External ballistic knowledge and range preperation

[plumbs7]

Jbm ballistic app on my iPhone , a Leica range finder , an anometer and a lot of luck. Read b litz about corialis and spindrift. Regards

Yep, I get all that GS, but do you and how do you, yourself, actually apply all that information to your usual range zeros, in preparation for a comp. Or do you feel that collecting the information for interest sake is enough for you?

Cheers,

Dennis , I zero at 100m (on the Farm) no wind and dial 50mm high ( taken off the jbm program) for a 200m zero ( hunting background) and also get a mag speed data as well.

I plug it into the jbm which with the iPhone app can get the exact atmosphere and temp at a push of an icon .

There are 2 types of coralis . Vertical and horizontal . Ok vertical is greatest at the equator and horizontal is greatest at the poles. In the Southern Hemisphere everything from jet liners to water going down the drain tend to go left including our bullets! Doesn't mater which direction u are facing , but vertical does matter! About 2" vertical at 1000 yds between East and west. Not worth worrying about .
So spin d is going right and corialis where we are is going left and is worth half a minute at 1000 yards. Spin d is worth a minute right for NATO .308. So gross correction from 700-1100 yards is .2 mills or a minute left . Half a minute 300 to 700 yds . This is always constant!

So at a comp I'll do a range recon at least 30 mins or more to pick up the bookends of a wind cycle and note maybe up to 3 or 4 conditions that I'll mentally burn into my brain so I can correct on the fly. The is where the anometer comes in as after 8mph I can't tell the difference . Maybe even take it next to a flag. And calibrate it and remember it!

Then I grab out the Leica and check the distance and I would say 50% of the ranges are out. This making u scratch ur head when u fired ur first shot. Most people blame Their loads or temp ( this does have an effect too!). Plug into the jbm and spits out a correction that I'll run with if it feels right from previous shoots !
Muckadilla all of the ranges are way out and the above methods kept me on the right side of the score board up until I choked again at the last range !

Dennis ( maybe this should be a PM) I watched you at the last northarm OPM and I say this with all the love and caring of a mate ! But I think you got lost in plotting ur shots on paper . What I'm saying is, I think it's distracting u and taking ur concentration away from the conditions that were happening. By the time u had plotted what had just happened . The conditions had changed about 3 times , it was that fast , almost unreadable and a few us noted the plotters did suffer except when one forgot to do their plotting and got a good score! Plotting is good for training or maybe bisley style it may work.

There is no substitute for brilliant wind reading ! I'll put like this , when a person is blind their hearing senses go of the chart and they can see with there ears !
Wind reading is similar . U may even notice when I'm shooting I'll take my princess Leah earmuffs of so my blinky bill hairy earlobes can feel the wind at my head or back .
Seen so many top shots throw a four because they were watching downwind but didn't feel the wind change at the muzzle .

Just a disclaimer , I'm by no means a top shot but I have some wonderful mentors to which I'm very grateful.
Cam once said that always keep looking down range at the wind , get a feel for it, don't take ur eyes of it!
I've given up writing conditions down at any OPM etc ant any range as by now I have bit of a feel for it and the Jbm is alway spot on .

So get tuned in like the blind person and you'll see everything on the range !
Keep on it Champ! Regards Graham.
Ps I hope I haven't overstepped my mark or offended anyone . Sorry in advance if I have .

[DenisA]

G'day Graham. I haven't plotted anything other than my sighters, often only my first, since the end of the National Queens last June. I had the same advice from a few shooters back then which prompted me to give it away once I was on. I've definately been scoring a little better since. I still always take a plot sheet to the mound though.

That said, I have plenty of problems to work on. If I started a thread on that I wouldn't know where to begin.

My intent for this thread was not to self diagnose but to understand how the technical ballistic info is being used by others and where I could improve my preparation.

I do appreciate your input GS. No offence taken.

[plumbs7]

Hi Mate , well the most important thing is to feed the jbm with precise info, watching the wind for at least one cycle and most important thing which for me is very hard , don't Gas bag before ur first detail.

Yep I still have heaps to learn myself and parallels between my life and my shooting again remind me of who I am . Hope to become a better person one day!

Thanks heaps Dennis hope to catch up at Crowsnest soon ! Regards Graham.

[williada]

Graham, I like the Leica idea. Cutting the general yap and concentrating on the wind cycles before shooting for a brief period is good practice. I often get a new shooter and talk one to one explaining the range conditions before I shoot or they shoot. It also re-enforces my own strategies for the day. Also, these phone apps are unbelievable. Unfortunately, where I live in the bush I have a black spot for phone reception.

You blokes must have got plenty of rain as cattle prices have shot over $2 a kilo down here. Must be a lot of re-stocking? A few lightening strikes have started a few fires tonight but the rain is knocking them out.

[plumbs7]

Yes 17 inches and counting, very nice!

[Norm]

Also, these phone apps are unbelievable. Unfortunately, where I live in the bush I have a black spot for phone reception.

Most of the phone apps don't need phone reception to function. Once it has been downloaded onto the phone you can use it with the phone in aeroplane mode in remote areas where there is no phone coverage, this saves on battery power.

Its only if you have your app linked to the local weather station and use their data for computations that you need coverage. I don't recommend this though as the data may be different to your exact location.

[DenisA]

Also, these phone apps are unbelievable. Unfortunately, where I live in the bush I have a black spot for phone reception.

Most of the phone apps don't need phone reception to function. Once it has been downloaded onto the phone you can use it with the phone in aeroplane mode in remote areas where there is no phone coverage, this saves on battery power.

Its only if you have your app linked to the local weather station and use their data for computations that you need coverage. I don't recommend this though as the data may be different to your exact location.

G'day Norm, do the phones sense temperature and pressure themselves? I thought all that info had to be taken from the B.O.M based on the phones location.

[williada]

Thanks Norm. I am reluctant to use a mobile phone because my brain surgeon told me my tumour was more than likely caused by one. He said he was seeing a lot this new phenomenon on the acoustic nerve/brain region. Of coarse, I used to rely heavily on the old analog phone which was probably as good as a microwave oven. I'm glad I had kids before the phones came on the market. Hope your guys don't put the phones in your pocket. We males were blessed with two brains.

Denis, I use and old Kestral wind anemometer which actually has density altitude, temperature, humidity etc. etc. However I don't use the wind functions as I have a picture in my brain of what flag speeds and mirage values are. If you use a phone, it must be similar to my Ipad which takes measurements from regional centres closest to you. This is better than no information and having a Kestral is better still for accurate range conditions.

[bsouthernau]

G'day Norm, do the phones sense temperature and pressure themselves? I thought all that info had to be taken from the B.O.M based on the phones location.

As Norm stated, there's little point in feeding your software BoM data - GIGO. I've just had a look at the two stations closest to my home range and the temperature and humidity are pretty consistent. However the wind readings would be useless and the pressures reported are reduced to MSL whereas what we need is the actual station-level pressure. The only way to get anything meaningful is to take the readings on-site and hope that the measurements you made behind the mound are representative of the atmosphere the bullet will fly through.

Barry

[bsouthernau]

We males were blessed with two brains.

Turn it up David. Blokes have only one brain and I think we both know where it's located!!

[Norm]

Denis,

No they don't unless you have a special model that can do it and I don't know of any.
What they can do is get information from the nearest weather station.

What I do is simply input the data into the phone myself. That way I am sure of the accuracy of the input.
I use a Kestrel 3500. This gives all the data required. This is mostly used for field shooting and not so much at the range.

I don't use it on the mound though as I think it is against the rules. I might however use it to check the pressure and temperature on arrival at the range. I then input this as part of my normal process in working out what my elevation needs are to get me onto the target at the first distance.

I find the first shot is an important check on my equipment. If I am shooting a regular load in that particular rifle, it will have been through a full trajectory validation process. The first shot should land where I expect it too. A clean bore may land slightly lower but that would be expected.

For wind drift, I simply leave the input at 10mph and see what adjustment is required for the first distance at that wind strength. Then when I am on the mound and about to fire my first shot. I look at the flags/trees/grass/mirage etc. and make a judgement call on the right angle wind strength. If it is say 4 mph I will use 4/10's of the full value wind correction.
I then use the horizontal point of impact difference between my guestimated wind strength value and what it actually is. I then use this to fine tune guestimation to what I can see in the flags/trees/grass/mirage etc.

This is the value of shooting on your home range. Local shooters get use to the local conditions and how to read the range. Visiting shooters must rely on the limited feedback that they are getting from their shots on the day and relate that to what they are seeing down the range. Its all part of the challenge to a travelling shooter I suppose.

The pressure throughout the day will not change much but the temperature might. So you may want to consider this as the day progresses.

[bsouthernau]

I find all this stuff very interesting but let's not lose sight (pun intended) of what we're talking about which is coming up with some sort of guess regarding the initial sight setting. Once you're on the mound all you've got to work with are the flags, the bullet holes and your head. I own and use some of the gear we've been talking about but all you really NEED is a book where you record your sight settings each time.

Barry

[mike H]

Technology is wonderful,but eventually you have to rely on your own judgement,for me,one of the pleasures on a rifle range,is to look over the range and make a decision on your first sighter and send one down.The closer to the center the shot is the better,but I don't fret so long as it is on the plate.
Mike.

[ecomeat]

This link is to an article about Density Altitude and its effect on bullet drift , on the Llilja Barrels website
It might be of interest to some, and is in laymans language.
http://www.riflebarrels.com/articles/50 ... ensity.htm

[DenisA]

I find all this stuff very interesting but let's not lose sight (pun intended) of what we're talking about which is coming up with some sort of guess regarding the initial sight setting. Once you're on the mound all you've got to work with are the flags, the bullet holes and your head. I own and use some of the gear we've been talking about but all you really NEED is a book where you record your sight settings each time.

Barry

I enjoy learning about all the technical stuff Barry, but I may not be pedantic enough to be currently making good practical use of it. Hence why I ask what other people do with it. I'd still love to hear from Dave Mc, Cam Mc, Rod, and many others on their own practical use of the info, if they have time.

I guess a racing car driver doesn't need to be a mechanic or an engineer, he just needs to know how to get 100% out of the car, if the cars doing what he wants it to and if its not he only needs the ability to describe the problem to his crew. We may not have a pit crew, but Ozzy shooters have Wiliada!!!