I assumed this also regarding the 214 and I also agree the factory gun is the way to go with this testing. With that said, IMO, I feel if a lighter weight pill with less BC can match or exceed the heavier higher BC pill then that really says something. And as others have stated, terminal performance trumps all for hunting.
Gel Test Data part 2
- Thread starter RockyMtnMT
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RockyMtnMT
Official LRH Sponsor
Without looking it up, I would guess the 199g Hammer Hunter out sells the 214g Hammer Hunter 5-1. Between required twist and coal the 214g Hammer Hunter is much less used.
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^^^^^^^^
The whole point is perfectly summed up here. A lighter bullet with lower BC with higher velocity can stay with heavier slower higher BC bullets with better terminal performance.
Past my bedtime, good night y'all.
I really like this test format you used. It is the same example that Litz gave in his WEZ analysis chapter from "Applied Ballistics for Long Range Shooting." High BC, Heavier, slower MV vs Lower BC, Lighter, and faster MV both shot from the same rifle.
Here is a link to part of the chapter that includes the information for anyone interested.
In the test you performed I think you showed that given high confidence in wind estimation, range estimation, rifle precision and velocity consistency, the faster projectile does not have a disadvantage out to the distances tested. This is not an unexpected result. The High BC argument comes into play when the confidence in wind call is reduced. Knowing the limitations of the system that we are deploying is really what it all comes down to. There are two questions that I ask myself. At what range and environmental conditions does my hit percentage rate drop below my personal acceptable limit? What is my expectation of terminal performance throughout the distances of my acceptable hit range percentage?
Thanks for posting!
IllinoisBurt
Well-Known Member
Aside from stabilizing the bullets at their lower velocity, do we know if the reduced start rpm would have a significant impact on observed terminal performance versus what we expected to see from a full velocity (and rotational speed) bullet when it impacts downrange? I don't believe the rotation decreases anywhere near as quickly as velocity over time/distance due to the difference in air resistance on the spinning side bearing surface compared to the front bearing surface pushing through the air. So in your testing we started with a full speed bullet from 1:8 twist versus reduced speed 1:9. My math may be off a little but it would seem a better comparison for the reduced start load be somewhere around 1:6 to approximate the rotation.
Hard rock
Well-Known Member
Sedancowboy,
X2. Well said and in my opinion, quite accurate.
Len's recent poll on LRH confirms that 95+% of hunters shoot to <500 yds.
Increased twist does better stabilize bullets and improves terminal performance and straight penetration.
I'm still chuckling. We realize that higher BC is of little extra value to the majority of us, and yet we insist on trying to "stack the odds" in our favor. Nothing wrong with that - just human nature. Higher BC sells bullets today!
Keep it coming all. This is great stuff. And thank you Steve! (He & Brian are working on a higher bc bullet as we speak)!
X3 couldn't have said it better, thanks for a very explanatory post .Sedancowboy,
X2. Well said and in my opinion, quite accurate.
Len's recent poll on LRH confirms that 95+% of hunters shoot to <500 yds.
Increased twist does better stabilize bullets and improves terminal performance and straight penetration.
I'm still chuckling. We realize that higher BC is of little extra value to the majority of us, and yet we insist on trying to "stack the odds" in our favor. Nothing wrong with that - just human nature. Higher BC sells bullets today
Keep it coming all. This is great stuff. And thank you Steve! (He & Brian are working on a higher bc bullet as we speak)!
Hard rock
Well-Known Member
Why not , especially being that lead is denser than copper , I think most of us realize a124 gr copper bullet is usually compared too a 140 gr cup and core in the 6.5 cal .
RockyMtnMT
Official LRH Sponsor
The goal with the reduced velocity was to have stability above 1.5 sg on the Miller formula. The 9" twist did this at 1.63sg with the muzzle velocity at 2157 fps. This is calculated at sea level without adding in the 3000' elevation at the shooting position. So, well above full stability. You are correct that the rpm's are lower than the full tilt load in the 8" twist. In all honesty, I did not consider rpm's for the test. I was focused on making sure both bullets were fully stable. Both bullets dealt with the same 9" twist for the 300y shot. The Hammer was lower in stability due to the lighter weight and longer oal.
Hard rock
Well-Known Member
That would be interesting, good question
X-4
I don't think they would like the results as the 199 is already hanging with the 215
That was what I was trying to say , Thank You
This wasn't designed as a BC test or comparison... And anyone with experience with monos vs C&C knows that monos are much longer for the same weight, so matching the weight would necessitate a size differential and you're still then not apples to apples. One could also argue that with Steve setting them up for similar impact velocities at range, he was in effect disadvantaging his own bullet due to its lighter weight... So many ways to look at this. Biases will always determine our sense of fairness.
IllinoisBurt
Well-Known Member
I suspect rpm difference could show up as a measurable change in bullet performance though it may be small. Still it seems easy enough to do a control in something like .224 barrels where faster twist is common to see if it's significant enough to matter. I know it's not apples/apples but maybe firing reduced load of a bullet dimensionally equivalent (bearing surface to length ratio of 22 versus 308) through 1:9 and 1:7 or something similar could provide data to potentially rule in or out the variable.
** Quick math here, we had about 30-33% initial velocity reduction so the rpm start would be equal reduction, so 1:7 v 1:10 or 1:8 v 1:12.
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