ballistic coefficient questions . 6.5 mm bullets

[Outlaw6.0]

That is some crazy fast twist... I guess I can see that if you are at sea level but wow! 7" twist in a 6.5 magnum.... you sure could make a purty shotgun pattern out of the Bergers with that couldn't you?

The 130's stabilize just fine out of my 8.4" twist.... which is substantially slower than recommended...


I'm not put off yet I'll let everyone know what I find out.


t

 

[Edd]

The Berger twist rate calculator shows that CE 130 gr bullet with an 8.4 twist starts dropping below the desired minimum 1.5 stability factor at an altitude of 3000 ft.

An 8 twist maintains 1.5 or above down to 300 ft and a 7.5 twist is 1.68 at sea level.

 

[MontanaRifleman]

The Berger twist rate calculator shows that CE 130 gr bullet with an 8.4 twist starts dropping below the desired minimum 1.5 stability factor at an altitude of 3000 ft.

An 8 twist maintains 1.5 or above down to 300 ft and a 7.5 twist is 1.68 at sea level.

What velocity range is that SF for?

I talked with CE this morning and they do have a 141 gr 6.5 bullet. I need to contact Dan for more info on OAL, BC and twist

 

[Edd]

What velocity range is that SF for?

3000fps and 59° F temps

 

[Outlaw6.0]

3000fps and 59° F temps

That would make the difference I suppose. I'm at 4300ft ASL & a "wee" bit faster in velocity dept.


t

 

[MontanaRifleman]

Outlaw is shooting them @ 3400 fps

 

[Outlaw6.0]

What velocity range is that SF for?

I talked with CE this morning and they do have a 141 gr 6.5 bullet. I need to contact Dan for more info on OAL, BC and twist

I emailed their tech line but haven't gotten a response yet. Was the 141 a hunting type bullet or?

t

 

[MontanaRifleman]

The guy at the shop said it was a "Max". Didn't know any other details so i emailed Dan

Guess we hijacked this thread eh.... sorry

 

[Cold Trigger Finger]

Great. ! Lots of great info. I looked at the C E B . Site. Your right about the price but they look like the 130 gr 6.5 bullet would be ideal it seems. My 6.5 Cm should stabilize them. The lowest elevation I would shoot them at would be around 500' and more usually in the 1000-2000 '

For volume target shooting hopefully I can find a conventional bullet that shoots to the same poi.

 

[Outlaw6.0]

The guy at the shop said it was a "Max". Didn't know any other details so i emailed Dan

Guess we hijacked this thread eh.... sorry

Not really, we're still discussing the merits of 6.5mm bullets & their Ballistic Coefficient right?


Ok, so maybe just a little...but at least were aren't completely in left field.


t

 

[Cold Trigger Finger]

Hey. Its all good info to me. I joined this site to learn about long range shooting. . And I put the info into the box.
There are only 2 kinds of hunting and shooting that really hold my attention.
Jump shooting brown bear at real close range, which I'm real good at. And killing wolves.
Tho I mostly enjoy all kinds of hunting. Those 2 I'm pretty passonet about. In the Interior. Wolves are the goal and coyotes and target shooting are the training.

I don't see the sense wasting money and time learning things wrong. So I appreciate you guys letting my pick your brains.

I want to keep my velocity between 2700+3000 fps so I need to match me bullet to work within that range. And a good pelt is more important to me than a bang flop.

 

[MontanaRifleman]

Great. ! Lots of great info. I looked at the C E B . Site. Your right about the price but they look like the 130 gr 6.5 bullet would be ideal it seems. My 6.5 Cm should stabilize them. The lowest elevation I would shoot them at would be around 500' and more usually in the 1000-2000 '

For volume target shooting hopefully I can find a conventional bullet that shoots to the same poi.

You might wan to run this twist calcultor. the CE 130 is 1.417" long

http://www.bergerbullets.com/litz/TwistRuleAlt.php

 

[bigngreen]

I thot the SST was basically a slicked up Interlock.
I wish Barnes would make a 140 gr TTSX. And that ATF would let them make their Banded Solids again.

Ive never shot a Berger bullet. Just never liked their description of the bullet shedding weight. . .
It would be nice if Hornady made a 140 gr Interbond

I'll research the Bergers . Thanks again. !

The SST is basically a smoothed out interlock but all that hold it together is a crimp ring which I've never seen one hold together enough to see if it works to stop the rapid expansion. The 140 Berger performs flat out!!
I really love bonded bullets and used to shoot hordes of copper bullets, took me two years of shooting Bergers before I trusted them enough to not load Barnes or Accubombs under them in the mag. Every cal I load for if available I have Accubond, TSX, TTSX, LRX, CEB, Berger, Matrix and a few Hornady. I pick the most accurate and start shooting deer, the best one gets loaded from then on out for elk. On game performance is what matters not the name on the box or hype!!!

 

[MontanaRifleman]

The SST is basically a smoothed out interlock but all that hold it together is a crimp ring which I've never seen one hold together enough to see if it works to stop the rapid expansion. The 140 Berger performs flat out!!
I really love bonded bullets and used to shoot hordes of copper bullets, took me two years of shooting Bergers before I trusted them enough to not load Barnes or Accubombs under them in the mag. Every cal I load for if available I have Accubond, TSX, TTSX, LRX, CEB, Berger, Matrix and a few Hornady. I pick the most accurate and start shooting deer, the best one gets loaded from then on out for elk. On game performance is what matters not the name on the box or hype!!!

I think CTF is fur hunting and not wanting massive hide damage.