Concentricity tools - opinions?
- Thread starter Irons78
- Start date
You do not want a tool that corrects runout, you want a sizing and seating method that prevents induced runout.
Meaning checking the neck of a resized case for neck runout and correcting any neck runout before seating a bullet. It also means checking bullet runout after seating and correcting any runout caused during seating.
Bottom line, you fix any runout problems during sizing and seating and not try to bend the case neck after the dies created the problem.
What you need is a runout gauge that spins the case on the case body and you can check both neck and bullet runout. And fix any problems "BEFORE" you have a loaded round, meaning is the sizing die causing the problem or the seating die.
I use the Redding neck thickness gauge below to check neck thickness variations and the "quality" of the brass. I have had Remington .223 cases with .009 neck thickness variations and cases like this are only good for blasting ammo in a AR15.
The average reloader does not need the most expensive gauges, you just need gauges to help you find out where the runout problem starts and fix the problem.
I have both runout gauges below and use the RCBS case mastering gauge far more for checking both neck and bullet runout and setting up my dies for minimum runout. The main issue with the Hornady runout gauge is you can not check case neck runout after sizing and can only check bullet runout on a loaded round.
I prefer Forster sizing and seating dies because they produce very concentric cases and loaded ammunition. And one of the biggest causes of bullet runout is if the dies expander is locked down off center and induces neck runout.
Below the Forster dies have a high mounted floating expander and the expander enters the case neck while it is held and centered in the neck of the die. Meaning the expander can not pull the case neck off center and induce neck runout.
Below the Forster seating die chamber holds the case and bullet in perfect alignment and prevent any bullet tipping during seating.
That being said even the cheaper Lee sizing dies have a locking collet that when tightened centers the expander and can make very concentric cases.
Meaning checking the neck of a resized case for neck runout and correcting any neck runout before seating a bullet. It also means checking bullet runout after seating and correcting any runout caused during seating.
Bottom line, you fix any runout problems during sizing and seating and not try to bend the case neck after the dies created the problem.
What you need is a runout gauge that spins the case on the case body and you can check both neck and bullet runout. And fix any problems "BEFORE" you have a loaded round, meaning is the sizing die causing the problem or the seating die.
I use the Redding neck thickness gauge below to check neck thickness variations and the "quality" of the brass. I have had Remington .223 cases with .009 neck thickness variations and cases like this are only good for blasting ammo in a AR15.
The average reloader does not need the most expensive gauges, you just need gauges to help you find out where the runout problem starts and fix the problem.
I have both runout gauges below and use the RCBS case mastering gauge far more for checking both neck and bullet runout and setting up my dies for minimum runout. The main issue with the Hornady runout gauge is you can not check case neck runout after sizing and can only check bullet runout on a loaded round.
I prefer Forster sizing and seating dies because they produce very concentric cases and loaded ammunition. And one of the biggest causes of bullet runout is if the dies expander is locked down off center and induces neck runout.
Below the Forster dies have a high mounted floating expander and the expander enters the case neck while it is held and centered in the neck of the die. Meaning the expander can not pull the case neck off center and induce neck runout.
Below the Forster seating die chamber holds the case and bullet in perfect alignment and prevent any bullet tipping during seating.
That being said even the cheaper Lee sizing dies have a locking collet that when tightened centers the expander and can make very concentric cases.
Munkey1973
CGN frequent flyer
- Location
- Regina, SK
X2 for bigedp51 comment … with the exception of the RCBS Gaugemaster….. DON'T BUY ONE. While they do a lot of things, they nothing particulary well. They are inaccurate, sloppy and too slow for concentricity testing. Buy-once and cry-once by getting a concentricity gauge from 21st Century Shooting. The best around...
http://www.xxicsi.com/concentricity-gauge.html
http://www.xxicsi.com/concentricity-gauge.html
Munkey1973
CGN frequent flyer
- Location
- Regina, SK
Your welcome. Yeah, I bought a RCBS new from Cabela's for a $175 or what ever it was... was greatly disappointed. Sold it $50 here on the EE, and bough 21st Century with no regrets. If you go that route, then my advice is to buy the .0005 dial on Amazon (or somewhere else) his markup on them is a bit. Keep the rubber ring on the wheel clean of oil and grease and the tool works perfectly.
Below the top image is how the Hornady concentricity gauge holds the cartridge, and you can not check case neck runout after sizing. When checking runout you need to find out if sizing or seating is causing the bullet runout. Meaning your checking your sizing die or seating die for the cause of the runout. And the Hornady gauge can only check concentricity or runout on a loaded round.
The bottom image shows how the majority of concentricity gauges spin the case on the case body. And you can check the case neck after sizing to check to see if the expander is pulling the neck off center. One of the biggest causes of runout is if the expander is locked down off center and inducing neck runout.
I agree with the other posters in saying the RCBS gauge is not the best, it is more of the Swiss Army Knife of gauges and I got it to check case thinning on my .303 British cases checking for possible case head separations.
I would pick the Sinclair gauge below as the best gauge for the money for the average reloader.
Last edited:
Thanks Ed! I've been leaning toward the Sinclair based on further endless youtube etc. searches.
Below the top image is how the Hornady concentricity gauge holds the cartridge, and you can not check case neck runout after sizing. When checking runout you need to find out if sizing or seating is causing the bullet runout. Meaning your checking your sizing die or seating die for the cause of the runout. And the Hornady gauge can only check concentricity or runout on a loaded round.
The bottom image shows how the majority of concentricity gauges spin the case on the case body. And you can check the case neck after sizing to check to see if the expander is pulling the neck off center. One of the biggest causes of runout is if the expander is locked down off center and inducing neck runout.
I agree with the other posters in saying the RCBS gauge is not the best, it is more of the Swiss Army Knife of gauges and I got it to check case thinning on my .303 British cases checking for possible case head separations.
I would pick the Sinclair gauge below as the best gauge for the money for the average reloader.
I modified my RCBS gauge like below to prevent the V-blocks from moving and being so sensitive to finger pressure and it helped greatly.
The idea came from http://www.larrywillis.com/ and his great idea for the fix.
"The RCBS Case Master is a great tool for about $90. Its main purpose is to measure case run-out. However, there is too much "spongy" movement as you roll your cases on the V-blocks. This mechanism is quite rickety because of the way the V-blocks are secured only to the front rail. This tool can be improved quite a bit with one simple modification. I've added a horizontal 4" x 5/16" square steel crossbar, that clamps both sliding V-blocks "down" to the base using a knurled nut. This upgrade removes all vertical play in the v-blocks, and gives very consistent readings without any unwanted fluctuation. This tool is now a pleasure to use."
"These are common parts that I used for this upgrade. They can be found in almost any hardware store. You can see how these parts are oriented in the first picture (on top) of the page. For a few bucks you can remove ALL of the play in this unit, and make it much easier to use. Of course, you can buy similar units that don't require any modifications. However, most of them are more expensive, and keep in mind that the RCBS Case Master also performs other important functions."
The idea came from http://www.larrywillis.com/ and his great idea for the fix.
"The RCBS Case Master is a great tool for about $90. Its main purpose is to measure case run-out. However, there is too much "spongy" movement as you roll your cases on the V-blocks. This mechanism is quite rickety because of the way the V-blocks are secured only to the front rail. This tool can be improved quite a bit with one simple modification. I've added a horizontal 4" x 5/16" square steel crossbar, that clamps both sliding V-blocks "down" to the base using a knurled nut. This upgrade removes all vertical play in the v-blocks, and gives very consistent readings without any unwanted fluctuation. This tool is now a pleasure to use."
"These are common parts that I used for this upgrade. They can be found in almost any hardware store. You can see how these parts are oriented in the first picture (on top) of the page. For a few bucks you can remove ALL of the play in this unit, and make it much easier to use. Of course, you can buy similar units that don't require any modifications. However, most of them are more expensive, and keep in mind that the RCBS Case Master also performs other important functions."
If nothing else, a person could build a v-block to mount on the Hornady carriage to use as roller for the cases. It isn't rocket science, likely wind up in the same ballpark pricewise as any specialized made tool for it would, maybe a bit less.
sharp shooter
CGN frequent flyer
- Location
- Essex county (Ontario)
Instead of buying a concentricity measuring tool, buy a Forster FL and seating die set and then you won't have to. Then, with the money left over, buy a salt bath annealing kit from ballistic recreations.
Call me weird but this is what I do - when I full size my brass I have the die stem loose to the lint where you can wiggle the pin that pushes out the primer with your fingers. The brass will self align itself this method seems to shrink my groups compared to a non-floating die stem.
I also have learned to do the same as IvoB. The slightly loose expander/decapper will self centre greatly reducing run out. Had a set of Lyman.270 dies that with the stem tight would literally bend the necks , slightly loose and they’re perfect. Only dies it won’t work with are older Hornady’s with the smooth stem as it will just slide up and down but they will send you a new threaded one.
Now that's something I hadn't thought of trying. Thanks!
I think most expander/decapping stems are flexible enough to self-center as the mandrel starts into the shoulder anyway, but loose may be better than tight.
