Max Acceptable Runout

[jwrowland77]

I recently got a Hornady Concentricity gauge for Christmas. I've never checked my runout but haven't done too bad shooting F-Class.

I was wondering what the max acceptable runout you would accept? Most places I've read say .003 or less.

I generally shoot 600 and 1000yd comps.

I also plan to do a test and induce a runout of .004 on say 10 rounds. Then shoot those 10 rounds and shoot 10 rounds of .001 runout (if I can correct them that much), just to see if there truly is a difference. Plan to shoot test rounds at 300yd. Plan to use a known load that I recently got groups around 1.2" to 1.5" groups at 300yd with. Had 10 straight groups with these groups.

Let's hear your thoughts on acceptable runout.

 

[rg1]

Most info I've read on runout is .002" or less for match shooting and .004" or less for hunting rounds.

 

[gamestalker]

I probably should pay some measurable attention to this, but ya know, not being a competitive shooter and all, I've never really felt the need to address it until recently. That being so, I'm going to follow this topic closely, there is always something to learned around.

GS

 

[jwrowland77]

Yeah gamestalker, I never have until now, but been shooting comp for a year now, and those dang fliers drive me nuts now. Lol.

I figured, with all the brass prep I do above my normal hunting rounds, I might as well try and squeeze out that last 1/4" or less doing everything I can to make consistent ammo. Lol.

Wife thinks I'm nuts. Lol

 

[Walkalong]

.001 or less is attainable. How much difference does it make? I dunno. How and where you measure for it is another debate.

 

[jwrowland77]

.001 or less is attainable. How much difference does it make? I dunno. How and where you measure for it is another debate.

That's the big question, does it make a difference.

I'm hoping to find that out. Plan to test on my .308 match ammo, and 7mm RM and .243 factory ammo that I have leftover from non-reloading days.

 

[Walkalong]

It makes a difference, question is how much for your application. I lost an aggregate by .0012 once.

 

[jwrowland77]

Oh wow.

Yeah, oh course you know us competition shooters, trying to squeeze out every bit of accuracy we can. If I can take my groups from .3000-.3400", down to .2300-.2600", I'd be happier than a pig in slop. I know it's not much, but as you know, every bit counts at the 600 and 1000yd range

 

[Walkalong]

Groups in the twos beat groups in the threes every time.

And of course in F-Class, they better be in the right spot as well.

 

[jwrowland77]

Yep. Seen a guy one day in Memphis shoot a 594 with something like 42x. It was crazy ridiculous, but awesome to watch.

 

[stubbicatt]

Years ago NECO posted a paper on the web concerning concentricity, which offered a suggestion and reported great results from + .004" out of round cartridges. The author said that if you marked the high side of the rounds with a sharpie, and fed them into the chamber the same way for each out of round cartridge, he was getting better groups than he was getting with the concentric rounds. In essence the tilted bullets were pointing the same way in the chamber each time.

I have never attempted to duplicate this test, but one day I might.

YMMV.

 

[joneb]

The author said that if you marked the high side of the rounds with a sharpie, and fed them into the chamber the same way for each out of round cartridge, he was getting better groups than he was getting with the concentric rounds

I knew a guy that filed a small notch in the case rim, he reloaded the cases orientated to that index mark and chambered them the same.

 

[flashhole]

Do you have a ball micrometer and do you sort your brass for neck thickness?

 

[jwrowland77]

I neck turn to same thickness

 

[flashhole]

So your challenge will be to measure runout on components prior to and after each processing step to see if your process is increasing or reducing runout. I use the Forster concentricity gauge and found it to be very helpful in correcting processing steps and selecting dies that reduce and/or correct runout.

I learned how to better align (technique) my sizing dies in the press. Which sizing die types gave the least runout. And the value of a good sliding sleeve seat die like the Forster or Redding. The Hornady seat die was not in the same league as Redding or Forster. When I buy new rifle dies I now go to Forster products as the preferred manufacturer. I also learned a lot about my rifles chambers and how to properly size brass to fit the chambers and the difference it makes in accuracy.

 

[jwrowland77]

The nice thing about the Hornady Concentricity gauge, is I can make the runout worse or better depending on what I want to do regardless of reloading practices.

I do however, want to check everything in my process to get the least amount prior to correcting the rounds runout.

 

[Walkalong]

Yep, if your brass is crooked, it won't load concentric rounds. Just checking the end result won't tell you where it went wrong.

 

[jwrowland77]

Yeah. That's why I've thought about getting another tool to help along the way and try and make sure I catch the problem before I get to Hornady gauge.

 

[jwrowland77]

I'm hoping though with the changes I've done in my process, that it's helped fix a majority of the runout.

 

[Fishalaska]

I have the concentricity gage also. I load with comp seaters and gold medal seaters and have no problem staying under .001 on .204 and .223 so far. I think you should find out what is causing your runout and fix it before just correcting it in the gage. Using the Hornady gage to correct it loosens the neck tension on the bullet and you cause more error with unequal neck tensions probably then leaving the runout.

 

[flashhole]

I wish they had a LIKE button for post #20. Finding the cause of the problem is the best use of the tool and the only real fix.

 

[jwrowland77]

I wish they had a LIKE button for post #20. Finding the cause of the problem is the best use of the tool and the only real fix.

Correct. That's the plan. I've had pretty decent accuracy without ever knowing, but then I'd have those unexplained flyers. Like with my match load, the has single digit SD and ES. I'm pretty good at calling my shooter induced fliers, it's those ones I get on a fairly calm day that I can't explain.

 

[Walkalong]

I wish they had a LIKE button for post #20. Finding the cause of the problem is the best use of the tool and the only real fix.

Agreed, but I bet 99% of users don't use the Hornady tool that way.

 

[Fishalaska]

Agreed, but I bet 99% of users don't use the Hornady tool that way.

I bet you are right. Makeing the rounds to within .001 with the tool just messes with neck tension and you chase your tail...using it to determine if you are within and finding the cause is what it should be for and is what I use it for. Comp seaters have proven the ticket for me.