Concentricity Gauge
- Thread starter Rockydoc
- Start date
Depends on what you're trying to do. Shooting for the tiniest groups with a rifle capable of those groups it can make a difference. It can also be used to check if there is a problem with die concentricity causing a problem. There are many bench rest techniques that are worthwhile especially when done together. Unless there is an issue such as dies in the average hunting rifle it would be pretty tough to know if it helped or not.
If you can't see it, probably doesn't matter for most of us. Another problem is trying to check concentricity on a powder coated cast bullet. Setup is usually a good V block and dial indicator. I used to check by setting a few loaded rnds on a flat plate and looking at the nose. Gross out-of-line nose is a toss. But then, I don't compete.
Dimner
Named Man
Years ago... 2004 ish, I got an amazing deal from grainger on a 3 inch thick by 14" x 18" marble reference plate. It is used to measure flatness to some sort of tiny degree. Something like 22 bucks shipped.
Anyway, I roll my finished loads on that to see if anything is out of whack after bullet seating.
So far, when all other variables are within spec, I've had .75 moa results by doing just this eye test. Never really felt a need to do anything more. But then again, I never shoot at a bench more than 100 yards.
I shoot prone at sandpits on steel at 350-400 yards and hunt upto about 250 in the places I frequent. So as of yet, the eye tests has fit all my needs.
Anyway, I roll my finished loads on that to see if anything is out of whack after bullet seating.
So far, when all other variables are within spec, I've had .75 moa results by doing just this eye test. Never really felt a need to do anything more. But then again, I never shoot at a bench more than 100 yards.
I shoot prone at sandpits on steel at 350-400 yards and hunt upto about 250 in the places I frequent. So as of yet, the eye tests has fit all my needs.
RicinYakima
High Steppes of Eastern Washington
It depends upon the chamber. Almost 20 years ago, I did a test with all the 30/06 dies I could find, plus mix and match sets. At the end of the summer the main thing I learned about my 1937 '03 National Match was the chamber was 0.003" from being perfectly aligned with the bore. That was from case head to the end of the neck. Dies and techniques that would consistently load cartridges of LESS the 0.003" would shoot the same as long as they were as straight as the chamber. Every thousandths over would increase 10-shot group size.
So I found the best combination of dies and techniques and now only check when I set up to reload match ammo. Doing that, the rifle won the CBA Scoped Military Rifle in 2007, and with Lyman 48, the Modified Iron Sight in 2016.
It is a waste of your time and components to try to bend the bullets straight, that just makes things worse. When they come out of the seating die, they have to be straight.
So I found the best combination of dies and techniques and now only check when I set up to reload match ammo. Doing that, the rifle won the CBA Scoped Military Rifle in 2007, and with Lyman 48, the Modified Iron Sight in 2016.
It is a waste of your time and components to try to bend the bullets straight, that just makes things worse. When they come out of the seating die, they have to be straight.