I have a harder question?

hardhit · July 8, 2009, 09:07 PM

Hi guys I have a harder question for ya, I am using 308 win Redding comp bushing dies for my bench gun. I am using lapua brass and 155 Lapua Scenars which are extremely uniform projectiles in my experience! Im also using a bullet comparator to measure loaded rounds etc. I have experienced a problem when seating, Im finding that batches seat spot on while others seat the bullet .5 lower than what I have set on the die. Even when I measured each bullet with a bullet comparator before seating it, I found it was difficult to pick up such a small variation. Someone said too much or uneven neck tension can give the variation in seating depths, But I thought it was a variation in the bullet jacket or the tip, what’s your opinion?

Shoney · July 8, 2009, 09:20 PM

Did you turn the necks?? Inside?? or Outside??

Creeper · July 8, 2009, 09:32 PM

1. Measure the bullets themselves for length with the ogive comparator... and the base and body diameter as well. The base "pressure ring" should be slightly larger than the bullet shank... a few ten-thousandths.
2. Are the case necks turned and have uniform wall thickness of less than .0002"... if not, this can be the cause of variation as the bullets may "jump" a bit from case to case fit, especially with a compounding press.
3. "Im finding that batches seat spot on while others seat the bullet .5 lower than what I have set on the die". I assume you mean .005" and not 1/2" here.
4. Where does your bullet seater cup contact the bullet... is that point on the bullet consistent with other bullets?
Using a smaller caliber comparator, something closer to where the seating cup contacts the bullet, measure your bullets again.
5. Have you considered using hand dies... like Wilson? If you're using bushing dies already, you're not too far away from benchrest loading practices.

I can go on and on... but you obviously have an inconsistency in your "system" or your components that will require a bit of sleuthing on your part.

Best 'O luck,
C

**Unclenick** · July 8, 2009, 10:00 PM

If the unit is 0.5 thousandths, it is irrelevant and won't be visible on a target. If, as Creeper said, it is 5 thousandths and the difference is a consistent 5 thousandths and with no other numbers inbetween, that is within ogive variance for different bullet forming tools. You could have bullets mixed that came off two different sets of tooling. It would surprise me if Lapua did that with their bullets, but they do it with their cases, as I have the histograms to prove.

hardhit · July 8, 2009, 10:44 PM

I haven’t turned the necks, im not sure weather there is any real benefit for the trouble, but I could be wrong?

Measure the bullets themselves for length with the ogive comparator.
I have done this but I found that if it jams a little off center you get different a reading or a little too much pressure and again a different reading. I have found that the comparator is quit often more concentric than the bullet it self which means there is a tiny amount of movement. so I abandon that idea.

I assume you mean .005" and not 1/2" here. Yes I do mean .005 sorry
Smaller caliber comparator.

Yeah dident think of that one.

Have you considered using hand dies... like Wilson? If you're using bushing dies already, you're not too far away from bench rest loading practices.

My shooting buddy has Wilson bench rest dies and arbor press and he has experienced the same problem.

July 8, 2009, 09:07 PM	#1
hardhit Senior Member Join Date: August 18, 2008 Posts: 343	I have a harder question? Hi guys I have a harder question for ya, I am using 308 win Redding comp bushing dies for my bench gun. I am using lapua brass and 155 Lapua Scenars which are extremely uniform projectiles in my experience! Im also using a bullet comparator to measure loaded rounds etc. I have experienced a problem when seating, Im finding that batches seat spot on while others seat the bullet .5 lower than what I have set on the die. Even when I measured each bullet with a bullet comparator before seating it, I found it was difficult to pick up such a small variation. Someone said too much or uneven neck tension can give the variation in seating depths, But I thought it was a variation in the bullet jacket or the tip, what’s your opinion?

July 8, 2009, 09:20 PM	#2
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	Did you turn the necks?? Inside?? or Outside?? __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

July 8, 2009, 09:32 PM	#3
Creeper Senior Member Join Date: September 9, 2008 Location: Woooooshington Posts: 1,797	1. Measure the bullets themselves for length with the ogive comparator... and the base and body diameter as well. The base "pressure ring" should be slightly larger than the bullet shank... a few ten-thousandths. 2. Are the case necks turned and have uniform wall thickness of less than .0002"... if not, this can be the cause of variation as the bullets may "jump" a bit from case to case fit, especially with a compounding press. 3. "Im finding that batches seat spot on while others seat the bullet .5 lower than what I have set on the die". I assume you mean .005" and not 1/2" here. 4. Where does your bullet seater cup contact the bullet... is that point on the bullet consistent with other bullets? Using a smaller caliber comparator, something closer to where the seating cup contacts the bullet, measure your bullets again. 5. Have you considered using hand dies... like Wilson? If you're using bushing dies already, you're not too far away from benchrest loading practices. I can go on and on... but you obviously have an inconsistency in your "system" or your components that will require a bit of sleuthing on your part. Best 'O luck, C __________________ Shoulder Drive Nicholson Club

July 8, 2009, 10:00 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,057	If the unit is 0.5 thousandths, it is irrelevant and won't be visible on a target. If, as Creeper said, it is 5 thousandths and the difference is a consistent 5 thousandths and with no other numbers inbetween, that is within ogive variance for different bullet forming tools. You could have bullets mixed that came off two different sets of tooling. It would surprise me if Lapua did that with their bullets, but they do it with their cases, as I have the histograms to prove. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

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July 8, 2009, 10:44 PM	#5
hardhit Senior Member Join Date: August 18, 2008 Posts: 343	I haven’t turned the necks, im not sure weather there is any real benefit for the trouble, but I could be wrong? Measure the bullets themselves for length with the ogive comparator. I have done this but I found that if it jams a little off center you get different a reading or a little too much pressure and again a different reading. I have found that the comparator is quit often more concentric than the bullet it self which means there is a tiny amount of movement. so I abandon that idea. I assume you mean .005" and not 1/2" here. Yes I do mean .005 sorry Smaller caliber comparator. Yeah dident think of that one. Have you considered using hand dies... like Wilson? If you're using bushing dies already, you're not too far away from bench rest loading practices. My shooting buddy has Wilson bench rest dies and arbor press and he has experienced the same problem.