Bullet runout

[Antifaz2006]

I have a problem with measurements here is the deal

I have one of this

http://bleerat.info/sinclair-international-sinclair-concentricity-gage-sinclair-conc-gauge-w-digital-indicator-concentricity-gauges.asp

I measured 50 rounds 6.5x284 and I have high bullet runout from "low" 0.002 to 0.008

Then I thought ok one of your friends has a
http://www.midwayusa.com/product/220200/hornady-lock-n-load-ammunition-concentricity-gage

So let give it a try..... Now I'm quite confused because most of the round where lower then 0.002 and a the highest ones 0.004 could correct all to 0.001

Back to the other one and :'( still the same numbers as before......

What is now the right number? How to measure the runout correctly?

If I measure the brass as indicated here
http://www.6mmbr.com/jgcaseprep.html

in step 7 I'm exact or better from the numbers as indicated.....
Does it help at all? But most important what do I do wrong in my measurement?

Thanks in advance

 

[rkj1313]

I will say that the Sinclair gage is very sensitive to finger pressure as you rotate the cartridge. It's a little difficult to get a complete rotation with out letting up a little.

 

[wapiti25]

how do the one's with a high runout shoot? If they shoot, problem solved.

 

[tenring]

I will say that the Sinclair gage is very sensitive to finger pressure as you rotate the cartridge. It's a little difficult to get a complete rotation with out letting up a little.

I rotate the case on my Holland guage with one of those soft 6" long and 1/4"thick fingernail files. Its more accurate than using your finger.

 

[rox]

The 2 gauges support the case in very different ways, so they are effectively measuring different things.

I recently switched from a gauge that supports the round between the extractor groove and the meplat (quite similar to the Hornady gauge), changing to a 21st Century gauge that supports the case body (like the Sinclair). I was horrified to see that my bullet runout had increased from practically 0.000" to sometimes as much as 0.003" with the new gauge. What I learned from this was that:
[list type=decimal]
[*]I have shot for years, very successfully, with ammo that occasionally reads 0.003" on a 21C gauge. I can continue to be satisfied with this based on performance.
[*]There is a little room to improve my process.
[/list] The general consensus of opinion (that I've read) suggests that the Sinclair technique is more relevant to centering and aligning a bullet along the boreline.

I suggest that your (Sinclair) instrument is the one you should pay attention to, and that 0.008" is quite high, so see if you can reduce this. It might just be a case of fireforming, or you may need to cull the worst of the cases. What type of brass is it, and what it its history?

..

 

[Antifaz2006]

@rkj1313
You are right, however using the same techniques for measurement as learned as mechanic I have to say no sensitive at all. Basically 1st thing is that the two contact areas were the brass made contact should be as much apart as you can. Then using both hands you have always one finger on it so you don’t have this nasty bumping in the measurement. Works pretty good.

@wapiti25
I would say depending on the application, for example if the application is deer hunting up to 500 Yards they shoot good because achieving because they are sub MOA. Application over 500 Yards deer hunting I wouldn’t take the shot. For other applications I would consider this a bad shooting round. Make this sense?
@rox
I was going the same direction “history of the brass” I did yesterday 3 blind rounds.
1. New brass (primer pocket uniformed, neck sized with my old neck size die)
2. One time fire uniformed (primer pocket uniformed, neck sized with my old neck size die)
3. Two times fire uniformed (primer pocket uniformed, neck sized with my old neck size die)

all of them are having the same result a high runout….

Please advise if my thought process is wrong:
1. I used the neck sizing die with the expander on all specially on the new ones to get them rounded
Don’t use the expander? Use another die? (Have to do so after the weekend, non fireformed brass right now that is not already sized)
2. Neck wall thickness? I didn’t uniform them (and I would need a cutter, recommendations?)
3. Too much seating pressure, I can check on that after the weekend as well have different bushes to do so.

What do you think?

 

[rox]

You could remove the expander from your neck die - they are a common cause of worse runout. But then you might end-up with very tight necks (not ideal). If your runout (or a significant part of it) is introduced by the sizing step, one of the easiest (and cheapest) ways to improve this is to use a Lee collet die.

You could switch to a bushing die, but to really get the best from these you'll want to neck turn (I use them without neck turning, but mostly with Lapua and similar brass).

..

 

[tom h]

High runnout with the sinclair gauge. Low runnout with the hornady gauge. Hornady gauge does not tell the true story. Ben there, done that. Got rid of the hornady gauge.

 

[Antifaz2006]

@tom h
Yea that’s what I thought after the test yesterday. As far it was a borrowed one I don’t have even to get rid of it. ;-)

@rox
I use Lapua brass as well, will check this weekend after shooting the rounds. So I have a bit to play with and test them. Thigh necks have been my concern as well, that was the reason why I let the expander in the die however I have several sizes of the bushes so I will start with that see what happens.

@All
Has someone of you a before after experience on runout? I'm new to that area.....

 

[jlow]

High runnout with the sinclair gauge. Low runnout with the hornady gauge. Hornady gauge does not tell the true story. Ben there, done that. Got rid of the hornady gauge.

My experience has actually been exactly the opposite. I had both and also a NECO. The Sinclair was useless to me because it was difficult if not impossible to get a reproducible reading on the same case/bullet - I send it back. The Hornady was 100% reproducible and its reading correspond well with that from the NECO.

 

[Antifaz2006]

My experience has actually been exactly the opposite. I had both and also a NECO. The Sinclair was useless to me because it was difficult if not impossible to get a reproducible reading on the same case/bullet - I send it back. The Hornady was 100% reproducible and its reading correspond well with that from the NECO.

:-\ :-\ :-\

That is an interesting point and it will be hard for me to explain because I’m not an English native speaker.
I take these examples to raise the question that I had as well.
The NECO and the hornady gauge VS. The Sinclair.
I’m only talking about the relation they measure concentricity. Let’s say 1. vs. 2.

In number 1 we have a centered point on the front of the bullet and one point on the back of the case. In that case I would estimate we nearly take the brass body out of the quotation and we try to measure how the bullet rotates around the middle line we produce while setting it up that way.
In number 2 I take (for example) my fire formed Brass (body measured =0.000 run out) and set the concentricity in relation to the brass body middle line.
Make it sense what I try to explain?
And if so what is now the right way to measure the run out the version 1. Point to point middle line or version 2. Brass body middle line ???????!!!!!

:-\ :-\ :-\ :-\

And second thought on that does it make a difference if I load with a Jump vs. to I press the bullet into the lens? Not what is better only the view into the measurement relation point to point vs. brass body middle line.

 

[wapiti25]

If you have more than .005 neck clearence in your chamber, that can cause you a problem on resizing. I have an 06' match rifle that was chambered to shoot factory ammo with .005" of neck clearence, I can not use bushings to size. I got run out as much as .007". I solved my problem by neck turning, annealing and using a std neck sizer with the expander, I use the Imperial Dry Neck lube to reduce the drag. My runout now is .001-.003 and they shoot OK at 600yd F-class club shoots, the barrel has lots of rounds thru it including rapid fire strings. It can hold less than 6" for 5 shots but not 15 without a flyer or two.
Back to the differences you saw with different tools is they all use different places on the case to measure from (datum). I do not like the Hornady tool using the rim of the case. I set up a "V" block in my mill and roll the body of the case with lever type indicators to check the neck to body, body to bullet run out. I can measure at several points on the bullet as a reference such as bearing surface, ogive, and tip. I like to use the "V" block as it averages the surface of the case instead of using a point/points on the case.
I have read that sizing with more than one bushing in steps will help with the run out. I believe in shooting "round robin" tests at ranges of 500yds or more to see how much it might effect your rifle, 5 rounds is min and 10 is better. Good luck

 

[Antifaz2006]

Thank you all for the informations. Really nice forum. I found my problem and can before I even seat the bullet tell how much offset / runout it will have.
I seated 15 blind rounds 5- not fired brass / one time fired and two times fired. I had small dots under the brass so I could seat them randomly.

Wall thickness is causing it, didn't believe it but I actually can calculate how much runout I have.

Lowest point = wall thickness 0.0150
Highest point = wall thickness 0.0130

Difference = 0.0020 * 2 = 0.004

And guess what yeap runout was 0.004

So did that with 15 and every single time a match. I took even the high 0.008 and measured it.... And here you go same situation!




WHAT neck turner should I go for? Is there something that cuts electronically?

 

[wapiti25]

I don't know what you mean by electronically. I use my lathe but most use "hand type" tools. Look at the Sinclair Int. catalog they have real good pictures of equipment/tools.

 

[Gillie Dog]

"Is there something that cuts electronically?"

I have never seen anyone do it and most folks could not afford the machine anyway.

But..........It would be the coolest thing for the guy with an EDM machine to do his brass. Never thought of it but that is one very good idea.

Should be able to get it concentric to the case plus or minus a few hundredth of a thousandth. The more you think about it the more it sounds way cool.

GD

 

[Antifaz2006]

I have never seen anyone do it and most folks could not afford the machine anyway.

But..........It would be the coolest thing for the guy with an EDM machine to do his brass. Never thought of it but that is one very good idea.

Should be able to get it concentric to the case plus or minus a few hundredth of a thousandth. The more you think about it the more it sounds way cool.

GD

Yea this or a real metal lathe, right now I would love to work again as an industrial mechanic were I had all this measuring tools and machines ..... Staying 1-2 hours longer at work and .... Done ..... good old times.....

 

[BoydAllen]

Since I have both types of tools, a Sinclair, and a H&H, I set them both up and measured runout on the bullet of a dummy 6PPC round at about .120 from the end of the case. The H&H indicated about .003 TIR, and the Sinclair was about a quarter thou. more, measuring the same dummy round. As long as I stick to one or the other, and measure at the same point, the differences in the numbers that they give will be meaningless. Then just for the fun of it, I used the H&H to straighten it to about .00025 TID. I got lucky, but .00075 is really easy and fast. This is really good for messing with the competition when you are loading at a match, but if you are shooting a tight neck chamber and seating into the lands, it is mostly for show. I read about fellows worrying about some of this stuff what seems to me to be way too much, unless you can shoot low twos and high ones with your rig, and not just a wallet group or two.

 

[Antifaz2006]

......tight neck chamber and seating into the lands, ......

What would you consider tight? Giving the +.001 the diameter is .299 and bullet seated brass diameter is .293.

I never did seating into the lands, always used 0.01-0.03 jump depending on the rifle. I may test this method out.

What drives me nuts is fire formed brass has a head runout of max 0.0005 and only 5 of the 50 the others had 0.

This time at 200 yards developing a new load I had the first 3 nice an snuggling in a less then 1 inch group and ..... Last one yea see what happen again..... And I don't know if this is to my method of jump or the runout comes into the quotation. I guess will try first to do it... Seating it into the lands. Is there some numbers how much into the lands?

Thank you in advance

 

[BoydAllen]

I usually start my workups with bullets .006 to .010 longer than an accurately measured touch. I never seat to jump unless I have to. DO NOT just take your jumping load and just seat the bullet longer. Drop back and do a proper workup. Are you shooting over a set of wind flags, or sticks and ribbons? Right now, I think that you have some tuning to do, need to make some sticks and ribbons if you do not shoot over flags. Has your stock been bedded? I think that having the ability to measure runout has you inordinately focused on it, given the other factors that may be more important. A tight neck chamber has a neck diameter that requires necks to be turned so that loaded rounds can be chambered. Depending on the pressure ring diameter and the thickness that I turn my brass to, I set up my rounds so that they have somewhere between .00015 and .003 total clearance, for a competition style 6PPC. What sort of bench are you shooting off of, what rest setup, what scope magnification, what trigger weight?

 

[Antifaz2006]

Thank you BoydAllen, I think you are right. Back to the beginning and start doing it step by step.