Why can't I get a consistant C.O.L.?

[KQguy]

I just started shooting a 240gr sierra MK out of my 300 win. mag.When I seat the bullet I cannot get a consistant C.O.L.,it varies + or - .005".I am using a Redding competition seater die,so I know my die is not the problem.All of my cases are trimmed to the same size.The wierd thing is,I can load my 110gr v-max's into the same cases and get consistant C.O.L.'s all day long,it's just the MK's that are giving me fits.I have to seat them all long ,and them seat each one with a different setting on my die to get my desired length,what a pain!Any suggestions?

[boomtube]

Just measure a few bullets OAL. I think you will find the main reason your cartridge OAL varies.

[BountyHunter]

Measure base to ogive and with most of the SMKs you can see the .005 variance right there. That will give you the variance in COL.

Bullet OAL will always vary on most bullets, but the seating die stem goes off the ogive or close to it so that is the reason to measure and sort by base to ogive.

Are you getting a variance in "feel" when seating? if so might have variable neck tension that can inhibit full seating.

BH

[royinidaho]

BH beat me to it.

[KQguy]

Come to think of it,some do have a different feel.For now,am I doing the right thing by adjusting each one individually to get the same C.O.L.?
Another problem is,some rounds are harder to chamber than others,even though they all have the same C.O.L.,I think some are hitting the lands,and some are not.What should I do?

[glassman]

If you think the bullet is hitting the lands, then there should be a mark on the bullet to show this.

You say you are checking the COL, what you should be checking is the Ojive of the bullet to the base of the case.
By checking it this way, you will know how far from the lands that the bullet is seated.

Nothing will be very accurate, if you go from the tip of bullet and measure (which is COL)

If the rounds are hard to chamber it can be three things:
The bullets are seated "off center" to the casing and bumping into the barrel.
The bullets are seated "out" to far.
Casing not "sized down" far enough.

I had a 06 one time that 8 shells out of 20 that I loaded, would not fit into the chamber. Reason was, the bullets were "out of alignment" in the case by 8 thousands. So being I had them seated to .020 off the lands, they were hitting the side of the barrel and not allowing the round to chamber. So this is something you may want to look into.

Hope this helps.

[goodgrouper]

Sounds to me like you might have inconsistent neck tension and/or the big bullet is crunching powder and impeding the seating process. This sounds very likely as the 110 vmax are seating fine because they are so much shorter.