Multiple reloading manuals suggest seating depths of between 0.020" and 0.050" from the lands, sometimes depending on bullet type (e.g., Barnes X).

So, say you go for 0.030" (using a conventional, non-monolithic bullet) as a reasonable middle figure to start with, and find a load that gives the velocity you're looking for and promising, but not ideal, accuracy. You decide to fiddle with your bullet seating depth.

Would you try going closer to the lands first, or farther away? By what increment--0.005" or more? And, how far down would you take the load before working the charge back up?

John

Pick a powder bullet and seating depth. load different charges with the same seatind depth. see what shoots. adjust depth to see that happens. tweek powder charge to best. enjoy the results.

My experience has been that relativly new barrels like the bullet seated back of the lands just a little while barrels that have a little throat erosion like the bullet just touching. As far as the actual distance away from the lands I don't know that any two are exactly alike.

On a "new" barrel I usually start about.005 off the lands -- find a load that shows promise and then start playing with seating depth from there.

It is my understanding that the Barnes bullets need to be seated well back as you stated. I didn't know that when I first tried them and was sorely dissapointed. Unfortunately, even after I began seating them back accuracy, while better, was still below par in the two rifles I tried.

John,

I start with a middle of the road powder charge, and .030 off the rifling, and see what happens. The first direction I move is toward the rifling at .005 at a time. Here is where it depends much on the use this rifle will get.

If it is a hunting rifle, I don't like to get any closer than .015-.020 due to field conditions, shooting from a dirty bore, or shot fouling, whatever you want to call it. In other words my hunting loads have to feed reliably, all the time, even in poor conditions. I am willing to sacrifice a little hair splitting accuracy for reliability. If I don't get accuracy I need I look at other options, bullet, powder, condition of bore/throat, etc.

A target or range rifle I don't limit myself to that, but I rarley find my rifles shooting well closer than .005-.010, except for my blackpowder and cowboy action rifles, mostly shoot cast bullets out of those. These are just my experiences with a few rifles, mostly winchesters, mine and my parties. I recognise that other rifles may be different and like bullets close to the lands, like Mike's.

If a powder doesn't seem to work, I try another and start over again. These are generalities, and if you've brought the charge up and want to move the seat depth, I usually drop 10% if moving toward the lands (UNLESS I AM CLOSE TO THEM ALREADY!), and 20% if moving away from the lands(increased pressure from smaller case capacity). Or to be safe go all the way back to the starting charge.

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Originally posted by John Frazer:
Multiple reloading manuals suggest seating depths of between 0.020" and 0.050" from the lands, sometimes depending on bullet type (e.g., Barnes X).

So, say you go for 0.030" (using a conventional, non-monolithic bullet) as a reasonable middle figure to start with, and find a load that gives the velocity you're looking for and promising, but not ideal, accuracy. You decide to fiddle with your bullet seating depth.

Would you try going closer to the lands first, or farther away? By what increment--0.005" or more? And, how far down would you take the load before working the charge back up?

John

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John. Sinclair notes in his papers that if you start at the rifiling and fireform and then work from there you only have one way to go,away from the contact point, .005 at a time works for me and then when you find the "sweet spot" for that gun with that bullet, you can attempt to gain a little velocity back to top load with the seating depth that gives the best groups, as you and others noted this is for "normal" type bullets and a slightly reduced load with the "top" load found after finding the seating depth preference for that gun/bullet combo, makes sense to me and works for me, good luck and good shooting!!!

Is this a game rifle with a magazine feed? If so you may be limited to how far out your bullet will be. If you feed one at a time your best bet is to have the bullet seated in the lands this way the bullet will be in the center line of your barrel while you are fire forming your brass to your chamber and working up a load. After you have fired your brass at least once and found a load the looks good then move the bullet back and check the runout on your fired cases. Good Luck

Bigdaddy got it right. If you start "at" the lands, there's only one way to go. More often than not, I start AND end at the lands, finding that (magazine permitting) the longest seating depth that leaves no visible land mark on the bullet of a chambered round is usually the most productive. And if there's no mark on the bullet, then it can't possibly interfere with feed and function.

You didn't say if this is a hunting round (max velocity), or a target round. For a target round I'm sure you have a favorite powder charge that probably not near the Max load. In this case load 5 of each 10,20,30 off the rifling and see which shoots the best. If your rifle shoots best at 20, then fine tune and go 5 up and five down to see if it makes a difference. O)f course shoot them all at the same sitting and clean - punch the barrel after each 5.
One note. You didn't mention what kind of gun you had butI have heard that weatherbys like it around 50.

If you are going to start at the lands, then go back, I would strongly suggest investing in a bullet comparator.