New Projectiles

[RockZ]

Thought these projectiles would be of interest. I asked if he was making some for slower twist barrels. Like a 338 for a 9.3 twist. Hopefully. The hunting bullets look very interesting.
Projectiles & New Systems - Sniper's Hide Forums

 

[JeffVN]

I know some guys that are shooting some of Noel's .375 banded solid bullets. They require a very fast twist for the caliber.

I have a gain twist barrel (14" twist gain to a 7" twist - finish at 32") on order from Bartlein for my 338LM Improved (should be delivered in early 2009) and will post results when I get the barrel delivered and test some of the bullets.

Jeffvn

 

[RockZ]

Jeff,
Great, look forward to the results. I have a 338Lapua Improved also but with a 9.3 twist. It shoots the 300smk's great and I am also going to try the HAT's. It's new so I am not wanting to rebarrel,yet. I have a Stiller Tac 300 to build on and was looking at various bullets to help decide on the next caliber. Looks like their are alot of good 30cal bullets coming out as well.

Are you going to build a 7mm Holy Grail to shoot those 7mm bullets?

 

[Tyler Kemp]

Rock I'm looking to build a 338 Lapua Ackley, any way I could buy a dummy round off you?

 

[RockZ]

Tyler,
I noticed before you mentioned you needed a dummy round, I thought someone was going to send you one.
I would have sent one out had I known you didn't get it.
No Problem send me your address, I'll send it out to you next week when I get home.
I can put a 300SMK in it.
What length would you like it?
Don't worry about it, on me. Merry Christmas!

 

[JeffVN]

Rock

Yes I'm building a swap barrel rig on my Stiller PreditorX; 338LM Improved for the first, and the second barrel is, in fact, a 7mmHoly Grail. I look forward to throwing some of my Cauterucio 189s at 3,300 fs.

JeffVN

 

[260shooter]

Jeff

What is a 7MM Holy Grail?

 

[JeffVN]

338 Norma Magnum necked down to 7mm.

Jeffvn

 

[260shooter]

Jeff

Do keep us updated on the 7MM Holy Grail. Very interested. What BC on the 189's?

260

 

[JeffVN]

according to Bob, .725 at 2,700 fps and over .800 at 3,100 plus.

I will have some real life comparrison data with the Berger 180 when I get my new 7WSM load tested, as I have Berger 180 data on it now, and will develop a load for the Caut. 189s as soon as I get a chance.

Jeffvn

 

[strictlyRUM]

What is the length on the 189? I am running some #s and want to know what speed/twist to stabilize them. Thanks

Jason

 

[JeffVN]

Jason

Here you go:

Berger 180 - my current lot anyway: Base to Ogive - 0.816" base to tip - 1.533"

Cauterucio 189 - Base to Ogive - 0.845" base to tip - 1.560"

JeffVN

 

[BryanLitz]

I'm gonna go out on a limb and make a prediction, just in the interest of academic curiosity.

I predict that the BC of the Cat 189's will be about 4% higher than the Berger 180 VLD's. In other words, the average BC from 3000 fps to 1500 fps for the 180 VLD is 0.659. I estimate the average BC of the 189 for the same speed range to be 0.685.

Of course I stand to be corrected; either way I'm interested to hear about your comparison.

-Bryan

 

[strictlyRUM]

Thank you much Jeff. Well the miller formula says I am good to go.

Don Miller's Twist Rule
Caliber 0.284 Inches
Bullet Weight 189 Grains
Bullet Length 1.56 Inches
Barrel Twist 8 Inches/turn
muzzle velocity 2950 fps
Temperature 80 degrees Fahrenheit (59 is standard)
Pressure 29.92 inches of mercury (29.92 is standard)
Sg =1.93
Sg shouldn't be less than 1.4. If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.






As far as BC I am guessing closer to .800 if not over. Bergers do not have rebated boattails and or closed tips like the Cauterucios. The last 176s I had I was getting a BC of .740 out of my 7RUM at 3300. Cant wait to get this project under way!

Jason