Have you ever used a concentricity gauge?

[Chills1994]

Well, have you?

 

Which one did you use?

 

Did accuracy improve after you tweaked some things either with your dies, your press, or your reloading method if/when you discovered you had too much bullet runout or case runout?

[uewpew]

No...but so far my LRS reloading has only been .223 for prairie dogs and 1/2 MOA is totally fine for me... i would venture a guess that in the long list of accuracy variables to control...case concentricity is in the "super attention to detail i need sub 1/4 MOA" section

My last load with PMC once fired brass, 55gr Vmax, & 24.5gr Varget...velocity was too low though and wind doping sucked!  Gonna find a new load for 2017.

 

Edited November 25, 2016 by uewpew

[427Cobra]

Yes I use one

I recommend the Sinclair without the digital gauge

I noticed a reduction in flyers

 

i don't use or recommend checking the concentricity of rounds for semi autos

[mlmiller1]

3 hours ago, 427Cobra said:

i don't use or recommend checking the concentricity of rounds for semi autos

Why?  Do you consider it a waste of time or is there a safety concern?

[427Cobra]

IMHO it's not worth the time because of how quick the rounds get shot up, plus I slightly crimp my ar ammo, YMMV

I like the Sinclair because it allows me check run out at each step of the process, fired brass prior to sizing will always have run out, here lately I found that running my bolt gun brass through a floating neck expander mandrel has really cut my TIR(total indicated runout) to .002 or less on most rounds, many are zero, and my ES/SD has improved to lower single digits, at distances beyond 600 I think it has helped

[Smokecloud]

I have not found enough inconsistencies with smaller calibers, especially if you have quality brass.  I did buy one about 10-12 years ago for my 50bmg though.  Bullet run out was so bad that I could roll the loaded round across a table and you could see the tip of the bullet moving up and down by almost 1/8" on some rounds.  Some of those were by manufacturers as well as my reloads.  I bought my concentricity gauge from a well known gentleman over on the 50bmg forum "Biggerhammer" George used to make them.  The construction was very nice, but had a cheaper gauge on it that is easily replaced, however the one on it has performed very well. 

I learned some new reloading techniques from some of the more knowledgeable guys over there on getting my run out down to reasonable levels.  Make sure your expander ball is a little loose, so it self centers when you draw it back out, this will prevent the necks from pulling to the side.  When full length sizing, run the ram all the way in, then back out enough that you can turn the case, but not engage the expander ball, then turn the case 180 and size the neck a 2nd time before engaging the expander ball on withdrawal. 

When seating bullets, do you best to ensure that the bullet is sitting as perfect as it can on the neck, so that its straight up, not cocked to the side.  If the bullet is leaning even a little bit, it will stress the neck and push it off center as the bullet straightens out as it goes into the seating die. Also only seat the bullet about 1/3 of the way, lower the ram, turn the loaded case about 1/3 and seat the bullet the 2/3 of the way, withdrawal, turn it 1/3 again and finish seating.  You really want your run-out to be under .010 for anything that is being shot at all, but you need it closer to .002 or less for distance shooting. 

I started out with 3 brands of loaded ammo before I was setup to reload this caliber.  One was from Talon and one was from another outfit that I can't remember the name of.  I was getting 18" groups at 100 yards from a $4k rifle.  I bought some match grade ammo from HSM with brand new Winchester cases and 750gr AMAX bullets, I managed to get my groups down to 6" at 100 yards, but I was ready to throw it in the garbage.  When I started reloading for it, I remained in the 6-10" range until I figured out that bullet run-out was the problem. I finally got one that was bad enough that it wouldn't chamber.  I felt stupid for not seeing it earlier, but in all the years I had reloaded, run-out was something I had never experienced a problem with.  I was using mostly 1x fired Lake City cases that I was performing a match prep on.  Once I started using the new loading techniques on the cases, I got my run-out problem resolved, my groups went down to 2" at 100 yards. 

I was using all crap components, pulled 700gr AP bullets, Pull down IMR 5010 powder and said cases.  I took the better part of a day and weight sorted all the bullets I had, then weight sorted all the prepped cases and numbered them.  I loaded them and shot them by the numbers and managed to start shooting 3/4" groups at 100 yards. 

I know this 50bmg story is a little off topic, but it taught me a few things along the way that brought a new level of recognition to my "smaller" caliber reloading.  I have never bought another concentricity gauge, but I have checked some of the smaller calibers on the big gauge.  They don't fit real well, but I am able to make it work.

[bigedp51]

I have the RCBS case master gauge and the Hornady gauge for checking runout. The biggest cause of neck runout is if the expander is locked down off center. The second would be not lubing the inside of the case neck and dry graphite works very well.

These gauges help setting up your resizing die and seating die to reduce neck runout.

I use Forster full length benchrest dies with the high mounted floating expander. The neck of the case is still held and centered in the die when the expander enters the case neck.

This design prevents the expander from pulling the case neck off center and greatly reduces neck runout.

Hand in hand with a runout gauge is a neck thickness gauge and I use the Redding neck thickness gauge. With one twist of the wrist it shows neck thickness variations.

I replaced my expanders on my RCBS dies with the Forster expander and spindle assemblies. And this also greatly reduced neck runout.

Life was simple before I had gauges, "BUT" these gauges let me know what I was doing wrong in setting up my resizing dies and seater dies.

If you do not want to buy the gauges then just use the Forster Full length dies and the competition seating dies that reduce neck runout.

Edited December 3, 2016 by bigedp51

[fastshooter03]

Unfortunately yes...

Got mad at Forster/Redding 223 match seating dies after measuring just the brass .001-.002" and then loaded rounds and seeing the runout vary .001-.005" after loading on my Dillon 650.

Part of the problem is that I'm using mostly new brass that is slightly smaller at the base but still....can't leave dies as they are!

Took die sleeves to work and shortened/bored them out to accept bushings that I made and pressed in to take all slop out of the bottom of the dies and to make sure the case was bottoming out inside the sleeve before it hits the shellplate.

A few hours of effort and now my loads are all .001-.002" although proving that they are more accurate might be tough in my AR....

 

Nick

 

[dauntedfuture]

One of the most useful functions of a concentricity gauge is to determine where in the process you have a problem.  Its entirely possible that with standard brass, dies and press you could get runout in the .002 range or less.  Its also possible that with match brass, dies and press that you can have runout over .006.  I have witnessed both.  The most common cause of runout is bad brass; I have some 7.62 LC91 M852 that's just junk and it happens.  with a concentricity gauge you can check runout after sizing brass and then after seating a bullet in the same cases to see if your seating dies are contributing to the problem.  Its very possible and I have seen it on my own equipment that some dies are not compatible with some bullets at some seating depths; this tool can help identify the problem and identify if your seating bullets off the tip or the seating stem is so far down in the case that the bullet and case are unsupported in even a match floating chamber type die like forster or redding. 

For LR shooting your looking for .000-.001, .001-.002 is more realistic and identifying if you have a .004+ loaded round in there somewhere.  Neck turning, just cleaning the case up, can usually eliminate most runout.  .005 or more can spell trouble. 

       

[Chills1994]

 

Somewhere, I had spotted some homemade versions of concentricity gauges.  Basically a steel plate, 4 metal spheres (ball bearings welded into place), a stop block that the headstamp rides against, a mag base, and a dial indicator.

 

 

I recently met a retired machinist who is selling off a bunch of hand tools.  I noticed he had a couple of mag bases and dial indicators.  He even had a total indicated runout gauge like what is pictured above.

 

So I might go that route, and possibly save a couple hundred dollars.

 

 

 

[Powder Finger]

On ‎2‎/‎27‎/‎2017 at 10:40 PM, Chills1994 said:

 

Somewhere, I had spotted some homemade versions of concentricity gauges.  Basically a steel plate, 4 metal spheres (ball bearings welded into place), a stop block that the headstamp rides against, a mag base, and a dial indicator.

 

 

I recently met a retired machinist who is selling off a bunch of hand tools.  I noticed he had a couple of mag bases and dial indicators.  He even had a total indicated runout gauge like what is pictured above.

 

So I might go that route, and possibly save a couple hundred dollars.

 

 

 

I built one similar to this and it works well and quick.

the wheel is at a slight angle so when you roll it the case moves to the rear stop so you don't have to mess around with where the case is positioned.

used rare earth magnets for positioning the bases.

[Matt in TN]

Don't do it.  It's like dating a redhead - it'll make you crazy!

[Bkreutz]

11 hours ago, Matt in TN said:

Don't do it.  It's like dating a redhead - it'll make you crazy!

 

Best statement I've heard in a while (my Mom was a redhead)

[Chills1994]

I cobbled something up.  It's not very pretty, but it works.  Or at least I think it does.  I might just get some drill rod to put in there to see how true that is.

 

The total indicated run out gauge I used has like only 58 thousandths of travel.  I am not a machinist...so the smallest increment it measures is 10 thousandths...I think.   So to this point: 0.0001 .  I had bought a regular dial indicator which has a total of one inch of travel.  So it appears that one of my SMK rounds has 0.008 in runout.  

 

Like somebody up above posted "it'll drive you crazy...."

 

No kidding!

 

The only factory ammunition I had on hand is Black Hills 55 gainers.  Yep, there was even some runout with that, but not nearly as much.

 

I plan on running some of my ammo back through the bullet seating die to see if that "straightens" them.

[Chills1994]

I shot some video:

 

 

 

 

[Chills1994]

I ordered a really fancy commercial concentricity gauge yesterday.

 

I should have it in a couple of days.

 

When I do get it back home, I'll be sure to post video.

[Chills1994]

Here you all go... first up my handloads/reloads:

 

 

And then compare that to a round of factory ammo (in this case, all I had close by was Black Hills):

 

 

My best guess for right now is that my .223 shellplate for my 650 isn't indexing properly.

 

I might have mentioned it already where I have (or had) an issue with the shellplate like "over clocking" and the primer punch hole wasn't centered up under the case.

[Chills1994]

Turns out the case necks are out of round.  It has nothing to do with my 650 or my Redding MA bullet seating die.

 

I suspect they had an expander ball pulled through the case mouths or case necks.  And in doing so, the necks/mouths got pulled off center.