Random thoughts on ballistics...
Jeremy has 32 years federal experience. Twenty-three of those were as a Special Agent and member of an elite Federal SWAT team. There he served as a trauma medic, firearms instructor, assaulter, assault team leader, senior tactical instructor, sniper, sniper team leader, and sniper instructor.
While serving in the USAF, Jeremy was certified in trauma care, munitions, freefall parachuting, SERE, and later, served as a Special Agent in AFOSI.
Jeremy has won first place in IDPA, USPSA, OFLEA, and PPC competitions. He has been awarded Oklahoma EMT of the year and the FBI Shield of Bravery, the second highest medal for valor in the FBI.
Jeremy loves spending time with his family and friends, serving with his church, and lifting heavy things.
Great day for off-angle shooting (and math)!
Here's a good example of where a 50/250 zero works on a varmint rifle. The rifle is dead on at 50 and 250 yards. The point of aim for both groups in the photo is the neck. So the 200 yard group hits a couple inches high, and the 300 yard group is a few inches low. That makes life easy when varmint hunting at night. Hold center and send it.
Two important lessons from the range today:
1. The MPX hates the trilug.
2. A sling stuck under the charging handle can shut the gun down hard.
First lesson: 10-shot groups with a 3x magnifier from a rest at 50 yards with a Rugged Obsidian on a trilug produced crummy groups:
Gold Dot 147: 6".
HydroShok 147: 3.75".
SXT 147: 5".
G2 147: 6.5".
Ball 147: 3.5".
Critical Duty 135: 4".
By way of comparison, a beat up 10.5" AR with a 1x Romeo put up a 1.5" group with junk ammo.
Second lesson: If you work a stoppage and your sling is under the charging handle when you rack it, it can shut the gun down hard.
October 1, 2021
When you realize you’re talking to your people:
October 16, 2021
Pick your “truck gun”:
4” MPX (9mm) vs 10.5” AR (5.56mm). What’s your pick and why?
Weight - Same (8 lb 2 oz).
Overall length - Same (when MPX is suppressed).
Accuracy – 5.56mm (1” vs 3” at 50 yards).
Range – 5.56mm = 300-400 yards. 9mm = 100.
Capacity – Same (30 rounds).
Lethality – With typical ammunition (M855, 55 FMJ), 5.56mm from a short barrel will be less effective than 9mm JHP. With a premium bonded round, the 5.56mm will outclass 9mm JHP.
Report –The 5.56mm will cause immediate and permanent hearing damage. The 9mm is hearing safe.
P.S. Is a rifle caliber always better than a pistol caliber? Check out the ballistics of a 5.56mm below 9” to a 9mm of the same length, and you might be surprised.
August 28, 2021
10mm vs 357 Magnum for back country. Which one would you pick?
August 4, 2021
I know a cartridge can’t make your barrel longer, but can it make it act like a longer barrel?
As it turns out, yes. We used a 55-grain open tip and a bonded soft point. For each option, we selected both 5.56 (hot) and .223 (normal) pressures as loaded from the factory.
The results showed that a .223 round, on average, is about 230 fps slower than one loaded to 5.56-mm pressure. So, hotter ammo is faster. That easy. But when dropping from a 14.5” barrel to an 11.5” barrel, you almost always lose 200 fps.
Here’s where the numbers are most interesting. Look at the blue shaded boxes in the chart. The 14.5” with .223 ammo and the 11.5” with 5.56-mm loads both end up at around 2,700 fps. It’s the same bullet, and it’s going the same speed. So, it’s the same ballistics.
Look at the orange box and you’ll see the same thing. The 14.5” with the .223 round produces slightly less velocity with the same bullet as the 11.5” barrel with the higher-pressure 5.56 loaded rounds. Again, you get the velocity back from the shorter barrel by loading 5.56 pressure rounds.
You might ask: who cares about a measly 200 feet per second? Well, remember that in real-world testing, the mighty 300 Win Mag launches a 168-grain slug at about 2,990. That’s only 230 fps faster than the lowly .308 when both have 24” tubes. So, yeah. 200 extra feet per second is a big deal.
You can’t load a round that makes your barrel longer, but you sure can make it act like one.
The Shield Arms S-15 magazine is arguably the best innovation in Glock aftermarket products for this decade.
I got to spend the day with my old buddy and US Border Patrol Firearms Program Manager. He brought me one of their G47s. You can’t buy one of these in stores! It’s like a G17 that can slide swap into a G19 or a G45. Cool stuff!
My most recent tinkering: I rebuilt an old AR that has been run hard. This blaster has had only 3 stoppages in 7,100 documented rounds! It has worn a suppressor for nearly all of it. There were a grand total EIGHT times it was cleaned in 11 years. In the photo, you can see the gas block was essentially 99% closed and seized in place. It’s evidence of how little gas a suppressed AR needs to run reliably, even when it’s filthy.
Autoglass is tougher than you might think. The trick is not to aim through the holes. Shoot through the holes. ￼
December 24, 2020
This is a good example of error from shooter/spotter offset.