Copper mono bullets in 11 twist 30cal

kman300

kman300

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Was wondering what your experiences are using mono metal bullets in an 11 twist 300 win mag or similar.

Using the Berger stability calculator, it would seem the 165 TTSX may work at prairie altitudes for good stability and the 150ttsx for sure.

Other considerations are that when not fully stabilized the BC takes a hit and the 175lrx which I wanted to use has its BC reduced to .45 which makes it silly to use at 3100 when the 150 can run at 3400fps.

165 gmx would be the same as the TTSX version I assume. The nosler etips have grossly exaggerated bcs in weights that would work and don't shoot as fast either due to no pressure bands seems to be the consensus .

Other consideration is just run 180 partitions/accubombs over a 150ttsx.

Has anyone shot mono metals in an 11 twist at 300 mag speeds and verified at distance that they are stable and how much the BC drop is due to reduced stability factors?

I'm using 700ft elevation and 10F for hunting conditions.

Don't understand why my Sauer 202 has an 11 twist to mess things up. I'm assuming it's because Europeans don't shoot game very far and don't care about BC.
 
I think it should work with 165s just fine.

If it prints a nice round hole at 100, it is stable. It will gain stability as it goes down range.

Higher velocity will increase RPM and stability. Choose a good powder like RL 17 or 22.
 
One of my 308 Norma Magnums has a 1/12 twist.

Loaded to 3200 fps, this twist stabilizes the 165 or 168 TTSX just fine, so I cannot see why a 1/11 twist will not work great.

Regards, Dave.
 
Don't all the tikka 30's run an 11 twist? Personally I'm planning to just run 180 accubonds in my 300wm. Should run about 2900-3000fps. I am considering the berger 130's in a 308 though to try and get the velocity up to about 3000.
If the 180's stabilize in your rifle I assume the 165 berger should as well.
 
I suppose I'm not so much worried about them making oval holes as I am concerned about the loss in BC due to only being marginally stable negating the higher BC of the heavier bullets and then I might as well just run a lower BC lighter bullet faster.

Dave, I don't know what altitude you live or hunt at but with my numbers the 168ttsx from a 12 twist has a BC of .415 rather than the advertised .47 when fully stabilized. Now unless you need the extra bullet weight for penetration, I can't understand why I would use the 168 with the lower BC over the 150 with a better BC and 200fps faster.

I guess that's what my conundrum is.

The 175 lrx is excellent in my 10 twist bee and I'm kinda bummed it doesn't make sense for my 300 wm.
 
Without sounding critical, I think you may be overthinking this stabilization matter.
FWIW, I live at 2200 feet altitude, and usually hunt within 1000 feet of that [up or down]

I have shot those 168 TTSX bullets out to 500 yards and they fly like .470 bullets, not like a .415 BC.
[drop figures are consistent with the higher BC]

A lot of those twist calculations err on the safe side, thus bullets will often work just fine in a twist
that apparently should not stabilize them.

I had a Douglas 6.5mm barrel with a 10 twist. By all the technical figures, this should only have stabilized bullets of 125
grains and lighter in my 6.5/06. I shot the 140 VLD right out to 1000 yards with that barrel, and they showed no signs of instability.

Regards, Dave.
 
Thank you all for the input. Seems like a fun summer project. I will load the TTSX and lrx to max speed in the 11 twist 300 wm and match that speed in my 10 twist weatherby and shoot them both at distance to see what happens to the BC.
 
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