I've been able to get my hands on 4 out of the 7 LR Accubonds; everything up thru 7mm 168 grain. The following summarizes my BC testing of these bullets.
One of the big questions is: are the BC's actually as high as they're claimed/advertised to be?
See the chart below for a summary of my live fire test results.
As you can see, the actual BC's can be quite close; within 1-8% of advertised if they're properly stabilized. If they're not properly stabilized (which you might not know according to groups), the BC can be 10-12% lower than advertised.
The LR AB's are well designed (low drag) bullets. One reality of long/low drag bullets is they typically require faster than conventional twist rates to stabilize. However Nosler doesn't provide recommended 'specialty' twist rates for these bullets (at least not that I could find) so users are left to assume that standard twist rates will work.
For example, the .270 caliber 150 grain LRAB fired from a 1:10" twist 270 Winchester only produced an SG (stability factor) of 1.19 under the conditions of the test. This low stability resulted in a G7 BC of 0.278, which is 12% below the advertised value of .317. Note that groups were good at this stability level. However, in order to achieve the highest BC, you need to generate a stability factor of at least 1.5*. Retesting the bullet in a 1:7" twist 270 Winchester produced an SG of 2.31, and a BC that's 4% higher (0.291).
It's the same story with the 7mm 168 grain. Fired from a 'standard' 1:9" twist 7mm Remington Magnum, the stability factor was 1.33, and the BC was 10% less than advertised. Same bullet fired from a 1:7" twist .284 Winchester produced an SG of 2.19, and a BC that's 4% higher, and within 6% of the advertised BC.
* New book plug
: A lot has been learned in recent testing focused on spin rate, stability and BC which is being published in my newest book: Modern Advancements in Long Range Shooting.
In summary, the Nosler LR Accubonds are a dramatic improvement over the standard Accobonds in terms of BC's which is a great thing for long range hunters. However you do need to be aware of the stability requirements for these long bullets and aim for a stability factor of 1.5 or higher.
You can calculate your bullets stability factor using this online calculator
None of my testing focused on precision/group testing other than the observation that groups were the same at the marginal and high stability levels.
If anyone has some 7mm 175 grain, or .308 190/210 grain samples of the LR Accubonds that they could spare for testing, I'll be happy to share results. I'd need about 15 bullets to test.
Take care,
-Bryan
One of the big questions is: are the BC's actually as high as they're claimed/advertised to be?
See the chart below for a summary of my live fire test results.
As you can see, the actual BC's can be quite close; within 1-8% of advertised if they're properly stabilized. If they're not properly stabilized (which you might not know according to groups), the BC can be 10-12% lower than advertised.
The LR AB's are well designed (low drag) bullets. One reality of long/low drag bullets is they typically require faster than conventional twist rates to stabilize. However Nosler doesn't provide recommended 'specialty' twist rates for these bullets (at least not that I could find) so users are left to assume that standard twist rates will work.
For example, the .270 caliber 150 grain LRAB fired from a 1:10" twist 270 Winchester only produced an SG (stability factor) of 1.19 under the conditions of the test. This low stability resulted in a G7 BC of 0.278, which is 12% below the advertised value of .317. Note that groups were good at this stability level. However, in order to achieve the highest BC, you need to generate a stability factor of at least 1.5*. Retesting the bullet in a 1:7" twist 270 Winchester produced an SG of 2.31, and a BC that's 4% higher (0.291).
It's the same story with the 7mm 168 grain. Fired from a 'standard' 1:9" twist 7mm Remington Magnum, the stability factor was 1.33, and the BC was 10% less than advertised. Same bullet fired from a 1:7" twist .284 Winchester produced an SG of 2.19, and a BC that's 4% higher, and within 6% of the advertised BC.
* New book plug
: A lot has been learned in recent testing focused on spin rate, stability and BC which is being published in my newest book: Modern Advancements in Long Range Shooting.In summary, the Nosler LR Accubonds are a dramatic improvement over the standard Accobonds in terms of BC's which is a great thing for long range hunters. However you do need to be aware of the stability requirements for these long bullets and aim for a stability factor of 1.5 or higher.
You can calculate your bullets stability factor using this online calculator
None of my testing focused on precision/group testing other than the observation that groups were the same at the marginal and high stability levels.
If anyone has some 7mm 175 grain, or .308 190/210 grain samples of the LR Accubonds that they could spare for testing, I'll be happy to share results. I'd need about 15 bullets to test.
Take care,
-Bryan
