BULLET SEATING?
- Thread starter Highflyer
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Re: BULLET SEATING?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Highflyer</div><div class="ubbcode-body">What is a acceptable tolerance for seating? I'm getting a .005 to 006 variance. </div></div>
Are you measuring to the ogive or tip?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Highflyer</div><div class="ubbcode-body">What is a acceptable tolerance for seating? I'm getting a .005 to 006 variance. </div></div>
Are you measuring to the ogive or tip?
Re: BULLET SEATING?
Double check your equipment. When using a Redding comp seat die I only get 5/10,000 variance if any. But usually every round is dead on.
Double check your equipment. When using a Redding comp seat die I only get 5/10,000 variance if any. But usually every round is dead on.
Re: BULLET SEATING?
might try sorting the projectiles by base to ogive measurement- I got a recent batch of 175 SMK's that sorted into 2 nice (.004) categories - but they were about .015 different, usually I find a lot less variation - would have caused a decent variation in loaded length to the ogive if I did not sort them
or if you find the lands and seat .01 - .02 longer they get pushed back into the case and end up consistent ( what's called jammed )
if you are jumping .02 than that .005 variation is likely meaningless
might try sorting the projectiles by base to ogive measurement- I got a recent batch of 175 SMK's that sorted into 2 nice (.004) categories - but they were about .015 different, usually I find a lot less variation - would have caused a decent variation in loaded length to the ogive if I did not sort them
or if you find the lands and seat .01 - .02 longer they get pushed back into the case and end up consistent ( what's called jammed )
if you are jumping .02 than that .005 variation is likely meaningless
Re: BULLET SEATING?
Unless you're competing, that's great. Recently switched to 175s from 168s. Mine vary .003-.007 and they shoot fine. Always going to have a margin of error.
Unless you're competing, that's great. Recently switched to 175s from 168s. Mine vary .003-.007 and they shoot fine. Always going to have a margin of error.
Re: BULLET SEATING?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: boltgunluvr</div><div class="ubbcode-body">Unless you're competing, that's great. Recently switched to 175s from 168s. Mine vary .003-.007 and they shoot fine. Always going to have a margin of error. </div></div>
Really? I struggled to get some 110gr 270 heads to seat better than .002" and i thought that was crap. Everything else was precise to within my ability to measure it 308, 270, 223... Drove me nuts
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: boltgunluvr</div><div class="ubbcode-body">Unless you're competing, that's great. Recently switched to 175s from 168s. Mine vary .003-.007 and they shoot fine. Always going to have a margin of error. </div></div>
Really? I struggled to get some 110gr 270 heads to seat better than .002" and i thought that was crap. Everything else was precise to within my ability to measure it 308, 270, 223... Drove me nuts
Re: BULLET SEATING?
Are these bullets new or have then been pulled. I have seen this problem on pulled bullets. If they use a collet style they can deform the jacket a little.
Are these bullets new or have then been pulled. I have seen this problem on pulled bullets. If they use a collet style they can deform the jacket a little.
Re: BULLET SEATING?
problem is: you measure from the tip or ogive and seat from a point in between - no matter how carefully you seat or the quality of the equipment if the bullets vary slightly, the seating depth will vary
think about the sharp conical shape of a bullet tip - if the diameter varies by .001 where the seating tip would contact it, that could cause .003-.004 variation of seating depth - when measured at a different location (such as ogive)
then what if your ogive location varied by .003 ( which is pretty damn good even after sorting)
now you can have tolerance stacking and end up with .006 - .007 variance without any 1 thing being seriously wacked
question is - how much does it matter?
IMO, that depends on your jump to the lands - if the jump is .001 than .006 variance is 600% percent -not so good
if you jamb .01 to the lands then the base to ogive will be consistent when the round is fired and the .006 is meaningless
if you are shooting magazine length and have a .06 jump then the variance is 10% and likely insignificant
of course to really answer the question, segregate the ammo and compare the results (to be sure try maybe 100 of each) - after which the results will likely be -------inconclusive
problem is: you measure from the tip or ogive and seat from a point in between - no matter how carefully you seat or the quality of the equipment if the bullets vary slightly, the seating depth will vary
think about the sharp conical shape of a bullet tip - if the diameter varies by .001 where the seating tip would contact it, that could cause .003-.004 variation of seating depth - when measured at a different location (such as ogive)
then what if your ogive location varied by .003 ( which is pretty damn good even after sorting)
now you can have tolerance stacking and end up with .006 - .007 variance without any 1 thing being seriously wacked
question is - how much does it matter?
IMO, that depends on your jump to the lands - if the jump is .001 than .006 variance is 600% percent -not so good
if you jamb .01 to the lands then the base to ogive will be consistent when the round is fired and the .006 is meaningless
if you are shooting magazine length and have a .06 jump then the variance is 10% and likely insignificant
of course to really answer the question, segregate the ammo and compare the results (to be sure try maybe 100 of each) - after which the results will likely be -------inconclusive
Re: BULLET SEATING?
I got rid of this issue in two ways. For my standard seating dies I changed them to "Dead Length" dies. A simple washer that fits over the case and sits on top of the shell holder will allow you to use the bottom of the die as a positive stop and makes sure that any crimp function is disabled. Some presses have a "thou or two" variation in their mechanism to allow for some variation, stroke to stroke. When the shell holder hits the washer/die stop, it's exact every time.
The other way I cured the problem was to buy a Forster Bench Rest Seating Die. Even better yet as it holds the case in a moving piece on the die and the bullet in a tight cylinder. The bullet and case move together while being held in perfect alignment and OAL is controlled from the datum point on the shoulder, just like it is in a rifle.
(Old Timers will remember this die as the old Bonanza Seating Die).
I got rid of this issue in two ways. For my standard seating dies I changed them to "Dead Length" dies. A simple washer that fits over the case and sits on top of the shell holder will allow you to use the bottom of the die as a positive stop and makes sure that any crimp function is disabled. Some presses have a "thou or two" variation in their mechanism to allow for some variation, stroke to stroke. When the shell holder hits the washer/die stop, it's exact every time.
The other way I cured the problem was to buy a Forster Bench Rest Seating Die. Even better yet as it holds the case in a moving piece on the die and the bullet in a tight cylinder. The bullet and case move together while being held in perfect alignment and OAL is controlled from the datum point on the shoulder, just like it is in a rifle.
(Old Timers will remember this die as the old Bonanza Seating Die).
Re: BULLET SEATING?
Getting to the point of where we are over thinking all of the details. In manufacturing there is always a plus or minus factor. The tighter the tolerance is the more expensive the item cost. Look into the cost of machining equipment, tooling, and hand tools.
What is the tolerance of your measuring tools? Then you can expand that to case dimensions, internal as well external. Have you spent time sorting and grouping like case within the same batches of brass. You can even go back to as far as the smelting the batch of raw materials.
There is only so much that we have control of and its easy to over think things.
Getting to the point of where we are over thinking all of the details. In manufacturing there is always a plus or minus factor. The tighter the tolerance is the more expensive the item cost. Look into the cost of machining equipment, tooling, and hand tools.
What is the tolerance of your measuring tools? Then you can expand that to case dimensions, internal as well external. Have you spent time sorting and grouping like case within the same batches of brass. You can even go back to as far as the smelting the batch of raw materials.
There is only so much that we have control of and its easy to over think things.
M
milo 2.0
Guest
Re: BULLET SEATING?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MR JOSHUA</div><div class="ubbcode-body">Double check your equipment. When using a Redding comp seat die I only get 5/10,000 variance if any. But usually every round is dead on. </div></div>
".0005", WOW
What do you get for runout.
Can the ammo shoot within these numbers. I'm curious, maybe I'm doing something wrong.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MR JOSHUA</div><div class="ubbcode-body">Double check your equipment. When using a Redding comp seat die I only get 5/10,000 variance if any. But usually every round is dead on. </div></div>
".0005", WOW
What do you get for runout.
Can the ammo shoot within these numbers. I'm curious, maybe I'm doing something wrong.
Re: BULLET SEATING?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Highflyer</div><div class="ubbcode-body">Thanks George 63. I'm seating them back 35 thousandth. </div></div>
yeah so really you are in a gray area, your variance is 15% of your jump likely -meaningless but not for sure
like I said before - try sorting finished, 10 each into .002 batches and fire/test to compare if there is meaningful difference my top options at this point would be:
try a different seating die - forester would be a good option ( hell, I have 6 around why shouldn't you)
try sorting by base to ogive - again I found 2 distinct lengths in a recent batch of 175 SMK - you may also have this situation
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Highflyer</div><div class="ubbcode-body">Thanks George 63. I'm seating them back 35 thousandth. </div></div>
yeah so really you are in a gray area, your variance is 15% of your jump likely -meaningless but not for sure
like I said before - try sorting finished, 10 each into .002 batches and fire/test to compare if there is meaningful difference my top options at this point would be:
try a different seating die - forester would be a good option ( hell, I have 6 around why shouldn't you)
try sorting by base to ogive - again I found 2 distinct lengths in a recent batch of 175 SMK - you may also have this situation
Re: BULLET SEATING?
I shoot the 190gr SMK's and get very little variance (if any) when using the Hornady LnL comparator.
I shoot the 190gr SMK's and get very little variance (if any) when using the Hornady LnL comparator.
