ballistics

fisrtcoueswas80inches · Nov 26, 2002

what is the difference in drop between a 30-06 shooting 125 grains and a 270 with 130. i aimed 6 inches high at 340 and dropped my deer with one shot, say my dad is faced with the same type of shot(him with the 270) how far about the point of impact should he aim with a 1 inch high zero at 100 yards? any suggestions?

OutdoorWriter · Nov 27, 2002

LAST EDITED ON Nov-27-02 AT 08:29AM (MST)[p]LAST EDITED ON Nov-27-02 AT 08:28?AM (MST)

Hang loose and I'll figure it out for you.

BUT..I also suggest he change his zero at 100 yards to at least 3.5" high! That will give him a zero at 300 yards. In between 100 and 200, the bullet will hit anywhere from 4" to 4.7" high and at 340, it will hit about 3.6" low. From there, the drop increases to just over 10" at 400 yards. So in reality, a rifle sighted this way had nearly a "dead-on" hold from 0 to 350 yards or so, plus or minus 5". And if you know the range is it is much easier to make MINOR adjustments and still hold on hair. -TONY

OutdoorWriter · Nov 27, 2002

Ok, at the 1" high at 100, your zero is approximately 195 yards and the 130 bullet with a muzzle velocity of 3030 fps will hit about 8.5" low at 340 yards. -TONY

Bura Nut · Nov 27, 2002

Tony: Glad to see you around. Hope your Mexico trip was relaxing. Casey, take Tony's advice, you and your dad need to be around 3.5 high at 100. I am 3.5 at 100 with a .257 weatherby mag which puts me dead on at 300 8" low at 400 and 23" low at 500. Most important is knowing where your rifle shoots so you make the proper adjustment for elevation etc....... Allen Taylor......

OutdoorWriter · Nov 27, 2002

Yeah, even though I spent most of the time in Mexico working on editing the book, I at least had the patio door open so I could listen to the crashing surf. -TONY

PotatoWhisperer · Nov 27, 2002

Tony- Sounds like a rough trip. I hope your glassing was better from your second location! Glad to see you here...the other place got pretty dead!

SCott G.

PS- That's all good advise on the .270...I shoot one and I'm 3.5 at 100 yards...Good out to 300 and aim top of the back at 400!

fisrtcoueswas80inches · Nov 27, 2002

wow so a 3 and a half high zero at 100 yards will be only about 5 inches low at 300 yards? thats amazing. i ha dmy 30-06 1 inch high at 100 and the drop with 125 grain was about 18 inches at 340

OutdoorWriter · Nov 27, 2002

Scott G,

Yeah, glassing at the second place did get a bit better because we were on the 4th floor right over the main pool! Lots, lots of chaise lounges to scan for beateous dears. (g)

I've owned several .270s myself. My son, who will be hunting with me next month, shoots an M77 Ruger in .270, and we already have it sighted just as I suggested to Casey.

Ironically, my Mod. 70 .264 with 140-gr, bullets has almost the identical trajectory, too. -TONY

OutdoorWriter · Nov 27, 2002

LAST EDITED ON Nov-27-02 AT 04:10PM (MST)[p]Casey,

No, 3.5 high at 100 gives you a dead zero at 300. It will be about 5" low at 340.

Your 18" is huge difference in the drop because judging how high to hold over is more diffcult at long ranges. You're always better off if you can keep the crosshairs on some part of the animal for reference.

Actually, you will find that you can sight most flat-shooting calibers dead-on or just a tad high at 25 yards and get the best trajectory from about any caliber. Then once you shoot it at the longer ranges, you can make minor adjustments. Just remember that any little bit the zero is off at 25 yards gets increased by a factor of 1 for every 25 yards downrange. So if you're off 1/4" at 25, you're off 1" at 100, 2" at 200, and so on. If you're off left or right, it can mean a clean miss at a long distance very easily. -TONY

fisrtcoueswas80inches · Nov 28, 2002

ok lets say that i set my 30-06 3.5 inches high at 100 where would that put me at say 300,400?
casey

OutdoorWriter · Nov 29, 2002

With 125-gr. bullets at 3140 fps, your trajectory wouldn't be much different than the .270 using 130-gr. bullets. With your sights set for 3.5 high at 100 yards, your downrange zero would be 295 yards rather than 300. At 400, you would hit about 12.5" low. The highest mid-range trajectory between 0 and 300 yards would put you 4.4" high at 170 yards.

BTW, the above pretty much mirrors what I said about a zero at 25 yards. At 20 yards, you're minus .2, and at 30 yards you're plus .4. -TONY