105gr Hybrid in an 8 twist.

[tbrice23]

A few years ago I bought some Berger 105 gr hybrid target bullets to shoot in a couple of 8 twist barrels. At the time the boxes say good for 1:8 twist.

Currently their website says the same bullet is recommended for 1:7 !

I've shot a few from one barrel at 3350 fps with no issues at 200 yards, no key holeing or anything. My other barrel is a 6BR and would only be good for 2920 fps or so( haven't tried them in that barrel yet).
JBM gives me stability at the muzzle of 1.34 !

Has anyone had problems or lack of BC from these bullets from an 8 twist barrel?

 

[can1010]

I have the bullet dimensions from when it was 1-8 twist. the 1-7 twist dimensions are very different your old bullets will be ok. new ones might be a little unstable. here is the old dimensions.
OAL 1.292
BOATTAIL 0.180
NOSE 0.731
BEARING SURFACE 0.381
you can find the new numbers on bergers site

 

[WAMBO]

I guess it would depend on your altitude, I shoot them in my 6BR with a 1-8" twist at 2200 ft with no problems, all my boxes say 1 in 8" twist or faster.
Depending on the lot they measure between 1.240" to 1.250" in length.

 

[tbrice23]

I have the bullet dimensions from when it was 1-8 twist. the 1-7 twist dimensions are very different your old bullets will be ok. new ones might be a little unstable. here is the old dimensions.
OAL 1.292
BOATTAIL 0.180
NOSE 0.731
BEARING SURFACE 0.381
you can find the new numbers on bergers site

I did notice thay my OAL is shorter than the current listing on Bergers website . I've been given mixed info from their personnel over the last few years as to whether the actual dimension have changed.
Fortunately I still have 600 of the same lot#.

Maybe I'll finish off this barrel with them.
Hybrids at high velocity kill well for me .

 

[AZShooter]

TBrice,

You said a few years ago you bought those bullets. I bought some at least two years ago and was concerned based on your information. Just went to look and found that the box contains the current bullet! Box says 1 in 7 twist. So it much have been more than just a few years ago when you got those bullets.

Your comments had me digging into Berger's information to see if I could find when they changed them etc. Guess I don't have to worry now as my friend and I have been using the newer version since the inception of our two 6 BR rifles.

Both rifles have a velocity of 2825 fps with 1 in 8 twist barrels. We shoot them at elevations from 2550 to 4500 ft. The SG is 1.52 for the worst conditions we encounter 2550 elevation and 50 degrees. Most of our shooting is hotter and higher elevations.
What inputs did you use to get a SG of 1.3?

Both rifles are shooting one ragged hole at 100 yds and do well when we go out to shoot small squirrel like rodents found in boulder fields near Tucson, which we call rock rats.

 

[tbrice23]

420' asl
38° f.
But the jbm library has the current bullet specs. My bullets oal is shorter.

 

[tbrice23]

Correction,
AZSHOOTER, can you measures a couple of your newer lot?
Mine average 1.255".
Berger Quick Reference Data Sheet list them ay 1.256".
So in theory my old box should have been labeled 1:7 all along.

 

[tbrice23]

I just manually entered the parameters with my bullet length, got 1.431. So still marginal but better.

 

[AZShooter]

mine are 1.250"

 

[reeldawg]

The bullet did not change. The box did. Berger changed the twist recommendation not the bullet.

Jay

 

[tbrice23]

Gotch, so back to my origional question. Has anyone seen any real loss of BC at distance out of an 8 twist?