xsn10s
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Bullet Construction vs Lethality
- Thread starter nralifer
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xsn10s
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TrackingPoint - Wikipedia
xsn10s
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- Joined
- Mar 7, 2016
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US Army testing start-up's smart-rifle system
TrackingPoint, which says its system can turn any rookie into a crack marksman, is also looking to apply the technology beyond firearms.
WHOA!
xsn10s
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So far in 33 pages, not one discussion on how SG affects terminal performance? Bullet stability significantly affects how a bullet performs in straight line penetration. AKA lethality. I always thought SG 1.5 and good to go for bullet stability. Yes, on targets but not necessarily so when shooting an animal in all sorts of conditions. Personally, I now believe a SG closer to 2.0 or higher will deliver the best lethality for any bullet. I also think a lot of bullet failures can be attributed to insufficient SG resulting in poorer straight line terminal performance.
Of course SG is the product of the rifle but if the rifle specifications cannot deliver a bullet to achieve its best performance, don't blame the bullet.
My 2¢.
Thank god for microwave popcorn.
nralifer
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I have a short video of a 145 gr 284BD bullet hitting a Bull Elk at approximately 425 yds in slow motion. I would like to post it here, so if anyone has a method of doing that let me know. For now, go to Facebook and search for the "George Fournier" The photo below is of a 375BD2 300 gr recovered from a Cape Buffalo by one of the Jarrett Rifles guys who used these bullets on their recent African hunt. They got 2 Buffs and a Hippo each with single shot kills. The Elk video also shows that despite the oblique shot the bullet exited.
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nralifer
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Thank you for the question, This is an excellent question, and deserves a thoughtful answer. I'll try and give it a just answer.
Recall that a bullet shot from a rifled barrel has two main movements. The linear motion towards the target, and spin motion imparted to it by the rifling, giving it a gyroscopic stability that keeps it going nose first to the target. The spin required to do this properly is largely a function of the medium density the bullet travels in, the caliber and length as well as the weight of ghe bullet. Initially it is the air the bullet encounters and the denser the air the more spin needed. Also, the length and caliber of the bullet is very important, as well as the density of the material the bullet is made of. Short fat lead bullets, say .45 caliber require a 1:14 twist, under standard atmospheric conditions, to be stabilized (1atm pressure, 50% humidity , and 59 degrees F), but a 100 gr copper high BC bullet 6mm bullet with a long ogive requires a 1:7 twist to achieve adequate stability because it is a much longer and thinner bullet. The 6 mm bullet needs to be spun at about 300,000 rpm to stabilize in air at sea level atmospheric pressure. When the bullet enters flesh or gel, suddenly the density of the medium the bullet is traveling in, increases. A long thin bullet can become unstable unless it shortens by expansion or is marginally stable at impact. This mushrooming or petaling also enlarges the bullet diameter at the mushrooming, both of which have a stabilizing effect because the bullet is still spinning. A marginally stable bullet at impact will start to tumble and not expand as intended regardless of bullet material.
nralifer
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Results of an explosive effect. Impressive. Photo shows an Elk hit at close to one mile with a 50 cal Bulldozer. Customer photos.
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Is there a limit to the ratio of bullet caliber to bullet length where the bullet can no longer be effectively stabilized?
