Run-out help needed

[Mike027]

Hey guys Im hoping that you can give some advice on the next steps I should take on improving my handloads. Ok here is my story.

In my pursuit of shooting tiny groups I went ahead and purchased an RCBS Case Master Gauging Tool because I wanted to verify the straightness of my handloads. As it turns out it would appear that I need to work on my bullet seating technique.

I checked the bullet run-out on about 50 loaded cartridges. Im getting measurements anywhere from .002 on up to .009 +. About half were .005 or over. Im using 30-06 Winchester brass with Speer deep curl bullets.

I checked the case neck run-out on several resized brass and they were all pretty consistent at .002 and less.

I also checked the case neck on several fired cases and the run-out was consistently .002 or less.

For years I struggled with golf because I practiced bad habits. I dont want to do the same with reloading so I figured I had best ask for some help.

Does this sound like a technique issue or would it help to try a different a different set of dies? Im currently using the standard RCBS dies.

I shoot a Weatherby Accumark and I can get groups below an inch at 100 yards but now Im concerned about the groups opening up at longer ranges. Also Im about ready to start reloading for my 7mm RM Sendero.

Thanks for any input you have. I will also look in the archives for info on concentricity and run-out. Mike

 

[Kevin Rohrer]

There has been lots of discussion on this subject on other boards. As I recall, the rule-of-thumb is that if the runout is <.005, you will not see a difference in those groups as compared to groups with no runout.

If you are getting sub-MOA groups at 100-yards, that is pretty good with the type of bullet you are using. And unless I am missing something, your groups will open-up at longer ranges in consistent proportion to the range.

If you want to spend money to try and reduce the runout, try getting a seating die that has the bullet sleeve in it. I use Hornady New Dimension dies and like them. Other companies also sell sleeved seating dies, and Vickerman sells one in which YOU manually start the bullet.

You can also get the Hornady comparator that in addition to measuring the runout, also has the option to correct it. I have one and it works as advertised, but see paragraph-1 on whether the end result is worth the expense and effort.

 

[Bullet bumper]

If you are chasing tiny groups then you need to use match quality bullets to start with.
Then buy a Redding competition seating die .
If your fired case has a .002 run out and it ends up .009 bullet run out then you and or the dies are not good.
To get good run out you have to start right at the beginning.
First anneal all the case necks. This gives consistent hardness radially around the neck and will last about 7 shots .
Then size the case neck with a Lee collet die . Freshly Annealed necks may drag a bit in the collet die so use dry lube inside the necks for two reloads then no lube is required . If you use an old expander ball type die it will bend the case necks as the ball comes out. Gets worse as the neck hardens.
Test the fired cases then anneal and neck size then test them again if the run out is still good your sizing is working.
Then chamfer the case necks paying particular attention to evenness and straightness of the chamfer edge on the inside . Don't over chamfer .
Do all the other loading steps then when you start bullet seating start the bullet a small amount first then back off and rotate the round about 90 degrees and seat a bit more then another 90 degrees and seat all the way home gently .
When testing run out don't put the dial gauge tip on the ogive of the bullet come back to the parallel part or at least closer to the case neck .

 

[AZShooter]

The last poster hit some good suggestions. This one really works:

"Do all the other loading steps then when you start bullet seating start the bullet a small amount first then back off and rotate the round about 90 degrees and seat a bit more then another 90 degrees and seat all the way home gently ."

You can also start the bullet partway in and then rotate cartridge 180 degrees and finish the seating stroke. Experiment with one of these mulitple seating rotations and it might help.

Be sure you have a good chamfer in the case mouth.

 

[Mikecr]

A Few things;
Anyone would struggle to get TIR off sized 30-06Win as low as seen from shorter & better designed cartridges. I would think consistently near 5thou would be about as good as you'll get -without more work than it's worth.
That is, your runout can't be expected to be as low as typical with something like a 6BR.

When you say "checked the case neck run-out on several resized brass" could you be more specific?
Were you checking only neck thickness, or overall case runout off the necks?
When your case TIR as measured off the necks on FIRED & UNSIZED is 2thou, well that is the very best you're going to get no matter what. This because, there is no good method to REDUCE case runout from there, other than re-firing in a chamber.
Dies only increase runout, and bending loaded necks is no good for anything we do.

Also without neck turning, or culling by thickness variance, you leave a contributing abstract to this. So if you don't do these things, to reduce runout, why bother measuring and worrying about runout?

There are improvements for your tool mentioned here:RCBS

 

[Mike027]

Mikecr I was checking the run-out on the necks. I havent tried measuring the case wall thickness. That seems to be a bit tricky with this gauge.

I will roll a few up this afternoon and try rotating the case as I seat the bullet to see if this helps.

Thanks all for the tips. Mike

 

[Mikecr]

Yeah, you're not gonna get accurate thickness with this tool.
Let us know what you observe in seating.

 

[ajhardle]

​

Glenn D. Zediker had an applicable chapter in "Reloading for Competition."
I was in the same boat as you when I got my RCBS gauge. I saw two things happening.
First.....the full length sizing die was constricting the neck to tight.
Second......The seating plug was not deep enough for my long bullets and was tilting the bullets during seat.
Combine both these problems and cases are bending slightly.

My solution was the Lee collet neck die and modifying my seater plug. I used a hand drill, which is a stupid method considering manufacturers will match a plug to your bullets for a small fee.

 

[Mike027]

Ok I just got back from the bench. I loaded up 6 cartridges and rotated them as I seated the bullets. Here are the results:

.008
.004
.003
.009
.004
.003

Kind of a mixed bag. The measurements were taken on the bullet just slightly past the case mouth.

If I purchase the Lee collet neck die would also need to periodically full size the brass? I apologize in advance for my ignorance on this but the RCBS standard dies are all I have experience with. With winter coming on its a good time to expand my horizons.

Thanks again. Mike

 

[farout]

Redding makes competition die sets that come with a collet neck sizer, a full length die, and a precision seater die. It will probably solve the run-out issue but they are expensive. I have a set I use with a 300 WSM and run-out is always between almost .000 and .002. With the majority at .001. The rifle usually shoots between .5 and .6 MOA.

I think a big question though is if your rifle will shoot any better with lower run-out. The run-out gauge I use says that best accuracy is achieved with less than .003 run-out, but I have never tested it. Why not group some of your loadings above and test the results. Group a bunch of the .008 and .009s and the .003s with the .004s and see if there is a difference in accuracy? Then consider going with the more expensive die sets. I would be interested in your results.

 

[Mikecr]

Redding makes competition die sets that come with a collet neck sizer, a full length die, and a precision seater die.

No, it includes a body die, micrometer neck sizing BUSHING die, & micrometer seating die.
No FL die,, No collet die..

 

[ajhardle]

A Lee collet die is cheap, and any run-out I can measure is from case neck thickness variation. When a case is fired , orsized it becomes nearly the shape of the chamber or die. Perfectly round on the outside. A less than perfect case will now hold a bullet slightly off center (non-concentric). Most brass will be about .002. Neck turned brass are just make the needle bounce from a less than perfectly smooth surface.

As for number of firings between collisions? Don't shoot over max and you'll get quite a few. I'm at six firings on this brass.

 

[Mike027]

I see Cabelas has a "Lee Collet Rifle 2 die set". is that what I would look for? My family usually ends up getting me a gift card for a stocking stuffer. Mike

 

[ajhardle]

That should work. You might find the collet die without the whole set for $20 or so.