Case/Bullet Run-out: How Big a Deal Is It?

[azsugarbear]

Looking at tightening up my groups a little more. How big a deal is case and bullet run out? Obviously, if it is very pronounced, it becomes a huge problem. But how often is it a factor in everyday reloading? How many of you measure run out as part of your routine when reloading & case prep? What type/manufacturer of measuring device do you use?

I'm looking at getting an RCBS Case Master, but not sure if it will be worth the cost just to satisfy my curiousity as to what, if any, run out is present in my reloads.

All comments are welcome.

 

[acloco]

It is a big deal. If a crooked case is presenting a bullet to a centered chamber...then...it will come out crooked on the other end.

 

[J E Custom]

It is very simple.
The more run out you have the worse the accuracy.

The main advantage of measuring run out is to improve your loading process and adjust
the way you are doing it to get the best results.

If you check run out in a fired case you should find little or no run out, then check the same
piece of brass after and find run out the reloading process or maybe even the dies may need
to be changed.

It is like everything else , The more consistant the loads are from one to another the better
The accuracy will be.

For short range it may not be enough to bother with but for long range shots it can be the
difference between success or failure.

J E CUSTOM

 

[lever-hed]

JE pretty much answered it.. I am of the opinion that once you cross into that realm, you are at beginnings of committing to a lot of work; then comes weighing brass, turning necks, sorting bullets/brass, annealing, etc etc… nothing wrong with that, but it gets old if you're not shooting bench all the time where tenths, hundreds and thousands count…
.. IMHO.

 

[Buffalobob]

First off, if you are shooting a factory chamber do not presume that the chamber is centered in the barrel. Take a fired case and roll it across a flat surface. If it wobbles like a '42 Studebaker on a dirt road then your chamber is not good in the first place. You can get the rifle to shoot with the right load but excessive case prep is not going to compensate for a whacked out chamber.

 

[azsugarbear]

Thanks for all the replies. I have two rifles I use for hunting/practice. The first is a 6.5-06 AI, the second is a 277 AM. Both are custom builds by Kirby Allen and based on a Rem 700 action.

I was just toying with the idea of buying an RCBS Case Master (CM) because I had never checked for run out on my cases. I can get a CM for around $90, but I am not at all sure that it would uncover anything worth the cost of the purchase - except maybe piece of mind. I don't mind prepping or working with my brass as I need exceptional accuracy from my loads to make up for poor shooter. Ha!

Is it worth it? If so, what did you buy?

 

[Winchester 69]

I was just toying with the idea of buying an RCBS Case Master (CM) because I had never checked for run out on my cases. A can get a CM for around $90, but I am not at all sure that it would uncover anything worth the cost of the purchase - except maybe piece of mind.

The RCBS is not the tool of choice. Sinclair's is the one that's usually preferred. However, as JE pointed, the tool only tells you about your process. Take some representative examples of your ammo and check them on someone else's tool. A machinist can check them with V-blocks on a surface plate. You can check them yourself roughly by rolling them across a flat surface, looking for wobble; a glass-top table will work. If your rounds have no run-out, you don't need a gauge. On the other hand, a gauge provides a way to monitor your process.

 

[Moman]

It is a big deal. If a crooked case is presenting a bullet to a centered chamber...then...it will come out crooked on the other end.

Well said! Occassionally I have been plagued with runout issues, most recently with a 300 RUM that I think is due to poor quality of brass. I was able to use a runout guage and sort the best three loads for a .25 group. Before sorting them, it was all over the place.

Two things that I think are very helpful. One is a case neck sorting tool by Sinclair. Use this to determine the quality of your brass lot. It will tell you a lot of what to expect with them. Link Below. I have used this for the past couple of years and was money well spent.

The other tool is the one you mentioned. But, as Winchester 69 mentioned, the RCBS is probably not the best choice. I know this because I own one. It does work halfway decent, but after seeing the Sinclair, that is the one I would get.

I start with the best quality brass I can get for the caliber and use these tools to sort through them.

One other suggestion and you've probably heard it somewhere along the line. Get the Zediker book on Handloading for Competition. Honestly, it may turn most of your guns into one holers.

Good luck.


Case Gauges & Headspace Tools - Sinclair Case Neck Sorting Tool w/ Indicator

 

[boomtube]

Run out passed a certain point, frequently about 6 thou in most chambers, doesn't matter. The chamber itself will correct for bullet tilt greater than that amount. I know of no one who can actually see less than 6 thou of bullet tip wobble while rolling a cartridge over glass.

Checking to find the actual run out and its source - sizer-expander-bad necks-bad seater - bad work methods - demands the use of a good gage. The Sinclair gage is good and their less expensive dial indicator is plenty good enough.

 

[azsugarbear]

A neck gauge for measuring neck concentricity would be quick & helpful in sorting brass necks. However, even a perfectly concentric neck could have run out, i.e. tilting or canted to one side. Does this mean I need two different tools?

It looks as if both Sinclair & Redding make good neck gauges. Who makes something to measure run out? Am I missing something here?

 

[Boss Hoss]

I use this one but have a different indicator that has another 0 in it..

Concentricity Gauge

 

[bigngreen]

I use this one but have a different indicator that has another 0 in it..

Concentricity Gauge

Boss,
I'm kinda trying to wrap my mind around this, if I'm looking right a tool like the RCBS or Sinclair gauge measures the run out of the bullet in relation ship to the neck. The tool you showed measures run out of the entire loaded round, correct?
I'm thinking that the previous style could show you a straight bullet and neck but it is in a banana shaped case were your tool would catch that.
I do like the RCBS for measuring wall thickness low in the case but it is a little crude for run out.

 

[Moman]

The RCBS measures runout along the entire case, or just to the neck when fresh out of the bag or sizing die. As do the Sinclair concentricity/runout gauges. Now the Sinclair tool that I posted is only for checking case neck wall variance (concentricity) of brass. If you don't have tight tolerance in your necks, good chance that will show through the entire brass body. That is what leads to the bannana effect.

The case neck sorting tool in mention is useful for quickly tearing through 100 or so pieces of brass and checking neck wall thickness (which does lead to runout). Basically, for me, in my experience I have had certain lots of brass that shot horribly. They are the groups that are 1"+, or the two together with one an inch out. We've all had those groups. If you were to take a tool like this and sort through the brass lot keeping only the best, groups typincally shrink. ALOT!

Typically if I use Norma Brass in my 300 WM, I'll end up keeping about 95 out of every 100. Same with Noslers 308 Win brass. When you start looking close at some of the cheaper brass, those numbers go way down.

The RCBS does work, but I also think there are better tools to check overall runout. The Sinclair is probably a little more precise with the roller bearing setup. But, the RCBS will tell you what you need to know within reasonable accuracy.

Some will say that this is too much work and trouble, but once done, it is amazing how much time you've saved by knowing that you have good brass and your gun is shooting one hole groups.

 

[Boss Hoss]

Boss,
I'm kinda trying to wrap my mind around this, if I'm looking right a tool like the RCBS or Sinclair gauge measures the run out of the bullet in relation ship to the neck. The tool you showed measures run out of the entire loaded round, correct?
I'm thinking that the previous style could show you a straight bullet and neck but it is in a banana shaped case were your tool would catch that.
I do like the RCBS for measuring wall thickness low in the case but it is a little crude for run out.

I understand your concern--my dies are all made by Speedy and use the same remers that are used to cut the chambers. My press has been set up correctly and my concern is with the loaded round only. I use this tool to check my process however it can be used to correct a round that needs it