Home Forums Reloading Big Game Rifles Runout question

I recently bought a Sinclair concentricity gauge and a trutool . How much runout is acceptable for ammo for hunting rifles? I'm not shooting over 150 yards hunting.

If I used my rifles in your stated application I'm pretty sure anything under .005 would be more than good enough.

Thank you sir. I thought under .005 was enough.

It’s gratifying to know that the ammo you’re making is as concentric as possible. However, in a typical hunting rifle at ranges 300 yds. or less, if you’re already getting good accuracy, agonizing over runout really isn’t worth it. If you’re a competition shooter striving for the elusive one hole group or a “turret twirler” wanting to kill critters at absurd distances then I can understand why runout could be an issue.
Not trying to be a know-it-all. Just MHO.🙂

As to the above I will just relate my experience. Have a 308 Kimber Super America (actually the wife's rifle) that always had decent but not stellar accuracy. Turned out the neck sizer I was using induced about .007 runout. Replaced the die and thought I had finally solved the accuracy problem. With loads running out less that .002 the groups shrank from about 1 1/2 at 100 yards to 1 1/4 inch.

Thanks for the replies. I'm retired and staying at home as we're supposed todo so I've got the time. If tinkering with the runout doesn't make much difference all I'm out is time which I have plenty of.

And it can be interesting/fun to problem solve for the source of your runout.

Dave I'm just getting into this as well. I made a homebrew concentricity gauge. Thought I'd relate some of my experience so far. I am only shooting under 200 yards (270 Howa) so we have similiar circumstances.

In my very limited testing, there seems to be less relevance to neck runout than there is to loaded cartridge runout, but you should probably do your own data collecting and testing to verify. The method I ended up using was to write the actual runout measurement on the loaded case (e.g. .00025"). Might seem a bit ridiculous, but, you can then take your loaded cartridges and group them together for the various shot strings you'll eventually take with those rounds. You MIGHT be able to make small predictions in group behavior if you were to shoot those strings and record the shot groups for the purpose of matching those groups to the measured cartridge runout. Make SURE you aren't changing little pieces of your cartridge 'recipe'. For example don't load a string that has a 20 thou jump, and then load a string that has a 60 thou jump. That will make your testing completely irrelevant. Same bullet, same powder, same charge weight, same primer, same case (prep'd the same way), , same shooter, same day....etc. Take your runout measurement on the same location of the bullet for each and every bullet (loaded cartridge).

There will be plenty of posts that say don't worry about it and just load and shoot, and they might be correct, but if you are like myself and few others that I know, you are interested in the rabbit hole stuff just as much as the bang.

Sniggly, good looking runout gauge. Thank you for your input. You posted some interesting points.

WoodsyAl, yep, something to pass the time and learn something.

I try to get less than .002” on everything I load. The ones that are more are straightened and are plinking loads. Not necessary I know for the distances at which I shoot (250/300 max) but I like having the best I can get. Besides, Mathman and BobinNH (RIP) made me a believer! And, I am anal about such things.

I chased answering the question of how much runout affects accuracy.....my results were inconclusive. Instead of answering that question, just eliminate the runout problem.

If your brass thickness is not uniform, you are chasing your tail trying to produce concentric ammo. Non uniform brass bends when you resize it.

I found that a reading body die, lee collet die, and forster bench rest seater produces <=2 thou.

Using the above dies, I don't even measure concentricity anymore because its always <=2 thou with Nosler or Norma brass.

Once I switched to Forster dies my run out went away. Now that's all I use an run out is not an issue.

Nothing wrong with that at all. I agree with the other comments that for 150 yard hunting it's pretty much irrelevant, but for a lot of us (myself included) the study of making rifles shoot well is just as interesting, if not more so, than the hunt itself. Personally I've become much more of a shooter and reloader than a hunter; I still hunt as well but find myself thinking of it as a rifle test too.

I'd also like to point out - all these runout numbers people throw out don't mean much unless you know where on the cartridge or bullet it was measured. Taking a measurement near the case neck is a lot different than at the tip of the bullet. And if you measure near the tip of the bullet, it makes a big difference if you're loading something short like an 85gr SPT, vs a long bullet like a 105gr VLD; the longer distance from the case neck to the bullet tip can result in larger apparent runout value than a short bullet with runout at the same angle.
Or, there are runout gauges that balance the cartridge base and bullet tip, and measure runout near or on the case neck; that gives a very different runout value.

So with that, where are you guys measuring runout, and how are you keeping the measurement consistent and comparable?

I've been taking my measurements just behind the ogive. If you asked me, "Why there?"; I'd answer that I had to pick some place on the bullet, and after having already given consideration to the issues you raised regarding the length of various bullets, it seemed a reasonable answer, even though I know it still isn't a perfect answer. As far as I can tell, and I'm early into this, so long as I take the runout measurement from the SAME PLACE on every LIKE KIND bullet after it's seated into the case, I can make use of the data derived. By contrast if I'm taking measurements from different locations on the same bullet, across a string of 5 cartridges...well then that's trash data. Completely useless. I suspect one could have range data taken from the tip of a bullet, say a range from .003-.006, or range data from just behind the ogive, say .0012-.0035, and you'd still have useful data in both cases. It should be noted that this method slaves me to the load testing of a single bullet brand and weight for however many strings of loaded cartridges I make, because once I set the measure point on my gauge, I cannot move anything on the gauge, and then expect to return to the previous point of measure on the bullet. I think this works in my favor because the cartridge indexes into my gauge in the exact same place every time. I tested it and it's perfectly repeatable. The seated position of the case does a good job of revealing runout either in the neck (if you are so inclined to measure it), and even more so when taken from behind the ogive on the loaded cartridge. In fact that principle is the same you mention above, relatively speaking.

I think the key to keeping your measurement consistent so that it is in fact comparable (useful), you need a gauge that allows you to index your case in the 'holder', the same exact place every time, and it needs to stay there as you rotate the case to take the measurement. That your data is useful is in my view, more important than the differences between things like nose to case head, or neck opening to case head, etc. I think you are correct that you will in fact get different data from those different methods. The thing I do NOT know is which is more useful when shooting targets or game under 200 yards. In fact, I'm skeptical that one method of deriving runout data (meaning where you take your measurements from and where you index the case itself) is superior to another method used on the same cartridge. I'm excluding the idea of taking runout measurements from the neck of the cartridge AFTER the bullet has been seated. Mostly because taking the measurement from a repeatable index point on the seated bullet seems more intuitive, especially since seating a bullet has a tendency to exacerbate neck runout measurements. Again - the context here is target work and game taking under 200 yards.

The biggest thing I learned with a concentricity guage was how much the expander button bends the neck. (Except for the Forster des where you can set the expander button to just below the neck shoulder junction when the case is fully in the die. That way, a portion of the neck is still in the die neck portion, as it is pulled back over the expander button.

Tha same thing can be achieved with RCBS dies. Just screw the expander button up to just short of the neck/shoulder junction. All of my dies are set up like that. I also let the button float so it centers in the neck. With this setup depriming has to be done separately.

I'm glad I don't have to do all the chit you guys do to load ammo that is less than .003" TIR.. That's with el-cheapo run of the mill RCBS dies. I have some forster benchrest dies and hate them. They are annoying. If they didn't come with my 6WOA and I could buy regular ol RCBS for that cartridge, I would have tossed them in the trash can a long time ago...

First deprime cases in universal decapping die. Then take your sizer die, run the decapping stem all the way up, then turn it back down 2-3 full turns and size your cases. When seating bullets I put a empty case in press run the case into seating die, I turn the die down until it makes contact on the case mouth. Then back the die a half turn back out. Back the seating stem out and screw it until you get whatever oal you want.. but those simple steps have eliminated any run out issues I have had. Like bsa all my dies are rcbs and hornady oh some Lee dies thrown in there..