Runout; Seat once or twice, and crimp myths

[berettaprofessor]

Thought those here would be interested in this little set of reloads. Based on your advice in this thread, I loaded 30 of the brand-spanking new Starline Valkyrie today without annealing....or doing anything else...cases were properly sized already at 1.589-1.591 and necks looked great so I just dived in. The bullet used was a Hornady 88grain ELD. But I wanted to answer some questions about runout and the Frankford Ultimate Precision Die set, so I loaded 10 with a Lee die seating firmly in one stroke, 10 with a Lee die seating partway, turning 1/4th turn, and then seating completely, and 10 with the Frankford Arsenal Ultimate Seating Die I recently purchased and a 224 insert. Then I hauled out the Hornady concentricity gauge and measured runout in all 30, ran them through a Lee LCD to crimp very lightly, and then measured runout again (runout measured in 1000's of an inch).

Results below:



I don't know about you, but looking at those numbers, I'd say that it doesn't make any difference if I use a Lee or Frankford die, or if I seat the bullet in one stroke or partially seat it, turn it, and seat it the rest of the way. The Lee FCD also doesn't seem to have made a difference in runout. Those averages, SD's, and ranges are all so close they're probably within my measurement error.

I suppose the only caveat here is that an average runout of 2-2.6 thousands is not very high to begin with. A higher initial runout might still be affected by seating twice or by using the FCD.

Now I wish I'd loaded another 10 with the RCBS 224 Valkyrie Seating Die I have.....Next time.

 

[Demi-human]

Interesting, very interesting...

Thank you for sharing.
Looks like doing it right the first time and no crimp just edges out the pack.

Hey, saves time too!

Sorry about the Frankford.

 

[Walkalong]

The only way to be sure is to check at every step.

 

[NMexJim]

Just a note that the press can have as much to do with runout as dies. If the press frame and ram aren't aligned or if the press ram diameter is smallish, then dies won't help. But, I'm not saying that's the case here. Just out of overt curiosity, what brand is the press?

And, I'm not surprised to see runout move around a bit, but .003+ might be getting a little on the high side.

I agree with Walkalong. I work on runout as I go. Once the round goes in the box, I know it's good.

Too, I don't worry too much about one of my AR calibres. If I need to crimp (which, btw, I've not in a long time), then I'm not as picky as a varmint rifle where I'll work to get as good a runout as I can get.

In my opinion, neck tension, and all that goes with it, is key. You can get an adapter for your LNL concentricity gauge that'll read neck thickness which can be a help. I mean, "you don't know what you don't know" is a motto of mine. My reloading buddies get sick of hearing it.

 

[DMW1116]

What is runout? I've seen the term but not an explanation.

 

[Swampman]

What is bullet runout?

 

[BWS]

This is a very slight tangent,mainly because of it being cast.

On cast rifle loads,am generally running from .002-.004 interference for bullet/case ID. It depends on what that particular combo likes from almost daily testing. This is over a dz rigs,and a BUNCH of moulds.

Crimping is from,none to maybe med-heavy.

One of the ops on cast is using an "M" die,or equivalent to not really "flare" the case as we do in handguns,but it is a slight expanding that ends up with a very short,straight section. I set this step depth,to where the gas check,installed on bullet,is exactly at the top of the case when ready to seat.

Hope that was clear enough.

We have every conceivable bit of metrology equipment available,and can pretty much make anything needed in the machine shop. So take the tools and techniques out of the equation when thinking about,"how" we're checking runout.

Now to the good part.

Similar to posted above(Walkalong),I would keep tabs along the processes to find out where any runout was being introduced. What happens to me,may not be where you're experiencing issues. Without a doubt,my problems were completely in the seating op. If I don't take the time to insure that the bullet is deadnuts straight,BEFORE being seated...... then no amount of indexing,two stepping,or any other fidgeting would yield perfect results. There would always be say,10-20% of rounds that were slightly wonky.

I'm not selling,or telling you to use an "M" die. Am just relating that paying WAY more attention to getting the bullet started perfect,before the final seating,cleaned up runout for me,BIGTIME.

Good luck with your project,and sorry for the novel.

 

[berettaprofessor]

The press is a Lee Breechlock Challenger. Nothing fancy. And yes, I was correcting anything over 0.002.

 

[NMexJim]

What is runout? I've seen the term but not an explanation.

Alright, I'll take a shot at this. Folks, jump in, and help me out.

It might be wise to go over the objective of things like fire forming, bullet runout, concentricity, neck thickness, neck tension, and such.

We're trying to take all of the errors that we might build into a cartridge out. We fire-form to "custom fit' our brass to our chambers - make them a better, tighter fit that is more centered in the chamber or concentric to the chamber. We deal w/ neck thickness because case mouths tend to have thick and thin spots. These spots in turn make the round sit a bit off in the chamber and caused the bullet to jump through the leade and into the bore a little bit off which increases bullet wobble. Uneven neck tension causes the same. All of these issues deal with the cartridge case.

Bullet runout, and thus its concentricity in relation to the bore axis, deals with how the bullet sits in the case mouth. If we go through all the work to make sure that a cartridge case is as "tuned" to a chamber as it can be, then we have to make sure the bullet tip is going to go down the axis of the bore or as close to center as we can get. Otherwise, all that work on the case was for nothing.

So, we seat the bullet in the case and then measure to see if the bullet is leaning a little. This "lean" is called runout and is read by turning the completed cartridge in a special stand with a dial indicator sitting on the ogive of the bullet. .005 is considered to be too much while .002 and under is considered to be good. When the ideal state is reached, we consider the bullet to be concentric to the bore. All this reduces bullet wobble and tightens groups.

There is a huge amount of info on the internet that will explain this better than I can. I can tell you that you'll spend a good amount of time learning and buying all the stuff necessary to gain concentricity. I'm still learning after 40+ years.

Or, if you're happy with how your guns shoots, don't worry about it.

 

[DMW1116]

I mean, most of my guns are relatively budget value ones. I've just started hand loading in the last couple months. I'm getting more than acceptable accuracy from my rifles with hand loads tailored to them. I think I'm probably not a good enough shot for this level of detail to be useful right now.

 

[NMexJim]

I mean, most of my guns are relatively budget value ones. I've just started hand loading in the last couple months. I'm getting more than acceptable accuracy from my rifles with hand loads tailored to them. I think I'm probably not a good enough shot for this level of detail to be useful right now.

I've said before that it's like dropping down the rabbit hole with Alice ...... When you start thinking in terms of MOA, it'll come.

 

[DMW1116]

The first load work ups I did in 223 and 308 I'm pretty sure were just dumb luck. I got what powders and primers were available, made fairly big incremental jumps, and ended up with a really good load for 223 and potentially a good load for 308. I have to confirm the 308. Its good to know what runout is, but its likely not something I'll pursue for a while.

 

[Swampman]

Accuracy is #1.

If you're already getting good accuracy with your current reloading practices, don't worry about it.

Just as with cleaning a weapon, 90% of the good comes from @ 10% of the effort.

 

[Walkalong]

Accuracy is #1.

I won't disagree with that, but straight is good, and since we have some control over that, why wouldn't we?

 

[Blue68f100]

If your breach face is not square, chamber not aligned with the bore, your just spinning your wheel.

 

[NMexJim]

Yes, true.

Blueprinting or truing an action to a barrel will certainly improve accuracy capability, and the cost runs from $150 up to $300+ unless you have or have access to the equipment and can do it yourself including headspacing.

BTW, community colleges can sometimes have good machine shops and programs if they'll let anything remotely resembling a "gun" on the property, gasp! You may have to brown-bag it.

But regardless, you still have to be able to utilize that capability by good reloading practices.

I often think Savage and the accuracy in their nutted barrels over the last, oh, 10-years or so has forced other manufacturer's to be more careful in their manufacturing process. I haven't seen factory work lately as sloppy as it once was.

Action and pillar bedding can give great results as well.

Like I said, down a rabbit hole with Alice ......

 

[marchboom]

But what is it about runout that causes (?) larger groups (if it, in fact, does)? Is it the fact that when the bullet starts to move in the barrel it touches one side of the rifling before touching the other side and this causes the bullet to "wobble" as it goes down the barrel only to continue to wobble (and possibly get worse) as it travels to the target?

If the bullet does enter the rifling a little off-center (due to runout) doesn't the barrel correct this by the time the bullet exits the muzzle? If not, that means the bullet is wobbling all the way down the barrel. Hard to believe.

Inquiring minds...

 

[NMexJim]

But what is it about runout that causes (?) larger groups (if it, in fact, does)? Is it the fact that when the bullet starts to move in the barrel it touches one side of the rifling before touching the other side and this causes the bullet to "wobble" as it goes down the barrel only to continue to wobble (and possibly get worse) as it travels to the target?

If the bullet does enter the rifling a little off-center (due to runout) doesn't the barrel correct this by the time the bullet exits the muzzle? If not, that means the bullet is wobbling all the way down the barrel. Hard to believe.

Inquiring minds...

That's a good question and gave me a moment's pause. The easy answer is that bullets - jacketed, copper, or lead - are soft. Once they enter the rifling and engraving starts, then that's how the bullet will exit. I'll venture w/o doing the research that "wobble" and "yaw" are two different peas in a pod.

I've read that some bullets that are extremely streamlined and aerodynamic will actually stabilize after 400 yards or so, but that's a bit off the subject.

 

[Walkalong]

Bullets "go to sleep" very soon after exiting the barrel. The straighter they start and the straighter they leave the better.

 

[BWS]

Cpl ways to look at this...

One,is if you and your rig are capable of wringing every last bit of accuracy out of the load. If you test,and it isn't showing on paper,don't bother. But I can tell on several of the bughole cast rigs here and honestly,after finding where the problem was being introduced,and fixed..... I don't give it a whole lot of thought anymore,just do it.

Another... we put some pretty good effort and $$ towards tools and techniques on the loading bench,somewhat irrespective of the rig. Finding ways to max the tools accuracy and efficiency sorta goes with the territory. Just sayin,if the dies are perfectly capable of producing straight ammo,why is there a hitch in the process causing issues?

 

[Offfhand]

At what point on the bullet(s) are you measuring for runout?

 

[NMexJim]

I use as near the ogive as I can get. My rig, a Hornady concentricity gauge, won't let me out toward the meplat.

 

[FROGO207]

All this will help with expensive firearms made to shoot accurately. This is a truth. Also if I am shooting a bone stock production rifle at 300 YDS or less setting my rounds on a table and rolling them will be a good enough accuracy check for runout. Something about diminishing returns IIRC.

 

[NMexJim]

"Or, if you're happy with how your guns shoots, don't worry about it." Just to clarify, I brought this line down from earlier in the string.

Yep, I've had a couple of rifles I gave up on and sold. But, I've got a couple of others that are doing just fine.

I'm curious, Frogo, as to what you consider the crossing point for an expensive rifle? For instance, is an M700 Remington considered expensive?

I'm not trying to be argumentative at all.

I enjoy taking a production rifle and making it shoot nice groups for lower costs than custom rifles. I do mess with them though. Although the basic rifle is still there, it's true that they are not bone stock.

 

[FROGO207]

It is not always a specific model of rifle but what it would cost IMO. A $800 or more rifle would be considered not low end. I am speaking of the Savage, H&R, or Ruger americian sort of rifle. Still I have a half dozen Savage rifles in assorted calibers that are 1/2 MOA if I do my part off sand bags with my hand loads. I figure if you can put a quarter over 10 shots at 100 YDS with my 270 then I need not be trying to better that for the distance. Better to practice my unsupported shooting than chasing a smaller group that is for a whitetail at that distance or less. Everyone has their point where they will accept the results and be happy I believe. Savage has always made a great stock rifle for the cost, at least until recently I guess but all mine are older. My newest is a SS 300WSM I purchased the year they were first made. Someday I might spend for a real precision rifle. My most expensive is a franken AR that I built with all the goodies using a Shilen 24 inch heavy SS barrel for varmint duty.