Altitude changes with load

[Doom2]

After seeing some of the ballistics output here, please make sure you understand how your application uses pressure (barometric or station) and altitude.

 

[BrentM]

Yes I completely agree. It is EXTREMELY unlikely I'd even consider a shot longer than 200-300 given my current skill level. My hunt is Oct 3. So I figured I'd see how my field practice goes over the next month and find my max safe distance for perfect conditions as well as light wind. For example, if it goes well and I get my drops and drift figured out up to 400, and then I have an ideal opportunity for 400 (flat ground, maybe prone position, 5mph wind max) then maybe I would consider taking the shot IF I can't get closer.

I don't really want to hunt long range. I consider 500 long range. I'm a bowhunter at heart, so I always want to get as close as possible! I just want to be able to shoot to 500, just as a tool to make sure I can fill my tag. But of course, that's along down the road somewhere after I get more experience.

I've dialed back my shooting expectations from 700 last year when I first got my rifle to 200-300 now. I've learned a lot since then haha

There are some top level shooters in Utah and good a PRS group you might be able to hook up with. I used to do the vortex extreme N Utah when they held it there as well. You might consider a long range hunter course if one is offered near you. It focuses on the positional shooting aspect and dives into the external ballistics pretty heavy. Wind, mirage, drafts, etc. The focus is on minute of deer shots and what it takes to be proficient with first round impacts. I've instructed a course here several times and it's always a great experience and people usually do quite well even with zero knowledge about LR shooting.

 

[Grandhunter]

View attachment 211784View attachment 211785

What Ballistic Cal are you using?

 

[Tac-O]

After seeing some of the ballistics output here, please make sure you understand how your application uses pressure (barometric or station) and altitude.

Yes... I've noticed the various options for pressure in the strelok app and am not sure how to correctly input that.

I'll do a search and see if I can find any specific guidance on how to use that in strelok

 

[Tac-O]

There are some top level shooters in Utah and good a PRS group you might be able to hook up with. I used to do the vortex extreme N Utah when they held it there as well. You might consider a long range hunter course if one is offered near you. It focuses on the positional shooting aspect and dives into the external ballistics pretty heavy. Wind, mirage, drafts, etc. The focus is on minute of deer shots and what it takes to be proficient with first round impacts. I've instructed a course here several times and it's always a great experience and people usually do quite well even with zero knowledge about LR shooting.

Thanks for the tip. I had looked into shooting courses around Utah awhile ago, but I couldn't find anything that was particularly affordable for me. Do you have any specific courses or people that do training in Utah that would be on the cheaper side?

 

[BrentM]

Thanks for the tip. I had looked into shooting courses around Utah awhile ago, but I couldn't find anything that was particularly affordable for me. Do you have any specific courses or people that do training in Utah that would be on the cheaper side?

shoot me a PM. I'll check with my Utah and eastern Idaho contacts.

 

[entoptics]

Might I suggest you play around with MERC - Maximum Effective Range Calculator

Obviously it's only as good as your estimation of your uncertainties, but it will definitely give you a feel for hit probabilities and what variables are most important to learn (spoiler alert...it's wind).

Regarding your original question, inside 500 yds, air density and temperature are going to have a minimal affect compared to shooter precision, mindset (buck fever), and physical variables (fitness, shooting position, etc).

Also, the affects of altitude are the same as temperature. High altitude = easier flight = higher impact. High T is the same. So if you go up in altitude from your zero, but down in temp, the effects cancel.

I applied the worst case scenario in JBM. Load zeroed at 2820 fps at 90° on a low pressure day (29.2 corrected) @ 5000 ft. Hunting scenario at 2780 fps, 10°, high pressure day (30.2" corrected) @ 4000 ft (spot the elk from the truck!).

This resulted in 3.9" lower impact at 500 yds. That is significant, but easily accommodated if you have a ballistics calculator, barometer (smart phone), and a rough temperature. Again, this is a worst case scenario.

 

[BrentM]

I have 2 contacts. Idaho and Utah. One has a class in Utah in Sept and the other is offering help in Idaho. If you want to learn how to shoot and do it right both of these guys are well known in the area and top shooters. Absolutely worth the time and money. There is nothing better than hands on coaching.

 

[Tac-O]

Might I suggest you play around with MERC - Maximum Effective Range Calculator

Obviously it's only as good as your estimation of your uncertainties, but it will definitely give you a feel for hit probabilities and what variables are most important to learn (spoiler alert...it's wind).

Regarding your original question, inside 500 yds, air density and temperature are going to have a minimal affect compared to shooter precision, mindset (buck fever), and physical variables (fitness, shooting position, etc).

Also, the affects of altitude are the same as temperature. High altitude = easier flight = higher impact. High T is the same. So if you go up in altitude from your zero, but down in temp, the effects cancel.

I applied the worst case scenario in JBM. Load zeroed at 2820 fps at 90° on a low pressure day (29.2 corrected) @ 5000 ft. Hunting scenario at 2780 fps, 10°, high pressure day (30.2" corrected) @ 4000 ft (spot the elk from the truck!).

This resulted in 3.9" lower impact at 500 yds. That is significant, but easily accommodated if you have a ballistics calculator, barometer (smart phone), and a rough temperature. Again, this is a worst case scenario.

Thanks! I have played around with figuring out the max point blank range on theoretical ballistics from my gun using shooterscalculator.com.

Would you suggest using JBM over that one?

 

[azarcher10x]

Yes I completely agree. It is EXTREMELY unlikely I'd even consider a shot longer than 200-300 given my current skill level. My hunt is Oct 3. So I figured I'd see how my field practice goes over the next month and find my max safe distance for perfect conditions as well as light wind. For example, if it goes well and I get my drops and drift figured out up to 400, and then I have an ideal opportunity for 400 (flat ground, maybe prone position, 5mph wind max) then maybe I would consider taking the shot IF I can't get closer.

I don't really want to hunt long range. I consider 500 long range. I'm a bowhunter at heart, so I always want to get as close as possible! I just want to be able to shoot to 500, just as a tool to make sure I can fill my tag. But of course, that's along down the road somewhere after I get more experience.

I've dialed back my shooting expectations from 700 last year when I first got my rifle to 200-300 now. I've learned a lot since then haha

The issue won't be accuracy at ranges such as 500 yards. It will be the terminal ballistics of the bullet from the '06 that's going to limit your range.

 

[NW Hunter]

Yes... I've noticed the various options for pressure in the strelok app and am not sure how to correctly input that.

I'll do a search and see if I can find any specific guidance on how to use that in strelok

The author of Strelok Igor Borisov is very helpful with his app.
On the "Calculate" window, hit the "About" button and you can send him a email.
He is extremely helpful and has dialed me in before.

 

[Tac-O]

The issue won't be accuracy at ranges such as 500 yards. It will be the terminal ballistics of the bullet from the '06 that's going to limit your range.

That is my self imposed limit!

 

[Tac-O]

My rifle hunt was a success! I was able to get my zero established for 200 yards at 9k elevation. I practiced sitting with my pack as a rest, trekking poles as a rest, off hand, and various other positions. I was pretty confident with shooting to 450 if there was very little wind and I could lay prone.

I was about to get into prone position on a very nice bull at 300 when a couple younger bulls ran through and the larger one took off. So I looked to see if I could find the younger ones and sure enough, one stopped between some pines at about 110 quartering away, so I let him have it off hand. He was a much better size for packing out from 10,800 feet!

I shot a .30-06 180gr Speer hot cor, loaded to 2850fps. So at 100yd, impact speed would have been 2700fps. It hit a rib on entry, and I hit him slightly farther back than I wanted. I think the bullet expanded quickly from the rib, and the front end of it must have destroyed the lungs and possibly the heart too. I couldn't inspect because it clipped the stomach and I didn't want to open that up. I found the base of the bullet still intact with lead just under the skin on the opposite side near the shoulder. He dropped within 50 yards!

 

[Stammster]

Congrats and thanks for sharing / following up with us. That's a tender size, and dang good eating.

2850 fps with a 30-06 with 180gr and H4350 is a stout load for sure.