10 Head of Big Game - 6.5 Grendel – 4 Seasons

[Stinky Coyote]

Thanks for great insight into a great cartridge. Interesting how as your experience grew the barrel length shrank!

Good observation! It sure did. The way I see this formula I like, which is 'for game intended' the proper sectional density, bullet construction and impact velocities. And they all have to jive together. The bullet construction of the eld-m lends well to performing in big game at lower impact velocities, the bullet retains it's SD better and therefore penetrates deep enough for game intended while doing good work along the way. I coined the term some time ago as SDRR (sectional density reduction rate). One can envision both ends of the spectrum where you run an overbore .257 wby mag and 80gr ttsx at warp speed and it needs two factors to do well on big game with that sad SD...it needs mega speed and it needs to be a tough bullet so it retains as much of its sad SD as possible....the other end of the spectrum is the Grendel, launch a much more pliable bullet with plenty of SD at speeds that allows it to also retain it's SD. I find one of these examples far more efficient than the other so I've migrated to it, neither camp is wrong, we can play all over the spectrum in between and largely that's what we discuss and compare all the time without using talking points like I just did.

The more SD you start with the more the bullet can be allowed to open and do work will still attaining your 18-24" penetration depths over an acceptable range of impact velocities in your preferred hunting ranges. This is where the Grendel ELD-M formula really shines as it does that very well for big game to normal hunting distances even out of a short barrel, it's not going to be driving through 4' of elk running away up the whazzoo but used responsibly it will drive through 18-24" at most ranges out to and beyond where 98% of game is taken.

I'd love to work with Hornady to develop the SDRR and ERR theories of mine further and incorporate into the next gen ballistics. It would sure alleviate alot of the arguments online and help explain actual terminal performance better imo. ERR (energy reduction rate). So with gel testing and measuring these things we could really compare things a lot better imo. Understanding how much energy will dump over how many inches combined with how much SD will dump etc. See we have great pre-impact in-flight understanding of bullet performance in BC, velocity, atmospheric conditions, wind etc. so we can get the bullet there...but we still have a pretty crude understanding of what happens after impact. We could tighten this down with better numbers and ways to look at it. As the SD of a bullet changes the instant you hit something, we don't measure that, we should, it will be a better predictor of terminal performance and also the energy dump over the travel as well. I digress...I'm a bit of a nerd. Hornady should hire me and give me an endless supply of gel and let me develop this out...

Looking at my 2100 fps impact velocity 200 yard whitetail buck where I got 18" penetration going in 2nd last rib and stopping in meat in front of brisket under hide for example. It hit with 2100 fps, dumped 1200 ft/lbs over that travel and 99.8 grains remained (81% retention) and it opened up to likely triple. So there's actually an SD to be measured there before and after and could be reduced to the 'per inch' loss, as well as the 1200 ft/lbs energy divided by 18" to give an energy reduction rate. The 420 yard doe I took impacted at 1800 fps, almost the same shot but less steeply quartering away so went in mid rib cage and existed inside front should after about 15" penetration with 1.5" hole so it was still doing work, and 885 ft/lbs energy. Penetration depth wasn't going to be an issue and it may have gone further than the 18" of the buck because it may have retained more of it's SD with that lower impact velocity. I've said for a long time that energy doesn't matter as much as SD/Construction/Impact Velocity...but it can give an indicator to what's going to be done internally. The 420 yard doe internal damage was awesome, everything above the heart obliterated and both these deer dropped on the spot. Same rifle and bullet.

So I'm doing in the field what could be done with gel. It's ok I have the understanding of what will happen but we could standardize this stuff going forward and become far more efficient with our gear and I think these numbers would also help drive future ballistics and design with the manufacturers giving us even better performing bullets and cartridges than we have now...win win imo. Are we ready for the future? Hornady?....bueller....bueller...

This is the sort of stuff that would explain Bell and his 1100 elephants and could cross over to all sizes of game etc. not just the stuff here in North America. It would be very beneficial in Africa as well, maybe even more important than here as half the stuff over there can kill you. Anyway...Hornady...lets do this. You're on top of the game currently, lets take it to the next level.

p.s. I've recorded the dates and links to when I first put these theories into the universe so no funny business manufacturers, I'll take royalties too but I'd much rather be apart of the process.