Causing case neck runout?

[Chris Edmondson]

For testing purposes? Or are you suggesting he neck size his brass?….
Wayne

If fired cases are neck sized only, and they retain low to no runout, which they should, and there's enough headspace, load 'em and shoot 'em.

 

[bozo699]

If fired cases are neck sized only, and they retain low to no runout, which they should, and there's enough headspace, load 'em and shoot 'em.

Idk what he’s doing but the key to accuracy is consistency and you can only be consistent f/l sizing the same every time. Eric Cortina proved for FClass accuracy which is less than benchrest but still accurate, he saw no difference in runout up to I believe.008 but I might be wrong on the number but it was a bunch. Neck sizing is old school short range benchrest and even they abandoned that years ago.
Wayne

 

[Chris Edmondson]

Idk what he’s doing but the key to accuracy is consistency and you can only be consistent f/l sizing the same every time. Eric Cortina proved for FClass accuracy which is less than benchrest but still accurate, he saw no difference in runout up to I believe.008 but I might be wrong on the number but it was a bunch. Neck sizing is old school short range benchrest and even they abandoned that years ago.
Wayne

Agreed. But it will help to isolate low to no runout as an objective in order to assess it's value. I've long ago given up on runout; it's a difficult control value, and a debatable result value.

 

[bozo699]

Agreed. But it will help to isolate low to no runout as an objective in order to assess it's value. I've long ago given up on runout; it's a difficult control value, and a debatable result value.

10-4
I do use n/k dies if I feel I need my case formed more, there are uses for them. I literally have 100’s of dies and I never buy a f/l set without ordering a neck die for the set. But I agree with your assessment, thank you .
Wayne

 

[BoydAllen]

Agreed. But it will help to isolate low to no runout as an objective in order to assess it's value. I've long ago given up on runout; it's a difficult control value, and a debatable result value.

I will tell you how to get excellent runout. Use a one piece die made or modified so that the ID of the die's neck is correct for the application. You can get this by ordering a custom die, or lapping out the neck of a factory die. There is a really good article on how to do this and where to buy the tool. I passed it on to a friend and he was able to achieve excellent runout and improved accuracy for a .264 Winchester. Bushing dies do not work well when you need to reduce the diameter of a fired case neck as much as many situations require, but a properly dimensioned one piece die will.

 

[Barzor]

EUREKA!!!!!! I figured it out. Its hard to drop things when you are a tinkerer like me lol.
SO there was someone in the replies above (forgive me if I did not mention be name)
They suggested that when I size with a bushing that is way smaller than what it originally is that the stretching of the brass can cause runout as its too much to go from greater to much lesser.

SO I measured the once fired brass neck with micrometer its .295 luckily I bought many Redding steel bushings as it was on sale (for 6.5 cm I have sizes that go from .295 to .281) SO I cleaned the RCBS fl bushing die and popped in the ,294 with the label up. Lubed liberally the case with imperial sizing wax and and first case since the die was so clean was a bit hard to go through so before measuring I decided to do another case same again with lots of lube and this time it was much easier.

SO I measure both cases the first one had .002 then the second was .001 THIS IS AWESOME I FOUND THE REASON FOR RUNOUT! I feel also if the case is well lubricated and it goes easy in the die (not make noise) then the runout is much less.

"down the rabbit hole again" DOES this mean that I have to ( i plan to go down by .oo2) use all the bushings to get to the desired neck tension size??? For example I want to go to .288 then I have to go through 3 bushings just to get to my desired neck tension. OMG. There has to be an easier way to prevent this.
I did anneal the brass so why is it stretching so much thus inducing runout???

I usually wait 24 hours after annealing as the brass neck and shoulder is very soft there after. Should I size right after annealing, will this cause more problems or solve it????

 

[Barzor]

I will tell you how to get excellent runout. Use a one piece die made or modified so that the ID of the die's neck is correct for the application. You can get this by ordering a custom die, or lapping out the neck of a factory die. There is a really good article on how to do this and where to buy the tool. I passed it on to a friend and he was able to achieve excellent runout and improved accuracy for a .264 Winchester. Bushing dies do not work well when you need to reduce the diameter of a fired case neck as much as many situations require, but a properly dimensioned one piece die will.

LOL I was just posting the similar thing. See above.

 

[Bc'z]

Be sure you clean your shell holder, it builds a lot of crud in the slot.

 

[Barzor]

UPDATE: So this is my process to get .001 or .002 runout of once fired brass, Clean and anneal. The next day position the Fl bushing die the best position for headspace. Measure the neck of fired case for mine its .295. Next I put in the bushing I have .294 and lube the case liberaly with imperial sizing die. The first time through the die its a bit hard to push down as the body is being sized. Once I remove the case I notice that the case shoulder has grown out. This is ok as Im going to put through the die a second time but with bushing .292
Then finally the .290. I measure the neck and its .289 exactly what I want. I measure the runout and its .002. I measure with my precision MIC and its perfectly where my headspace number for my chamber is.
I did it again for another case and this time .001. I haven't put through the mandrel yet but from experience the runout value stays the same.

Very happy but a lot of work for one case.

 

[Sandstorm]

Have you tested to see how much your accuracy was suffering from the worst case runout to your
best with only .001 or .002 of runout. Im inclined to believe that your not likely to shoot the difference
at distance. I could be wrong but I never bother with checking runout and my scores don't seem to suffer
from this. I need more work in the wind reading department, as its where im getting killed.
just my 2c and worth no more than that Sir.

 

[fkimble@charter.net]

You might try going in .003 steps. This would eliminate one step. Check the runout, if still good your ahead of the game.

Frank

 

[bozo699]

UPDATE: So this is my process to get .001 or .002 runout of once fired brass, Clean and anneal. The next day position the Fl bushing die the best position for headspace. Measure the neck of fired case for mine its .295. Next I put in the bushing I have .294 and lube the case liberaly with imperial sizing die. The first time through the die its a bit hard to push down as the body is being sized. Once I remove the case I notice that the case shoulder has grown out. This is ok as Im going to put through the die a second time but with bushing .292
Then finally the .290. I measure the neck and its .289 exactly what I want. I measure the runout and its .002. I measure with my precision MIC and its perfectly where my headspace number for my chamber is.
I did it again for another case and this time .001. I haven't put through the mandrel yet but from experience the runout value stays the same.

Very happy but a lot of work for one case.

If your putting lube on your shoulders you will not get consistent shoulder bump
Wayne

 

[Coyotefurharvester]

Can you answer my question from post 7, it could save you a lot of time,frustration.

 

[SeabeeKen]

My mighty armory dies dont over work the necks and the expander is perfectly centered and causes no runout, at least in my experience so far. Very happy with them. They only dies I use the expander in.

 

[dellet]

EUREKA!!!!!!

Lubed liberally the case with imperial sizing wax and and first case since the die was so clean was a bit hard to go through so before measuring I decided to do another case same again with lots of lube and this time it was much easier.

SO I measure both cases the first one had .002 then the second was .001 THIS IS AWESOME I FOUND THE REASON FOR RUNOUT! I feel also if the case is well lubricated and it goes easy in the die (not make noise) then the runout is much less.

Somewhere between the amount of lube you are using now, and so much lube a dent is formed in the brass, is probably your answer.
If you can feel a chatter when sizing the case, it’s not enough lube. If you are getting noises, you are close to disaster by sticking a case in the die.

The resizing stroke should be relatively easy, and as smooth as glass.

Hopefully you’re on the way to perfection!

 

[Barzor]

Can you answer my question from post 7, it could save you a lot of time,frustration.

I will give it a try...an let you know.

 

[Barzor]

Somewhere between the amount of lube you are using now, and so much lube a dent is formed in the brass, is probably your answer.
If you can feel a chatter when sizing the case, it’s not enough lube. If you are getting noises, you are close to disaster by sticking a case in the die.

The resizing stroke should be relatively easy, and as smooth as glass.

Hopefully you’re on the way to perfection!

I get the glass feel on the second stroke. The first stroke no matter how much lube I put (imperial) is a bit hard as its sizing the body. (Its not the sound more of a harder up stroke to get the case up into the die. This happens on all once fired case I put first time into the die.) I can see evidence of this when I first measure head space before I put the case in die then measure after the first stroke, it has grown, the shoulder has move .004-.005 longer. Then after the second time in the die it brings the shoulder into spec and this second time feels like glass smooth.

 

[Barzor]

Ok guys Im very happy now and will shoot this perfect brass. Promise.

I better not have bullet runout on my new Wilson inline dies....Just kidding...LOL

 

[dellet]

I get the glass feel on the second stroke. The first stroke no matter how much lube I put (imperial) is a bit hard as its sizing the body. (Its not the sound more of a harder up stroke to get the case up into the die. This happens on all once fired case I put first time into the die.) I can see evidence of this when I first measure head space before I put the case in die then measure after the first stroke, it has grown, the shoulder has move .004-.005 longer. Then after the second time in the die it brings the shoulder into spec and this second time feels like glass smooth.

About the only way this can happen, is if the case is not completely entering the die the first time. Check the space between the bottom of the die and the shell holder. There may be a gap the first time, and none then second time, or just more the first time. You could check that with a feeler gauge. The die is not touching the shoulder on the first size, so the difference is a bit more that what you measure.

It almost sounds like a poor match between bore diameter and die diameter, or some pretty hot loads.

The only other option would be over annealing and stretching the case on removal, but that is not likely.

 

[Dave Way]

I completely disagree with the “throw away the concentricity gauge” responses. After all, without it, where would you be right now? As far as checking each loaded round for run out, that probably isn’t necessary, but to test the various parts of the reloading process it is certainly necessary. Don’t forget a few things, excessive chamber dimensions are bad. Excessive neck sizing is bad. Dies are not perfect and can cause runout. Presses are not perfect and can cause runout. Shell holders are not perfect and can cause runout. Bushings are rarely perfect and can cause runout.

I do check all my ammo for runout before matches mainly to make sure I use the few worst for sighters. In Long Range Benchrest, my goal for 600 yard groups is under 1”. My goal for 1,000 yard groups is under 2”. My rifles are capable of achieving both of these goals. It can’t hurt to check runout and it certainly builds confidence that you have created nearly perfect ammunition. The extremes you go to should be dictated by your accuracy goals.

Dave.