New bullet question

[Dave M.]

Been shooting the Berger 105g VLD and I recently measured the following:
Hard Jam at 1.8415”
Just barely at the lands at 1.8095”

then I just switched to the Bart’s 105g Hammers and I shocked at how much of a difference I’m seeing in hard jam and to the lands. Just measured the following:
Hard jam at 1.8860”
Lands start at 1.8580”

does this make sense guys??
and if so, I was getting great performance with the VLDs at .009” into the lands (ie CBTO = 1.8185”). Should I load the Barts at .009” into the lands as well (ie CBTO = 1.8670”)?

dave

 

[jackieschmidt]

The Barts has a different ogive than the Bergers, so you will get different amounts of marking from each at a given depth Of into the lands.

The only thing that really counts is what seating depth produces the best results. There is no “set figure” for any bullet/barrel/powder combination. You simply have to try different depths to see what the target tells you.

Do you have the ability to load at the range? It sure simplifies things.

 

[Dave M.]

The Barts has a different ogive than the Bergers, so you will get different amounts of marking from each at a given depth Of into the lands.

The only thing that really counts is what seating depth produces the best results. There is no “set figure” for any bullet/barrel/powder combination. You simply have to try different depths to see what the target tells you.

Do you have the ability to load at the range? It sure simplifies things.

I do not. Shooting a 600 yd competition this weekend. I was planning to shoot the barts at the same .009” in to the lands I was shooting the Bergers. Since the barts will be slightly further out of the case I’m expecting lower velocities, do you agree with this logic

 

[RegionRat]

Dave, the curvature difference between two different bullets can explain those dimensions.

For a given land/groove height, the difference between a tangent and secant ogive can really swing the seating depth difference.

I'm going to fall on the side of saying you will want to re-test your seating depth tests for any bullet change, but there is certainly nothing wrong with giving the idea you have a try if it means the difference between staying on the sidelines and not shooting at all.

When I run really wide swings in seating depths with a fixed charge, I don't find the velocity climbing with deeper seating, in fact I usually find a slight decrease. It would be anybody's guess if the new bullet tunes to the same load and seating depth.

Good Luck and in for the range report.

 

[stevenpoplin]

I was shooting Berger VLDs also, still are at .006 in lands. I got some 105 Hammers and did testing and yes same thing less bullet left in neck, shot best at .018 in lands. Same powder charge and neck tension. Just my experiance
Unfourtunalty I have no idea what my velocities are, I dont care, and nobody can make me
Hammers shoot a little smaller, the few I've shot.

 

[Dave M.]

I was shooting Berger VLDs also, still are at .006 in lands. I got some 105 Hammers and did testing and yes same thing less bullet left in neck, shot best at .018 in lands. Same powder charge and neck tension. Just my experiance
Unfourtunalty I have no idea what my velocities are, I dont care, and nobody can make me
Hammers shoot a little smaller, the few I've shot.

Thanks I’ll do a full seating depth test but I really want to give the hammers a shot for the first time. .018” into the lands may ultimately be where I end up but I’ll start at .009” where the Bergers were to keep the pressures down from being so far into the lands at .018”. Thanks. I’ll let you know how they do. Since I’ve only dropped 6 total points in my last 5 competitions at 600 yards, it should be pretty easy to compare them to what I’ve been shooting the last 1.5 years.
dave

 

[stevenpoplin]

go get em Dave. sounds like your gonna give them every chance you can to see where they want to be

 

[Dave M.]

go get em Dave. sounds like your gonna give them every chance you can to see where they want to be

Thanks. If I don’t fire 598 or better this weekend we’ll know the seating was off. Should be fun though. I just got a surprise pack of 3000 new Barts 105g Gungnirs on the porch today. Plan to shoot them exclusively in my next 6 dasher .134FB. My current barrel has a .104” FB which I heard is better for the hammers.

 

[Ranger188]

If you have a low neck tension, you might not be that far into the lands.
That bullet might be being pushed back into the case a little bit.
This would be hard to test. If you do have light neck tension, I'd be
leary to try to take one out after closing the bolt. Bullet might be jammed
and you would have some powder spill possibly into the trigger area.

 

[Dave M.]

If you have a low neck tension, you might not be that far into the lands.
That bullet might be being pushed back into the case a little bit.
This would be hard to test. If you do have light neck tension, I'd be
leary to try to take one out after closing the bolt. Bullet might be jammed
and you would have some powder spill possibly into the trigger area.

Easy to test. I load dummy rounds and remove the firing pin. You can easily check CBTO both before and after closing the bolt to find the lands. To find jam it is also easy to see if the bullet is partially retracted from the case by just coloring the bullet with a sharpie.

Dave

 

[stevenpoplin]

If you have a low neck tension, you might not be that far into the lands.
That bullet might be being pushed back into the case a little bit.
This would be hard to test. If you do have light neck tension, I'd be
leary to try to take one out after closing the bolt. Bullet might be jammed
and you would have some powder spill possibly into the trigger area.

When I first found my touch length with the Hammers I wondered about that with so little of the bullet in the neck. Once I setteled on the .018 jam I too checked by striping my bolt down and running a dummy round through and measuring after to see if I was really shooting at .018. But I am useing a .265 bushing in a no turn chamber so apparently that's plenty of tension to hold the bullet from moving in and out of neck. I don't know but I bet a .104 fb would work better for the Hammers. I was really suprised how well they shot with so little in the neck.

 

[Dave M.]

When I first found my touch length with the Hammers I wondered about that with so little of the bullet in the neck. Once I setteled on the .018 jam I too checked by striping my bolt down and running a dummy round through and measuring after to see if I was really shooting at .018. But I am useing a .265 bushing in a no turn chamber so apparently that's plenty of tension to hold the bullet from moving in and out of neck. I don't know but I bet a .104 fb would work better for the Hammers. I was really suprised how well they shot with so little in the neck.

Lol. I’m also using a .265 bushing with a no turn .271 neck and .104” FB, and unturned Lapua 6BR to dasher brass. I typically run pretty high neck tension. My finished rounds measure approx .2685”. Hopefully they well in my setup too. I have over 1900 rounds on this barrel and it is still shooting great. Just wanted to try the hammers before I switch in a few months to the .132” FB new barrel. With the new barrel I intend to use the 105g Barts gungnirs
Dave

 

[stevenpoplin]

do the gungnirs have more bearing surface than the Hammers

 

[Dave M.]

do the gungnirs have more bearing surface than the Hammers

Not sure. I don’t measure bearing surface. The bullet base to ogive is nearly identical on both at .6260”
Bart told me the hammers are better for the shorter .104” FB that I have now, the gungnirs are better for the .132”FB that is coming in my new barrel