Crazy Berger Bullet 30 cal. Bearing Surfaces

[NW Hunter]

I shoot a 300 WM with 185 gr. Berger Hunting VLDs going down a 24' Bartlein 5R tube starting .003 off the lands. With 82.8 grains of H1000, I'm only getting 2930 feet per second with an ES of 10 fps for 10 shots. The ES I'm happy about, the velocity. not so much.
I was emailed a surface bearing chart from Berger. I checked the difference in bearing surfaces between the 185 gr. & the 190 gr. 30 cal hunt VLD and was shocked to see the 185 gr. bearing surface is .021 longer than the 190 gr. The 185 bearing surface is 0.471 long with a base to ogive of 0.671. The 190 gr. has a bearing surface of 0.450 and a base to ogive of 0.640. I called Berger and talked to a tech from Sinclair International (I found out they represent Berger ). He said that there was no particular reason to shape the 190 differently than the 185 other than to make that weight work in a VLD bullet.

After ALL THAT, my thought is this... Would the 190 grain be faster than the 185 grain with a shorter bearing surface? My barrel is throated to have the 185 on the lands with the base of the bullet at the bottom of the neck. My one concern is that if I move a 190 grain up to touch the lands, I won't have enough bullet in the case for proper tension on the bullet.

What do you guys think?

Maybe Eric Stecker would like to comment on the subject...

Randy

 

[Gene]

I would shoot them over a chronograph, then decide which you want. Bearilng surface is just one consideration in the velocity equation. In general, the more streamlined a bullet is designed, the less bearing surface it has.


2,950 fps for that caliber and bullet does not seem too shabby to me.

 

[Senderofan]

Please keep us posted with your progress and findings. It's been 15+ years since I've had a 300 WM....but I do recall shooting some Federal premium rounds with a 180 gr. bullet and getting right at 3000 fps...this through a 26" tube.

Having said that...I'm having great success with the 185 gr. Berger in my .308. I haven't finalized my load...but we found an extremely accurate load giving me 2750 fps with an ES of 10-12. I'm using a 30" tube with 1:10" twist. My concern isn't velocity focused..but more on the accuracy. For my rifle...these bullets are amazing.

Forgot to ask you.... " How are your groups? "

Wayne

 

[ICANHITHIMMAN]

I think you speed is right on. Im shooting the 185g VLD at 3030 with 81g of H1000 but my barrel is 3 1/2" longer than yours. I would say you have a very hot load! You could try switching to RUTUMBO or switching to the 190.

 

[NW Hunter]

Gene, good solid advise. I did not know that bearing surface got shorter with more streamlining. Yep, the chronograph will tell all.

Senderofan, I shot a 3/8 inch group at 100 yds. at about 50 rounds through the barrel. At 400 yds., I shot a 3/4" group for 3 shots at 60 rounds.

Icanhithinman, Jon Beagle of J. Beagle Rifles said I should be able to load 2 grains over max with no pressure signs. At 82.8 of H1000, no pressure signs at all. I was afraid to go any higher though. I bought some Ramshot Magnum to try. Heard it's temperature stable and a margin faster than H1000 in the 300WM. Have you had good luck with Rutumbo in the 300WM?

Thanks to you all, Randy

 

[Derek M.]

use 190s

 

[BIG MO]

No pressure signs- keep going up the powder charge. Let your rifle, brass and primer tell you when its at max. Each rifle/barrel/chamber is its own entity, you don't have far to go to hit 3000fps+. COAL and other load variables will also effect pressure, and how much powder it takes to generate max velocity/pressure. Even the finish of you bore will effect how much powder it takes to reach max velocity/pressure.

Sure, be cautious and take it slow, but your not going to hurt the rifle or blow it up by creeping over book max while using a chronograph and monitoring bolt lift, brass, and primers for signs of overpressure.