Sinclair Concentricity Gauge

[FEENIX]

Thanks Ed, It is interesting, but I have the Sinclair. Definitely educational though

Unless the Sinclair has a ram (or similar) like the Hornady to have the capability to adjust how the bullet is oriented, then you might not be able to adjust it, but I can be wrong. As noted in the first video link, the Hornady concentricity gauge is just another tool to help a reloader improve their hand loads. For me, it's an excellent investment. Good luck!

Ed

 

[misterc01]

No, the affects of runout do not manifest as linear. Given this, for as many who think runout matters, their are those who don't. An abstract.

Runout can matter, but not for the reason written about in gun rags, and most books. These describe runout as a concentricity(misnomer for eccentricity) issue, causing chambered bullets to point off-axis with the bore, causing degraded engraving and release.
That's dead wrong, and easily proven so.

The truth is that runout (TIR)(not eccentricity) matters only when exceeding chamber clearances for it.
This, causing chambered pressure points, affecting barrel vibrations. If you were to press against your barrel at the chamber in the middle of a group, you could simulate this, likely seeing thrown shots.

To manage TIR, and stay clear of this, you should know your chamber clearances.
Just keep your TIR within this, anywhere.
It's not just necks, or bullets. It's the entire cartridge.
The root cause of runout is sizing of thickness variance. More of either = more TIR.

Just what does the acronym"TIR" stand for?

 

[FEENIX]

Just what does the acronym"TIR" stand for?

IIRC, it's Total Indicator Runout; one of those machine shop lingos /acronyms.

 

[Beluebow]

So back to the original intend! Eccentricity of bullet to case. 1) How much is too much for hunting under 500 yards. How is over 500 yards (all my rifles are hunting, I don't do competition shooting)
How can I correct eccentricity after a bullet is seated?
I should probably check the bullets before loading to see how far out of "round" they are

I'm all about having confidence in my rifle and ammo and "if it makes me/you feel better do it". Lord knows I do stuff that doesn't matter and I can't shoot the difference...how do I know, because I've tested it for myself to find out. And yet I still do some of the feel good stuff....cRaZy. ...........................for me and my equipment, run out is waaaayyyyyy down the list.

Honest question.....if your rifles are just "hunting rifles" are they accurate enough to shoot the difference and would you be able to tell at 500yrds?

 

[asd9055]

I'm all about having confidence in my rifle and ammo and "if it makes me/you feel better do it". Lord knows I do stuff that doesn't matter and I can't shoot the difference...how do I know, because I've tested it for myself to find out. And yet I still do some of the feel good stuff....cRaZy. ...........................for me and my equipment, run out is waaaayyyyyy down the list.

Honest question.....if your rifles are just "hunting rifles" are they accurate enough to shoot the difference and would you be able to tell at 500yrds?

The more I read about it, the more I agree with you. I have rifles that shoot 0.4" at 200 yards, loaded using RCBS tools/dies and had never even thought about it. Checking those loads now after my kids got me the gauge, I find they can be as much as 0.006". So, like someone else said...check it on the range

 

[TRexF16]

Among the other questions the OP has asked are:
1 - How can I reduce runout? (for which he has received a little help)
2 - Can runout be corrected in loaded cartridges. (which I don't think anyone has addressed)

I won't pile on too much with "1" except to note that there is lots you can do to load straighter ammo. Google is your friend on that. Buying precisions match type dies is one but that's expensive. Also, lots of options to adjust your own dies to size and load straighter - easy to look up.

For "2", straightening loaded ammo, the answer is it's super easy - just buy a "TruTool" if you can still find one. It's just a piece of heavy aluminum angle with a dozen or so precision holes bored through it. Not sure if the old manufacturer still makes them - could not find them online. But this is easy to make. Hole diameter is critical - don't make it sloppy. I have added two custom holes in mine, one to make it a perfect fit for a cartridge I neck turn, and another for the .270WSM, whose neck walls tend to run 2-3 thou thicker than the .270 Win, for which the precision hole in the TruTool was bored.
The key to this device is that nothing touches the bullet itself. Some homemade and even commercial tools just tilt the bullet in the case and that is not what you want - the TruTool actually corrects the problem by aligning the neck with the case body if it's off a few thou. You slip the neck into the hole and adjust the neck to body relationship with very slight hand pressure. I understand the common wisdom that .003 runout is plenty good for hunting purposes but I make every round I load under .001 just because I can!
In the attached pics you can see the board I attached to mine so I just clamp it to my bench when I need it and store it otherwise.

Hope this helps,
Rex

 

[Alibiiv]

Thanks Ed, It is interesting, but I have the Sinclair. Definitely educational though

Something that I learned from the forum to help with runout was to rotate the round as you are seating the bullet. Run the ram up half way seating the bullet, then rotate the Bullets 180 degrees and finish the seating. It helps with minimizing the runout. Also if you want to maintain consistency, put a reference mark on the casing with a magic marker before you remove the casing from the press then use that reference point when chambering the round in the rifle. I also use a Sinclair mandrel tool and turn the necks, found that to help with run out. I also use the Hornady concentricity tool.

 

[Alibiiv]

Among the other questions the OP has asked are:
1 - How can I reduce runout? (for which he has received a little help)
2 - Can runout be corrected in loaded cartridges. (which I don't think anyone has addressed)

I won't pile on too much with "1" except to note that there is lots you can do to load straighter ammo. Google is your friend on that. Buying precisions match type dies is one but that's expensive. Also, lots of options to adjust your own dies to size and load straighter - easy to look up.

For "2", straightening loaded ammo, the answer is it's super easy - just buy a "TruTool" if you can still find one. It's just a piece of heavy aluminum angle with a dozen or so precision holes bored through it. Not sure if the old manufacturer still makes them - could not find them online. But this is easy to make. Hole diameter is critical - don't make it sloppy. I have added two custom holes in mine, one to make it a perfect fit for a cartridge I neck turn, and another for the .270WSM, whose neck walls tend to run 2-3 thou thicker than the .270 Win, for which the precision hole in the TruTool was bored.
The key to this device is that nothing touches the bullet itself. Some homemade and even commercial tools just tilt the bullet in the case and that is not what you want - the TruTool actually corrects the problem by aligning the neck with the case body if it's off a few thou. You slip the neck into the hole and adjust the neck to body relationship with very slight hand pressure. I understand the common wisdom that .003 runout is plenty good for hunting purposes but I make every round I load under .001 just because I can!
In the attached pics you can see the board I attached to mine so I just clamp it to my bench when I need it and store it otherwise.

Hope this helps,
Rex

Would you please explain this process a little bit more. Are you saying that the neck of the brass is moved to correct the run out of the bullet?

 

[asd9055]

So I just measured a few Federal Premium cartridges, and get a TIR 0.006-008 with mine I get 0.006 or less...

 

[QuietTexan]

Something that I learned from the forum to help with runout was to rotate the round as you are seating the bullet. Run the ram up half way seating the bullet, then rotate the Bullets 180 degrees and finish the seating. It helps with minimizing the runout.

Works in sizing steps also. Size once, rotate, size a second time. Mandrel in and out, rotate 90*, mandrel in and out again.

My assumption is that this has to do with applying any eccentricities in the die or mandrel to two points in the case sequentially, and ending up with an ultimately less precise but better average size.

How do you get a flat rock if you have nothing but not-flat rocks? You grind three at a time. How do you get a round object from not round objects? You squeeze it in multiple directions so it averages out.

The Whitworth Three Plates Method — Eric Weinhoffer

By using the Three Plates Method, developed by Joseph Whitworth, flat surfaces can be created by using gravity and a simple hand-scraping tool, or by lapping the plates against each other.

ericweinhoffer.com

 

[TRexF16]

Would you please explain this process a little bit more. Are you saying that the neck of the brass is moved to correct the run out of the bullet?

Well, yes, because most of the time it's the case neck to case body relationship that's the culprit. Often it's not the bullet so much that has the runout as the case. I find that if a case is straight, and I have my dies adjusted well with a seating stem that matches the profile of my bullet (which you can custom make for yourself with some epoxy), then the bullet will be straight too, and vice versa. IF the cases are very straight but the loaded round has bullet runout, I would be exploring fixes to the seating process. So, back to your question:

If you look at how a concentricity gauge works when you're measuring case neck runout (no bullet loaded yet), it is basically measuring the misalignment of the case neck to the case body. Let's say that's .003 "TIR." You seat your bullet, use the gauge to check the runout now and it's .004, which isn't too bad since you only induced a thou in seating the bullet, and that might just be because you're moving the measurement point further from the case. As you roll the cartridge around in the gauge, note the point where the needle on your dial indicator (or the digits for yuppie digital guys - LOL) is at its lowest value. Slide the cartridge into the appropriate hole with the same side "up" that was "up" when your TIR readout was at its least. With the heel of your hand braced against the benchtop, use your fingers to put a slight upward pressure on the case body. Then put it back on the gauge and check the new runout. It's subtle, but you will very quickly get the feel for it. it is pretty easy to get a cartridge that has some runout, no matter how much, down to the .001 range. I could swear I have seen a video of this being done but a search is not succeeding now. There are a couple threads on the 24 hour campfire about it, and the tool is also sometimes called Tru angle.

Hope this helps,
Rex

 

[Mikecr]

The Hornady neck bender approach focuses on eccentricity, which will not lead to straight & straight chambered ammo.
You DO NOT have straight ammo until it measures so on a V-Block.

 

[TRexF16]

Mikecr,
I'm unfamiliar with the Hornady Neck Bender, so maybe it is not the same as the process using the TruTool, but if it is, the measurement of the "fix" on the V-Blocks IS the metric that defines having "straightened" out the loaded cartridge. It really works, and the performance of ammo made straight by the TruTool versus that made straight by using Gucci dies is indistinguishable. there is no difference in the concentricity gauge measurement of ammo that is "straight" because it came off the dies straight, and ammo that is "straight", because its runout was fixed with the TruTool
But maybe you're responding to something entirely different?

Cheers,
Rex

 

[asd9055]

Where can one find the trutool? Or I do you just get an aluminum half inch thick angle drill holes to fit the various case necks!