Does seating your bullet into the lands help to negate the need for checking runout?

Seating into the lands is not anything I want any part of. Bolts failing to open after chambering a live round, and ejecting a piece of brass from a round that didn't get shot, with a bullet stuck in the barrel is no fun.

Just don't check run-out.

Seat, lower the ram, rotate the brass 90° to 180° seat again.

Put the ammo in the box.

No, I don't look as those as related.

If your processes and equipment is good, there isn't a reason to check runout unless you think you have an issue. I have a concentricity gauge and I bet it gets used once a year...if that. When I first started loading I used it a lot because I wanted to prove my equipment and process. Those days are gone. Same thing with checking length after seating...I might check one and once that die is set, if I don't move it or something isn't loose...I don't check it because it's right.

I only load touching or jam if it's a target gun...for hunting gun, I try to stay close but away from touching...for the reasons JG mentioned.

Understood….but there is a difference between jam and when the bullet first touches the lands. I’m talking about seating somewhere in between. (Answering Jason).

Unfortunately, Judd, my loads are usually good but I do get maybe 10-12% that are in the .005-.007 range. I’m currently touching the lands and wonder if that means I can stop checking runout. I suppose I could chamber them all and check, just asking first.

Experiment to come!

So, you are loading CBTO to .000" of the lands? No jump, no jam?

Bad idea. It introduces problems as JG mentioned, as well as increasing pressure of the load.

Well, that was simple….touching the lands does not eliminate runout. Maybe touching them more might but no need to foul up a good seating depth. Appreciate the input.

Jason, using the Speedy method of dropping a cartridge into the chamber (barrel off gun) to find the lands, (load long, then shorten until it drops all the way in), I found my lands at 2.137 OBTO. With the barrel on the gun, I loaded rounds long, with fully sized brass, and chambered them letting the bolt seat them until they started being pulled out: jam. Jam was at 2.267 OBTO. Backed off .020 and started loading, finding best seating depth at 2.231 OBTO. .036 off jam but .096 into the lands.

I’ve come to realize that jam is any distance into the lands and not necessarily so far as to make a bullet stick…sometimes various terminology can be confusing. However, having read about people getting good results seating .100 into the lands, (and thinking to myself they were nuts), I now find sometimes mistakes can yield bonuses.

Seating to the lands, jamming, whatever you want to call it helps align the bullet and case in the bore/chamber. Doesn't 'fix' bad ammo. An off-center bullet will 'bounce' around going down the barrel.

Most of the time you can't jam anyway due to magazine/mag box constraints, unless you're gonna be a single shot guy.

Don’t forget a chamber that is not perfectly reamed will change things as well.

That can depend a lot on bullet profile, VLD much of the time that would be true. Nosler BT, and many older bullet profiles it can be done with many factory rifles or that is my observations.

Today, I was able to touch lands on a Savage .280 A.I. with a 175 gr ELD-X and still had plenty of room in the mag.
But, I started the load development with a .005" jump anyway.


They did good with just the right amount of free bore.

Never considered doing it.

Runout isn't as big of a concern as most people make it out to be.

You’re making this way more difficult than it needs to be…

Jump/Touch/Jam

Jump = bullet ojive is not touching lands (no marks on the bullet)
Touch = where bullet ojive makes contact with lands (slight marks on the bullet)
Jam = heavy marks on bullet ojive (significantly heavier/longer marks on the bullet)

If you want to know (it doesn’t matter as long as it shoots and your length is consistent) measure touch and base everything from there.

YouTube hero’s (and TCD) like to make up new terms so they seem superior to you…ignore that dumbassery!

https://storage.googleapis.com/wzuk...e88bebc30/What%20Causes%20Dispersion.pdf
Jeff Siewert on barrels and dispersion. Bulletology.com

My Theory

I think runout is far less relevant than setting your shoulder back too far. Oversizing the brass too much will create a cartridge that’s loose in the chamber. At least to my thinking. On a push feed action, which most are, the brass will sit at the bottom of the chamber. If it’s a loose fit this can create more bullet to bore misalignment issues than cartridge runout unless it’s extreme. In that case kissing the lands might help a lot. This probably also true on a CRF action but I haven’t thought it through enough yet.

I have no actual knowledge of this, but thinking it through brought me to this conclusion.

I’ve long thought it was stupid to check. You’re either using good bullets or you’re not. They get deformed the moment they contact the rifling anyways.

It has more to do with case necks than it does bullets.

Why can a guy get virgin brass to shoot extremely well? I've seen shoulders flow forward .015" from virgin to fired.

The diameter of the brass at the web and at the datum line still keeps the brass aligned with the bore.

Yes/no

I agree virgin brass can shoot very well. At the same time load development is always recommended on fired brass. I don’t know that it will have much effect, I’m just arguing that alignment is better with less shoulder set back. Now does better alignment equate to better accuracy? I don’t know.