What's your tolerance with OAL?

MEATSAW · February 16, 2012, 01:56 AM

I am currently loading up some 155 gr 40S&W flat points on a Lee turret press. I set up my die to about 1.129" OAL. I am noticing that from round to round I will get anywhere from 1.1285" to 1.134" -- the ones that have been running a little long I just run it another stroke on the seater die and its usually spot on. My personal tolerance is I'm okay with any round that is between 1.1285" and 1.1305". Is this reasonable or should I be less forgiving?

I loaded up 150 rounds and all of them where within this tolerance. I checked all of them and they cycled through the pistol perfectly. I will be shooting them Sunday.

Comments?

Jammer Six · February 16, 2012, 02:07 AM

I use a Dillon Square Deal.

Talking with Dillon support, the machine is only accurate to ± .007, which gives a range of .015.

So I set a COL, and if the round measures to that COL ± .007, I'm happy.

Zach W. · February 16, 2012, 02:21 AM

1.129" to 1.131" is awesome for a high speed cranck em out, if you ask me.

Dr. Strangelove · February 16, 2012, 04:33 AM

Sounds good to me. Shoot 'em.

Shootest · February 16, 2012, 05:18 AM

For an OAL of 1.129 I would keep it between 1.124 and 1.134.

Kayser · February 17, 2012, 02:25 PM

For me, anything up to +-0.005 is fine. Though in general I find it pretty easy to keep it within +- 0.002

hk33ka1 · February 17, 2012, 04:37 PM

It's not the press or dies that cause the variance. It is the shape of the bullets.

It's due to where the seater stem touches the bullet. The ogive (first part wide enough to touch rifling) is not in the exact same place on every bullet.
This is still ok and accuracy won't suffer due to this factor alone.

Imagine 10 men all 6' tall, but with different shoulder heights. The die is seating by the shoulders, not the top of the head.

February 16, 2012, 01:56 AM	#1
MEATSAW Senior Member Join Date: May 1, 2009 Location: Burnet, TX Posts: 727	What's your tolerance with OAL? I am currently loading up some 155 gr 40S&W flat points on a Lee turret press. I set up my die to about 1.129" OAL. I am noticing that from round to round I will get anywhere from 1.1285" to 1.134" -- the ones that have been running a little long I just run it another stroke on the seater die and its usually spot on. My personal tolerance is I'm okay with any round that is between 1.1285" and 1.1305". Is this reasonable or should I be less forgiving? I loaded up 150 rounds and all of them where within this tolerance. I checked all of them and they cycled through the pistol perfectly. I will be shooting them Sunday. Comments? __________________ Veteran OEF (2002) and OIF1 (2003) - US Army Member of the Burnet Gun Fighters, Inc. and of course the NRA Oregon State University alum -- Go Beavs!

February 16, 2012, 02:07 AM	#2
Jammer Six Senior Member Join Date: April 3, 2005 Location: Seattle Posts: 827	I use a Dillon Square Deal. Talking with Dillon support, the machine is only accurate to ± .007, which gives a range of .015. So I set a COL, and if the round measures to that COL ± .007, I'm happy. __________________ "Huh?" --Jammer Six, 1998

February 16, 2012, 04:33 AM	#4
Dr. Strangelove Senior Member Join Date: August 1, 2008 Location: Athens, GA Posts: 1,436	Sounds good to me. Shoot 'em. __________________ Just remember, when you pull the trigger, the bullets come out going very, very fast. So make sure to keep the weapon pointing away from you.

February 16, 2012, 05:18 AM	#5
Shootest Senior Member Join Date: February 9, 2011 Location: Just outside Cleveland, Ohio Posts: 722	For an OAL of 1.129 I would keep it between 1.124 and 1.134. __________________ The private ownership of firearms is an American Heritage. Anyone who disputes that is Anti-American and unpatriotic. NRA Life Member

February 17, 2012, 02:25 PM	#6
Kayser Senior Member Join Date: May 29, 2002 Location: Illinois :( Posts: 550	For me, anything up to +-0.005 is fine. Though in general I find it pretty easy to keep it within +- 0.002 __________________ ----------------- Box Of Truth Afficionado!

February 16, 2012, 02:21 AM	#3
Zach W. Member Join Date: March 4, 2010 Posts: 72	1.129" to 1.131" is awesome for a high speed cranck em out, if you ask me.

February 17, 2012, 04:37 PM	#7
hk33ka1 Senior Member Join Date: April 20, 2010 Posts: 275	It's not the press or dies that cause the variance. It is the shape of the bullets. It's due to where the seater stem touches the bullet. The ogive (first part wide enough to touch rifling) is not in the exact same place on every bullet. This is still ok and accuracy won't suffer due to this factor alone. Imagine 10 men all 6' tall, but with different shoulder heights. The die is seating by the shoulders, not the top of the head.

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