107 SMK question

[JEFFPPC]

Longtrain, sounds like your referring to pre tipped 107s. I find the current factory tipped to be very consistant. I have been through quite a few barrels and usually , but not always, jam hard. Close to a square mark. Barrels on both guns I currently shoot with these are both jammed about .012.

 

[HTSmith]

Longtrain, sounds like your referring to pre tipped 107s. I find the current factory tipped to be very consistant. I have been through quite a few barrels and usually , but not always, jam hard. Close to a square mark. Barrels on both guns I currently shoot with these are both jammed about .012.

Yep--my current lot of Sierra's are more consistent BTO than 105 Bergers.

 

[JEFFPPC]

Last Bergers I bought early last yr in 6.5, I meaured 20, gave them away. Not just the 20 , the whole box.

 

[Longtrain]

Probably 6 years ago I started shooting my Dasher with 107 SMK’s. I don’t recall if they were pre-tipped or not. As I stated their Length to Ogive varied. I loaded them long, measuring each round, sorting them into groups by LTO. I had to adjust my seating die for each group. Even though the overall cartridge length varied when I finished, the distance from the bullet ogive to the lands was as consistent as I could make it, trying to jump them .025, allowing the bullet to jump the same distance until it engaged the rifling. They shot very well.

If Sierra has improved this issue, that’s great. I have had no issues with several 500 round count boxes of 108 Berger’s, their LTO has been very consistent.

 

[Bill Norris]

I am no bench rest shooter by far but my most consistent bullet (BTO) measurements are with the Sierra 107 gr. MK. I am loading the tipped version. My tightest groups so far out of my 6mmBR 1 - 8 Tw and my 243 AI 1 - 7.5 Tw have been with this bullet.

 

[johara1]

Probably 6 years ago I started shooting my Dasher with 107 SMK’s. I don’t recall if they were pre-tipped or not. As I stated their Length to Ogive varied. I loaded them long, measuring each round, sorting them into groups by LTO. I had to adjust my seating die for each group. Even though the overall cartridge length varied when I finished, the distance from the bullet ogive to the lands was as consistent as I could make it, trying to jump them .025, allowing the bullet to jump the same distance until it engaged the rifling. They shot very well.

If Sierra has improved this issue, that’s great. I have had no issues with several 500 round count boxes of 108 Berger’s, their LTO has been very consistent.

Here we go, no matter if the bullet length was seat depth would be the same..... it seats off the ogive. Jumping or into the lands it makes no difference, OAL makes no difference an 80 gr. 6mm and a 110 gr 6mm seated with same seating die will be the same distance from ogive to the lands..... jim

 

[Lefty Trigger]

The sweet spot for the 107's in my rifle was .018 off the lands (jump). I had one barrel that shot really, really well with them loaded to Sierra's COAL length and in my gun that was like a .064 jump.

 

[JFrank]

I had lighting in a bottle while shooting the old 107 s then I ran out of that lot number.
Oh well

 

[TylerFromMS]

Here we go, no matter if the bullet length was seat depth would be the same..... it seats off the ogive. Jumping or into the lands it makes no difference, OAL makes no difference an 80 gr. 6mm and a 110 gr 6mm seated with same seating die will be the same distance from ogive to the lands..... jim

So I might be dumb... I just seated some for a match tomorrow, 2 different bullets. Same powder charge. Between seating them, I did not touch the in-line die with the VLD stem. They measure 0.010 differently cartridge base to ogive. What have I messed up on?

 

[TylerFromMS]

If they are 2 different bullets while ogive to lands will remain the same base to ogive wii vary due to a difference in bullet profile

How good are you at drawing? I can’t wrap my brain around this. I’m trying to visualize the seater stem as the “lands” and hitting the ogive seating the bullet. But the cbto should correlate, right?

I promise I’m not trolling. I just can’t get it through my head.

 

[johara1]

How good are you at drawing? I can’t wrap my brain around this. I’m trying to visualize the seater stem as the “lands” and hitting the ogive seating the bullet. But the cbto should correlate, right?

I promise I’m not trolling. I just can’t get it through my head.

Because you bore out the seating stem and make tooling to pick the outer most edge at the ogive. Been doing it for ever and with the 110 SMK you need it .... jim

 

[johara1]

You can not have the nose of the bullet touching the seater....... jim

 

[TylerFromMS]

Because you bore out the seating stem and make tooling to pick the outer most edge at the ogive. Been doing it for ever and with the 110 SMK you need it .... jim

So the tip of one bullet may be hitting seater stem? That makes more sense. I'm using the "VLD" stem on a wilson seater but after seeing this, I may have to get it modified.

 

[johara1]

put a bullet in the stem and see, no big deal.... jim