Hi guys. Got a new rifle and scope for sheep hunting. rifle is Tikka T3 lite in .270 win. scope is 3x9 swaro with plex reticle. i am trying to dope out the holdover for longer shots on a sheep. the ballistics table says w/200yd zero my bullet (rem 130gr sp) drops 7" at 300yds, 20.9" at 400yds, and 43.3" at 500 yds. The scope manual for this plex reticle says the distance from the top of the post and the cross hairs is 7.2"@ 100yds. I'm guessing that a typical sheep measures about 18" from backline to brisket. I may be wrong on this estimate, but if so, given the ballistics,etc. I estimate hold over as follows.
300 yds: hold xhair at or just below backline w 7" drop = about center of sheep.
400 yds: bullet drop 20.9", space between top of post and xhair = 28.8", so put top of post on belly line. this puts xhair about 10" above backline, with 21" of bullet drop should = about the middle of the sheep.
500 yds: bullet drop 43", space between top of post and xhair=36". put top of post on backline. this puts xhair 36" above backline, w/43" bullet drop=about middle of the sheep.

Am I thinking about this the right way?
Any assitance appreciated. Thanks, Paul W

Paul, Its tough to take data from a PROGRAM AND APPLY IT TO an unknown range.
First you need to pin down the velocity to within a few feet per second.
I sight my 270's in at 1.5" high at 100yrds
I shoot on ranges out to 300 yrds and I hold right on. under a 100yrs it get a little tricky.
For most hunter shooters out past 300 yrd is doable But you will loose most of the energy with a 130gr bullet.
The altitude will also effect bullet drop along with air density.
The only way I know to get accurate tables is to shoot at those ranges and do a lot of it.
A 10mph cross wind will move the point of inpact 10 or more inches at 300yrd.
Dave

Paul, if you intend to hunt long range, the long term solution is to get rid of the plex reticle, and move up to something with either standard MOA, or MIL markings, that you can just "dial and shoot" Of course, this takes time and money, so here's what I would do for a short term solution:

In general 1 MOA is about 1" at 100 yards.
Convert each of your hash marks to MOA.

Plug in your BC, velocity, altitude ect here:

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

Set your drop data to MOA.

Make your drop table.

With this method I was able to reliably take game in the 400-500 yard range for years until I was able to buy a real long range scope.

quote:

Originally posted by Antelope Sniper:
Paul, if you intend to hunt long range, the long term solution is to get rid of the plex reticle, and move up to something with either standard MOA, or MIL markings, that you can just "dial and shoot" Of course, this takes time and money, so here's what I would do for a short term solution:

In general 1 MOA is about 1" at 100 yards.
Convert each of your hash marks to MOA.

Plug in your BC, velocity, altitude ect here:

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

Set your drop data to MOA.

Make your drop table.

With this method I was able to reliably take game in the 400-500 yard range for years until I was able to buy a real long range scope.

I totally sympathise with the thread starter

I too is toying with a z3 3-9 which only come in plex or 4a

Swarovski will Not Fit any other reticle or ballistic turret to this scope

This scope is perfect size for a stutzen that I am building

Hence with medium range either one guesstimate or use reference points

I have my .270 130gr & 140gr rifles and my ballistic twin .300 Win 180gr travel rifles all shooting 3000 fps (Swaro Z6s). I also have them point blank to 300 = 3" high at 100 which goes 3" low @ 300. That way you need- less of a "cheat sheet" for the longer shots. Which you will memorize on the drive to your hunt.

I can't comment on reticles- I actually prefer the non plex fine crosshairs over any plex - just me.

With good equipment most shots missed are becasue of the 90% between the ears. I've shot a Red stag at 310 snap shot, a fallow at 299, 2 mule deer at 318 back to back, one at 257, elk at 227 and 279 all on sticks and all without any delay ie didn't have to think.

If you can afford the sheep hunt yopu can afford a very good laser range finder.

I use ther laser to range the mill dots or balastic plex reticles for hold over. With just a little shooting it is easy to know where your bullets well be in relation to the dots or hash marks on the reticle.

Having them a couple inchs off at a given distance is easy to adjust for compared to 20 or 30 inchs off.

Thanks, guys. I really appreciate the thoughtful replies. I am going to stick with this scope and plex reticle for a while and practice as much as I can. There is a 300m range about 2hr from my house and a gravel pit with safe backstop of about 200yds about 5min from my house. I am not aware of any longer shooting range available to me. I think there may be a 1000m range on the base but don't know if that is available to civilians. I do have a very nice range finder (Leuo TBR 1000). Again thanks for your help with this question. Regards, Paul.

There's another way to apply that plex reticle for downrange zeroing. Just use it as a 1-stadia ballistic reticle. Ok you know that the plex post tip at 9x subtends 7 MOA. your 300-yd. dope is 2.3 MOA, and your 400-yd. dope is 5.25 MOA. Just divide that dope by the 7 MOA subtension to get your "mil-hold" sort of--

300-2.3/7=.3 (i.e. aim 30% down to the PPT from center x-hair).

400-5.25/7=.75

See how it works? It's not difficult to interpolate (guess) your holds along the reticle like this, and you may be surprised just how accurate it can be with a little practice.

Thanks sscoyote. i will try that on the range. btw my numbers on the original post are a little off. i checked on the range the distance from tip of post to x hair at 100 yds is 3.6" @9x (i was missreading the scope manual) but the concept should hold. thanks again. Paul

Well 3.6 [actually 1 mil], is gonna be a little small. Here's what you could do though. OK you know that 400 yds. is ~5 MOA. Subtension is ~inversely proportional to magnification in 2nd focal plane reticles. Therefore the following holds true--

3.6/5 = .72
.72 x 9X = 6.5X

That means that if you set your scope to 6.5x the lower post tip is now your 400-yd. zero. See how that works?

500 would be 3.7x for 8.7 MOA [43.3/5], but that's not a lot of power for sheep hunting...IMO...but...it could work. I have taken a Ruger Mk III Target to 425 yds. using a 2x Barska, and would have no qualms at all using that power for 500-yd. big game.

Few shooters use this plex reticle subtension vs. magnification system for longer range shooting, but it works very well every time i've done it.

Thanks, Steve. Starting to get a glimmer here. I think the method you are describing is alluded to in Barnsness' excellent book Optics for the Hunter. The idea being you adjust the apparent "space" between cross hair and post using the magnification for a known range and bullet drop. One thing I am not clear on how do you know that 400yds equals 5MOA? Sorry if this is a stupid question. Regards, Paul.

Paul--got it from your original post of 20.9" drop at 400 yds. is 5 MOA [21/4=5.25 SMOA...or 5 MOA].

1 MOA=1.05 SMOA [also referred to as inch per hundred yds.]

Had an interesting experience with just this system last antelope season. Buddy's kid had a permit and he was using his dads 270 WSM Browning A-bolt with some factory load. I found the advertised mv of that load and his zero range. He had a 2.5-8x Leupy VX-III on top with their std. Duplex. Now Leupold's Duplex is really not my favorite system honestly since they designed if for reticle-rangefinding [Leupy RES] instead of downrange zeroing/windage, which is a much more practical system of app. IMO. But that's another story. Anyways the Duplex subtension is actually too small at 2.65 SMOA x-hair to plex post tip [PPT] at 8x. But i knew that if he cranked the optic to 4x it would then be 5.3 SMOA, which is workable. I developed a system for him to ~500 yds. or so, and it actually worked very well even though it was only 4x.

Well turns out we didn't have any luck with antelope, but i thought to test the system on a small snowy patch on the side of a ravine at a lasered 400-something [can't remember exactly, it's been awhile]. So this kid gets set up off a bipod and i told him that at that range the "dope" was something like 80% of the plex gap down to hit it @ 4x. Several seconds later he nailed the snowy patch and it disappeared in a cloud of dirt. Talk about rewarding for this kid--he was stoked, i tell ya'. The system works, almost every time.

Thanks, Steve, for your help with this question and the example you provided. I am definitely going to experiment with the information you and the others provided. Most helpful! Regards, Paul