bullet seating pressure

[Billyboy]

I've been fiddling with my .50 Encore trying some different bullets/777 loose powder loads.  I can get some good (1"-2") groups at 100yds, but always end up with some crazy fliers.  I know my powder loads are consistent and I swab the barrel between shots but I cannot explain the fliers.  Could it be inconsistent seating pressure?  How hard do you folks seat your bullets?

300gr .452 XTP/MMP black sabot
250gr shockwave/easyglide sabot
230gr .451 XTP/MMP black sabot

All of these with 90-100grs 777ffg produce pretty good accuracy with the occasional fliers.

[coop2564]

I seat mine very firm. Could be your sabots warming up (softening), sometimes if my barrel is getting hot I get a flier esepcially if I take my time and let the temp have a few mins on the sabot after loading.

[alsaqr]

My Encore likes a tight fitting sabot seated very hard on the powder. 

[Double 30]

Tight fitting loads are a big help, but consistent pressure is at least as important as the amount.Take a bathroom scale to the range and use it to find your pressure sweetspot and stick with it.i find black powder is much less sensative to seating pressure variations than T7 or pyro.Ymmv

[Semisane]

I'll add two things that I believe have helped eliminate those pesky fliers for me.

1.  A stop collar on the ramrod.  I seat the first bullet until I just feel it touch the powder.  Then I set the stop collar with about a 1/8" gap between the collar and the muzzle, then finish seating the bullet until the stop collar is against the muzzle.  After that, each bullet is automatically seated to the same place with the same pressure when the collar hits the muzzle.  Of course, if you change the amount of powder or type of bullet, you have to re-do the setting.

2.  Indexing the sabot.  I don't recall who it was on what forum mentioned it, but he proposed that positioning the sabot petals the same way each time so that the petals ride on the lands gives greater consistency.  Whoever it was - thank you.