Checking runout

[dbaird]

What is the easiest to use and most accurate tool to check for case/bullet runout?

 

[BoydAllen]

What is your budget?

 

[Fotheringill]

Yep. There are tools and then there are tools.

 

[dbaird]

What is your budget?

What is your budget?

Not as concerned about cost as I do accuracy/ease of use. On the other hand I don’t want to mortgage the farm.

 

[Someoldguy]

Watching with interest.

 

[BoydAllen]

For checking both cases and loaded rounds you will need a gauge that supports the case on its body. I would avoid units that use the rim because after firing it may not be perfectly aligned with the body of the case due to uneven expansion at the back of the case caused by unevenness in brass thickness in that area. Also I like bearing balls for the ease of turning cases, preferring them to any sort of wheel or ball bearing that turns because of the potential to introduce runout. All of this points to the Sinclair unit and I prefer a simple dial indicator so that I can see the total range of the needle's swing. If you only want to look at loaded rounds with the added benefit of trying your hand at straightening I recommend the H&H. Built like an aluminum brick, it handles a wide variety of sizes and is easy to use. Personally I think that these gauges are best used to diagnose equipment problems and that after any problems have been fixed that the results should be relatively consistent from that point forward. If you want to drive someone crazy, who has not yet gotten away from stock one piece sizing dies (loading for factory chambers) , loan him a concentricity gauge for a week after showing him how to use it using your own, relatively straight sized cases, and reloads.

 

[Someoldguy]

Personally I think that these gauges are best used to diagnose equipment problems and that after any problems have been fixed that the results should be relatively consistent from that point forward. If you want to drive someone crazy, who has not yet gotten away from stock one piece sizing dies (loading for factory chambers) , loan him a concentricity gauge for a week after showing him how to use it using your own, relatively straight sized cases, and reloads.

To be clear, I presume you are referring to sizing dies with pull-thru expanders. (?)

Are bullet seating dies that much different?

 

[BoydAllen]

Some things require better quality rifles to see the difference on the target, but yes, I do believe that if the rifle and load is up to showing the difference that improvement can be seen with Wilson Forster or Redding competition seaters, assuming that the cases that bullets are being seated in are straight. While seating dies can make things worse, they cannot compensate for crooked brass. On the expander thing, the fault is not with expanders but rather that the neck IDs of the typical one piece dies are too small.

 

[ridgeway]

Not the most expensive, but works. I can do ID and OD

 

[Someoldguy]

Some things require better quality rifles to see the difference on the target, but yes, I do believe that if the rifle and load is up to showing the difference that improvement can be seen with Wilson Forster or Redding competition seaters, assuming that the cases that bullets are being seated in are straight. While seating dies can make things worse, they cannot compensate for crooked brass. On the expander thing, the fault is not with expanders but rather that the neck IDs of the typical one piece dies are too small.

Understood. Thank you.

 

[SG4247]

I like the 21st century run out gauge.

However, I did replace the indicator provided with a Mitutoyo that reads in .0005” increments.

 

[jepp2]

I bought the Hornady unit: https://www.midwayusa.com/product/220200/hornady-lock-n-load-ammunition-concentricity-tool Want to buy it?

Then I bought the Sinclair unit: https://www.brownells.com/reloading/measuring-tools/concentricity-gauges/sinclair-concentricity-gauge-prod37479.aspx
Pretty nice, but still not quite what I needed.

Finally I bought the 21'st Century unit with the wheel: http://www.xxicsi.com/concentricity-gauge.html
I wish I would have started here. This is the one you want.

 

[Someoldguy]

Looks like I'm doomed to follow in your footsteps. I had a Hornady unit, didn't like it and sold it. Now I'm looking for a Sinclair . . . .

 

[jepp2]

Looks like I'm doomed to follow in your footsteps.

Quality, Buy once, cry once.

 

[Someoldguy]

Quality, Buy once, cry once.

I know. I can take a lesson. It's the 'learning' part that grieves me . . . .

 

[Murray Brook]

Quality, Buy once, cry once.

So very true

 

[BoydAllen]

I own a number of different concentricity gauges and have tested and written about many more. I only rarely use one. The reason is that I have the bugs worked out in my dies and they produce consistent results. Of course a unit with a built in wheel is easier to use, not to mention looking trick, but honestly no more often than I use one, why would I tie up the money when I can find more useful ways to spend it?

Years ago I asked around about what level of straightness is adequate for short range benchrest. I was told that on the bullet (I measure about where the rifling will first make contact.) as long as the TID is .002 or less you are good to go, that anything better will not be seen on targets.

If you like expensive toys that work very well for doing things that you seldom need to do then buy the best, or if you like to measure things for the fun of it then go for it. On the other hand if you have a tighter budget and have more important things that you prefer to spend the money on, you might consider trying out some of the units that have been discussed here to see if the difference in price is worth the difference in function. Personally, once I get something that does what I need done, I consider that inquiry to be finished and move on.

 

[Someoldguy]

I own a number of different concentricity gauges and have tested and written about many more. I only rarely use one. The reason is that I have the bugs worked out in my dies and they produce consistent results. Of course a unit with a built in wheel is easier to use, not to mention looking trick, but honestly no more often than I use one, why would I tie up the money when I can find more useful ways to spend it?

Years ago I asked around about what level of straightness is adequate for short range benchrest. I was told that on the bullet (I measure about where the rifling will first make contact.) as long as the TID is .002 or less you are good to go, that anything better will not be seen on targets.

If you like expensive toys that work very well for doing things that you seldom need to do then buy the best, or if you like to measure things for the fun of it then go for it. On the other hand if you have a tighter budget and have more important things that you prefer to spend the money on, you might consider trying out some of the units that have been discussed here to see if the difference in price is worth the difference in function. Personally, once I get something that does what I need done, I consider that inquiry to be finished and move on.

Kinda what I was thinking. I don't plan to use this tool frequently, just when I change set-ups or calibers.

I believe you've pointed me in the correct direction. Thank you.

 

[Bart B.]

None made commercially, as far as I know, hold a rimless bottleneck cartridge like they are in the chamber when fired. Depending on their type and where the dial indicator touches the cartridge, the same round will show different runout numbers.

Best design lets the case pressure ring rest in a V block and case shoulder center midpoint in a round "headspace" hole. No part of the case body forward of its pressure ring touches anything. Dial indicator contact with case is opposite either point the pressure ring touch point in the V block.

Push the cartridge full into shoulder ring pressing its back end into the V block, twist it then observe bullet tip runout exactly like it is when in the rifle chamber.

Meanwhile, pick out one you think you'll be comfortable using.

 

[BoydAllen]

For you guys that like to play with your measuring tools and experiment, here is one that is easy and may show you something worth pondering. Some time when you are Fl sizing a bunch of cases with a FL bushing die, measure the runout of several cases at the case mouth, then pull the bushing out of the die and size a couple more and measure them the same way. Then you can put the bushing back in the die and run them back through to size the necks. Let me know what you discover. After that you can load the cases and record the on bullet runout. The next step will require the addition of a Lee Collet die. First size all of the necks with the Lee die (If you need more neck tension you can sand down the mandrel or order a smaller one from Lee for a reasonable price.) Then pull the bushing from your FL die and and use it like a body die set to bump the shoulder the same amount that you usually do. Load the cases and measure the runout on the bullets at the same point that you did before. Tell me what you get and if the runout is different from that of the previous batch.