Comparator vs Head space kit?

spclPatrolGroup · March 15, 2011, 03:38 PM

I am still very new to reloading, thus far have been using my calipers on the case itself and comparing to the technical drawings in my manual. I have been thinking I would like to get to start getting a little more technical and squeeze a little more accuracy out of my reloads. I know how the Hornady OAL gauge works, you chamber the fake cartridge with a bullet in the chamber and push out the bullet until you meet resistance to find your optimal seating depth. But can someone tell me the difference between the Hornady “headspace kit with body” and the “Chamber All Bullet Comparator”? They look very similar.

PA-Joe · March 15, 2011, 03:45 PM

The headspace guage is used to measure from the case head to the shoulder of the case. The bullet comparator measures from the case head to the ogive of the bullet. It is used to get you COL but you use the ogive measurement instead. They both use the same red caliper connector or base.

spclPatrolGroup · March 15, 2011, 03:49 PM

Thanks, so if you only full length size, is there a need to measure the head space since it should be set back to the standard length? Sounds like this would be more for neck sizers as a indication when to full lenght size.

wncchester · March 15, 2011, 05:04 PM

"...fake cartridge with a bullet in the chamber and push out the bullet until you meet resistance to find your optimal seating depth."

Not quite so. That simply finds the max OAL for that bullet to touch the lands. If that is "optimal" or not is a much larger question and it usually isn't, not for many factory rifles anyway.

The case shoulder gages have one use; compare the shoulder length between fired and resized cases so you can get the sizer set properly for a snug chamber fit.

Improving accuracy requires much more than frequent use of a micrometer or caliper (or weighing powder to .0000001 gr. precision). Case prep and load development are the greatest challanges.

PA-Joe · March 16, 2011, 06:29 AM

The purpose of measuring the headspace is to reduce the amount of sizing to the minimum. You do not want to keep setting the shoulders back more than a few 0.001. Reducing the shoulder setback also helps to align the bullet better with the bore.

March 15, 2011, 03:38 PM	#1
spclPatrolGroup Senior Member Join Date: August 19, 2010 Location: North Dakota Posts: 349	Comparator vs Head space kit? I am still very new to reloading, thus far have been using my calipers on the case itself and comparing to the technical drawings in my manual. I have been thinking I would like to get to start getting a little more technical and squeeze a little more accuracy out of my reloads. I know how the Hornady OAL gauge works, you chamber the fake cartridge with a bullet in the chamber and push out the bullet until you meet resistance to find your optimal seating depth. But can someone tell me the difference between the Hornady “headspace kit with body” and the “Chamber All Bullet Comparator”? They look very similar.

March 15, 2011, 03:45 PM	#2
PA-Joe Senior Member Join Date: June 9, 2010 Location: NEPA Posts: 909	The headspace guage is used to measure from the case head to the shoulder of the case. The bullet comparator measures from the case head to the ogive of the bullet. It is used to get you COL but you use the ogive measurement instead. They both use the same red caliper connector or base.

March 15, 2011, 03:49 PM	#3
spclPatrolGroup Senior Member Join Date: August 19, 2010 Location: North Dakota Posts: 349	Thanks, so if you only full length size, is there a need to measure the head space since it should be set back to the standard length? Sounds like this would be more for neck sizers as a indication when to full lenght size.

March 15, 2011, 05:04 PM	#4
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"...fake cartridge with a bullet in the chamber and push out the bullet until you meet resistance to find your optimal seating depth." Not quite so. That simply finds the max OAL for that bullet to touch the lands. If that is "optimal" or not is a much larger question and it usually isn't, not for many factory rifles anyway. The case shoulder gages have one use; compare the shoulder length between fired and resized cases so you can get the sizer set properly for a snug chamber fit. Improving accuracy requires much more than frequent use of a micrometer or caliper (or weighing powder to .0000001 gr. precision). Case prep and load development are the greatest challanges.

March 16, 2011, 06:29 AM	#5
PA-Joe Senior Member Join Date: June 9, 2010 Location: NEPA Posts: 909	The purpose of measuring the headspace is to reduce the amount of sizing to the minimum. You do not want to keep setting the shoulders back more than a few 0.001. Reducing the shoulder setback also helps to align the bullet better with the bore.