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Location: Choudrant, Louisiana
Joined: 07/07/2007
Posts: 28
Don, a question about sighting in.

Hey Don, I have been reading a while now and I see you are very knowledgable about ballistics so I thought I would ask you a question or two.

I will be going on my first antelope trip in Oct. and need some advice on sighting in my savage 110 in .270 win. I will be using 130 gr. Remington accu-tips and I am currently set at 2" high at 100 yds. What will my MPBR be? Whatever distance that will be will definitely be my maximum range. as I am not comfortable taking anything over about 375 or so. Also, I will have a remington model 7 in 7mm-08 shooting 140 gr. Federal premium nosler partion bullets. I am taking this gun both as a back-up or if it looks like I will have to make an extremely long stalk.

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Location: Antelope, Ore
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Don, a question about sighting in.

Welcome to the site and thanks for the compliment. I don't know that I'm that knowledgeable but I deal in practical ballistics. To get the data I've posted I use a Pact Mk IV chronograph with a ballistics calculator built in. I've checked it in actual shooting and against other data found in different places, it's very accurate.

With your 270, I selected a bullet similar to the one you'll be using and a velocity of 3000fps. Claims for the 130gr load are 3100fps+ but I wonder if factory ammo reaches those claims. At any rate, the data I ran will certainly have you in the ball park, eve if you are getting 3100fps. Just go out with this data and shoot at say 100yds, 200yds and 300yds and compare what you have.

Using data for a 130gr Nosler Ballistic Tip:
MPBR.............................290yds
MPBZ..............................249yds
bullet path:

@100yds........................+2.5"
@200yds........................+2.1"
@300yds........................-3.7"
@350yds........................-8.8"

This data is also compiled using a 6" vital zone. If you a\want an 8" zone let me know but the bullet path won't change drastically.

For the 140gr Nosler partition:
MPBR................................276yds
MPBZ.................................236yds

bullet path:

@100yds........................+2.6"
@200yds........................+1.7"
@300yds........................-5.1"
@350yds........................-11.0"

data also for a 6" vital zone. Notice the difference in bullet path of the two loads? For practical purposes, just not much. If your 270 does do 3100fps there just won't be enough practical difference to worry about. Go out and shoot both these and check the bullet path against these numbers. I think you'll find them pretty close. My program also allows for altitude and temp but for this I fed in what they call "standard atmosphere" which is something like 59 degrees and sea level if I remember right. It is all I use for my own stuff. I tried once to enter my own altitude and temp and once again the difference just wasn't that great. If you want to know what it is at the altitude you'll be at, let me know the altitude, or close, and I'll just use say 50 degrees, or what ever you want. But don't be to optimistic about temp. You could hit bluebird days or snow storms depending on where you go.

Anything else I can do, feel free to ask.

Though I would edit a bit. You talked about the longest shot maybe being 375yds I think it was. I doubt you'll have to shoot that far but if you should have to, a hold on the top line of the animal with either load should drop the bullet into the chest cavity.

Location: Choudrant, Louisiana
Joined: 07/07/2007
Posts: 28
Don, a question about sighting in.

Thanks Don, that was exactly what I wanted to know. I really thought there would be a greater separation between the 2. As for as the altitude goes, we will be hunting the Shirley Basin area of Wyoming. The altitudes appear to range from somewhere around 6600 feet upto 7800 feet. My friend went there last year and when they checked their rifles they shot an inch lower than what they had them set at home. Is this normal? I just thought of something else, the barrel on the model 7 is 18 or so inches long how will this affect the tables you posted? Thanks again for all the help.

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Don, a question about sighting in.

I suspect that neither will effect you that much. The 1", at what range? I'll re-run the numbers for the highest altitude and let you know.

As far as the short barrel, it would be hard to say what velocity loss would be there. I've heard many different stories over the years and all are due to barrel lenght. The truth is there are more factors involved. If you take two exactly the same rifles with the same make barrels and shoot the same box of factory ammo in them you'll get two different ave velocities.

I'll do those new numbers in a while and get back to you.

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Don, a question about sighting in.

Here it is for your 270. As I suspected, no radical changes. Probably about the same for the 7mm-08.

Used 7,200', split the difference between what you gave me, and temp of 45 degrees. Should be a reasonable temp for that time of year. That changed the BC of the bullet from .433 to .550. This tells us something about the real effect of BC I think.

MPBR.....................299yds............improvement = 9 yds
MPBZ......................255yds........................................6yds

Bullet path:

@100yds............+2.5'..................................no change
@200yds............+2.2".................................+.1"change
@300yds............-2.9"..................................-.8" change
@350yds............-7.8"..................................-1" change

As you can see, the changes are less than most of us can hold in field conditions and most people can't hold that well from sand bags and a bench.

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Location: Phila., PA
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Don, a question about sighting in.

I know this question was for Mr.Fischer, not trying to "step on anyones toes"...

Here is a link to a really great on-line ballistics program...
I have found the results of this software to be very accurate. It will defenitely "get you in the ballpark" so to speak. Thumbs up
Of coarse, there is no substitute for firing your rifle, with your ammo.
Have at it...http://www.eskimo.com/~jbm/calculations/traj/traj.html

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Don, a question about sighting in.

I might add that I've heard of several and have seen the Hornday one. I checked my figures against their's and they match. also checked against the Nosler book figures and they match. There is info out there and Hammer seems to know how to find all that stuff. But if you want me to run it for you, just say so. I like doing it.

Location: Choudrant, Louisiana
Joined: 07/07/2007
Posts: 28
Don, a question about sighting in.

Thanks guys for all of the help. The info that you have given me is exactly what I needed. Sorry I didn't respond sooner. This will be my first trip out west and I guess I just don't want to leave anything to chance. I have killed several whitetails over 200 yards and one at 350+ so it isn't just the long range that concerns me so much as the wide open spaces that can making judging distances with the eye difficult. we will have a range finder, but one of the guys that went last year said that sometimes it was hard for the range finder to focus on the antelope because of their size,but that could just be him.

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Location: Antelope, Ore
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Don, a question about sighting in.

I've never had a range finder but I keep thinking it would be a good idea. I stopped at a Cabellas in Nebraska once and checked them out. Tried to range some things out a window and never got two straight answers from the thing. I'm sure there's a right way to use them and I don't know it. I've heard that you need to range a large object near the target. That could be a trick in places in Wyoming. I understand the expensive Lecias don't have that problem. Key word expensive.

In my youth up in Montana, a friend of mine and I used to guess ranges then step them off. 99 of my paces was 100yds. We got awful good at guessing ranges out to close to 400yds. Then we just sorta started falling apart. Out in the wide open spaces, things seem to be farther away than they really are.

Have a good trip out there and bring back some photo's.

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