How i find the lands in chambers


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OKIE2
October 28, 2009, 08:14 PM
Split 2 sides of sized case neck insert bullet of your choice just enough to hold it then chamber it
remove carefully and measure as picture. this will give you the most accurate measurment you can get. THEN SET SEATING DIE TO THIS LENGTH.
the lands will push bullet back into case.
http://i661.photobucket.com/albums/uu340/OKIE2-photos/my%20guns/HOWTOOALMEASURMENT.jpg

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atblis
October 28, 2009, 09:26 PM
Rather than cutting splits in the neck, you can also kiss a fired case with a neck sizer to hold the bullet lightly.

ranger335v
October 28, 2009, 09:33 PM
Boy, oh boy, now I finally know how he does that!
And measures stuff with a caliber too, that's neat!

??

1858
October 28, 2009, 10:36 PM
How do you know that the seater plug in the die contacts the ogive of the bullet in the same place as the pistol case? Wouldn't this make a difference to the OAL?

I don't seat any bullets so that they contact the lands when the round is chambered and certainly don't seat any into the lands. I seat all bullets 0.020" off the lands with excellent results. I have both OAL gauges shown in the link with modified cases for every caliber that I shoot. I find the Stoney Point (now Hornady) system, with the bullet comparator, to be excellent in determining the exact OAL for any bullet/case/chamber combination.

http://www.hornady.com/story.php?s=485

:)

Horsemany
October 28, 2009, 11:00 PM
I believe he's just using the empty pistol case to measure with. Just like a comparator in that regard as long as you save that pistol case. I'd get a hex comparator from Sinclairs that does a group of different calibers.

I usually just measure to the tip and forget about comparators. I'll measure 5 bullets from the box and make sure I'm using one that's average. If my bullets vary by more than a few thousandths in length than they're not precise enough for me to worry about anyway. I make note of the bullet length used for measurements in my loading notebook.

I agree with NOT seating bullets into the lands. Most of my rifles provide the best accuracy with .020" to .010" jump to lands.

JimKirk
October 28, 2009, 11:01 PM
What pistol case do you use for each caliber? The way I look at it the inside of the pistol case would have to be the exact diameter of the lands and the pistol case rim diameter would have to be the exact diameter of the lands too. I think that this would be hard to find for many calibers must less for every caliber. I'm always open to new ideas, but.......

Jimmy K

atblis
October 28, 2009, 11:12 PM
How do you know that the seater plug in the die contacts the ogive of the bullet in the same place as the pistol case? Wouldn't this make a difference to the OAL?
Doesn't have to. The pistol case is for measuring. You just use it to measure when setting the die too. You don't need to use it even. Just use the same bullet for determining max oal, and also for setting your seating. Measure to the tip of the bullet.

1858
October 28, 2009, 11:15 PM
I believe he's just using the empty pistol case to measure with. Just like a comparator in that regard as long as you save that pistol case.

I still don't get that from the OP's post. If he's using the pistol case as a bullet comparator, why subtract it from the measured length to get the OAL (he states that in his method)? Surely he'd keep seating the bullet and checking the length (from base of rifle case to base of pistol case) until that length matches that which he obtained from the "special" case. In other words, no subtraction of the pistol case length required.

:)

ants
October 28, 2009, 11:33 PM
Which pistol case do I use? 25acp?

32 caliber and larger are all MUCH larger diameter than a .308" bullet. None of them perch on top of a bullet as drawn in the diagram.

Must be a 25acp.

JimKirk
October 28, 2009, 11:38 PM
I see using the pistol case as a comparator, but there is no way to get an accurate OAL unless the pistol case meets the standards I stated above.

Jimmy K

The 25 ACP is the only case even close, but the mouth diameter is different too!

JimKirk
October 29, 2009, 12:01 AM
Looking again
Jimmy K

Sport45
October 29, 2009, 12:16 AM
Aside from the misspelling the only problem I see is that what he calls the OAL (Overall Length) is actually the length to his reference ogive. This method should work fine assuming you can find a pistol case that doesn't swallow the rifle bullet. Maybe you could chamfer the inside of a short piece of brass or copper tubing to do the same thing.

1858
October 29, 2009, 12:21 AM
This method should work fine assuming you can find a pistol case that doesn't swallow the rifle bullet. Maybe you could chamfer the inside of a short piece of brass or copper tubing to do the same thing.

Why go to all that trouble though? Just buy a bullet comparator set from Hornady and be done with it. While you're at it order an OAL gauge too and all of this is moot.

Hornady bullet comparator (https://www.hornady.com/shop/?ps_session=2100e29d30ea777817952829d061b02e&page=shop%2Fbrowse&category_id=ed0a24f7da507b583bac1a8d6e16635b)

Hornady OAL gauge (https://www.hornady.com/shop/?ps_session=2100e29d30ea777817952829d061b02e&page=shop%2Fbrowse&category_id=fd215786476a600bb3a34eaef6e83165)

:)

Sport45
October 29, 2009, 01:27 AM
I was just offering an alternative to finding an appropriate pistol case.

I couldn't care less where the lands start in my rifles. At least I'm not there yet. :)

Horsemany
October 29, 2009, 08:43 AM
I couldn't care less where the lands start in my rifles. At least I'm not there yet.

Aside from the obvious safety issue of no regard for bullet seating depth, it is one of the best ways to control accuracy and pressure. It is worth the time to at least chamber that split case and bullet several times. Extract it carefully and measure it. Once you've found the distance to lands subtract .020" and start with that. Carelessly loading into the lands could easily blow your gun apart and put the bolt in your face.

I no longer use the Hornady OAL gauge. I had 2 different calibers that the case was oversized and would not chamber fully. Not knowing this I kept getting OAL's too long. Had I not been measuring the old way in these rifles I may not have caught the error and loaded rounds dangerously long. A quick call to Hornady confirmed they do not final size the cases used to make the gauges. I now use my tried and true method of using a bullet pushed into a case with one slit down the side of the neck. I chamber the case and measure this 10 times in a row and measurements usually vary by no more .001". IMO there's no more accurate or easier way to measure OAL.

rattletrap1970
October 29, 2009, 09:12 AM
I bought the Sinclair seating depth gauge P/N 59-4000. Neat little thing, but I use it with a twist.

1. Use the gauge to get an accurate measurement from the base of the case to the base of the bullet.
(This is where I break with the instruction)
2. I made another gauge with a .060 dia piece of drill rod with a stop collar on it.
3. I set the stop collar on my homemade gauge to the measurement I got with the Sinclair gauge.
4. I insert the homemade gauge into the flash hole of the brass I used with the Sinclair gauge (which has a snug sliding fit to the bullet).
5. I push the bullet into the case till it hits the gauge.
6. Then I measure the OAL with a gauge that measures from the base of the case to the ogive of the bullet.

Now I know that the length that my OAL gauge is telling me is the "On the lands" measurement. I set my Redding competition bullet seating die to that length, read the number and noted it (so I know never to exceed it). Then I dialed the bullet into the case by .009. So, I'm .009 back from the lands.

Sport45
October 29, 2009, 10:43 AM
Carelessly loading into the lands could easily blow your gun apart and put the bolt in your face.

I'm not being careless. Magazine length cartridges will not reach the lands in a Wylde chamber. Nor will M2 Ball seated to the cannelure in a M1 or 174gr BTHP loaded to magazine length in a 7.7mm Arisaka.

Careless would be loading longer than published length without checking this dimension. :)

I agree that trying to stretch a bullet out to the lands without knowing where they are could be dangerous.

R.W.Dale
October 29, 2009, 11:17 AM
Do yourself a huge favor and get one of these and skip the monkey business with pistol cases to find the exact origin bullet's ogive on ANY bullet

http://www.midwayusa.com/viewProduct/?productNumber=746974
http://www.midwayusa.com/viewProduct/?productNumber=365474

http://www.midwayusa.com/mediasvr.dll/image?saleitemid=746974

This is one of my most often used reloading and measuring tools


To find the head to lands measurment I simply black sharpie a bullet and insert into a fired casing with a small dent in the mouth to hold the bullet and scrape off marker. Chamber, eject and compare the marking to the case mouth. Average this over 3 times and you now have a measurement that you can use on EVERY bullet for that rifle thanks to the precision of the above comparator

fguffey
October 29, 2009, 11:35 AM
I drill the flash hole (10 cases) to a diameter that will accommodate a cleaning rod or dowel, I size the case, seat a bullet (no primer/powder), remove the bolt, chamber the test case then through the drilled out flash hole I push the bullet out until it contacts the lands, from that I have determined the max overall length of that case, that bullet in that chamber, if I change bullets I start over.

I then place the test case in the shell holder, with the seater die backed out and with the seater stem backed out of the die I rraise the ram and start to lower the die down until it just makes contact with the crimp portion of the die, I then back the die out a guesstimate of 1/2 turn (.0355 thousands) and secure the seater die with the lock nut, then I lower the seater plug until it contacts the bullet, then secure the seater plug stem with the seater plug locking nut while holding the stem, THEN measure the height of the seater plug stem above the die, the measurement is referred to as being .000 (ZERO) off the lands, If I want to seat a bullet .020 off the lands I reduce the height of the stem by .020 thousands.

I have found chambers that had been throated for what ever reason know only to the person with the throating tool but in pushing the bullet out of the case the bullet came out of the case before the bullet hit the lands, one custom 7mm Gibbs by .150 thousands when a 170 grain bullet was used. even the magic of the 280 Remington could repair that one.

By drilling the primer pocket on 10 cases you will be ahead when you change bullets, drill bit, drill and a dial caliper and cleaning rod, skill not understood cost money.

Plus: Head space, meaning when the test case is chambered and pushed forward, head space is not considered unless the reloader knows the amount of head space, therefore, .000 could be plus head space.

I know it could make some tired when they push the bullet out of the case and into the lands, bullet hold, some call it tention, I like to know the effect the case neck has on bullet hold and when loading that case with that bullet for that chamber, I can use that test case to set up the seater die, again.

F. Guffey

atblis
October 29, 2009, 01:13 PM
You don't care about an actual measurement of cartridge OAL. You're simply trying seat the bullet a known distance off of the lands. That is what you're measuring.

ranger335v
October 29, 2009, 02:24 PM
"You don't care about an actual measurement of cartridge OAL. You're simply trying seat the bullet a known distance off of the lands. That is what you're measuring. "

Yeah, that's what you're measuring IF you use a proper diameter bullet comparitor, such as the Sinclair nut or the Hornady/RCBS Precision Mic tools. Using any spent pistol case tells you none of that, and mouth of pistol cases are really too thin/soft to take a consistant measurement on a bullet's ogive anyway.

Think I'll stick to using a marked wooden dowel from the bolt face and to the bullet poin, then transfering that length to the seater. Since precious few factory sporter rifles shoot well seated to the lands, all we really need is a repeatable OAL we can vary around until we find the best length anyway.

30Cal
October 29, 2009, 03:34 PM
I do it as such:

1. Seat a bullet in a FL sized case with the OAL set very long (typically, it's primed and charged).
2. Stuff into the chamber with my thumb
3. Seat deeper in small increments (I go with 0.005") till it drops out of the chamber with gravity alone. When it does this, the bullet is no longer touching the lands (and as a bonus, my seating die is now set for zero jump). With my micrometer seating die, I just add in the jump that I want to set and it's ready to rip.

Quick, repeatable and several birds are killed with one stone.

1858
October 29, 2009, 05:42 PM
I no longer use the Hornady OAL gauge. I had 2 different calibers that the case was oversized and would not chamber fully. I chamber the case and measure this 10 times in a row and measurements usually vary by no more .001". IMO there's no more accurate or easier way to measure OAL.

Why didn't you simply run those cases through your sizing die? Are you measuring the headspace of your sized or new cases as well? If not, you may be getting a lot more variation in the distance between the bullet and the lands than you realize.

I called Hornady to ask them about their modified cases and they're all SAAMI spec brass. That means that the cases are all sized by the manufacturer within SAAMI specs ... BUT WHO CARES?!! I measure ALL of my Hornady modified cases and compare them to the SAAMI standard that comes as part of Redding's Instant Indicator Case Comparator. Looking back through my notes, these are the headspace measurements of five Hornady modified cases before I sized them (if necessary) to the same headspace dimensions as the cases I use in each particular rifle.

.223 Rem
Length = 1.751"
Headspace = SAAMI - 0.002"

7mm-08
Length = 2.024"
Headspace = SAAMI + 0.003"

.308 Win
Length = 2.004"
Headspace = SAAMI + 0.001"

.300 WSM
Length = 2.091"
Headspace = SAAMI - 0.001"

.300 WM
Length = 2.609"
Headspace = SAAMI - 0.012" (measured at shoulder but case headspaces on belt)

You can go on and on about how accurate your system is to measure the OAL but bear in mind that very good new factory brass such as Lapua will have a headspace deviation by as much as 0.004". Lower quality brass may deviate by a lot more than that. Now consider the repeatability of your case sizing process. Do you run all of the cases through a case comparator to measure headspace after full-length sizing? Do you know the tolerance that you can consistently hold with your sizing procedure? If you don't, then the accuracy and precision of your OAL method is irrelevant.

:)

JDGray
October 29, 2009, 08:45 PM
I now use my tried and true method of using a bullet pushed into a case with one slit down the side of the neck. I chamber the case and measure this 10 times in a row and measurements usually vary by no more .001". IMO there's no more accurate or easier way to measure OAL.

I use this method, but slightly neck size a case to just hold a bullet. Do this with each and every bullet profile, and write it down. Subtract .010" and call it Max OAL. I was very surprised to find that Federal Gold Medal Match ammo, was only .005" off the lands, in my Savage .308

Horsemany
October 29, 2009, 09:17 PM
I was very surprised to find that Federal Gold Medal Match ammo, was only .005" off the lands, in my Savage .308

I'm surprised to hear that too! Does your gun have a factory barrel and chamber?

JDGray
October 29, 2009, 10:26 PM
I'm surprised to hear that too! Does your gun have a factory barrel and chamber?

Yes, 10FP with 20" heavy barrel. Shoots GMM to about .900" at 100yrds. Shoots 168 SMKs over Varget, to .500" at 100, using the factory ammo's 2.805" OAL:)

Maybe Savage did that on purpose, for accuracy using factory ammo? I don't know, but I not complaining:)

JimKirk
October 29, 2009, 11:53 PM
Unless the pistol case rim is the same diameter as the bullet, there is no way using the drawing to get OAL. The inside diameter of the case would have to be the diameter of the bullet too. By turning the rim to match the bullet diameter and expanding the case mouth to bullet diameter THEN it would work.

Jimmy K

Sport45
October 30, 2009, 01:45 AM
Unless the pistol case rim is the same diameter as the bullet, there is no way using the drawing to get OAL. The inside diameter of the case would have to be the diameter of the bullet too. By turning the rim to match the bullet diameter and expanding the case mouth to bullet diameter THEN it would work.

I don't think he's shoving the pistol case into the chamber. He's just using it as a spacer to measure from a reference diameter (pistol case mouth ID) on the bullet's ogive.

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