6mm 115 VLD in a 1-8 twist

[Frankr]

i'm quite sure this has been covered but I must have missed it.
what do you think about shooting a Berger 6mm 115 VLD out of a 1-8 twist?
Berger say's it's marginal stability SG=1.20 loosing 9% of it's BC. what does it m-e-a-n....? ???

 

[ShootDots]

I tried them in my Dasher... I ended up with 3" groups at 300 yards... Horrible at best!

 

[Frankr]

thanks shootdots.

so we have one not going to work so far.

yea Berger say's ya need a 1-7 twist minimum.? I don't know

 

[ShootDots]

I believe a 7.5 twist will work>>>>but marginally. An 8 twist>>>forget it..

 

[Frankr]

Berger's twist calculator say's 7.5 twist marginal stability SG=1.33 loosing 5% of it's BC. ?

 

[ShootDots]

That is correct... A "straight" 1-7 will make that bullet hum out to 1000 yards in a Dasher or some larger 6mm..

 

[Frankr]

well from what I have read it looks like a SG greater than 1.0 is what is needed for bullet stability but to allow a margin of error it is recommended to have a SG of 1.4 ah hun? I guess shoot a few and see if they work. I will.
But i'm sure more than a few people on here have tried it.

not that I doubt what you are saying shootdots. Im sure they did not work for you. They may not work. i'm just trying to learn about this as I have never ventured in this area of shooting before. I allways shoot light bullets so I don't have these kind of problems ..lol....

I really am just a super fun guy..i try to be humorous.

 

[ShootDots]

Remember, the further you go out, especially 500+ yards, the more the stability disintegrates, on an already "stability compromised" bullet.. Out to 800+ yards, you need absolute stability or your score will suffer significantly!

 

[Frankr]

ah ha playing with the twist calculator once you drop below 1900FPS you drop below the 1.0 SG and are unstable.
so if you started at 2950MV that would be around 700 to 750 yards(guess) you would be unstable. but loosing stability all the way out...I think I get it...I do have a 1-7 twist on order due next june or so. so if you started at 1.4 or 1.5 SG then you would not have to worry till you dropped to about 800FPS.My chart looks like 800FPS would be beyond 2,000 yrds.

 

[TAJ45]

Hmmm, I just committed to a 7.5 in 6mm..........I sure do HOPE it works - in that Krieger. I'll be groaning if it doesn't but will be using more capacity than a Dasher gives.

 

[R.Morehouse]

A lot of 8 twist barrels shooting D-Tacs just fine. Personally my 243AI w/29 Kreiger at 2960ish is a 1/4 min gun....

 

[6fatrat]

.243 win. with 115's in a 7.5 twist @ 3080 fps works great in my any rifle.

 

[Rtheurer]

Shot the Berger and JLK in a Cut rifled 1:8 Satern barrel. It worked as I was pushing above 3000 fps at the muzzle. If I did it again I would go to the 1:7.5twist knowing what I know now.
Went to the 105Hybrid instead and don't expect to shoot the 115's anymore.

Best to be a little on the safe side im thinking.

RussT

 

[Bob3700]

Have shot both the DTACS and Berger 115 VLD in a Bartline 1-7.5 out to 1K yds with no problem. That was out of a 243 SLR with a muzzle velocity of 3050 fps.

Bob

 

[racesnake]

My 6XC with a 1-8 shoots dtac's just fine. I have some 115 vld's loaded and will find out if they work, Friday.

 

[ShootDots]

DTACS and Berger VLD's are 2 ENTIRELY different animals. You can, for the most part, shoot DTACS out of a 1-8, however, not so the case with those L-O-N-G Berger VLD's.

 

[Frankr]

it looks like muzzle velocity in not as relevant as altitude and temperature is. If you were at say 5000 ft altitude at 75 deg F you could stabilize the 115 VLD out of a 1-8 twist. but not if you are at 800 ft altitude 30 deg F. so even if you jack up the MV to 3,400 FPS at 800 ft 30 deg F it's no more stabile than 2950 FPS(slightly more not much).
but air density alt/temp seems to be the biggest factor.

I wanted to shoot the 115 Hunting VLD for slightly better BC and the high SD. over the 105 Hunting VLD.(I have 500 of em on my shelf)
I have never seen a 115 DTAC but they say the BC is somewhere in the .580's? I don't know how it could have such a high BC with out being a long skinny bullet like the 115VLD

Oh and i'm going to in a 1-7 twist barrel . going to chamber it in a 6mm competition match. If I can find die's. if not .243 30deg AI.

I'm a little scared to try a 7.5 twist knowing what I know. at the same time it seems no one shoots a 1-7 twist so a little scared to buy too many 1-7 twist till I try one and see how it does.

 

[rcol317]

I shoot a 7.5 twist in my 6 XC and a 7 twist in my 6 AI. Both seem to shoot the 115 VLD's and the 115 DTAC's about the same. My 7.5 6 XC shoots the VLD's about 1 1/2 inch group @ 600 yards 2950 fps. and feed just fine. I was advised against the 8 twist when I built my 6 AI if I wanted to shoot 115's. Good shooting

 

[Frankr]

rc01317 what is the altitude where you shoot at.

I have a 1-7 twist on order. I have not decided what I will chamber it in. will be the 6SLR.6 CM OR 243 IMP 30 one of them three. I having a hard time deciding .

 

[spclark]

what do you think about shooting a Berger 6mm 115 VLD out of a 1-8 twist?
Berger say's it's marginal stability SG=1.20 loosing 9% of it's BC. what does it m-e-a-n....? ???

Means it's unlikely they'll work well, if at all.

I tried 'em ~ 10 years back in a Schneider 26" 1:8 on a T2k, several never made it to the 300 yard line let alone the targets at 600 yards. It was July but not hot for the season, loads weren't extreme either. (Embarrassed I was what with Sherri Gallagher scoring for me that day.)

DTAC 115's worked OK in that barrel, better still in the 1:7.5 PacNor that came after.