Received concentricity gauge today. Time to start playing golf?

Got the 21st Century Concentricity Gauge today. Very high quality, but the wheel stopped working after 15-20 rounds being checked. Case lube a likely culprit as I don't tumble after loading, just wipe with a towel. Suspect the cases will need to be cleaned better after resizing for this tool to work. Ball bearings are smooth as they can be. Wheel turns smoothly but case doesn't. Case lube I'm almost certain. It's a very high quality feeling tool.

UPDATE: wheel working fine now, day after posting. Heard from John at 21st overnight. It was excess case lube. Wheel works great now, nothing changed. Case lube must have dried over night. I need to find a more effective way to get case lube off. Gauge works great. High end stuff.

Surprised no instructions came with it. Guess most folks buying high end stuff like this don't require them. I'm not sure how to set the indicator up. Little set screw and infinite ways to angle it. Doubt I'm using this tool to its potential. Which is apparent. But the numbers below were checked, then double checked not using wheel, and remained the same more or less. +/- half thou fluctuation.

Big question, how far off the brass should I have this little ball indicator? I am off the brass far enough to have another ball indicator between mine and the brass. What I mean, I have the indicator ball touching the bullet with pressure, what distance from the case mouth should this ball be? Pic below.

Anyway, I pretty much suck as it turns out. Been reading all you guys talking about 1-2 thou of runout. Hah. I will list below my first findings. Uniformed, trimmed within 0.001" on Forster, primer pockets shiny, wt sorted Lapua, with 77 SMK gently seated using the 180 turn advice I got here after half seating. Redding Deluxe 3 die set. Shoulder set back 0.005" per my new Hornady headspace gauge. Rock Chucker. Talked to the bullets. Played music. I was quite proud of them yesterday when I made them. Time to start playing golf I guess. What's the use, love golf too, and suck at it as well. Ha ha.

What do these numbers mean? What should I be doing differently?



My variation in thou...

7
3.5
6
6
3.5
3
2.5
6.5
2.5
7
4.5
3
4
3
4
3
4.5
3
3
2.5
1.5
4
3.5
1
3
6
5





Dan

 

Lee collet die....for neck sizing.

Measure a few unloaded rounds on the neck and see what your brass is after sizing.

 

Sorry, should have mentioned these rounds are for Barnes Precision AR-15 that I just put a Kreiger 20" barrel in. Full length sizing is required. Also why I set headspace to 0.005".

My interest in reloading isn't for a AR-15, that's just what I'm loading now. Want to buy a 260 model 12 next for long range events. Wanted to sharpen up my reloading skills before dropping $3,000 on a setup.


Dan

 

Golf and shooting are very similar games. Never ending list of improvements and equipment to facilitate a better game!

 

Sometimes Dan you have to let the targets tell you what's working for you...

When working with tools such as the one you've purchased it is not unlike a lot of other things in the shooting game.. You can buy a Harrells powder measure but that doesn't mean you'll be dropping charges to within a half tenth , it takes time and a feel to utilize it properly.

Another example might be where a person builds a rifle , does the load work and has a competitive combination capable of winning on a national level... he sells the rifle to someone and they can't get 5 shots to touch each other to save their own life. These things take time...and you can't buy experience.

 

Just to be certain, are you reading the dial indicator correctly? My 21st century concentricity gauge came with a .0005 dial indicator.

I try to put the ball of the indicator on the bearing surface closest to the Ogive.

Use the gauge on empty brass before and after resizing, inside and outside the neck. I this is previously fired brass it should be most concentric after fired. Using it through all stages of reloading will help cull out the deficiencies in your reloading process.

 

Dan,

I share your pain.... been there.... still doing it.

I don't have a 21st Century Concentricity gauge, but have an Accuracy one Concentricity gauge (which is similar). Run out for me varies depending on how much pressure I set the needle of the gauge on the round, and where it is positioned on the case neck (or bullet if checking a seated round). Is there a right way to do this? I don't know. Maybe one of the experts can provide some insight....

Good luck,
-Bob

 

Put it to you this way..... if you play with a concentricity gauge to the point where you actually take your "crooked" rounds and try and straighten them it's time to throw the baby out with the bath water. Lol

As box car mentioned it is a useful tool when used properly to determine at what point you induced runout... then you begin to pin point the flaws in the loading process.

Good luck.

 

You are one of the reasons I bought this thing :-\

I got it as a diagnostic tool so I could identify weaknesses in my equipment and reloading technique. Just didn't expect such a kick in the teeth. Ha ha. Assuming I'm measuring properly, what are some of the more common culprits for runout? What potential deficiencies do these high runout numbers point to?


Dan

 

Dan, if you are Mag feeding what do you think the violent ride into the chamber does for your runout? ;D As for the indicator setup, are you looking for angular or coaxial error? For angular I would keep it out as far on the major diameter as I could. For coaxial you would need to check both close to the case and out to the end of the major diameter. Use as little pressure on the indicator needed for the range you are looking at and watch using sharp angles on the needle as this will induce measuring error.

 

The first thing I would do Dan is to practice using the tool with ONE case...That's going to tell you if your technique is ready to move on to doing a whole batch of others with unknown runout.

Once you're comfortable that the tool is giving you good results then you start with a fire formed case , don't do anything with it just chuck it in the gauge and see what you get... let's say it shows .001" OK great .

Now let's size the case , now you've got a sized case , Chuck it in the gauge... what does it say?? If it's .001" lovely move to the next step.. If it reads greater than that then you know at what point you've induced runout.

How do you control it at that point? Well it depends what type of tools you are using.. If you're using a bushing die then you can try sizing the neck in two steps as opposed to bringing it down with one bushing.

Generally the sizing step is where most runout is induced... In some really bad cases I've seen runout numbers decreased after they were run through the seating die if it was one that was an exact copy of the chamber fired in.

My honest opinion on the matter Dan... For what you are doing with the rifle you are using I wouldn't be too concerned if the ammo was within .004" .

Certainly nothing wrong with trying to make it better tho..

Good luck.

 

Questions for you Dan:

1. How many times have these cases been fired?

2. Have you annealed any of them?

3. Have you checked the run out of fired but not sized cases? They should read "0" with that fine gauge.

JFYI, I have gotten great results using a Lee Collet Die (LCD) and a Redding Body Die together, without using the expander at all. There is plenty posted on this site about this system, I think Boyd Allen's post was the one that gave me the inspiration to try sizing this way.

Shoot up the ones you have resized, bet they shoot just fine.

But now you've got a tool that will send far down the path of reloading for accuracy OCD craziness. Welcome to the club!

 

Speak English

I want to know what you mean. I bought this gauge to measure runout. And boy, how did it. Ha ha. I need to learn what parts of the case you guys measure.

 

Thanks man. Just what I need. How to use this gauge in a process, ruling things out individually. This is what made me buy the gauge. Already sized or loaded all my brass. Will take measurements along each stage next time. What exactly should I measure. Just the neck, outside, etc.

 

Thanks man. Lapua brass is 2-3x fired. I just measured some fired but unsized brass from last week, it was all 1.5 thou and under variation. Some was 1/2 thou. These are not ones I'm working up load with, but from same box of Lapua. Wt sorted, using the 65 or so within a grain. These fired but unsized were from the heavy batch, but were fired through this new Kreiger barrel.


I measured case neck outer diameter on 33 pieces I just uniformed, trimmed, full sized, etc in garage. The variation was 1-1.5 thou on 25%, 1.5-2.5 thou on 50%, and 2.5-4 thou on 25%. Didn't take time to jot down all numbers, but that's close.

Does this mean my redding deluxe full sizer is introducing runout or is it a reflection of a lack of consistent neck diameter?

These numbers are better than my loaded rounds, in the first post. Looks like I'm jacking up my case concentricity as I go. Guess the goal is to isolate which steps introduce the most runout and try to minimize it in each respective step. Any suggestions on best way to approach this.



Thanks again guys for all the help.



Dan

 

Quick question. :

Just checking over a loaded round. Looking at outside case neck, like I just did with all this prepped, sized, but unloaded brass. Variation was 3 thou, but I saw bullet wobbling. Set indicator up on bullet and it was 5.5 thou variation. Seating die adding that much or is it just getting more out of whack the further down I measure?

 

Dana I have the same setup as you. Keep in mind that some of the best shooters here say stuff like "runout don't mean squat on paper".

These are guys who actually shoot world record groups and scores, not just guys who pound internet keyboards. I am inclined to believe them. I think there are better places for me to spend my time than doing concentricity testing, nice a tool as it is.

 

Another quick question, you don't run those rounds through your rifle with the lube still on them?

joe Salt

 

Intersecting thought Michael. I don't have a firm opinion yet obviously. Hoping to improve the quality of my reloads. That's the only goal. In general, not for this gun.


Joe, I wipe the lube off with a towel after loading rounds. I tumble after shooting. However, this wheel on 21st Century Gauge won't turn loaded rounds. Just spins on them, without turning the round. Works great on empty cases. Cleaned the rubber outer section on the wheel with alcohol wipe, cleaned a few loaded cases by hand to ensure no rcbs lube was still on them. Still didn't work. Will either roughen up the rubber with sandpaper, take it off and put rubber band around it, or just send the tool back. I could just use it without the wheel, but it was quite a bit more expensive than the model without wheel. Not very happy it won't spin cases. Need to put more thought into the cause of the problem and potential solutions.




Dan

 

Dan, keep in mind; a case neck that has a variation in thickness can't very well be concentric on both the inside and outside simultaneously.