, though I can't take credit for the design.

Jay , these look the same . I have had them for a few years now. http://greensrifles.com/New_Products.html

Those are bullet comparators from Bob Green - the tool I posted is a COAL comparator. It does look very similar (simple tools tend to look the same IMO) though, so I get the confusion.

The COAL tool is designed to measure the seating depth achieved on each *loaded* round with reference to the lands (i.e., it doesn't measured where your seating stem contacts, it uses the bore diameter/lands as the reference). I don't bother to sort bullets anymore, because I only care where the bullet ends up in relation to the lands. Which is what this tool tells me, with a high degree of accuracy and repeatability. If you get really crafty, you can use the tool to *predict* where your seating depth will end up at (will it be longer or shorter than what you are shooting for, and by how much?), so that you can adjust your die to compensate *before* you actually do the final seating.

Personally, I use it both ways - the "crafty" way, where I adjust my seating die to compensate for the predicted seating depth, or I measure all my rounds after they come out of the press and adjust them (if needed) after the fact. I've found that with good seating habits, I only need to adjust about 1 out of every 10 - 15 rounds or so to maintain a <.001" total spread on seating depth. With the "crafty" method, it is possible to maintain a smaller seating depth E.S. than that without too much more time spent, if you feel you need to.

 

[snowpro440]

Look the same as a cylindrical design, yes Measures the similar objective in a different manner, Measures the bullet , yes , caliper tool measures the BTO, yes

Ok I got it now Jay, your sorting loaded rounds even though your bullets could differ in dimensions from your ogive to the tangent point of were your seater stem contacts the bullet , then you would have to go back and adjust the seating depth . Greens tools sort the bullets with the comparator then all loaded rounds are at a uniform seating depth by measurement with the caliper tool. Eliminates the need for the extra step of going back to reset the seating die because all sorted bullets are uniform to begin with , You still get there but its a different route.

 

[Brians356]

Those are bullet comparators from Bob Green - the tool I posted is a COAL comparator. It does look very similar (simple tools tend to look the same IMO) though, so I get the confusion.

The COAL tool is designed to measure the seating depth achieved on each *loaded* round with reference to the lands

So that COAL (really CBTO) tool sits down over the entire loaded round, and bottoms out of the table top (or stone bed)? (In use, you wouldn't be able to see the cartridge at all?)

 

[Jay Christopherson]

Look the same as a cylindrical design, yes Measures the similar objective in a different manner, Measures the bullet , yes , caliper tool measures the BTO, yes

Nope. It does not measure the bullet at all, only uses it as a index/reference point. There are no calipers involved.

 

[Jay Christopherson]

Those are bullet comparators from Bob Green - the tool I posted is a COAL comparator. It does look very similar (simple tools tend to look the same IMO) though, so I get the confusion.

The COAL tool is designed to measure the seating depth achieved on each *loaded* round with reference to the lands

So that COAL (really CBTO) tool sits down over the entire loaded round, and bottoms out of the table top (or stone bed)? (In use, you wouldn't be able to see the cartridge at all?)

Yes. Actually, you just need a flat reference surface. I happen to have piece of surfaced granite leftover from a kitchen remodel. A Wilson base is generally used.

 

[Brians356]

Look the same as a cylindrical design, yes Measures the similar objective in a different manner, Measures the bullet , yes , caliper tool measures the BTO, yes

All cylindrical, true. But, Jay's is not for measuring a bullet by itself (although if the indicator had a long enough stem, I suppose it could.) Green's simple bullet comparators leave most of the bullet hanging out exposed. Jay's engulfs the entire loaded round (!) and you can't see any of the round (bullet or case) when it's being measured.

Big difference, wouldn't you agree?

 

[snowpro440]

Those are bullet comparators from Bob Green - the tool I posted is a COAL comparator. It does look very similar (simple tools tend to look the same IMO) though, so I get the confusion.

The COAL tool is designed to measure the seating depth achieved on each *loaded* round with reference to the lands

So that COAL (really CBTO) tool sits down over the entire loaded round, and bottoms out of the table top (or stone bed)? (In use, you wouldn't be able to see the cartridge at all?)

How would you know when it bottoms out ? Is there a possible measurement there ? Is there a way to tell if the shoulder is contacting first or the ogive with your tool ? Just trying to understand how it works ?

 

[Jay Christopherson]

Those are bullet comparators from Bob Green - the tool I posted is a COAL comparator. It does look very similar (simple tools tend to look the same IMO) though, so I get the confusion.

The COAL tool is designed to measure the seating depth achieved on each *loaded* round with reference to the lands

So that COAL (really CBTO) tool sits down over the entire loaded round, and bottoms out of the table top (or stone bed)? (In use, you wouldn't be able to see the cartridge at all?)

How would you know when it bottoms out ? Is there a possible measurement there ? Is there a way to tell if the shoulder is contacting first or the ogive ?

It's really not overly complicated - like most tools, you spend some time with it in the beginning, checking it against other tools, and once you build up your trust in it, you really don't think about it. It just works. And I'm really trying not be mysterious here because I know it's annoying as sh*t when people do that, it's just that I didn't come up with the idea for the tool, I'm reluctant to go into detail without his permission and I want to be able to attribute it so that people don't get the idea that it's "my" tool. I got a prototype and then made a copy for a different caliber (for my own use). The copy is what you see in the picture. The original is much shinier...

I've just gotten a lot of mileage out of it and I'm hoping this thread will encourage him to jump in.

Is there a way to tell if the shoulder is contacting first or the ogive

Yes. The tool will only provide a reading based off the bullet as it sits in the case. If the shoulder is contacting, then the tool wasn't made correctly. If you aren't getting a reading, then you are doing-it-wrong.

 

[Brians356]

Those are bullet comparators from Bob Green - the tool I posted is a COAL comparator. It does look very similar (simple tools tend to look the same IMO) though, so I get the confusion.

The COAL tool is designed to measure the seating depth achieved on each *loaded* round with reference to the lands

So that COAL (really CBTO) tool sits down over the entire loaded round, and bottoms out of the table top (or stone bed)? (In use, you wouldn't be able to see the cartridge at all?)

How would you know when it bottoms out on the granite block ?

Well, you might just hear a solid "click" as steel tapped granite. And you might notice that you couldn't push the device downward any farther, no matter how much force you applied. Otherwise, I guess you're on your own.

Seriously, when both the cartridge base and the tool's barrel are both sitting on the same flat, hard surface, they now are tangent to the same datum line. And if the surface is flat enough and hard enough, the juxtaposition between case and tool body will be very, very repeatable. FWIW. (Quite a lot in my estimation.)