Need some advice regarding adjusting seating depths

[BMG]

I have recently purchased a new custom built 22/250, with a 26 inch barrel. I have performed a ladder test and have elected to use Nosler 50 grain balistic tip bullets, Fedral Gold Medal GM210M primers, Norma brass, 37.6 grains of Varget obtaining an average velocity of 3781 fps and the bullet ogive is seated 0.005 off the lands. No pressure signs occurring.

My question is if I want to increase the distance of the ogive off the lands what will the consequences be? Will I have to perform another ladder test using the new seating depth to find the optimum barrel harmonics with this new setting or just see how the group performs at 100yds not worrying too much about the increase in pressure? I would like to try 0.010 and 0.015 off the lands? Having never performed this function before I would like to obtain advice before attempting this extra phase in load development.

Thank you in advance for your advice.

 

[RonAKA]

My view is that velocity is what defines the sweet spot. If you have already found the sweet spot velocity, then test your loads with the different seating depths with the same load. I would also try 0.010" into the lands as well (but you may want to back off a grain and work back up first to be sure the pressure is OK). Once you find the best jam or jump, then tweak the load to get back to the sweet spot velocity. I have found that seating depth does not change velocity very much, and between the various small jumps, sometimes not even measurable.

As another tweak, I would also try some Berger and Sierra flat base bullets with the same velocity and see how they do. Bullets can have large effects on accuracy.

 

[necchi]

Right on with Ron.
Use the same charge, try your variations in seating and you may need to tweek the load up or down a tenth of a grain of powder.
In other words, Yes, some adjustment to the charge may need to be done to find an optimum accurate,, but not a FULL ladder like you used to find your enicial charge

 

[BMG]

RonAKA, Necchi,

Thank you very much for your input, it is greatly appreciated. Your information is exactly what I was looking for. The advice about the need to maybe alter the load or not and if so only by a tenth of a grain was of particular interest.

I love this site, the people contributing are extremely helpful and are very knowledgeable.