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08-29-2015, 08:54 PM
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Join Date: Aug 2013
Location: Drayton Valley
Posts: 1,251
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Quote:
Originally Posted by elkhunter11
As I posted, the actual measurement doesn't matter, as long as you are able to set your seating die to produce the best accuracy.
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I'm a truck driver so be patient with me. Just trying to wrap my head around what you are saying. I get that the actual number doesn't really matter in that you find what works best and stick with it. That is what most do - I think. But they measure the bullet length. Where do you start? You use a slip case to find the lands - right? Then you decide where to seat the bullet from that, be it on the lands or 0.020" or 0.050" off of the lands, shoot it for group and then try another depth if desired result not achieved. With the micro seater you would turn up or down on the stem that is marked with numbers and lines. It is still a measurement - you don't bother to measure the loaded round itself - correct.
For the Op. The comparator is a great tool for measuring length of bullets. As said before P&D sell them.
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08-29-2015, 09:07 PM
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Join Date: Oct 2014
Posts: 310
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Thanks for the tips and thoughts! Mainly brought this topic up because I'm having a bugger of a time getting any kind of consistency with the 7mm besides a consistent bird shot. I just wanted to know if this would be a option to change that before it goes to the gunsmith
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08-29-2015, 09:13 PM
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Join Date: Jan 2012
Posts: 2,443
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Quote:
Originally Posted by Hotwheels81
There is a bit of voodoo in ogive construction that's for sure...
http://www.accurateshooter.com/balli...ogive-bullets/
A good seating die will seat off the ogive of the bullet meaning any bullet you seat with it will have the same seating depth to the lands... But the world is not perfect nor are dies... Nor are bullets... It is nice with a bit of testing when you can seat a 139gr interlock instead of a 162gr Amax with no die adjustment and still be bang on tho
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I apologize for my pedantry, but feel it is necessary to comment that,
the ogive is not a datum point on the curve of the bullet, but it is the entire curve from the bore riding cylinder to the point (or meplat).
When we speak of measuring to the 'ogive' we really mean 'to the point on the ogive having a 1 caliber diameter'.
Most (but not all) seaters do contact the bullet on the ogive, but not necessarily at the point having a 1 caliber diameter. Bullets having differing ogive profiles will have a differing distance to the lands if seated with the same seater setting.
Good Luck, YMMV.
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08-29-2015, 09:19 PM
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Join Date: Dec 2008
Location: Camrose
Posts: 44,829
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Quote:
Originally Posted by PartTimeHunter
I'm a truck driver so be patient with me. Just trying to wrap my head around what you are saying. I get that the actual number doesn't really matter in that you find what works best and stick with it. That is what most do - I think. But they measure the bullet length. Where do you start? You use a slip case to find the lands - right? Then you decide where to seat the bullet from that, be it on the lands or 0.020" or 0.050" off of the lands, shoot it for group and then try another depth if desired result not achieved. With the micro seater you would turn up or down on the stem that is marked with numbers and lines. It is still a measurement - you don't bother to measure the loaded round itself - correct.
For the Op. The comparator is a great tool for measuring length of bullets. As said before P&D sell them.
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It appears that we are on the same page. I use the slip case as you call it to determine a starting point, and then I vary the settings on the seater die until I find the best accuracy. I may take another measurement once the load is finalized , to get an idea of where the bullet is seated in relationship to the lands, but that number in itself really doesn't matter.
I should add, that starting point also takes into account the magazine length, and it also is based on leaving enough bullet shank in the case neck to make sure that the bullet will stay in place with normal handling. I like to start out with about a .010" jump to the lands with a cup and core bullet, and .050" with a monometal bullet, but in some cases, with some boat tailed bullets, I can't seat anywhere close to the lands and still have enough bullet shank in the cartridge case. Examples are my Sako and Tikka rifles in 6.5x55 using the Accubond LR or Matchking, where I load to 3.100" , in order to leave .200" of bullet shank in the case neck. In both cases that leaves a jump to the lands of well over .100" , but the Tikka Varmint shoots either bullet sub 1/2moa in spite of the jump, and the Sako Carbine is averaging sub 3/4moa. In other situations, I have to load shorter than I would prefer , in order for the cartridges to function in the magazine.
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08-29-2015, 09:35 PM
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Join Date: Aug 2013
Location: Drayton Valley
Posts: 1,251
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Quote:
Originally Posted by elkhunter11
It appears that we are on the same page. I use the slip case as you call it to determine a starting point, and then I vary the settings on the seater die until I find the best accuracy. I may take another measurement once the load is finalized , to get an idea of where the bullet is seated in relationship to the lands, but that number in itself really doesn't matter.
I should add, that starting point also takes into account the magazine length, and it also is based on leaving enough bullet shank in the case neck to make sure that the bullet will stay in place with normal handling. I like to start out with about a .010" jump to the lands with a cup and core bullet, and .050" with a monometal bullet, but in some cases, with some boat tailed bullets, I can't seat anywhere close to the lands and still have enough bullet shank in the cartridge case. Examples are my Sako and Tikka rifles in 6.5x55 using the Accubond LR or Matchking, where I load to 3.100" , in order to leave .200" of bullet shank in the case neck. In both cases that leaves a jump to the lands of well over .100" , but the Tikka Varmint shoots either bullet sub 1/2moa in spite of the jump, and the Sako Carbine is averaging sub 3/4moa. In other situations, I have to load shorter than I would prefer , in order for the cartridges to function in the magazine.
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Kinda what I thought. Most measure the cartridge length and use that to work off. Same result. And you're right to magazine length, my son's T3 doesn't go as long as I'd like to but it seems to work good
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08-29-2015, 09:58 PM
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Join Date: May 2007
Location: SE Calgary Ab
Posts: 2,627
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Quote:
Originally Posted by Eagle Trapper
Thanks for the tips and thoughts! Mainly brought this topic up because I'm having a bugger of a time getting any kind of consistency with the 7mm besides a consistent bird shot. I just wanted to know if this would be a option to change that before it goes to the gunsmith
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Are you sure you don't have a somewhat different issue other than seating depth? Such as mounts or rings or scope. How many differnt bullets and powders have you tried? IN my mind seating depth is more of a final tweek and wouldn't cause birdshot groups.
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08-29-2015, 10:16 PM
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Join Date: Oct 2014
Posts: 310
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I've tried 160gr AB 175gr LRAB 140gr Partition w/ imr 7828,4350. H4350,Retumbo. RL 19 and RL22. W/ mag. And non mag win primers as well as BR-2's and rem 9 1/2.
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08-29-2015, 10:28 PM
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Join Date: Aug 2012
Location: Northeast of Edmonton
Posts: 427
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Does it shoot factory ammo decently?
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08-29-2015, 10:33 PM
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Join Date: Dec 2008
Location: Camrose
Posts: 44,829
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Quote:
Originally Posted by Eagle Trapper
I've tried 160gr AB 175gr LRAB 140gr Partition w/ imr 7828,4350. H4350,Retumbo. RL 19 and RL22. W/ mag. And non mag win primers as well as BR-2's and rem 9 1/2.
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What are you using for a rest? What kind of groups are you shooting with your other rifles? Does the rifle shoot the same when other people shoot it?
I would be looking at things other than seating depth. I would start by visually checking the crown for obvious damage. Then I would remove the barreled action from the stock, check and clean the bedding area, make sure there are no cracks in the stock. Then reinstall the stock and torque the action screws. If that doesn't make a difference, I would be looking at your scope , and mounts next.
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Only accurate guns are interesting.
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08-29-2015, 10:59 PM
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Join Date: Oct 2014
Posts: 310
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I am shooting off a bench( which if anyone is looking for a bench design this one is nice n easy to make) with Caldwell rest and bag. I've been shooting 1/2 moa on a good day with a sako 25-06. I haven't let anyone else shoot it, its like a baby that I just cant trust anyone to hold yet. just kidding, but not really. It's a new (this spring) mod. 70 super grade with a vortex 4-16, had to save my pennies for this one. I've checked the barrel for free float and it is. I'm not completely confident with disassembling a rifle like this, especially with no proper tools. I have had two good .6-.7 groups @ 100 with handloads but I am feeling they were fluke. As for factory I haven't had any luck there either.
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08-29-2015, 11:35 PM
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Join Date: Jan 2012
Location: Valleyview AB
Posts: 1,376
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Quote:
Originally Posted by qwert
I apologize for my pedantry, but feel it is necessary to comment that,
the ogive is not a datum point on the curve of the bullet, but it is the entire curve from the bore riding cylinder to the point (or meplat).
When we speak of measuring to the 'ogive' we really mean 'to the point on the ogive having a 1 caliber diameter'.
Most (but not all) seaters do contact the bullet on the ogive, but not necessarily at the point having a 1 caliber diameter. Bullets having differing ogive profiles will have a differing distance to the lands if seated with the same seater setting.
Good Luck, YMMV.
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I think you should play around with that a bit as I have... I was surprised with the results from bullet to bullet and even die to die...
As to eagle trapper...
Please ensure your seating plug is actually pushing on the ogive and not the bullet tip giving you variations... As funny as it sounds I've seen it more than once and some times you really need to look close to tell this is happening...
Another suggestion I have is to work backwards to what elk said and start with a starting load of powder, try seating depth from the lands back just as Berger instructs with the VLD's and if you find a seating depth that groups very well load up a ladder...
Will the rifle group well with factory ammunition?
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08-30-2015, 12:00 AM
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Join Date: Dec 2009
Location: Spruce Grove, AB
Posts: 3,039
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I had several boxes, (different lots) of nosler bullets. Thought I was smart to sort all of them by weight. Then found out that the ogive was different on some so bought the comparator to re-sort by ogive. Lesson learned. Don't mix lots. No idea if this is helping me or not but am satisfied with my minute of moose accuracy so will leave it at that. Just another tool in the toolbox.
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08-30-2015, 11:48 PM
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Banned
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Join Date: Jun 2009
Posts: 1,779
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Quote:
Originally Posted by Eagle Trapper
Thanks fellas, since your all here, do you measure your max C.O.A.L of your specific rifle with the method elk hunter mentioned or do you use an actual devise?
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I started using the method described and then went and bought the Hornady tool. It took a while but I eventually found the special modified cases I needed and compared the results from the tool to the other method. I found them to be exactly the same. Another $50 down the drain....
I also read something interesting written by Brian Litz of Berger that was critical of using the COAL tool because the modified case may not sit the same way in your chamber that a fire formed case would. Here's a link
http://www.bergerbullets.com/wp-cont...13/03/COAL.pdf
They use the term Cartridge Base To Ogive or CBTO to describe the measurement made with an ogive tool rather than COAL.
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08-31-2015, 12:03 AM
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Join Date: Jun 2007
Location: Ft. McMurray
Posts: 38,527
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For myself I measure my COL from the ogive because of differences in individual billets can vary, and the fact of the matter is that the variable will be the distance that the bullet ogive is from the lands , because that is where the accuracy will be determined .
The amount if bullet past that does not matter as long as the ogive distance to lands is the same and the bullets used are the same.
the COL is then marked on the box.
Cat
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Anytime I figure I've got this long range thing figured out, I just strap into the sling and irons and remind myself that I don't!
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08-31-2015, 11:09 AM
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Join Date: Mar 2009
Location: Gr Pr / 357 / ES4
Posts: 1,053
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I got the Sinclair nut one and got it at RPS international in Spruce Grove, super easy to use, real handy as sp bullets have various oals i found where as the plastic tips ones are pretty good.
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