How deeply do you seat extra heavy bullets?

[Robert357]

I am working up some heavy bullet loads for a 7.7x58 Japanese Arisaka Type 99 rifle and for a 7.62x54R Russian MN 1891/30.  I will be using a 215 grain .312 inch diameter Woodleigh bullet (designed for the .303 Brit) in each.  It is a round nose bullet and very long

I have used the "unprimed case and bullet partially seated in the case" trick to determine max theoretical OAL in both rifles.  The ultimate theoretical max OAL in both rifles has the bullet seated, so that only about half the neck is supporting the bullet.  I would like to seat them deeper, but the question, is how much deeper.

Any suggestions would be appreciated.  I am leaning toward 3/4 to full neck support of the bullet.  There is no crimp ring on the bullet.

Max theoretical OAL based on bullet un an unprimed case is way way past all of the reloading manual max OAL's.  Even way past max manual or book OAL's it will feed from the magazine and will eject a case that is not fired.  

Thanks for any suggestions

[hunter]

Hi robert,
 In my 7x30 waters bbl on my contenter i seat bullets to about 2.79".
With out going looking i the mamual   i think the o.a.l. is 2.55". at 2.79" i'm still .003" of the rifling. This makes for a very accurte round. So you see 2.55" is .027" away from thr rifling--thats a long way--but make sure you back off .003 to .005--be safe.

[Robert357]

For my 7.62x54R MN1891/30:

measured theoretical max OAL on the 215 grain bullet was 3.150 inches. Hornady Vol 1 lists Max COL as 3.048 inches, Lyman & Lee lists 3.037 inches as Max OAL.

My first thought would be to seat bullets until they have close to a full neck worth of support or maybe a little less, but this would be about 2.96 inches OAL by eyeballing things. That would put the bullet about 0.19 inches off the lands, THIS IS ABOUT SIX (6) TIMES GREATER THAN MOST RECOMMENDATIONS I see on sporting rifles.

3/4 neck support of the bullet is about 3.055 inches OAL, which is just a little more than the Hornaday 3.048 inch value.

On my 7.7x58 Japanese:

The Max theorectical measured OAL was 3.316 inches.  The 215 grain bullet is really long.  It looks like it is only seated slightly less than half the neck length.  

If I were to seat the bullet for full neck support, max OAL would be about 3.175 inches.  My Lee reloading manual indicates Max OAL should be about 3.130 inches, Hornady says 3.10. and Hodgdon say for 180 grain bullet 3.150.

Conclusion is that 2.79 is WAY TO SHORT.

Any suggestions as to how fare down the neck I should seat bullets (half way, 3/4 way in, full neck support of bullet) would be appreciated.