What increment do you adjust your seating depth when fine tuning loads?

This isn't gonna be a great answer.Depends on bullet and cartridge. Handguns depend upon cylinder length."Shorter" rifle bullets may stretch them further out than "longer" ones.

Fair enough, I didn't think about the question being too broad. I'm only concerned with bolt action hunting rifles using Accubonds and Partitions.

Calibers:

270 Win
7 SAUM
308 Win

It all depends on ogive and where your jump on ascertain bullet likes to be. Either flush or kissing the lands or backed off to jump. You need to use an OAL gauge to determine where you need to start.

So, nobody has a set increment that they like to move the bullet?

I don't have any increments that I use but would like to have a long action .308 so I could go longer to see just how good I could make my loads. Your max length will be limited to what your magazine will accept.

I think I'll give 0.005" a try.

Thanks

Lead bullets I always start with the ogive at .010" off the rifling or at the maximum magazine box length
Barnes bullets I always start with the ogive .050" off the rifling and then usually end up working my way back a little.

You'll have .005" or more worth of error from plastic tips if you're just measuring the overall length of the cartridge

When you start working the bullet back, how far do you like to move it? I'm just curious as to what's too much or too little.

I have always preferred loading within .005 of the lands, but some of my guns will not let me seat the bullets this close due to magazine limitations. Some of them are less finicky than others about seating depth. My 308 just plain shoots and seating depth has not been a major factor. Long throat and I seat Hornady 168 gr. AMAX's about .140 off the lands due to the magazine. My Remington 700 338 WM wants 225 gr. AB's very close (<.005) to the lands.

For the best accuracy, always use a bullet comparator which measures to the ogive, not the bullet tip. Lead tip bullets will have the most variance in OAL, but all bullets (tipped, hollow point, etc,) will have some variance.

For a good tutorial on seating depth, read the Berger Bullets manual. Try 4 different loads which are adjusted by .030 between each load. One of these should show more accuracy than the others. You can fine tune your seating depth up or down in smaller increments from this preferred seating depth.

Trying to find the best seating depth by making very small (.002) adjustments can be an exercise in futility. If you measure the ogive on many of the bullets you will variations equal or greater than this amount. I tried Nosler LRAB's and found variances up to .008 when I measured about 20 of them.

Usually .020" at a time

I normally start .01-.02" off the lands. Then after I find something that looks promising I adjust seating depth in .01" increments.

Riflenut, You start at .01" or .001" I think you meant to say one thousandth not one hundredth, a lot of difference between the two, or ten thousandths? I usually start at ..010" off and work back til I find the best results of 3 shot groupings. Then shoot some five shot groups to prove it out.

Good advice right there.i watched a guy on YouTube get his coal for a bolt action rifles. He first slightly seated a bullet in a dud case. Then he chambered the round and the bullet seated it's self to the maximum coal.

If anybody has a load that they've already established loading it at SAAMI lengths and it's pretty hot.......... be careful about jamming that same load up in the lands. It will make the pressure increase a fair amount

If you are going to experiment with different seating depths, ALWAYS start with a below maximum load and start with the seating depth closest to the lands of the rifling. Succeeding test loads should then have the bullet seated deeper (i.e. - shorter OAL). Once you have found the optimum seating depth, then you can experiment with increased powder charges. As BrentM said, pressure will increase the closer you seat the bullet to the lands.

Nope, said what I meant. .01" is 1/100th which is 10/1000ths. From there, I work in increments of .01".

I use an OAL gauge to find my lands. I back off .003 from the lands and start at the minimum powder charge and work up in .5 gr increment. I usually don't go up to max powder charge. I'll shoot these loads round robin style to find the powder node.

Repeat the above process with the powder charge being static and reduce the seating depth from .003 off the lands in .005 increments. Round robin again to find the seating depth node.

Once you have both of those dialed in you can rinse and repeat the process in .1 gr powder increments and .001 seating depth increments from the established baseline above.

Again that's just what I do and everyone has their own process.

http://www.hornady.com/store/Lock-N-Load-OAL-Gauge-Straight-1Each/

Bullet to bullet variation will often times negate any ultra-fine tuning. I load for a smoking little 222 Rem and a 308. Both times I used a spent case with a slightly crimped neck and let the 'bolt close on the chamber' tell me where everything was lengthwise. I tried ten of the bullets I was interested in shooting from a box, got the average and backed off 0.005". I was prepared to adjust from that if needed, but both rifles liked this number (after running a charge ladder, and finding a good recipe), so I just stuck with it.