I have been working on 185gr VLD's, they are a bit longer...
I don't have a chamber/throat depth gauge, so when I do my first reloads, I usually seat the first bullet long (like 2.9"), chamber 1 round, unchamber it and re-measure. This gives one a length where one can be pretty sure that one is engaging the rifling. You need to start a data sheet and record this OAL. Of course you might want to check how that works with your magazine too, that way you will know if your mag is a limiting factor. There are competition shooters who say that the best way to load VLD's is longer than the chamber so that when you chamber them they are jammed for sure. David Tubb subscribes to this theory.
One of the reasons to start there is that the longest OAL also provides the most room for powder and would fire a given amount of powder with near to the lowest pressure compared to when loaded in shorter OAL's. Then pick a starting point for your powder and load several groups of 3 rounds each with 0.5gr more powder to the listed max. All to the same OAL. Now go and shoot them. You can sight the rifle/scope in with any other ammo you have with a similar bullet size. At this point you are not shooting for POI, you are just shooting for group size with the same point of aim. It actually helps if your bullets do not hit your aiming point so that it stays consistent throughout. Stop when you see pressure signs, even if that means you have to pull the bullets from some of the higher loads. Stay safe.
If you are in good current form and everything else about the rifle is sorted, you should be able to identify some nodes which group better than the others. For many shooters, that is a big if... If you are not sure, bring another rifle with loads that work well in it, and verify that your have your technique down. You can't be learning how to shoot when doing load development...
Most shooters will try to find an accuracy node that is as high up the powder weight ladder with as little vertical dispersion as possible. Then go home and reload that particular load, except this time adjust the seating depth in 0.010" increments shorter x 3 bullets each. Watch carefully for pressure signs as the seating depth gets shorter, as powder volume is being reduced and you can run into a pressure limit. Hopefully you will see group size shrink significantly with one of those seating depths. Now you have narrowed down load and seating depth somewhat. At this point you will want to take note of where you are at. Then you need to load larger batches at this load point and shifted just 0.2 grain up and down. You are now trying to see how consistent this load is performing for larger numbers of shots in a group. I cannot stress enough that load refinement (particularly when you get to 0.5MOA and better) is something you can only do when in the right frame of mind, no distractions and when you are on your game. Don't rush it, or you can go on some wild goose chases...
When you think there is nothing to be gained in powder charge, refine the OAL a bit in 0.005" increments. At some stage, if the primer and powder is working for you, you will decide you are done (or where your own technique is dominating the outcome). Then you can call it good. It helps to start a file and record the path it took to get to an optimized load for that barrel. Then if you decide to shoot a different bullet you can go over your notes and should be able to optimize the new load in fewer steps, or you might come up with a great shooting load right off the bat. (1) how much did you have to back off the rifling, 2) how much down from posted max did you end up ?)
