Bob Green comparator

[jsthntn247]

Im looking at getting something to start sorting my bullets by. It seems allot of people are using this tool. I just can't wrap my head around how this is going to help me though. Right now I'm using a Hornady comparator on my calipers to measure each case from base of the case to ogive of the bullet. I understand that the comparator might not actually be the right diameter and measure to the exact ogive, but it measure to some point, and if all my bullets measure the same from base to that given point (which I have determined by a seating depth test using the same coparator to be the best for my rifle) then how will the Bob Green tool help?

 

[Jay Christopherson]

Just because your loaded round measures that same from base-to-ogive, doesn't mean the bullets you are using are identical. Imagine (as an extreme example) that you had two bullets, both from the same lot, same weight, etc..., but for whatever reason one is .125" longer than the other - your OAL would likely be the same (assuming your comparator indexes off the same spot on both bullets), but in one round, you have a bullet that is .125" longer than the other - it's just sitting deeper in the case, even though outwardly, things measure up the same. The point being as stated - just because your loaded round measures the same base-to-ogive length, doesn't mean the bullets you used to load with are identical.

The B.G.C. won't fix this particular case - you would do that with some sort of bullet sort, like a bullet base-to-ogive sort or maybe a bearing surface sort if that is your thing. What the B.G.C. *does* do is let you micro-sort your bullets into sub-lots that have identical ogive contact points, so that when it comes time to seat, your bullets will all be contacting the seating stem at exactly the same point and (ideally) your bullets will all be seated *exactly* the same.

So, the only reason to invest in a B.G.C. would be if the thought of micro-sorting your already sorted bullets seems like a valuable thing. It's a lot of work and takes a while to develop a good feel for it.

If you are just starting to sort bullets, I would looking into something that allows you to sort by base-to-ogive (my preference) or bearing surface, before you invest in a B.G.C.

 

[Cigarcop]

Bob's tool is is going to measure the point on the bullet that is actually going to contact the same point it will in your barrel at the lands. The tool will sort the bullets into sub lots, usually you may have two lots that have many the same measurement. You may also have some that are just out, then you may find two or three singles that are WAY out... These might be your fliers taking u out of the X or 10 ring so you might use them for fowlers.
When you set up your seating die and use the bullets you just sorted into sub lots all your seated bullets will measure the same from base to ogive of your loaded round. You'll be doing away with varying seating depths.

 

[jsthntn247]

Bare with me fellas, I'm having a brain fart trying to understand this. The way I do it now is seat all bullets about .010 long of desired seating depth. I then measure each loaded round with my calipers with the ogive tool on it and see what all the rounds measure. I group the rounds together in lots based on their mesuremnts. I then take each lot and seat them to my desired measurement of 2.307 to ogive. After doing this none have more than a 1/2 thou difference from the base of the case to the measurement I have determined to be .017 off the lands. I am having some fliers that are waay off from the others with no wind change, mirage..hold felt perfect..etc damn bullet just went 8" off from the others at 600 yards. If this tool will help eliminate bullets that could be causing it, I am all for it, 250$ is worth my sanity, I just want to make sure it could help me before dropping the $

 

[Cigarcop]

With his tool you wont have to group loaded rds into lots to reseat them as your doing now.... They will all be the same from first and only seating!
If you need to talk via phone pm me

Keith

 

[Jay Christopherson]

With his tool you wont have to group loaded rds into lots to reseat them as your doing now.... They will all be the same from first and only seating!
If you need to talk via phone pm me

Keith

The tool won't do him a lick of good if he isn't sorting his bullets base-to-give or otherwise first.

OP: You need to understand that your case base-to-ogive measurement has absolutely nothing to do with the consistency of your bullets. That measurement only measures the consistency of your seating depth. There could be a wide disparity in the bearing surface of your bullets or your bullet base-to-ogive measurement.

 

[Cigarcop]

With his tool you wont have to group loaded rds into lots to reseat them as your doing now.... They will all be the same from first and only seating!
If you need to talk via phone pm me

Keith

The tool won't do him a lick of good if he isn't sorting his bullets base-to-give or otherwise first.

OP: You need to understand that your case base-to-ogive measurement has absolutely nothing to do with the consistency of your bullets. That measurement only measures the consistency of your seating depth. There could be a wide disparity in the bearing surface of your bullets or your bullet base-to-ogive measurement.

Sure it will, but you keep measuring those bearing surfaces if it makes u feel warm and fuzzy.

We just disagree