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Old March 31, 2013, 10:30 AM   #1
BumbleBug
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How do you find the bullet seating measurement to the lands...

I read all the time about bullets seated just so many thousands of an inch off the lands. When I first started reloading, following the load books, I use to blackened the bullet to find the OAL by trial in error.

Now I use a cleaning rod, tape & caliper to measure the distance from bolt face to bullet tip. A stoney point comparator then convert this measurement to a universal ogive OAL. I know this method is not precise!

I'm aware stoney point also makes a gadget that required you to make or buy a tapped dummy case. This does not seem ideal to me either.

Is there a better way? What do other reloaders do?

Also, using my comparator, I find a variation in ogive OAL for hunting bullets. Or is it just me?

TIA...

...bug
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Old March 31, 2013, 10:43 AM   #2
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Your approach worked for me and many others for decades until we read that we needed to buy fancy gear to measure more accurately. I bought the fancy gear and use it, but I don't see a huge change in accuracy that I can attribute to the fancy Hornady gear.
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Old March 31, 2013, 11:11 AM   #3
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I'm not sure why the Stoney Point tool (now Hornady) isn't ideal. It works great if you understand how it's different from you actual cases. I use it, it's great.

I'll have to check some bullets when I get home but I don't see more than a thousandths or two variance in a box of bullets.
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Old March 31, 2013, 11:28 AM   #4
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Quote:
What do other reloaders do?
I know my method isn't the best, but it works more consistently for me. I have a somewhat more accurate method of what you are using. It is the rod method with 2 - 0.500" wide stops. It just makes the measure exact without having to do math. And I know the tip isn't as accurate as the ogive, but it is accurate enough for me. I have a Stoney point gage, but the margin for error is greater with it, IMHO. And I have had issues with the modified cases not fitting correctly. I got my entire gage for less than $25 shipped and it fits everything.




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Old March 31, 2013, 12:26 PM   #5
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I don't have any of the fancy measuring tools but this is how I do it. I re-size the case to get enough neck tension so that a bullet will slide in with a little resistance. Start the bullet in the case and leave it long. Now lay the bullet in your chamber and slowly close the bolt. Carefully open the bolt and don't let it eject. Pick it out and measure the oal. You can do that a couple times to verify. Subtract what ever you want your bullet to be off the lands and your good to go. You have to have enough neck tension so that the bullet doesn't slide in and out too easily. Works for me.
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Old March 31, 2013, 12:35 PM   #6
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This is a good topic to do a search on. It has been covered in detail many times before.

BumbleBug,

The difference you are seeing in hunting bullets is possibly due to the bullets in the box being the combined output of bullets made on several different sets of forming tools that the factory that were operated simultaneously. It depends how big the difference is. There is always some small variation even when the forming tool set tied to a lot number is kept the same, as with Sierra's products, and I'd say two or three thousandths is what springs to mind as normal.

Then there is the fact that as you go down the ogive with the steep angle at which the bullet and measuring adapter hole are meeting, you have a lot of wedging mechanical advantage. It becomes important to apply the same force to the measurements every time and to get the base of a bullet squarely on the opposing caliper jaw. It's easy to be off a couple thousandths this way, too.

All that said, when you ask people how small a change in seating depth they can make before they see group size change on the target, usually about 0.010" is the number you hear. A few claim 0.005" will make a difference, but it is hard to know how good they were at isolating variables to demonstrate it was a real difference. Bottom line, though, even if they are right, is that being able to measure more accurately than 0.005" isn't going to get you anything on the target.


Brain,

I think he's saying he has the Hornady comparator body and bullet ogive adapter, but not the Overall Length Gage.


Jepp2,

In a bottleneck cartridge the thing that determines how close the bullet gets to the lands is how far the ogive is from the case shoulder, not from the case head. So, if you use the Hornady case headspace insert for your cartridge and measure a number of your cases as you've resized them for reloading (the way they will be in the chamber prior to firing) and take an average, then subtract the same measurement for the Hornady adapter case, you will have an average value that's an offset that should be added to calculated overall lengths to be measured using the Hornady bullet adapter on your finished ammunition.

For example, suppose the Hornady case measuring insert tells you your resized cases are 0.005" longer, on average, than the Hornady threaded adapter case for their Overall Length Gage is. You take the land contact measurement using the adapter in the OL gage. You subtract the distance off the lands you want the bullet to be, then you add 0.005" back in for the the shoulder being further forward on your cases. That's the number you want your finished cartridges to average.
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Last edited by Unclenick; March 31, 2013 at 02:02 PM. Reason: typo fix
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Old March 31, 2013, 01:02 PM   #7
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Per Gster - "I don't have any of the fancy measuring tools but this is how I do it. I re-size the case to get enough neck tension so that a bullet will slide in with a little resistance. Start the bullet in the case and leave it long. Now lay the bullet in your chamber and slowly close the bolt. Carefully open the bolt and don't let it eject. Pick it out and measure the oal. You can do that a couple times to verify. Subtract what ever you want your bullet to be off the lands and your good to go. You have to have enough neck tension so that the bullet doesn't slide in and out too easily. Works for me."


This method works well for me. I've also found that since most die seating stems locate the bullet on the ogive and not the tip, trying to actually measure and control OAL (base to tip) is frustrating. I can see as much as .005-.010 difference in OAL, just because of variations in the bullet format and tip damage, etc. Take that into consideration when adjusting for the free-bore amount you desire.
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Old March 31, 2013, 02:18 PM   #8
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And I should have mentioned you can improvise. If you have a caliper you can use spacers whose holes are close to the desired case datum diameter (shown) or just under bullet diameter for an ogive measurement to get the necessary relative measurements due to resizing or changing seating depth.



The only issue I have with the light neck tension approach (most don't have bushing dies or Lee Collet dies that will let them control neck tension, so they just resize normally, then split the neck with a hacksaw blade to get a less tight hold) is seeing false long readings come from it due to the bullet getting stuck in the lands a little bit and partly pulling out. This may be what Gster meant by not extracting.

The way to fix that is to insert the case and bullet and just push the case to the end of the chamber with your finger. The shoulder is going to land at the end of the chamber during firing, so this is what gets you the right amount of bullet protrusion with respect to the shoulder position. Next, use a cleaning rod to push on the bullet nose to gently back the pair out of the chamber. Since only the bullet can stick and the case moves freely, this avoids disturbing the bullet position in the case neck any.

When you withdraw that pair, take a single-edge razor blade or a sharp knife or a scribe and trace around the neck with it to mark the bullet. This will let you quickly see whether or not the bullet has moved during any subsequent measurements and will let you get it back in position if it does.
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Old March 31, 2013, 02:28 PM   #9
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That is the free way, but I prefer the easier Hornady/Stoney Point way.
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Old March 31, 2013, 05:04 PM   #10
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Naw, it's merely the cheaper way. I had to buy that caliper and the bushing and someone had to pay for that slotted case.

I've actually owned the Stoney Point gear since it was new on Commercial Row at Camp Perry, circa 1990. It's a good basic concept with a couple of minor limitations and, as you point out, it's a convenience.

The limitations are just the earlier one I described for compensating for difference in the gage case and your own resized cases. The other is that the aluminum inserts for case length headspace measurements don't have dead sharp edges on the hole, with the result that headspace in absolute units comes out short. You have to calibrate against a good quality headspace gage to work around that. But then, the RCBS Precision Mics I have also tend to miss absolute by a thousandth or two, so the same thing applies to them.
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Old April 2, 2013, 11:00 PM   #11
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Thanks everybody for the info...

First off, I’d like to thank everyone for their responses. They are all very constructive & I learned a lot from this thread. To clarify I don’t have the Overall Length Gage that uses a modified cartridge case.

Jepp2

Code:
I got my entire gage for less than $25 shipped and it fits everything.
I like the looks of that tool, where can I get one?...TIA

Here is what I learned or at least what makes sense to me. As a handloader, I want to determine the distance from the case shoulder to the bullet ogive where it just touches the lands. Then by varying the seating depth I can tell exactly how far the bullet jumps. BUT determining the actual “sweet spot” is a trial & error process & the exact distance will vary by the load & the bullet. Therefore knowing this exact measurement is not very important. All of the above suggested methods will give a plenty good enough starting point to begin finding the exact seating depth. But you won’t be able to say quantitatively best accuracy came this certain distance from the lands. It makes no real difference as long as I can repeat that seating depth (i.e. bullet jump to lands relationship).

Unclenick makes a good point about the difficulty in accurately using the dial caliper trying to keep things straight, closing with consistent pressure & soft bullet/insert edges. It’s a knack or finesse I haven’t mastered yet.

Unclenick also makes a good points in that measuring ogive to the bolt face using the comparator is imprecise since most cases are not a precise chamber fit, especially in most hunting rifles & using standard sizing dies. It also occurred to me that the sized case itself will vary due to its own hardness. Brass works so well in our rifles because it expands under high pressure then contracts slightly for an easy extraction. It makes sense that brass, once it is removed from the sizing die, will also “spring” back slightly based on its hardness. A batch of sized case should all have some variances. This could account in part of my trouble in making precise measurements using the comparator.

As a quick test out of curiosity, I used the compactor to measure the ogive consistency of 10 bullets each of 3 different bullet brands. All are .277 caliber.

Speer 130gr HC SP - Low: 1.521” High: 1.526” Spread: .005”
Sierra 115gr HPBT Match – Low: 1.475” High: 1.476” Spread: .001”
Barnes 110gr TSX BT – Low:1.486” High: 1.489” Spread: .003”

Using a fixed seating die, each batch of 10 bullets would have a slight seating variation just due to the ogive. I wish I had some Bergers to try this test on as well as on some custom match bullets.

At least now I feel a bit more confident in my methods & I’m more comfortable with some of the variations I’m getting, even though I can’t tell someone my bullets are exactly .001234" off the lands!
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Old April 3, 2013, 09:08 AM   #12
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The tool that jepp2 uses is "cool" but you almost need 3 arms to use it. Remember, someone or something needs to be holding a bullet against the rifling at the same time. You can do the same thing with a wooden dowel and a razor blade, which is what I do when I don't have a modified case.

The Hornady tool should give you precise results very easily. Most folks who think it's inconsistent don't realize that it won't match their own cases exactly and fail to make the calculation.
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Old April 3, 2013, 12:43 PM   #13
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I have used the Stony Point/Hornady OAL gauge for years with satisfactory results. The thing is, even if you have a perfect value for your OAL, you still have to experiment with loads at the range in order to find what your arquebus likes best, namely, touching the lands, .02" off, .04" off, or etc. So, if your resized cases are close to the dimension of the test case, the Stony Point is quick and easy way to get a good starting point for your OAL work.
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Old April 3, 2013, 03:45 PM   #14
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I hold the bullets against the lands with wooden dowel, and mark the end of the receiver. Same with case in chamber. Distance between marks + bullet length gives me a starting oal. I tried the slit case method but found it harder to get repeatable measurements. Too tight and you jam the bullet into the lands, too loose and the bullet gets pulled out a bit by the lands.
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Old April 3, 2013, 07:59 PM   #15
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Ha, why am I more confused than I was in the beginning?
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Old April 4, 2013, 10:08 AM   #16
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Quote:
Originally Posted by mapsjanhere
I tried the slit case method but found it harder to get repeatable measurements. Too tight and you jam the bullet into the lands, too loose and the bullet gets pulled out a bit by the lands.
This is also the issue with the gage that comes with the RCBS Precision Mic. That's why I recommend pushing in with your finger and out with a cleaning rod or a dowel rod from the muzzle. Even a bullet stuck in the lands won't pull from the case when you push it out from the muzzle. If you measure the difference from the shoulder to the bullet ogive, the fact the finger pushes the case in further than your bolt face does is not an issue.

One note on shooting: Hatcher showed a chamber can set a shoulder back up to 0.006" when you operate a bolt rapidly. If you are playing with distances off the lands that are very short, like 0.010", this becomes a consideration. You would then need to constrain yourself to chambering gently.
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Old April 4, 2013, 10:47 AM   #17
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So the real questions becomes, how does average Joe Handloader with his factory Rem 700 varmint rifle, using off the shelf RCBS dies with a box of his favorite Sierra bullets assure his bullets jump .014" to the lands every time? And, how do you create a dummy round for future seating?

BTW: I was surprised in the ogive variance for the Barnes bullets. I don't know how they make them, but I thought they'd be more precise than the "swage" method.
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Old April 4, 2013, 10:55 AM   #18
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Quote:
So the real questions becomes, how does average Joe Handloader with his factory Rem 700 varmint rifle, using off the shelf RCBS dies with a box of his favorite Sierra bullets assure his bullets jump .014" to the lands every time? And, how do you create a dummy round for future seating?
Use the Hornady OAL tool. Write down what it tells you.

Use the Hornady Headpspace gage or make your own. The right size socket will work fine, or any other shim that touches something close to the center of the shoulder and is long enough to extend past the neck.

Measure the headspace on the Hornady modified case. Zero your calipers on it. Measure the headspace on your PROPERLY SIZED cases. Properly sized means neck-sized or full-length sized with 0.001-0.002 shoulder bump. If the number is negative, you'll subtract it from your ogive OAL. If it's positive, you'll add it.

Realize that the OAL gage is measuring the shoulder to ogive distance. The head of the case could be any distance behind the shoulder. There are only two fixed points, shoulder and rifling.

If you measure from the head and don't compensate for the difference in headspace between your cases and the modified case, the OAL (ogive) will be off the expected value by the difference between the headspace of the two cases.
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Old April 5, 2013, 10:56 AM   #19
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Dummy rounds: Again, depends, I make transfers and standards I use for verifying, to call a case ‘a dummy round’ would be determined by who is going to use them. Then there is the practice round designed to be used for practice, show and parade, then there are inert.

Transfer and standards. I start by drilling the primer pocket/flash hole to a diameter that accommodates a cleaning rod for the purpose of pushing bullets out of the case and into the rifling when determining the length of the chamber for maximum COL. YES! WE all know! Weatherby rifles have free bore for jump starts/running starts, I am the fan of the running start, I want my bullets to hit the lands A-RUNNING, I do not want my bullets setting at the lands at a dead stop when everything behind it gets busy, because time is a factor. And, we all know the case COL of the case must allow the ammo to be feed through the magazine, that means loading shingle shot with disregard for the magazine, or the maximum OAL is determined by feeding through the magazine.

Back to maximum COL, when COL stands for the length of the loaded round from the head of the case to the tip of the bullet meaning the ‘O’ represents overall as in one word, Then there is COAL.

Transfers: A reloader can pile tools on the bench, tools are nice, not necessary but nice. I make transfers to adjust my seating die, that is the purpose of drilling the flash hole/primer pocket, I seat a bullet, remove the bolt then place the test case with bullet into the chamber, then, push the bullet out of the case until it contacts the lands, then I stop, I then carefully push the bullet out of the lands with a longer cleaning rod ‘carefully’. And that is it, no Hoirnady/Sinclair etc., tools and modified cases, and I have bullet hold. The neck of my drilled out cases have not been modified for easy bullet sliding, again, I am the fan of all the bullet hold I can get.

Purpose of making a transfer: I use the transfer to adjust my seating die for that chamber with that bullet, I place the transfer into the shell holder, raise the tam ‘THEN!’ adjust the seating die to the transfer, to avoid crimping the die must be adjusted off to avoid crimping first, after adjusting the die to crimp or not to crimp the seater plug is adjusted down to the bullet, once the seating plug is adjusted the height of the plug must be ZEROED with a height gage as on above the die. The height of the seating plug can be adjusted to seat the bullet off the lands by measuring the height of the seating plug.

WORKS, but more expensive, seating dies with micro adjusters, I have 7 seating dies with micro adjustable heads, but still, I have to have a transfer, other reloaders do not, they oile the tools on the bench and go back and forth with making an adjustment, remove, measure, place in the shell holder, raise the ram and start over.

I use transfers, I transfer dimensions of the chamber to the seating die with a case with the flash hole/primer pocket drilled out, if I drilled a hole through the case body I would still be required to drill the flash hole/primer pocket.

Head space: I skip head space and go straight to the length of the chamber from the shoulder/datum to the bolt face. Again, with cases with drilled out primer pocket/flash holes I form cases by controlling the length of the case from the shoulder back to the head of the case. My favorite case? The one that is too long to chamber because of the length of the case from the shoulder back to the head of the case. My favorite case must be sized to chamber, meaning I must shorten the distance from the shoulder back to the head of the case, not a problem, my presses and my dies are adjustable, all I am required to do is know how to adjust the die to the shell holder, and it helps to know how to measure the length of the case with tools from the shoulder back to the head of the caser, again, there are tools that accommodate that task, they are nice and expensive but not necessary.

Transfers, I use transfers as tools, it would cost me $80.00 ++ to purchase modified case for a Hornady/Sinclair type modified cases to accomplish the same task, I have a slight advantage, I have more bullet hold. Another method requires sheading the case neck to reduce bullet hold, again, I want all the bullet hold I can get, and, I do not have to worry if the bullet wants to stay jammed in the rifling.

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Old April 5, 2013, 11:06 AM   #20
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“If you measure from the head and don't compensate for the difference in headspace between your cases and the modified case, the OAL (ogive) will be off the expected value by the difference between the headspace of the two cases”

I would add chamber length from the shoulder/datum to the bolt face.

Brian, it is a matter of keeping up with more than one thought at a time. Making transfers with fired and sized cases to fit the chamber would eliminate the difference in length between the modified case and chamber from the shoulders back to the bolt face and case head, again, I want bullet jump, I want ‘the running start, all I want to know is ‘HOW MUCH JUMP’, “RUNNING START’ for consistency .

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Old April 5, 2013, 11:54 AM   #21
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Again, I make transfers, I transfer the dimensions of the chamber to the seating die, I adjust the seating die to the transfer.

Side note, a reloader shooter/builder took one of his wildcats to a shop with a bore scope, everything looked great, nothing they did help the accuracy of the rifle, Then he called me, he knows how to aggravate, he told me the whole boring story, then, finally, he asked me “What would you do and where you your start”, I told him, the next day he shows-up, with the razor blade and dowel, bullets and test cases. Again, aggravation, he went to the Internet and decided the best way to determine if my starting point had any validity.

He started setting up his test, I told him I want to know in thousandths. with hesitation he gave up a few formed cases for making transfers, I drilled the flash hole/primer pockets, I seated 7mm bullets, removed the bolt, stuck the transfer into the chamber and then pushed the bullet out to the rifling, before the bullet hit the rifling it came out of the case, the bullet traveled another .175” after it left the the case and before it hit the lands. My friend build 5 rifles, all from 03 Remington and Springfields, all with the same reamer???

We loaded a pile of ammo with different bullets and powders, we varied the weight of the bullets, we varied the amount of powder, we moved the bullet in, we moved the bullet out, most strange, with every attempt there was a point between maximum and minimum that made the rifle look good.

He has not decided on a plan, I could modify his chamber, something like Hatcher’s modified 30/06 +.080”, I could modify his chamber to resemble a Gibbs chamber with a long neck (30 Gibbs neck is .217” long), BUT! no matter what, the magazine is too short, moving the barrel back will leave a gap between the barrel and stock etc., etc..

Anyhow, he wanted to know how to check and where to start.

His cases were formed, he does not have a sizing die, and, he borrowed a seating die from me. I then suggest making a sizer die, I suggested we use his reamer, not a chance, he dropped it, it broke. Then he asked if I was familiar with another method/technique for making dies, and I replied with ‘yes’ but I have no interest, nothing impossible about making a different type of die, there is something about a few reloaders that reminds me of ‘SWEAT HOGS’, that causes me to think it is not a good ideal.

SWEAT HOGS as in “I am so confused” “I do not understand” etc..

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Old April 5, 2013, 12:40 PM   #22
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Quote:
Originally Posted by F. Guffey
Brian, it is a matter of keeping up with more than one thought at a time. Making transfers with fired and sized cases to fit the chamber would eliminate the difference in length between the modified case and chamber from the shoulders back to the bolt face and case head, again, I want bullet jump, I want ‘the running start, all I want to know is ‘HOW MUCH JUMP’, “RUNNING START’ for consistency .



The properly resized case isn't the same size as the modified case. Making the adjustment is a simple, one step process.

The gauge is a lot easier than drilling out a case every time and it holds the bullet in place much more reliably.

Running start or otherwise, the OAL gauge is accurate and consistent when used properly if the user makes the adjustment... "transfers"... the dimensions from one to the other.
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Old April 5, 2013, 01:23 PM   #23
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The difference in my modified case and my properly sized case shouldn't matter to any but myself... Of course theres a different measurement between the two but I still measured it with my modified case and found the measurement that MY RIFLE likes,. You guys have to understand that my TRANSFERS or resized cases are going to be different, don't make this an MIT grads game cause it's not hell I'm proof of that, I don't get hung up on what my fired cases measure, and likewise I know that my resized cases loaded to my measurements will perform nicely and they are not finished if they don't... See Like F. Guffey wants everyone to know He verifies and makes transfers, ( which is genius, cause it's a faster way to set up dies and get perfect numbers), I finish my loads, They never get wrote down or recorded if they are not accurate and precise. But I digress...
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Old April 5, 2013, 01:28 PM   #24
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“The properly resized case isn't the same size as the modified case”

Properly sized case is not a term I use, I size cases to off set the length of the chamber, my methods and techniques allow me to cut down on all that case travel, UNLESS! I am reloading like a bench rester, if I was sizing cases like a bench tester I would be returning the case to minimum length/full length sized length.

They sell one modified case, one modified case can not be used for all chambers. Again, I have one chamber that has an addition .016” added to the length of the chamber from the shoulder to the face of the bolt face, when keeping up with more than one thought at a time and determining the ‘off the lands’ I have to consider the added length when sizing and measuring COL (case overall length).

F. Guffey

”Brian, it is a matter of keeping up with more than one thought at a time. Making transfers with fired and sized cases to fit the chamber would eliminate the difference in length between the modified case and chamber from the shoulders back to the bolt face and case head, again”
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Old April 5, 2013, 02:36 PM   #25
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Quote:
They sell one modified case, one modified case can not be used for all chambers. Again, I have one chamber that has an addition .016” added to the length of the chamber from the shoulder to the face of the bolt face, when keeping up with more than one thought at a time and determining the ‘off the lands’ I have to consider the added length when sizing and measuring COL (case overall length).
Which I explained very clearly in a previous post.

A fired case matches, or very nearly matches, your guns chamber. A properly resized case will match your guns chamber minus 0.001-0.002, maybe a bit more for a gas gun.

The modified case will work in any chamber. One need only know the difference between the modified case and the chamber. A difference that exists, not at the front, but at the back.

Therefore, properly resized cases match your chamber, minus however much you moved the shoulder, 1 or 2 thousandths. The difference between that measurement and the modified cases shoulder, added to the modified cases OAL at the ogive will give you the exact length from the bolt face to the rifling. You can even add back in that extra 0.001 that you moved the shoulder, if you really want to be anal.

Really makes no difference if you have a "special" gun with a long or short chamber or a long or short throat.

Add the difference between your chamber shoulder (fired, properly sized case shoulder) and the modified case and you have your number.

There's really nothing complicated about it.
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