Author Topic: sighting in a 30/30 (Read 2481 times)

Larry R · « **on:** September 25, 2005, 04:48:53 PM »

i know the best way to do this is to just shoot at the range i want to zero it in but i'm hopeing someone might be able to save me a lil time...where should the bullet be hitting on the target at 25 yrds for a 150 yrd zero?
i will be shooting soft point remington core lokt 150 grain factory loads..
after doing this i will check it at 150yrds before hunting with it im just looking for a lil help on getting it close..

Coyote Hunter · « **Reply #1 on:** September 26, 2005, 03:38:52 AM »

Larry -

If you go to www.huntingnut.com you can download "Point Blank", a FREE and easy to use ballistic calculator. Once you have installed it you can calculate the trajectory for whatever range you want.

I do it a bit differently. Rather than pick a range, I pick a kill zone size and then have "point Blank" calculate Maximum Point Blank Range (MPBR) accordingly.

For example. I use a 6" diameter kill zone. Imagine a 6" diamter tube from the end of your barrel to the target. The MPBR calculation provides a trajectory that will stay within this imaginary tube and will give you the maximum length of the tube (maximum range to target). With this information you simply look at the data to determine how high to sight in at a particular range.

Since I have my hunting buddy's .30-30 data handy, I used iPoint Blank to calculate MPBR for his load - a Speer 150g bullet at 2341fps. Using a 6" kill zone, MPBR is 222 yards with a 190 yard zero. That puts the bullet 2.97" high at 100 yards, 2.28" high at 150 yards, and 0.84" low at 200 yards. The bullet will, of course be 3.00" low at MPBR or 222 yards. If you are one of those people who use 1,000 foot-pounds as the minimum energy needed for deer, "Point Blank" tells you that this load carries 1,001 foot-pounds out to 220 yards.

Point Blank also tells you that a 10MPH wind will cause a 8.13" deflection at 220 yards and that if the target is moving at 5MPH you will need to lead it by 2.41 FEET.

You will need to know the velocity of your load and the Ballistic Coefficient of the bullet, or at least a close approximation of both.

Winter Hawk · « **Reply #2 on:** September 29, 2005, 08:34:09 AM »

Coyote Hunter,

I agree on Point Blank, a great program. Larry's question was how high the POI should be at 25 yards with Rem. core-lokt factory loads. If you could find the factory balistics for the 150 gr. bullet and plug them into the program with a 6" kill zone, maybe you could then give him how high he needs to be at 25 yards? I'd do it but am at work and have to get back to it....

-WH-

IntrepidWizard · « **Reply #3 on:** September 29, 2005, 08:44:13 AM »

At 25 yds it will be very close to 100 yds grouping.

Graybeard · « **Reply #4 on:** September 29, 2005, 09:45:44 AM »

No, no, no no. We've gone over this a thousand times. There is no way under the sun you can shoot at 25 yards and have even a remote clue where it will be at 100 yards or beyond. Anyone who tells you that you can has very limited real world experience shooting on a range. Sorry it just don't work.

Generally speaking you want a centerfire from rifle or single shot handgun to be about 1/2" to 2" low at 25 yards to be "on paper" at 100 yards. Where on paper. No one knows. Might be anywhere on an 8.5" x11" target sheet.

I've done this literally thousands of times and never yet have I seen it be the same at both 25 and at 100 yards. Either shoot the blamed thing at the distance you want to sight it in or don't take it hunting.

IntrepidWizard · « **Reply #5 on:** September 29, 2005, 10:33:01 AM »

On a 8" by 11" sheet of paper at 25 yds it will be close enough to adjust at a 100 yds,been doing in for many years.

Graybeard · « **Reply #6 on:** September 29, 2005, 11:01:22 AM »

Dead on at 25 yards WILL NOT always put you on an 8.5" x 11" target sheet at 100 yards. From 1/2" to 2" low will "almost" always do so. Seen it way too many times. Precisely how much low changes with the round being fired, the bullet weight, the velocity, what sighting device is used and how high it is above the barrel.

I gave up trying to shoot dead on at 25 and hope to be on paper at least 20 years ago when too many times it wasn't there at 100 and you had no way to be certain where it was.

big medicine · « **Reply #7 on:** September 29, 2005, 11:22:22 AM »

If you go to remingtons web site they have a ballistic calculator for their factory ammo. According to their data you would be almost dead on (-0.06 inch) at 25 yards and be dead on at 150 yards.

Keith L · « **Reply #8 on:** September 29, 2005, 12:55:40 PM »

I'm with GB. That engineered data is fine, but nothing beats shooting in similar situations to how you are planning to hunt. I even suggest shooting from your tree stand whenever possible prior to the hunt to see where those slugs go. You might be surprised.

big medicine · « **Reply #9 on:** September 29, 2005, 01:29:16 PM »

I agree that one needs to actually shoot to verify the data. But I have found most of the data to be very close.

Larry R · « **Reply #10 on:** September 29, 2005, 04:23:45 PM »

according to remingtons calculater 0.03 at 35 yrds will be give you a 200 yrd zero....does this sound right to you more experieced shooters?

big medicine · « **Reply #11 on:** September 29, 2005, 11:09:31 PM »

The only way to know for sure is actually go out and shoot it to make sure, but it sounds pretty close.

Winter Hawk · « **Reply #12 on:** October 03, 2005, 09:44:30 AM »

Remember that Larry is going to make sure he is on target at 150 yards, he just wants to get reasonable assurance of being on paper when he does. If I recall, the 25 yard zero was developed by the military for the 30-06 Garand with military ball ammo. Depending on bullet weight, ballistic coefficient and velocity it will change for other cartridges and loads. The ballistic calculators use those variables and physics equations to derive what the trajectory will be, and how high the bullet will be at what distance. This all goes out the window if you are shooting a barrel length different from the test barrel used to determine the velocity. In days of yore, the test barrels were all 26" and actual velocities were invariably lower because most rifles had 20" or 22" barrels, so using factory ballistics gave only a rough idea of what was really happening.

I'm rambling. Sorry. I'll shut up.

-WH-

sprest22 · « **Reply #13 on:** October 03, 2005, 01:48:24 PM »

I was just looking at the Remington remshoot ballistic calculator and for 150 yd zero with the Rem 150's it says you should be 0.79" high at 25 yds.I don't think you'll be anywhere close to 150 yd zero at 0.03" or -0.06",more likely closer to a 100 yd zero at these numbers.
With 170 gr Win silvertips in my 336 I'm about 1/2" high at 25 and dead on at 100 yds.Hope this helps

jcrane · « **Reply #14 on:** October 04, 2005, 02:43:42 AM »

My 336 is zeroed dead on at 50 yards with Winchester 150gr. Silverips. At 100 yards it is dead on. My 336 has a 3x9x40mm scope and medium weaver rings. There are lots of variables when zeroing. I would zero at 25 and check at 100. You might have to tweek the zero at 100.

jcrane

big medicine · « **Reply #15 on:** October 04, 2005, 10:20:18 AM »

I went back to the Rem Shoot and put the data back in. It does say that with the 150 gr bullet that it is -0.06 inches at 25 yards for 150 yard zero. If you want a 200 yard zero it is 0.50 high at 25 yards. Either way it gets you in the ball park to fine tune it at the range.