105gr berger VLD

[Greg Duerr]

Does anyone have any experiance using the 105gr VLD? I was wondering if a .243 AI with a 1x9 would be able to stabalize that bullet or would you HAVE to go to a 1x8? What kind of velocity are you getting out of your 105's in a .243 AI

 

[Danny1788]

I have been using them in a 6mm-06 with a 1-8 twist with great results i have pushing them at around 3250 just a guess as i havent chronographed them yet. But my brother is shooting a 243AI with the 105's and a factory 1-9 twist barrel recut to AI and they stablilze just fine.

 

[dig]

I have tried them in a factory 1x10 twist with ok results. The 95 grainers shot 1/2 MOA so stuck with those. You may have a bit more luck with the 1 in 9. Let us know how it turns out.

 

[azsugarbear]

I use the 105 gr. VLD's in my .243. It has a 1-in-8 twist barrel that seems to stabilize them just fine. I'm pushing them right at 3,000 fps. With the higher velocity provided by the AI version, I would think your 1-in-9 twist barrel should stabilize them just fine.

 

[Skyking]

I just did some load development this week for my brothers new 243AI. It has a 1-7.5 twist. I tried 4831sc and h1000 in Lapua brass, CCI-BR2 primers Berger 105vlds 26 inch barrel. End up getting 3315fps with 48g H1000. Dropped down to 47.3 3275fps. Fire-formed with 40g 4831sc 105 Amax. Shoot out at 1020 yards yesterday. Had a five inch 6 shoot group. Here is his 4 shot group from 100 yards. H1000 47.5 and 47.3

 

[Wile E Coyote]

Someone gave me this equation a while back. It is called the Greenhill Formula. Out of curiosity, I have done the math on a few of my rifles with the bullets that shoot well and it does work as long as one allows for some wiggle room.

where:

• C = 150 (use 180 for muzzle velocities higher than 2,800 f/s)
• D = bullet's diameter in inches
• L = bullet's length in inches
• SG = bullet's specific gravity (10.9 for lead-core bullets, which cancels out the second half of the equation)

 

[BradArnett]

Does anyone have any experiance using the 105gr VLD? I was wondering if a .243 AI with a 1x9 would be able to stabalize that bullet or would you HAVE to go to a 1x8? What kind of velocity are you getting out of your 105's in a .243 AI

My 243AI wears a Rock Creek 1-9"tw at 24". It shoots the 105VLD very well. I'm running them at 3200 with 44gr of R-17 in Lapua brass. I also moly them.

@100yds

@200yds (there's 3 under there)

@705yds

 

[backwoods83]

Its always better to slightly over stabilize them, imo i'd use an 8 twist then you can use 105 and 108 bergers, 106 clinch rivers, 108 BIB bt's, 107 smk's, and 115 DTAC's, I think swampy makes a 108 as well, and matrix has one in that ballpark, most of these bullet makers reccomend an 8 or faster but with 3200fps+ a 9 would work but an 8 is for sure and a 8.5 is a good compromise.

 

[LouBoyd]

where:

• C = 150 (use 180 for muzzle velocities higher than 2,800 f/s)
• D = bullet's diameter in inches
• L = bullet's length in inches
• SG = bullet's specific gravity (10.9 for lead-core bullets, which cancels out the second half of the equation)

Greenhill's equation is useful as a quick check, but what is missing in the equation is the effect of air density. Higher temperature, higher altitude, and higher humidity all reduce air density. Bullets are least stable in a cold dry high pressure atmosphere.

Berger recommends an 8" twist for their 105 grain VLD hunting bullets. I live and shoot in Arizona at over a mile elevation. I have pre-64 243 Win 70 with a 10" twist which shoots them very well. Despite that I chose an 8" twist for my most recent LR-243 build to be sure it will work in cold and low elevation conditions too.

 

[Wile E Coyote]

I bring the Greenhill equation here as a conversation point and just that, a quick check or a place to start. Certainly not an absolute. Backwoods83 also makes a good point about turning faster. For the next step, lets combine the two thoughts. For example, lets say a particular caliber/bullet combo works out to a 1 in 10, then I would be thinking 1 in 9.5 or 1 in 9.

I'm sure there would eventually be a penalty to pay for turning too fast such as centrifugal force tearing the bullet apart. One of my friends who shoots benchrest comps swore a gun he had, did this.

 

[backwoods83]

Yes, you can over twist berger vlds with a J4 jacket for instance take a 130 6.5mm berger and run it at 3250fps from a 7 twist 264winmag and the jacket will come out in pieces and the lead core will go tumbling.

 

[Edd]

What's the maximum velocity you can have with a 105 gr 6mm bullet and a 7.5 twist?

 

[backwoods83]

I'm not real sure never had a 7.5 twist but id guess anything over 3400fps would distort it pretty bad, some of my benchrest buddies shoot 8 twist 6x47lp with 105s at 2870 or so and they stabilze just fine at that speed at 1700ft elevation in decent conditions so 7.5 is a bit fast, you can probably shoot 115bergers if you can get them to 2940 or so.

 

[Loner]

Your max. vel. is going to be different with the depth and cut of the groves in the barrel.
A six land barrel is going to be much easier on a jacket than a 4 land ect... , in most cases.