Home Forums Reloading Big Game Rifles Would switching my brand/type of dies help me?

Runout is not the cause of consistent 2 in 1 out grouping.

Yes, I know....you already new that.

Shod

I believe Mule Deer explained it very well from a practical standpoint.

If one is loading for a factory barreled rifle .005 run out will net all of the accuracy the rifle is capable of. Any dies made are capable of producing ammo with .005.

Its more a matter of learning to use the dies properly and a runout gauge will tell you when your getting it right.

I have noted that some dies are a lot easier to learn to use and get results.

I'm not a fan of expander balls unless the die is a bushing die or a die that is modified to not overwork the neck. Overworking the neck in my opinion is one of the biggest contributors to ammo with excessive runout.

Shod

A while back a friend of mine came into a good number of ammo cans full of Lake City 7.62 M852 and M118 Match ammunition. This was quite a windfall since we both liked to shoot out 308's a bunch.

In several of our rifles the grouping with the M118 ammunition showed flashes of brilliance, but overall the grouping was not that great and there were flyers we couldn't explain.

I grouped the ammo by the lots indicated on the boxes, and then I opened the packages and sorted the cartridges by runout. The results were an eye opener, a large percentage had runout from .006" to .010" which is not good for precision work.

To test the effect, I made up some batches with differing amounts of runout. I marked them in a way so I knew what each batch was, but no one else did. I got my friend to shoot them from an accurate rifle, but I did not tell him what he was testing. My instructions were to hold as consistently as possible.

What happened was the bad runout cartridges shot elliptical groups, and they had nearly empty centers. Here's where I get to your two in, one out point. In an elliptical group of seven shots or more it's pretty easy for two holes to be close together, say at 8 o'clock on the ellipse. Now pick a lone hole near the 12 to 3 o'clock side. Suppose those were the only three shots fired. Voila! A two in, one out group.

I yet to see a viable answer, that's for sure. Theory as to why goes on forever. Bedding vs COAL, yada yada. I've even sworn by the COAL theorem myself.

Mix and match any three and you can think a lot of things.



Straight ammo certainly fixes the odds of hitting schit.

I have the RCBS guage, and after checking a good bit of previously loaded ammo, I got the TruAngle Cartridge Run-out Correction Tool on MD's recommendation. Now, if I have something out of alignment, I can correct it.

I've just found I have an issue with a set of Redding dies. It kept making crooked ammo, so I took the depriming rod out and then measured some cases - looks like pulling the case back over the sizer button was really screwing up the straightness of the cases. I'll have to figure out if I can leave the sizer button out (I can deprime in other ways) and still seat the bullets, of try to straighten the deprime rod.

Yep. I took some of the low runout M118 Match cartridges and did the trick of seating the bullets slightly deeper to pop the asphalt sealant the military put in the case necks. That ammo shot some groups that were hard to beat with my best handloads.

When I talk to handloaders I meet at my range I'll hear about gnat's ass weighing of powder, charge increments of .2 grains, multiple seating depth tests, trying different primers, yadda yadda. But it's the rare bird that knows about runout in any depth.

I was typing while you were, I knew a math guy would have to had tested it out.

That makes sense to me. If its an eliptical pattern, then the triangle theory and 2/1 theory/COAL doesn't work because both are possible.

Get one of the tapered expander balls Redding offers for their dies, and expand the necks by pushing them over the ball in a separate step.

Or get a Lyman M-die or other separate mandrel type neck expander die.

The thing to do is increase sample size to get a handle on what you're really looking at.

My BR buddies don't fret it, but they are into arbor presses an all that crap.

I did that sorta thing with my 6x45, never once taking runout into consideration.

Old dogs still learn tricks.

Math - it already has a tapered expander ball, but the shaft seems to be slightly bent, thus making the case crooked. When I removed the expander ball, the cases come out nice and straight

What Mathman said....2 in 1 out caused from runout is a mathamatic possibilty give sample size is rather limited.

Increase the sample size and the rest of the story is told. Separate the runout into groups as mathman did will tell the story even more.

Shod

Kinda sorta.....

If the rod can be straightened, then certainly do so. Once that's done I still recommend pushing the necks over the tapered ball.

This target tells me the first 3 cold bore shots are in the pressure node for a nice triangle group.

Because pressure and velocity slightly increase when warmer the two consecutive targets tell me you are right at the top of a node cold bore hence the vertical stringing begins and then slightly increases on target 3 when temperature and pressure go just above the node causing vertical stringing.

Group 4 screams no AO on the scope increasing the chance of error as far as shooter form or weather such as wind or the Sun causing mirage or both. It has to be because target 1-3 say bedding is a non issue. 9 rounds fired is a respectable sample size with no obvious fliers yet an obvious stringing pattern.

I'd drop the load in .1 gr increments and see if group 2 and 3 lighten up on the vertical string.

Shod

I do not think it was all of my problem I do think it was some of my problem.

It doesn't help for sure, and its one less thing to blame!

Does the title of this thread show up the same for everyone as it does for me in the "last post" column?

I’m the OP. My Sinclair concentricity showed up this afternoon. I’ll list my results, but if you just want the summary, my RCBS FL dies seem fine. The Lee collet are better, and my problems seem to be from seating.

My Kreiger on the Rem and the Tikka both have the fired cases come out with right around .001, but my AR-15, which is really accurate, has the fired cases come out much larger. I wonder if my chamber has a problem? I’ll list those cases further down.


I tightened the little nut on the seating stem, but what’s the next step? The dies are clean on the inside, what else can I do to them? Should my next purchase be the Tru-angle tool to straighten the mistakes, or should I skip to a comp. bullet seater?


I started with the 308 I started the thread with. The cases I used with the three rifles had been checked through the neck sorting tool first.


The fired cases had .001 or really close to it.
I’ll list two numbers. The first number is the run out after FL sizing (bumping the shoulder .001), the second number is the same case, but with the measurement taken on the seated bullet.


My dial goes to .001, so when I list to the 4th place, I’m guessing from looking at the needle between the marks. I’m rounding to the half.


Case #1 .0025, .0035
#2 .0025, .009 (That one would probably ruin my group!)
#3 .003, .002
#4 .0025, .003
#5 .003, .0025
#6 .003, .004


The next set were with the Lee die, then the second number is the same case with a bullet seated and the reading taken on the bullet.
#1 .001, .001
#2 .001, .002
#3 .001, .002
#4 .001, .002
#5 .001, .003
#6 .001, .001
#7 .001, 0
#8 .001, .002
#9 .001, .004
#10 .001, .002


The next cases were from my AR-15 and Hornady 556 brass. The dies are regular RCBS dies. The first number is the fired case, then FL sized, then with a bullet. Rather than type it repeatedly, add a .00 in front of the listed number.
#1 3,2,3
#2 4,3,.0035
#3 3,2,.0035
#4 3,.0015, .0035
#5 .0025, 2, 6
#6 4,2,.0055
#7 5,2,4
#8 3,1,3
#9 2,.0015, 2
#10 3, .0015, 2
#11 5,2,3
#12 5,2,3
#13 5,1,5
#14 .0015, 2,4


Lastly, I did my Tikka 7-08 with its Rem brass.
First number is the fired case, then the same case FL, then the loaded round on the bullet.
#1 1,2,4
#2 2,2,5
#3 2,2, 5
#4 2,2, 4
#5 1,2,4


Next with a Lee collet die.
1,2,3
0,2,4
1,1,1
1,1,3
1,2,2

I’m typed out, but that was interesting to me. The gauge seems to be very repeatable, especially with using both index fingers, one to apply even pressure and one to roll the case.