Seated bullet runout---real world practicality

[Sixgun]

Rotate exactly 180 degrees 4 times on sizing and seating....regardless of dies or methods...you're going to get bullet runout less than or equal to .001. That's on once fired cases.

 

[Uncle Ed]

So @Uncle Ed and mikecr, are you saying that the runout measurement from the Hornady gauge is inaccurate?

I'm not saying the Hornady gauge is inaccurate at all, the reading difference is how the case is held and spun. And its only major fault is you can't check runout until you have a loaded case. The other type gauges that spin the cases on their body can be checked for runout after the case is sized. Meaning this type of gauge helps troubleshooting your sized cases before they are loaded. And the only choice you have with the Hornady gauge is to straighten your bent mistakes.

So again the Hornady gauge holds the case like it would be in the chamber. But the more common type concentricity gauge like the Sinclair might be reading a warped egg shaped case because it spins the case on it body. So the gauges are only as accurate as the person taking the readings.

 

[F Class John]

Less than .002 overall is my goal but honestly I can nail right around .001 most of the time now. I use an Accuracy One gauge and it’s dead nuts on in its measurements. It takes time, experience and good equipment to get there. For me it was a process of not going from .010 to .002 overnight magically but as I tuned my loading over the coarse of a year with help from my friends I worked my way down. Change one thing at a time, perfect it, and then move on.

 

[mikecr]

Rotate exactly 180 degrees 4 times on sizing and seating....regardless of dies or methods...you're going to get bullet runout less than or equal to .001. That's on once fired cases.

No, that would be on fired cases -before sizing of them.

For the folks that dismiss oval & banana cases, you're not going to make straight ammo with that.
Our brass comes with thickness variances. By manufacture this thickness difference runs full length of cases. Thicker brass springs back more than thinner brass, and if you size FL of long bodies, a curve builds with each cycle. Curved ammo is not straight ammo and you only have so much chamber clearance to accommodate this without chambered tensions.

The ONLY die that acts to improve this condition is your chamber (your best die). Fired cases are always improved, but this can only counter moderate thickness/sizing problems, so runout usually grows a bit with each sizing cycle.

If your plan is to make straight ammo, the first step is to choose a modern cartridge or wildcat chamber with better reloading design than your everyday 30-06. Reduced body taper, higher shoulder angles, and lower clearances. Steer clear of relatively long cases for cal. Here, you're lowering your sizing requirements and runout growth.
-Then cull out new cases by thickness variance, as seen at necks. And before you decide that you can 'fix' this with neck turning, -you can't. The variance runs all the way to webs, and that's a lot further than neck lengths.
-Plan for fitted sizing dies, made from your fire-formed cases. The less you counter-size cases pulled smoking from your best die, the less you release the evil in them.
-Turned or not, pre-seat necks with an expander mandrel to drive thickness variance away from seating bullets. This also establishes an inward tension relax, instead of outward.
-Straight seating is easy with an inline hand die(Wilson). Using these, I've found best with a slight press of bullets -just barely into & held by necks, followed by a 180 turn and full remainder seating right there. OCD turning a bunch of times in seating has not improved on this(for me), and is detrimental to accurate seating depths.

There is another factor people rarely check, that shows up on a v-block gauge: case head square to body line. You can roll a case to see a bad skew. This is as much a part of ammo straightness as anything else.
A reloading co-worker had a custom Sendero built. He load developed, had it shooting really good. But with each loading cycle groups crept open. He chased his tail on this for a long time, before noticing case head skew. I don't know if it was the action/bolt/lapping, but a gunsmith fixed it. By 2nd re-fire-forming the groups tightened to better than ever. Given a throat no more than 1/2thou over cal, I don't think that was chambered misalignment. I'm sure it was chambered tension.
The case heads pressed against that boltface to throw shots, just like pressing metal (pretty much anywhere) with a thumb during firing can throw shots.

 

[TAJ45]

That there is very interesting, Mike.

 

[jackson1]

Thank you Joe R the video you made. I enjoy looking different perspectives on precision handloading. Very well thought out.

 

[T-shooter]

There is a variety of ways to measure. Here are some I did with a Sinclair gauge several years ago. (Before anyone jumps on this, the last digit is estimated.) I did use a .0005" increment dial indicator and you can estimate if it's 1/4, 1/3, or 1/2 way over or under between the markings. These are 3 Lapua .308 cases measured several times each. All were prepped exactly the same. Basically a waste of time, I just measure runout like the #3 test.

 

[mikecr]

Awesome pic T-shooter.
Standard V-block measure is #3 or #6. #5 before seating bullets.
Hornady(or any other neck bender) is #7, showing half or less of actual runout.

The neck benders are merchandised as being able to fix eccentricities.
But reality & chambered condition is a different story, as the gauge from #7 will show little of a crooked case behind it (which can't be bent to straight).
I could warp a case to outright difficult chambering, and still have it reading below 1thou deviation at #7, by bending the neck to counter arc with sufficient ratio. This ammo would be considered 'concentric', but it would be nothing close to straight.

 

[Lucky Shooter]

I've watched Joe's video and understand his message about the relationship
between good case prep and runout.

I've seen other posts on using gage pins for neck expansion but have never done this.

I have however come up with a fairly simple method of using gage pins for the collet sizing mandrel.

I don't think the gage pins work any better than the Lee mandrel----but they do offer
an increased range in neck tension at less expense. You can get a set of Class ZZ pins
from .219 to .224 in .001 increments for about the price of a single neck sizing bushing.

This method seems to produce at least a fair degree of loaded round straightness:

222 Rem----Lapua case---neck turned---collet sized neck with gage pin mandrel---case sized with Lapua body die----SMK52 seated with Redding 222
Competition Seater-----bullet runout approx .001 on Sinclair gage

220 Beggs----Lapua case---no neck turn---collet sized neck with gage pin mandrel---case sized with Beggs/Hornady FL bushing die w/o bushing---SMK52
seated with Redding 22 PPC Competition Seater----bullet runout approx .001 on Sinclair gage

I think I can take this setup and easily produce fairly straight rounds. Have used it a little at the range without measuring runout---the 220 Beggs seemed
to want to be a shooter.

Would appreciate any opinions on collet sizing with a gage pin as opposed to expanding with a gage pin .

A. Weldy