Most of the past two weeks have been spent working on the drone, and the accompanying website. I pretty much picked up where I left a year ago and have been ordering and assembling everything together. There have been a few issues that I’ve had to work out. However nothing that has been substantial. A few days ago I put together a write up detailing everything that had been done to date.
Photogrammetry Drone: Putting Everything Together
There is some additional work to be done, mainly the final touches prior to test flight. We will also need to find a suitable test field to fly on and put together a mission plan. The nice thing about the autopilot is we should be able to get a tremendous amount of data on how the flight went. Everything from airspeed to battery life. We will use the data to evaluate changes we make to the airframe, especially as we look to integrate the camera into the build.
Looks like we won’t get the props until the 18th, so any test flight will have to occur after that date. I’ll have additional write ups to discuss the lead up to, and the results of the test flights.
In terms of firearms news. A friend and I had an interesting discussion regarding calibers, barrel length and elk. He wanted me to talk him out of purchasing a 45-70 lever gun. He was concerned his 308 Ruger American rifles with a 18in barrel wasn’t enough to do the job. He was considering either purchasing a 45-70 or another Ruger American with a 24in barrel, chambered in 308 Win. He stated that he wanted a rifle that he could comfortable take an elk from 0 to 300 yards. (My first response was his beard was not long enough and he did not live in a log cabin in the mountains to justify the 45-70)
I stated to him that I believed that he would be fine with the 18in 308 Win, especially if he switched to a 150gr monolithic bullet such as a Barnes TTSX or a Hornady GMX. The reason being the copper monolithic tend to penetrate deeper, track straighter and have less mass lost when compared to a a conventional cup and core lead bullet. After getting off the phone with him, I decided to run the ballistics to see if my statement was accurate or if I was just blowing smoke.
At the muzzle, there is no doubt that the 45-70 Govt. has the energy to take down an elk. However due to the flat nose bullet design of the 250gr Barnes TSX Bullet, the energy is lost quickly. As we approach 200 yards we drop below the 1500ftlb of energy that the Colorado Parks and Wildlife recommend as the minimum amount needed to reliably down an elk. In addition the bullet drop on the 45-70 is pretty dramatic, nearly twice that of the 308 Win at 300 yards.
The differences between the 308 Win barrel lengths is less dramatic. The criteria is from 0 to 300 yards as that what my friend felt were the ranges he’d be shooting. So if we look at the energy requirements we see both bullets make the cut off but the 18in barrel squeaks by at that 1500ftlb threshold while the 24in barrel imparts 1700lbs or a difference of around 13%. Now, is the elk likely to notice if it go hit with a bullet with 200lbs more force? No, I don’t believe so. The terminal ballistics are going to be very similar.
There is one thing that does matter which is the minimum velocity needed to reliably expand. Nosler claims there minimum expansion velocity is 1800fps. What I don’t know is the level of expansion you get at 1800fps. Is that the expansion that yields the picture perfect expansion you seen in the magazine photos or is that just enough to open up the tip to claim the bullet expanded. (Perhaps a couple test shots are needed with some wet newspaper). With the 1800fps spec provided, we can say that the 18in barrel will meet the spec yielding 2023fps.
At the end of the day, I told him he did not need to buy at 45-70 Govt. and that he was likely fine with the 18in barrel. Now that I’ve taken the time to run the numbers, I am more confident in the conclusion. His 165 Nosler Partition load will be fine for elk when shot from his 18in American Predator. Yes the energy threshold is just barely there, but as long as he does his part to place the bullet in the proper location he will fill the freezer.
So how about my advice on the loads? Switching from the 165gr Nosler Partition Bullet to a 150gr Monolithic? Well, I substituted a 150gr Barnes TTSX, and adjusted the load using QuickLOAD to get an estimated velocity of 2515fps. Since the bullet is a little bit lighter we get a bit of a velocity boost.
The minimum velocity for expansion for the Barnes 150gr TTSX is 2000fps, when purchased as a handloading component. The bullet used in their 308 and 30-06 factory loads have an expansion window down to 1600fps, but to my knowledge, is not sold as a handloading component. So he is likely on the edge for the stock 308 150gr TTSX handloading bullet on store shelves.
As far as terminal ballistics goes, it is true that the copper monolithic penetrate deeper, track straighter, and retain more weight when compared to traditional lead core hunting bullets. Undoubtedly the 1500ftlb minimum was set with traditional bullets in mind, and the advancement in bullet technology may reduce the amount of energy needed for an ethical kill. That is up to an individual hunter to decide. I am not convinced it will make as big of a difference as I initially had thought.
Well that is all I have for this week. We did decide to move to Parler, but are keeping our Facebook and Instagram account live for now. You can find us @TheBallisticAssistant. We are looking at MeWe, but haven’t finished the set up over there yet. For right now we are treating Parler kind of like Instagram sharing photos but we may expand how we use the platform. We will see.
As always, you can reach me at jay@theballisticassitant.com. Email me with your comments suggestions or questions. I have no new updates for the load database this week but if you’d like to add your pet load, the submission sheet can be found here and we will get it added ASAP.
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Stay Safe Out There!
The Ballistic Assistant