Bullet seating depth

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15 December 2008, 02:53

Mort Canard

Bullet seating depth

I am trying to tweek some loads for 22-250, 257 Roberts and 6.5X55 and am wondering about bullet seating depth. I have been using the nominal COL from the bullet manufacturers but now have a way to check the maximum COL with a range of bullets.

I have seen folks on the forum talk about seating bullets out to just touch the lands or leave certain amounts of free travel before engaging the lands.

What do most folks around here use as a starter amount of free travel to the lands?

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15 December 2008, 04:18

Fjold

If my magazine length will allow it, I start at .010" off the lands and adjust in, in .002" increments until I find the sweet spot.

Except for Barnes monometal bullets. I start them at .050" off the lands and move them in and out in .005" increments.

Frank

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16 December 2008, 00:14

Markhpb

why the difference in monometal bullets vs. conventional?

Mark

16 December 2008, 04:51

Mort Canard

quote:
Originally posted by Markhpb:
why the difference in monometal bullets vs. conventional?

Mark

My question also.

*******************************************************
For every action, there is an equal and opposite malfunction.

16 December 2008, 06:15

Ol` Joe

quote:
Originally posted by Markhpb:
why the difference in monometal bullets vs. conventional?

Mark

The mono bullets need the running start to keep pressures down when they hit the rifleing. Std cup & core bullets engrave with the rifleing much easier, and don`t tend to spike pressure like the harder solid metal bullets.

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16 December 2008, 06:37

TrophyShotPrints

quote:
Originally posted by Ol` Joe:
quote:
Originally posted by Markhpb:
why the difference in monometal bullets vs. conventional?

Mark

The mono bullets need the running start to keep pressures down when they hit the rifleing. Std cup & core bullets engrave with the rifleing much easier, and don`t tend to spike pressure like the harder solid metal bullets.

I knew there was a difference but never knew why...

Thanks...Now I know why...

16 December 2008, 06:47

buckshot

...and Barnes recommends .050" for the exact reasons listed above. Given what they cost, I'll take their word for it. My guns do their best with monometal bullets seated anywhere from .050" to 1/10".

That said, I make changes in seating depth in increments of .010" as I can detect no appreciable difference in increments of .005". Most cup & core bullets do their best somewhere between .010" and .050".

17 December 2008, 02:32

shootaway

Seating depth has no effect on accuracy,IMO.Just seat them normally and that's it.

17 December 2008, 06:52

amamnn

Seating variation can have a fairly big effect on accuracy IF IF you have a rifle capable of exploiting it. The huge majority of factory off the shelf rifles do not. What many people see as an improvement due to seating is actually the lessening of neck tension as they reduce bearing surface of the bullet.

Using bushing type neck dies (accurately) in factory rifles can be even better at helping accuracy in factory rifles.