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Why am I getting some variation in my OAL...
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Member Posts: 168,427 ✭
from the case head to the Ogive??? I switched from 180 grain Nosler BT's to 180 grain Nosler E-Tip bullets and the E-Tips are seating .005 longer than the BT's. I loaded 10 BT's then switched over to E-Tips...
We all know that the die seats off the Ogive...so why am I getting a longer OAL with the E-Tip bullets???? It's exactly .005.
I just measured the bullets and the BT (which I had my dies set up for originally) measure .307 and the E-Tips measure .308.
Shouldn't it have still seated the larger diameter bullets at the same depth as the smaller ones.?.? You would think the Ogive of the dies would seat any bullet the same diameter or larger to the same OAL.?.?
Thanks!
We all know that the die seats off the Ogive...so why am I getting a longer OAL with the E-Tip bullets???? It's exactly .005.
I just measured the bullets and the BT (which I had my dies set up for originally) measure .307 and the E-Tips measure .308.
Shouldn't it have still seated the larger diameter bullets at the same depth as the smaller ones.?.? You would think the Ogive of the dies would seat any bullet the same diameter or larger to the same OAL.?.?
Thanks!
Comments
EDIT Here is a link, 'splains it a lot better than me, IT IS YOUR ANSWER.
http://accurateshooter.wordpress.com/2007/07/10/283/
Bullet shape, one is probably a 7 Ogive Tangent and the other one an 8.
I just measured the bullets and the BT (which I had my dies set up for originally) measure .307 and the E-Tips measure .308.
Shouldn't it have still seated the larger diameter bullets at the same depth as the smaller ones.?.? You would think the Ogive of the dies would seat any bullet the same diameter or larger to the same OAL.?.?
Just for fun, and to satisfy yourself, mark the bullet and see where it hits the seating die, than measure that diameter (hint, it will be a dimention smaller than .300).
What bpost is saying is that the E-Tip is longer from the ogive line to the nose, and that's what your seeing.
Just for fun, and to satisfy yourself, mark the bullet and see where it hits the seating die, than measure that diameter (hint, it will be a dimention smaller than .300).
What does that have to do with the seating depth. I'm measuring these with a comparator...which measures from the case head to the Ogive. It shouldn't matter if the one bullet is longer from the Ogive to the tip of the bullet...should it.?.?
Or you could cut a couple of them, but you would have to have some accurate cutting gear to get an accurate representation.
Whatever way you do it, seeing a cross section will help.
quote:Originally posted by ECC
quote:Originally posted by Tailgunner1954
What bpost is saying is that the E-Tip is longer from the ogive line to the nose, and that's what your seeing.
Just for fun, and to satisfy yourself, mark the bullet and see where it hits the seating die, than measure that diameter (hint, it will be a dimention smaller than .300).
What does that have to do with the seating depth. I'm measuring these with a comparator...which measures from the case head to the Ogive. It shouldn't matter if the one bullet is longer from the Ogive to the tip of the bullet...should it.?.?
Your compairitor and your seating die DON'T work off the same diameter.
ECC
Your compairitor and your seating die DON'T work off the same diameter.
No...but the OAL should still be the same, should it not.?.? The dies seat off one diameter...the comparator is a slightly different diameter...but all of the cartridges are being measured with the comparator and should be the same...or am I off in my thinking here.?.?
but all of the cartridges are being measured with the comparator and should be the same...or am I off in my thinking here.?.?
Yes.
Numbers for example only. If the seater is contating at .250 and your compairitor at .300, there could very well be a .005 difference in the distance between those to measurments with only a slight change in the bullets ogive. Just changing the nose closing punch (at the factory) for a new one can cause that kind of difference, due to manfacturing tolerances on the punch.
quote:Originally posted by ECC
but all of the cartridges are being measured with the comparator and should be the same...or am I off in my thinking here.?.?
Yes.
Numbers for example only. If the seater is contating at .250 and your compairitor at .300, there could very well be a .005 difference in the distance between those to measurments with only a slight change in the bullets ogive. Just changing the nose closing punch (at the factory) for a new one can cause that kind of difference, due to manfacturing tolerances on the punch.
They are still being measured with the same tool, regardless. The tool does not measure the die...it measures the loaded cartridge...and it's going to measure from the head of the case to the exact same Ogive on each and every cartridge loaded (the Ogive of the tool). It doesn't matter whether or not a particular bullet protrudes further into the bore...the Ogive is what counts.
...unless I'm not thinking straight.[^]
I'm hoping JustC and NN will weigh in here.
Why are you worried about only a half thousands difference [?]
What about a slight difference in bullet shape causing your tools to hit the ogive different, giving you the different lengths [?]
Why are you worried about only a half thousands difference [?]
That does not matter...the Ogive is the Ogive, regardless of the shape. I seated the bullet several times and checked/rechecked the OAL several times...nothing changed...and it shouldn't. I'm worried about 5 thousandths...not .5 thousandths...and the reason I'm worried about it is b/c it can make a very significant difference in the accuracy of this load (not to mention the fact that I'm seating into the lands).
Let me be blunt
Step away from the loading bench, and go bck to shooting FACTORY ammo (or at least BOOK SPEC reloads).
You DON'T have the technical knowlege, or patence, to be loading precision ammo. This is NOT something you can learn over the internet, or from reading a book, this is something you have to be born with.
IOW owning a cookbook and a measuring cup dosn't make you a gourmet chef.
That does not matter...the Ogive is the Ogive, regardless of the shape.
WRONG; it IS the shape.
quote:
I seated the bullet several times and checked/rechecked the OAL several times...nothing changed...and it shouldn't. I'm worried about 5 thousandths...not .5 thousandths...and the reason I'm worried about it is b/c it can make a very significant difference in the accuracy of this load (not to mention the fact that I'm seating into the lands).
Lead is a dead metal, when deformed it does not spring back to shape. Bullets, even from the same lot vary a bit in final shape and length. Your OAL is not at critical as 50 other things when it comes to accuracy. I load 6BR for extreme accuracy and OAL, while important has proved less of an issue than case concentricity and bullet run-out. I have a bigger heartburn over .003 run-out than I do over slight variations in OAL. Seating into the lands is not new or dangerous, it is something you need to take into consideration, but not something to fear.
Go back and read your thread opener then read my first reply, again. Think about it and the fact that ogives are different on different bullets, you will have your answer.
OAL is measured from case head to tip of bullet. Comparator length is from head to ogive. Comparators are sized to be about .006 smaller than bore diameter to duplicate the rifling (lands) of the barrel. If you measure the 2 bullets (BT and E-tip)with your comparator, you should see the E-tip is .005 longer. The bullet diameter should not affect the comparator reading since it measures off the ogive. The ogive of these 2 bullets are not the same just as bpost said so your OAL will not be the same.
If you re-read my post, I was referring to the comparator length (although I phrased it the "OAL Length to the Ogive"). Your sentence in bold is what I've been saying all along. Everything you've stated supports what I've been stating all along...and leads me to my question.
Are you calling the ogive the point at which the bearing surface ends and the tapered part begins? If yes- the seating stem does not seat off of this point. It seats at any contact point determined by the diameter of your seating stem ---example two 30 cal bullets 110 gr hp 150 gr nosler ballistic tip --with seating stem removed placed each one in seating stem with best ability to measure from stem to ogive on 110 hp it is .175 on 150 gr its .240-- different bullets different shapes- different depths. If I were to seat each bullet in a 308 case by setting one first the other would be off .065 at the ogive area compared to the other. Hope I explained this ok and hope I'm right in my thinking Every bullet shape has to be set individually. Best Dave [:)]
I understand this concept and have considered it but a technician at RCBS told me several years ago that their dies were designed to seat off the ogive, which of course could lead to variations in OAL cartridge length...but it should ensure that every bullet is the same distance off the lands...or into the lands
A light bulb just went on! ...so you are saying that the dies are not set up to seat off the actual ogive but a measurement significantly smaller than that...enough so, that the shape of the bullet can vary between where the die contacts the bullet and where the comparator is contacting the bullets.?.? If this is the case, you are the only one who's been able to effectively explain that to me but it is contrary to what RCBS told me
Several years back (there's even a post in this forum about it), RCBS told me that their dies seated off the Ogive. If in fact they do not, I can see your point. Thanks for clearing that up.
Eric
Let me be blunt
Step away from the loading bench, and go bck to shooting FACTORY ammo (or at least BOOK SPEC reloads).
You DON'T have the technical knowlege, or patence, to be loading precision ammo. This is NOT something you can learn over the internet, or from reading a book, this is something you have to be born with.
IOW owning a cookbook and a measuring cup dosn't make you a gourmet chef.
Tailgunner...for what it's worth, I've been reloading for accuracy for years...used to have a 500 yard range right outside my back door and could get 1000 yards on the other side of the property.
It's been about 3 years since I've relocated, and done any reloading. I have Gulf War Disease and one of the problems associated with that is SEVERE memory loss. I have a very hard time retaining things...but as you can see from the post below, I was basing my information on what the folks at RCBS had told me (and that was that their dies seated off the Ogive). If that had been the case, everything I stated would have been perfectly logical.
Your comments above are not constructive in any way. You would have been better off to just keep quiet and let someone else, who could better explain the situation, answer my question. Attitudes like that are what keep folks from trying to learn more.
cash777...thank you for explaining it in a way I could understand. I now realize that I'll need to adjust my dies when changing bullets. In the past, I've always used a dedicated die set for that particular bullet...and I've always stuck with Nosler BT's. I will call RCBS Monday morning to confirm this, as it was one of their techs that told the the wrong information. At the time, it really did not matter b/c I was using separate dies for each different bullet. Now I'm using one die set for all my different loads. Thanks again!
quote:Originally posted by ECC
That does not matter...the Ogive is the Ogive, regardless of the shape.
WRONG; it IS the shape.
quote:
I seated the bullet several times and checked/rechecked the OAL several times...nothing changed...and it shouldn't. I'm worried about 5 thousandths...not .5 thousandths...and the reason I'm worried about it is b/c it can make a very significant difference in the accuracy of this load (not to mention the fact that I'm seating into the lands).
Lead is a dead metal, when deformed it does not spring back to shape. Bullets, even from the same lot vary a bit in final shape and length. Your OAL is not at critical as 50 other things when it comes to accuracy. I load 6BR for extreme accuracy and OAL, while important has proved less of an issue than case concentricity and bullet run-out. I have a bigger heartburn over .003 run-out than I do over slight variations in OAL. Seating into the lands is not new or dangerous, it is something you need to take into consideration, but not something to fear.
Go back and read your thread opener then read my first reply, again. Think about it and the fact that ogives are different on different bullets, you will have your answer.
...and this is something I learned today. Just like Dan Lilja states in his article, I had always referred to the Ogive as being the point where the bullet intersects the bearing surface (or the rifling). Thanks for the link!
quote:Originally posted by Tailgunner1954
Eric
Let me be blunt
Step away from the loading bench, and go bck to shooting FACTORY ammo (or at least BOOK SPEC reloads).
You DON'T have the technical knowlege, or patence, to be loading precision ammo. This is NOT something you can learn over the internet, or from reading a book, this is something you have to be born with.
IOW owning a cookbook and a measuring cup dosn't make you a gourmet chef.
Tailgunner...for what it's worth, I've been reloading for accuracy for years...used to have a 500 yard range right outside my back door and could get 1000 yards on the other side of the property.
It's been about 3 years since I've relocated, and done any reloading. I have Gulf War Disease and one of the problems associated with that is SEVERE memory loss. I have a very hard time retaining things...but as you can see from the post below, I was basing my information on what the folks at RCBS had told me (and that was that their dies seated off the Ogive). If that had been the case, everything I stated would have been perfectly logical.
Your comments above are not constructive in any way. You would have been better off to just keep quiet and let someone else, who could better explain the situation, answer my question. Attitudes like that are what keep folks from trying to learn more.
What does memory loss have to do with your ability to think and reason? This isn't the first thread where you've taken the attitude of "I'm right and the world is wrong".
Several people gve you the exact same (correct) answer, and YOU decided that they were all wrong and you were correct.
If a simple slap in the face got you back on track, than it was worth it.
quote:Originally posted by ECC
quote:Originally posted by Tailgunner1954
Eric
Let me be blunt
Step away from the loading bench, and go bck to shooting FACTORY ammo (or at least BOOK SPEC reloads).
You DON'T have the technical knowlege, or patence, to be loading precision ammo. This is NOT something you can learn over the internet, or from reading a book, this is something you have to be born with.
IOW owning a cookbook and a measuring cup dosn't make you a gourmet chef.
Tailgunner...for what it's worth, I've been reloading for accuracy for years...used to have a 500 yard range right outside my back door and could get 1000 yards on the other side of the property.
It's been about 3 years since I've relocated, and done any reloading. I have Gulf War Disease and one of the problems associated with that is SEVERE memory loss. I have a very hard time retaining things...but as you can see from the post below, I was basing my information on what the folks at RCBS had told me (and that was that their dies seated off the Ogive). If that had been the case, everything I stated would have been perfectly logical.
Your comments above are not constructive in any way. You would have been better off to just keep quiet and let someone else, who could better explain the situation, answer my question. Attitudes like that are what keep folks from trying to learn more.
What does memory loss have to do with your ability to think and reason? This isn't the first thread where you've taken the attitude of "I'm right and the world is wrong".
Several people gve you the exact same (correct) answer, and YOU decided that they were all wrong and you were correct.
If a simple slap in the face got you back on track, than it was worth it.
I did no such thing. If you took it that way, that's your problem. I was merely trying to understand the situation. Several other folks were able to help me do so. BTW...I still believe my logic was very sound (given the parameters I outlined). The actual parameters were slightly different than the parameters I was using...thus the difference.
If you can show me faulty logic, using the parameters I established, please do so...but your insults and personal attacks do nothing to contribute to the board.