6mm base-to-ogive measurements?

[tovaert]

Curious if anyone has measurements (or has done a comparison) of base-to-ogive lengths for 6 mm target bullets, greater than 95 gr? Not interested in lighter-weight projectiles. Thanks!

 

[Mike TackleBerry]

Peterson brass, Berger 105 VLD-TGT 1.800 CBTO

 

[bozo699]

Curious if anyone has measurements (or has done a comparison) of base-to-ogive lengths for 6 mm target bullets, greater than 95 gr? Not interested in lighter-weight projectiles. Thanks!

It’s just an arbitrary number, so what I measure with my equipment would more than likely be different than your numbers from your equipment. Every bullet is going to be different even different lots of the same make can be different.
Wayne

 

[Zero333]

It’s just an arbitrary number, so what I measure with my equipment would more than likely be different than your numbers from your equipment. Every bullet is going to be different even different lots of the same make can be different.
Wayne

I totally agree... I have 2 different Hornady 30cal bullet comparators that read differently, as well as 2 different 6mm and 22 cal comprators... They just don't seem to agree

That's why the ones I use all the time I marked with red marker.

 

[Ranger188]

Not sure what your asking.
Are you wanting to know what bullets have a more consistent BTO?
Or just BTO's for 95 grain + bullets from different companies for comparison?
And for what reason?

 

[dgeesaman]

Curious if anyone has measurements (or has done a comparison) of base-to-ogive lengths for 6 mm target bullets, greater than 95 gr? Not interested in lighter-weight projectiles. Thanks!

If you provide me the comparator I’ll measure all of the 6mm bullets I have on hand.

Like the others said everyone’s comparator has a different diameter and edge break.

 

[tovaert]

Not sure what your asking.
Are you wanting to know what bullets have a more consistent BTO?
Or just BTO's for 95 grain + bullets from different companies for comparison?
And for what reason?

Sorry for the confusion...my fault. I'm looking to seat 6 mm bullets > 95 gr weight about .010" to 0.015" back of the rifling (it's a 6x45 AR target rifle), minimizing the distance that the bullet extends into the case. I agree the actual number is not consistent, but I was curious if anyone could rank some bullets, say, relative to the 95 gr Berger and 107 SMK as references (which I have on hand).

 

[dgeesaman]

All accuracy issues aside, I'm still not sure if comparator numbers will help, since the comparator are bored much smaller than rifling and pick up way forward of where rifle lands touch the bullet. Hybrid and secant ogive shapes could throw off this by a large margin.

Are you looking to maximize case volume with the bullet at .010" off the lands? Maybe the easier thing to do is fit sample bullets into the muzzle end of a barrel and see which bullets protrude the least.

 

[Dave M.]

CBTO numbers from someone else will do you no good. This is why they are called comparators and not an absolute measurement. For what it’s worth I’m running Berger 105gr hybrids at a CBTO = 1.807” using a SAC comparator.
Dave

 

[tovaert]

Are you looking to maximize case volume with the bullet at .010" off the lands? Maybe the easier thing to do is fit sample bullets into the muzzle end of a barrel and see which bullets protrude the least.

Yes, and thanks for the suggestion. I'm hoping someone else may have done similar and had that info. across a range of bullets.

 

[JFrank]

I have several 6 mm here. I’ll measure a few and post you some numbers for thought.

 

[dgeesaman]

I can do the same using a bit of barrel stub and my 6mm bullets.

 

[JFrank]

This information value is directly related to the amount you paid, basically nothing…lol
Anyway, using my calipers and a Hornday comparator with a .24 insert I measured the following bullets, excluding lot numbers.

Vapor Trail hand pulled 103 gr VLD -BTO .632
VTac automated 103gr VLD -BTO .6175
Berger 108 gr Tangent ogive BTO .671
Sierra 107 gr Tangent ogive BTO .688
(Don’t have any 95gr handy)

Hope that helps you.
Jim

 

[dgeesaman]

I took my 6BRA barrel, which has a recessed flat crown, and measured from the recess surface to the base of various bullets.
Bart's Infinity 105: .614"
Ammerman 103: .650
Vapor Trail (hand pulled) lot v2074: .607
Vapor Trail VT-TAC lot 3817: .614
Roy Hunter 106: .632
Roy Hunter 103 (made by Wheeler) .633
Berger VLD Target 105 .638
Berger BT Target 90 .530

 

[JFrank]

I took my 6BRA barrel, which has a recessed flat crown, and measured from the recess surface to the base of various bullets.
Bart's Infinity 105: .614"
Ammerman 103: .650
Vapor Trail (hand pulled) lot v2074: .607
Vapor Trail VT-TAC lot 3817: .614
Roy Hunter 106: .632
Roy Hunter 103 (made by Wheeler) .633
Berger VLD Target 105 .638
Berger BT Target 90 .530

Would that be the bore or the bottom of lands ?

 

[dgeesaman]

Would that be the bore or the bottom of lands ?

It's the muzzle end, a flat square crown. It isn't tapered like the lands but it is consistent and touches the bullet at basically the same diameter as the lands (which a Hornady comparator does not)

 

[JFrank]

It's the muzzle end, a flat square crown. It isn't tapered like the lands but it is consistent and touches the bullet at basically the same diameter as the lands (which a Hornady comparator does not)

If I’m understanding you, the measurement is taken off the bottom of the lands ( .243) rather than the bore, which in mine is .237

 

[dgeesaman]

If I’m understanding you, the measurement is taken off the bottom of the lands ( .243) rather than the bore, which in mine is .237

It should be the bore. This is a Bartlein and I think all of their are .237 bore.

 

[tovaert]

I took my 6BRA barrel, which has a recessed flat crown, and measured from the recess surface to the base of various bullets.
Bart's Infinity 105: .614"
Ammerman 103: .650
Vapor Trail (hand pulled) lot v2074: .607
Vapor Trail VT-TAC lot 3817: .614
Roy Hunter 106: .632
Roy Hunter 103 (made by Wheeler) .633
Berger VLD Target 105 .638
Berger BT Target 90 .530

I have Berger 90 gr Target bullets as well...so I can make a similar measurement for comparison. I also have 105 Lapua, 95 Berger, and 107 SMK.