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Discussion Starter #1
It seems like there are a few tools to do this with. The Hornady one is the "expensive" one that sticks out. Then there is the Frankfort Arsenal tool, which seems like it works. But both have complaints in the reviews.

I was wondering about something even simpler. Basically a version of the Frankfort tool. Two drill bit collars. Those little screw on things that you clamp to drill bits to limit drilling depth. Same idea, cheap and should work using the cleaning rod.

Any thoughts? I ask because I already have them. Unfortunately I haven't had the chance to try it out yet as I keep the rifle I reload for (22-250 savage 12FV) at my parents since that's where I do my shooting. And I, for some annoying!! reason I keep forgeting them and the bullets.
 

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You are speaking to the author.

The problems with all "cleaning rod" methods are that they only measure to the bullet tip, which is not consistent in length. Second, unless you use a flat tip, part of the bullet fits inside the rod's threaded end; and that again is not consistent.

The one thing you are trying to locate is the point on the bullet that first touches the lands, and that is a diameter, not a length. Solution: determine the point on the bullet where that diameter first occurs and set the seating depth much like you set headspace - from the breechface.
 

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Discussion Starter #5 (Edited)
LOL dopey me, you are the author.

I understand what you mean about the rod needing to be flat. I was either goin to use the male end (and hope the tips touch) or make an attempt at finding the rods I used to use for launching my estes rockets.

I know that there is some inconstintency about the tips. But it would seem to me that (the plastic tips anyway) would be awful close.

Edit: I went back and reread your article. I completely missed what you were saying I get what you are saying now. But my question is, why is that the same for every bullet regardless of bullet make/type? It would seem that if one's ideal is .04 away from the rifling, another could be .02 away. Say a 90 grain Berger versus a 53 grain Barnes TSX.
 

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No sweat, I learned as a jet instructor that some people need to hear something explained differently before it clicks.

Guns can vary, but in my experience, a gun that likes one bullet to be a given distance off the lands will like all or most other bullets at that same distance. Changing from a super-long plastic tip to a roundnose or hollowpoint doesn't change that. So that's why I came up with my method.

Using a rod method, you'd have to start over from scratch when making such a switch. With my method, you don't. Just mark the new bullet at the same diameter as the first bullet, seat it so that mark is the same distance from the case head and you are done.

Some very minor tweaking might improve groups from that initial seating, but often not. The major advantage is that I never have to learn where the lands actually are - something which is pretty difficult to measure. I only have to know where the bullet needs to be - and that is simple indeed.
 

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How to measure quickly and easily

If you are wanting to measure the bullet, to determine proper seating depth, here is how to do it.

Load a dummy round with the bullet you are going to use....but, do not seat it all the way, leave it long.

Now, take a piece of steel wool, and burnish the bullet.

Load the round into the chamber, and close the bolt, or the action.

Open the action and remove the round.

Now, what you just did is seat the bullet so that its ogive is just bearing against the rifling.

But, you don't want it there. You need a small amount of "run-out"

Generally, it's between .020 and .040"

So, measure the OAL of the dummy round, and then seat the bullet about .020-.040" deeper than this measurement.

An expert gunsmith who built rifles for Palma Team shooters once showed me that trick. And it works!
 

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The Troll Whisperer (Moderator)
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Might as well throw my .02 into the discussion.

For every cartridge/chambering and every rifle, I use the dummy round explained above with a minor alteration.

I take a sized case, get a jeweler's saw and split the neck down to the shoulder in quarters. Fine emery cloth smooths the inside/outside of the neck after cutting. Using finger pressure to squeeze the quarters back together to provide some neck tension, the bullet of choice is seated out with just enough depth to hold in the case. The round is carefully inserted into the chamber, bolt closed and dummy round again carefully extracted so as not to disturb the setting. COAL is measured and the process is repeated several times to assure the consistent measurement. Ten to fifteen thousandths is deducted for offset from the lands and that figure is recored for that particular bullet/cartridge combination. I use the Stony Point (now Hornady) collimeter to determine ogive settings.

Every rifle, every chambering will have different dimensions and this process should be repeated for each and every rifle/bullet being considered.
 

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You are speaking to the author.
Rocky Raab, what is the practical value in measuring ogives :confused:

Is it a useful data point, beyond knowing it's a round nose, flat nose, or pointy bullet?

Is it important to a guy who won't shoot past 300yds at anything but a varmit?

Is it just as useful to look at BC, and knowing that's a variable property with changes in velocity?

When I go to the link, I see a bunch of "go daddy" stuff.

Your thoughts?
 

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Discussion Starter #10
No sweat, I learned as a jet instructor that some people need to hear something explained differently before it clicks.

Guns can vary, but in my experience, a gun that likes one bullet to be a given distance off the lands will like all or most other bullets at that same distance. Changing from a super-long plastic tip to a roundnose or hollowpoint doesn't change that. So that's why I came up with my method.

Using a rod method, you'd have to start over from scratch when making such a switch. With my method, you don't. Just mark the new bullet at the same diameter as the first bullet, seat it so that mark is the same distance from the case head and you are done.

Some very minor tweaking might improve groups from that initial seating, but often not. The major advantage is that I never have to learn where the lands actually are - something which is pretty difficult to measure. I only have to know where the bullet needs to be - and that is simple indeed.
Would that Sinlair tool work for what you are describing? That block with the different holes in it I mean.
 

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First, you must be using Internet Exploder, which scrambles the page. Switch to Firefox or Chrome.

Now, we aren't really measuring the ogive curve. What the article explains is how to reliably set an optimum seating depth (off the lands) for any bullet. Once you have established a seating depth that gives you the accuracy you want, you set your caliper jaws at bore diameter (NOT groove depth) and lightly scribe a line by turning the bullet in the caliper jaws. Example: for a .30-caliber round, set the jaws at .300" NOT .308". I call that the Ogive Datum Line (ODL).

Now, measure from the ODL to the cartridge base. Record that distance. The practical use is simple but huge: You can now set that exact off-lands distance for that rifle with ANY bullet, without expensive test shooting. And all you need is a caliper.

Here's the ODL:


 

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For those using the "seat it long and measure the COAL" method, what do you do if the bullet you used has a nose that's a wee bit longer than the rest of the bullets in that box, or the next box. Or shorter? What if it's irregular like some hollowpoints? Your precise off-lands distance is off by whatever error the COAL gives you.
 

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Might as well throw my .02 into the discussion.

For every cartridge/chambering and every rifle, I use the dummy round explained above with a minor alteration.

I take a sized case, get a jeweler's saw and split the neck down to the shoulder in quarters. Fine emery cloth smooths the inside/outside of the neck after cutting. Using finger pressure to squeeze the quarters back together to provide some neck tension, the bullet of choice is seated out with just enough depth to hold in the case. The round is carefully inserted into the chamber, bolt closed and dummy round again carefully extracted so as not to disturb the setting. COAL is measured and the process is repeated several times to assure the consistent measurement. Ten to fifteen thousandths is deducted for offset from the lands and that figure is recored for that particular bullet/cartridge combination. I use the Stony Point (now Hornady) collimeter to determine ogive settings.

Every rifle, every chambering will have different dimensions and this process should be repeated for each and every rifle/bullet being considered.

I'm not sure that I understand the purpose of splitting the case?
 

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Rocky Raab, what is the practical value in measuring ogives :confused:

Is it a useful data point, beyond knowing it's a round nose, flat nose, or pointy bullet?

Is it important to a guy who won't shoot past 300yds at anything but a varmit?

Is it just as useful to look at BC, and knowing that's a variable property with changes in velocity?

When I go to the link, I see a bunch of "go daddy" stuff.

Your thoughts?
It's important because if the bullet is not seated deep enough, the bullet will be jammed against the rifling lands when the round is chambered. Upon firing, this can raise pressures.

Conversely, if the bullet is seated too deep, this can also raise pressure inside the case. Not only that, but excessive run-out means that the bullet travels a longer distance, then it slams into the riflings, which can upset its path.
 

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The Troll Whisperer (Moderator)
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So you can seat the bullet by hand and then not have to use a bullet puller to reset it.
 

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kdub, how consistent are your measurements that way? When I tried it, the bullet would "catch" in the lands and be pulled out a bit when I extracted the case - and never the same amount twice.
 

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Not bad, Rocky -

There may be a variance of 2 or 3 thousandths - that's why I do at least several measurements to derive at an average. The trick is to really squeeze down on the neck segments and get as tight a fit as possible.

By allowing the .010" to .015" standoff from the lands, figure the average is well within the safety margin so as not to be abutted against them and subsequent possible pressure problems.
 

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I know you guys mentioned that the Hornady gauges are expensive, but I have found it to work extremely well. On multiple measurements they only vary on average from .001-.002 If your are careful about things, and I think most of that is from user error. I usually take about 4-5 measurements, and get an average.

I have thought about using the split case method for some of my odd calibers, but have yet to try it. I have however taken a few of the Stoney Point/ Hornady cases and resized them to accomidate other calibers, such as I went from .25-06 necked up to 6.5-06 and with a little polishing of the inside of the neck they worked like a charm!


I would be lost without my Ogive measureing tools!
 

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I suppose I come at the thing from the other direction.

My goal is to be able to reliably repeat a rifle's most accurate seating depth - not to find where the lands are. So my method allows me to duplicate a "best" seating depth without ever learning how far off the lands that might be.

I can't tell you what my off-lands distance is, and I don't care. That presumes I'm not jammed into them, which I know by virtue of extracting a round and making sure there are no marks on the bullet. That and feeding from the magazine are the only non-accuracy issues involved.

But I start with accuracy, not prospecting for lands.
 

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Maybe I'm miss understanding you guys, but it sounds like the RCBS Precision MIC is exactly what you want. It come with a "collet" to the right size as your cartridge and is micrometer graduations for measuring. I use this in conjuction with the RCBS competition seater die (also Micrometer graduations) to perfectly seat bullet X amount off my lands. all Measured from the ogive
 
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