HELP! GET DIFFERENT CALIPER READING EACH TIME!

Guys, I got so much great info here. OK I so far, been able to clean my brass, decap, and flare the mouth so I could seat the bullet. Now please tell me if I got it right. The bullet sits on top of the mouth, I can pick the brass up and turn it 45 degrees gently and bullet will not fall over unless I shake it a bit. Is that about right?

OK then I seated the bullet slowly and slowly until my Cabalas Electronic Caliper showed 1100 OAL. According to Hornady, 1100 OAL is the max. However, once I got that to that exact reading, subsequent checks on same bullet gets me 1097, 1101, 1096, this is driving me crazy! anybody else getting variances using same bullet? I could see this happening if I used different brass and different bullets but using the same bullet, I get the readings above. Am I using the caliper correctly? Yes I checked to make sure it was zero. I am measuring round nose copper jacketed. I make sure I take the reading from the center and highest position. Maybe the Cabalas brand is ****. My concern is if my reading is 1096 to 1101, and I use the recommended 4.7 to 6.7, and I start from 5.0 .will that give me enough leeway where if my case is that far off 1097 through 1101, to not make the pressure dangerously high? any of you get inconsistent readings using an electronic caliper?

My other question is using a lee hand press, I did exactly what the instruction said, Screw the die in until it touches shell plate. then back out 3 full turns. Then with the cartridge in, screw the adjusting nut until it just touches tip of bullet. Then take cartridge out and turn half turn in to do a light crimp. However, even before doing that, When testing it out by putting the shell, on its' own it seems to be crimping in spite of not screwing the adjusting nut down yet. Is it normal to feel tension on the cartridge? I thought that was what the crimp was for.

Assuming you seated a bullet, measured, pulled that bullet, seated it again, and got a different reading: If you used a kinetic puller, you likely changed the bullet's profile when it hit bottom in the puller.

Assuming you used different bullets of the same type - the bullets are likely somewhat different.

Assuming you measured the same cartridge multiple times without changing it in any way . . . measuring cartridges with calipers isn't all that easy. Measurements can differ if:

- the cartridge is not perfectly perpendicular to the base of the case
- the base of the case is not perfectly flat
- the cartridge is ever so slightly bent (think "banana")
- you don't really find the high point on the round bullet . . . while the base of the case is flat on the other caliper blade
- the high point rests first on one edge and then the other of the caliper blade
- you applied different pressure on measurement #2 than on measurement #1.
- the primer projects slightly
- the calipers are flaky, plus the inherent measurement error is never zero.
- and so on.

Yes, I've had issues like that . . . it takes some experience to know when the cartridge is positioned correctly, and "locked in" between the caliper blades. And even then . . .

If you got 1.100" as the COL listed for a load from the Hornady manual, that's the minimum COL. Your variations - even if real - are safe at the powder charge you are using. Shoot for a minimum COL of (eg) 1.100", but don't fret too much if you're a thousandth or two under or a few thousandths over. And remember you may have to adjust the COL (longer) in order to feed in your pistol.

Your flare is enough if the bullet will sit flat on it, and when seated does not shave the bullet on the edge of the case. More than that isn't a huge deal, but needlessly works the brass.

Sorry, but I can't help with the Lee Hand Press question.

Edit: change "shave the brass" to "bullet".

COAL variations

Do you have the (3) die or the (4) die Lee Reloading Die set? What cartridge are you reloading for?

Checking the COAL" on multiple reloads, using the same brand/style bullet in each, will almost always vary in the exact measurement because of little differences in the bullet's shape. Some brands/styles are worse than other in this matter. The range in readings you mentioned are common. Don't sweat it. Just adjust the die so the average is where you want it. If you get one that is way off from the others, double check it though.

Yes, if you seat a max &/or compressed load deeper than intended, it can cause increased pressure. I always seat my auto bullets out as far as possible without going over the max COAL" for that cartridge and still pass the plunk test.

thanks

Twoboxer said:

Assuming you seated a bullet, measured, pulled that bullet, seated it again, and got a different reading: If you used a kinetic puller, you likely changed the bullet's profile when it hit bottom in the puller.

Assuming you used different bullets of the same type - the bullets are likely somewhat different.

Assuming you measured the same cartridge multiple times without changing it in any way . . . measuring cartridges with calipers isn't all that easy. Measurements can differ if:

- the cartridge is not perfectly perpendicular to the base of the case
- the base of the case is not perfectly flat
- the cartridge is ever so slightly bent (think "banana")
- you don't really find the high point on the round bullet . . . while the base of the case is flat on the other caliper blade
- the high point rests first on one edge and then the other of the caliper blade
- you applied different pressure on measurement #2 than on measurement #1.
- the primer projects slightly
- the calipers are flaky, plus the inherent measurement error is never zero.
- and so on.

Yes, I've had issues like that . . . it takes some experience to know when the cartridge is positioned correctly, and "locked in" between the caliper blades. And even then . . .

If you got 1.100" as the COL listed for a load from the Hornady manual, that's the minimum COL. Your variations - even if real - are safe at the powder charge you are using. Shoot for a minimum COL of (eg) 1.100", but don't fret too much if you're a thousandth or two under or a few thousandths over. And remember you may have to adjust the COL (longer) in order to feed in your pistol.

Your flare is enough if the bullet will sit flat on it, and when seated does not shave brass on the edge of the case. More than that isn't a huge deal, but needlessly works the brass.

Sorry, but I can't help with the Lee Hand Press question.

Click to expand...

Wow! You are definitely way better than any instruction manual I ever read! Have you considered quitting your day job and becoming a support agent for Lyman?....lol.. you certainly understand this stuff better than anybody there I talked to....all I got was blank answers. So I guess I just have to not fret over one bullet being a few thousandths off. I thought I could achieve perfection by doing it one at a time but evidently not.

9mm

BLUEDOT37 said:

Do you have the (3) die or the (4) die Lee Reloading Die set? What cartridge are you reloading for?

Checking the COAL" on multiple reloads, using the same brand/style bullet in each, will almost always vary in the exact measurement because of little differences in the bullet's shape. Some brands/styles are worse than other in this matter. The range in readings you mentioned are common. Don't sweat it. Just adjust the die so the average is where you want it. If you get one that is way off from the others, double check it though.

Yes, if you seat a max &/or compressed load deeper than intended, it can cause increased pressure. I always seat my auto bullets out as far as possible without going over the max COAL" for that cartridge and still pass the plunk test.

Click to expand...

I am reloading for 9mm. So far I got the brass cleaned, resized, flared. Now I am in the process of trying to figure out how to use the 10 10 scale I got from RCBS. once I figure that out, I will load the bullets, then seat it, and then crimp. hopefully the fact some OAL are off, won't make too much of a difference. I don't know how off one has to be before a bullet becomes too compressed and poses a dangerous condition

The 1010 RCBS scale is a good one, I've been using one for over 30 years. There are three adjustments for weight. But 1st make sure it is on a flat surface and properly zeroed with just the weight of the pan. Then set the 10 grain increment (10, 20, 30, etc). Then you turn the wheel so the vertical line is where you need it for the single grain, (1, 2, 3, etc). Then on the wheel itself is the 1/10th grain marks. Roll it to the proper setting (.1, .2, .3, etc.).

Once you do it a time or two it becomes automatic.

What units is 1101? ? ? Normal units to use for reloading is Inches and the overall length for the 45 ACP will typically range between 1.200 and 1.260 inches, depending on the bullet used and the powder recipe. BTW, you do want to use the length called out in the recipe in order to obtain the pressures that recipe calls out.

If you have dropped a decimal point and are loading to a length of only 1.101 inch you need to state the caliber, powder, bullet, and recipe in your posts. Doing so allows us to double check what you are doing. I am going to assume that you are loading 9mm because 1.101 inch is too short for any other caliber I can think of. Please, look more closely at your calipers and please don't neglect critical decimal points in your posts, we are not mind readers. I'll also note that reloading is a detail oriented activity and dropping the decimal point in your posts doesn't give me any confidence you are a detail oriented person.

Variation in overall lengths. A variation of as much as 0.010 inch total is not something to be concerned with, there is a bit of a safety factor built into most recipe's. The variation I normally see is in the 0.003-0.005 inch range but I make sure to use a Round Nose seating stem with Round Nose bullets and Flat nose stems with Flat Nose bullets and this does provide better control. Lee and some others only supply one seating stem with their dies (typically flat point) and this doesn't give you as much control with divergent bullet types.

Taper crimps. You wont be able to see a correctly done Taper Crimp because it will range between 0.000 and 0.005 inches smaller than the diameter in the middle of the bullet bulge. It's also difficult to measure a taper crimp with calipers because you have to catch the VERY EDGE of the case with the caliper tips. It takes a bit of practice, and for me reading glasses, to insure that you are taking your measurement at the very edge of the taper crimp. As for why it's so important to get that exact edge, it's a TAPER crimp, any distance back from the edge will give a false reading. Many simply feel to insure that the flare for insertion has been removed and do a plunk test in their barrel and doing that seems to work just fine. Me, being a detail freak "I gotta Know" so I measure and set my taper between 0.003 and 0.004 inch.

I had the same issue with Sierra 9mm 115gr. I discovered a variance in the shape of the bullets. If your seater seats on the ogive, your OAL will vary. Sierra denied any issues but in speaking with others, they noticed the same thing. The variations were plainly visible. Actually, seating on the ogive will give better results, assuming you don't have any feeding issues, since the "jump" to the rifling in the barrel is more consistent.

OP, don't sweat the small stuff. I've never gotten perfectly identical COLs with any case, any die, any bullet, or any combination of the above. A variance of .003-.004 is fine. How closely it falls depends on several things, some previously mentioned. Usually it's because the bullet used is not a perfect match for the seater--and even then you'll have variances from bullet to bullet.

As for the Lee hand loader, setting up the dies is no different than any other press.
For the seat/crimp die, Back the die body out enough so there's NO crimping. Seat the bullet to desired COL in an "unprimed" case. Back the seating stem out.

Screw in the die body until you get the crimp you desire. Lock the ring in place! (That is my issue with Lee dies--the lock ring does not lock in place.)

With the round fully inserted in the die, lower the seating stem until it rests firmly (Not tightly) on the bullet. Lock the seating stem in place.

Seat/crimp another round and confirm the COL and crimp you want is there. Minute adjustments may be needed. If 1.100 is your goal and if all your rounds come out 1.098-1.099, you're fine. You want consistency, not exactness.

marathonrunner said:

I am reloading for 9mm. So far I got the brass cleaned, resized, flared. Now I am in the process of trying to figure out how to use the 10 10 scale I got from RCBS. once I figure that out, I will load the bullets, then seat it, and then crimp. hopefully the fact some OAL are off, won't make too much of a difference. I don't know how off one has to be before a bullet becomes too compressed and poses a dangerous condition

Click to expand...

MMmkay ... its a reasonable concern I suppose, so I won't pick on you too much
rule of thumb, the shorter the OAL the higher the pressure, all else equal.
What you had in the fist post was about a .005 runout.
its not spectacular, but its not half bad either considering your new to all these things.
part of that .005 is likely your measurement technique, another part is probably the runout of your bullets, and the rest is press flex
thats where it comes from.
now, given the nature of your questions, past and present, I'm assuming your read more than one reloading manual cover to cover at least five times, and prepared note cards equal to the weight of the book in the process
(didn't say I wouldn't pick on you ... just not too much)

that being the case, you are familiar with the concept of minimum starting loads.
this largely negates any OAL issue you might have here.
that starting load is so soft warm and fuzzy, it might not effectively cycle the action of your firearm.
Pressures will be low and expectations will not be met by this starting load.
at this stage, you can be significantly under OAL and still be within safe pressure ranges.
That being said, your .005 runout means something next to nothing.
load a test string of 7 rounds.
first of these 7 you load only one into the mag, chamber it, hold on your target, say a prayer to God as you believe him to be, close your eyes and yank the trigger just like every new reloader must do.
round number two ... load into the mag, chamber, and actually try to hit something with it.
3 through 5 will then be loaded into the mag, and the real test string begins where you will listen for uniform report, feel for uniform recoil and see how it groups on target, as well as functions in your gun.

after this, you go home, raise the charge weight a little, load a string of 5 and see how they group and function.
repeat said process till it sings.

I get unusual readings sometimes when my caliper's battery needs to be replaced or if I forget to zero it out before opening.

Do you check its reading with a Gauge Block from time to time? Here's what I use: Gage Blocks & Spacers | MSCDirect.com

I think that there are a couple things at play.

One of my most respected analytical professors is fond of saying "there is no measurement without error" and I think this is something to keep in mind, especially with the differences you are reporting.

Calipers(whether vernier, dial, or electronic) all have some inherent flaws that limit their precision. Please note also that I'm using precision to refer to the repeatability of the measurement. The jaws may not be ground perfectly parallel, and measuring at different points may give a different value for the same sample. An often overlooked, but none the less significant source of error is thermal expansion of caliper that occurs just from handling it use-this can induce measurable error. For watchmaking work, I often avoid using any hand-held measuring tools and instead use a bench micrometer which is more immune to this type of error.

Finally, in order to get repeatable results, the user needs to be consistent in their use of the tool. Applying different amounts of force with different readings can induce a fair bit of error. This can be especially true in less expensive calipers, as their is often both "flex" and "slop" in their construction, but even in better quality instruments applying too much force can distort the thing you're trying to measure and can induce some error. Most micrometers have a clutch, which reduces this error, but I'm not aware of any calipers that contain such a device.

The variations you're reporting are small, and if you were to some basic statistics you might find that the variations are not even statistically significant.

Or, in other words, don't worry about it.

Don't use.....

Don't use the sharp part of the caliper jaws on a lead bullet or even if you are using the flats of the jaws don't put to much pressure on the bullet because the small bearing area is susceptible to deforming. One of the trickiest things about using a caliper is making sure all parts are aligned. Putting very light pressure on the cartridge move it around very slightly it to make sure everything is perpendicular. You can usually feel when it is right. When you find the smallest dimension so that even if you put more pressure on it won't substantially change, take your reading.

Until you get your technique right and are sure the the calipers are reading right, make the cartrideges a few thousandths short of max OAL.

Just like they make test weights for scales, there are polished length gages for calipers, micrometers, etc. They are hard and polished to a mirror finish. Use one of these to check the caliper and learn the right 'feel' for it.

Fine measuring instruments do require some practiced technique.

M&PUSER said:

I get unusual readings sometimes when my caliper's battery needs to be replaced or if I forget to zero it out before opening.

Do you check its reading with a Gauge Block from time to time? Here's what I use: Gage Blocks & Spacers | MSCDirect.com

Click to expand...

+1... try changing the battery. My electronic caliper from Midway was giving me flakey readings until I put in a fresh battery.

Measure off the ogive of the bullet and you will get a more accurate seating depth as the tips are usually not always the same. Measure the length of your bullets prior to seating and you will see a difference.

Welcome to statistics and the real world, even the best measuring devices won't have the same value every measurement. Every device has tolerance, every measurement is fundamentally an approximation and every measurement is guaranteed not to be a perfect replication of the previous one.

First, there is nothing wrong with your calipers. 1097, 1101 and 1096 are fundamentally the same measurement. You can't compare single measurements against one another meaningfully just by comparing them, you need to compare each measurement against the mean and the standard deviation. If you were to measure the length of the same object multiple times, you will get multiple measurements due to the intrinsic error in the measuring device. The device will report U+/-X+/-Z, where U is the actual length of the object and X is the random error in the measurement from the device and other factors and Z is the systematic error in the measurement from poor technique. As you take more measurements the measured mean will approach U within some degree of error. Random error from X will become less important and will approach zero on average since it is random and can be positive and negative. Z will not approach 0 since it is systematic error and will be in every measurement. Good measuring practices and reproducibility minimize Z so we don't have to consider it, but an example would be a poorly calibrate device which reads higher every time.

To determine the validity of the measurements you should compare to mean and standard deviation assuming it is normally distributed. With your three trials you have a mean of 1098 and an SD of 2.645. So if you were to make an infinite number of measurements, 65% of the measurements will fall between +/- 1 SD (1098+/-2.645), 95% within +/-1.96SD (1098+/-2.645*1.96). So even measuring the same thing the numbers you get will be different every time, but they will fall within certain ranges from the true mean, so a measurement is only questionable if it falls well outside of the 1.96SD range since that should only occur at random in 5% of measurements. I'm not saying do this when you measure OAL just demonstrating that you're calipers are not broken.

Additionally, your measuring device has a specified number of significant figures, or number of decimal places it actually accurately measures. In general, the last digit reported is always 'uncertain' so in reality the measurement of 1097 and 1096 may very well be the same value since the '7' and the '6' are uncertain. This is in addition to the intrinsic error of the measuring device.

Finally, if you are reseating the calipers between measurements you may not be measuring the same exact portion of the bullet and the bottom of the cartridge. This will introduce error. On the flip side if you aren't reseating the calipers you don't have replicate measurements and the methodology is incorrect. It is almost impossible to replicate measurements with calipers since they are effected by placement of the measuring surface, the pressure you use, calibration and that measuring the cartridge can change the length of the cartridge if you push too hard with the calipers or if the bullet isn't seated tightly.

Aside from these issues the other things to consider are that even if you could be certain that the cartridge is 5 units longer or shorter, it won't make any difference really since you aren't at max and even then max is rarely the true maximum that the cartridge or gun could handle (don't go above max charge nonetheless). So don't worry about it, you have normal and expected error in using a measurement device. What you should do is set the OAL on one cartridge, measure it a few times to make sure you are close enough to the desired value and remeasure maybe every 50 or so to make sure the die hasn't moved.

Crimp does not hold the bullet primarily, that is done by neck tension therefore prior to crimp it should still require some force to remove the bullet. These rules about measurement apply to everything by the way, measurements are not infinitely precise nor infinitely accurate, but calipers and your values are 'good enough', just make sure they are calibrated.

allow me to add a little more info for ya

45-70
factory Hornady FTX rounds ....
2.592
2.582
2.593
2.595
2.594
2.596
2.589
2.599

45-70
first run of cast 405G RNFP
2.544
2.542
2.543
2.543
2.545
2.544
2.542

Hornady, put ammo on the shelf with a .017 runout
I managed .003 on a first run
I expect mine to tighten up some as the mold, and all dies are new, and have yet to really break in and find a good working groove.
the .002 difference between us, is simply a matter of my experience versus your noobness.
your doing pretty good.


As ya know by now, I'm kinda keeping an eye on ya, and ill take a crack at your next set of questions, before you ask em.

powder charges as thrown can have some runout just like everything else, but you are looking for absolutes.
the cheapest effective tool for this is a piece of rifle brass.
308, 30-06, 300 win mag, 243, 338 ...
you should be able to find a few at most ranges for free.
clean it up and keep it by the scale.
set your measure to throw a few tenths of a grain low, put 3 or 4 charges into the rifle case and roll it between the fingers over the scale pan to add powder till the scale reads your desired goal.
yeah I have a powder trickler too, but I actually find the 338 case more convenient when im loading strings for testing, as you will soon be.
the RCBS tool comes out for large runs of ammo demanding exact charges, such as my subsonic 30-06 load that I try to keep at exactly 1050 FPS.
other than that, the runout of the measures thrown charges do not bother me as the ideal load was raised in a development string, proven safe, and probably raised again.
thus, anything that comes out of the measure will be within safe ranges.


to keep your OAL run out low, load and seat your rounds, but do not crimp them when seating.
run the batch uncrimped.
then back out the seating punch, remove the barrel from your pistol and run the die body down till it passes the plunk test.
you can use the search function of this forum to find an illustrated description of the plunk test.


aside from a scale question or two, this should get us all to pictures of your first targets with reloads, with a fraction of the waiting time for all of us

SMSgt said:

OP, don't sweat the small stuff.

Click to expand...

Exactly. I load .45 ACP with SWC bullets, and never measure the OAL. I simply load the bullets with about 1/32" (according to my calibrated eyeballs) of the shoulder exposed.

You may think that is sloppy work, but it has gotten me on the winner's podium at Camp Perry 3 times.

shooter5112 said:

Exactly. I load .45 ACP with SWC bullets, and never measure the OAL. I simply load the bullets with about 1/32" (according to my calibrated eyeballs) of the shoulder exposed.

You may think that is sloppy work, but it has gotten me on the winner's podium at Camp Perry 3 times.

Click to expand...

got to love that exposed shoulder.
even with a 1/16 spacing the effects of a lube plugged die are easy to spot.

What you describe is simply what is called "Error of Measurement". When dealing with measurements in the manufacturing world most instruments must be calibrated periodically (for certification purposes) and error of measurements established for each type of measurement taken.