a little help ples

S

stoker150

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Full Member
Minuteman
Mar 29, 2009
17
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67
#1
hello there peeps. a bit of help needed I have recently started to use a kestrel 4500 nv with horus. trying to figure it out at the moment going out soon to try it at about 750m. I am shooting a trg 42 .338 lap mag 1x12 twist, with a 250gr sierra gk bullet with 85.5gr h4831sc of pwder na fedrall magnum primers. also hornaday 250gr interlock with 70gr same powder same primer. glass is s&b pm2 5x25x56. any help very much apreichiated as the user hand book is about as much help as tits on a bull. also have wind to contend with but living in the highlands of Scotland you get used to it that and webbed feet :)) thanks again.
 
#5
stoker150 said:
Ok sorry I haven't been more specific. My issue is with true drop ? What is it and what does it do and is it a game changer ? .
Click to expand...
On the "how" I will defer to others with better knowledge of that particular unit than I have, but I will try to give you a basic answer. Say you go out to the range and your Kestrel tells you for your conditions you need to dial 11.6 mil elevation to hit your target. You dial that, are shooting on a known distance target and are confident your muzzle velocity is dead on to what you entered (and all other inputs as well), yet you have to dial 11.9 mil elevation to get rounds on target. In this case you would want to "true" your elevation and this would give you adjusted BC and other scaled output data to get better hits on target.

Is it vital? Maybe. If you are confident in your data you're putting into the unit, then it can be a good idea to true it up. However if you are doubtful on your MV or range, have guessed on other input items rather than putting in specific data, you should look at what you may have done wrong. Like any software, junk in, junk out.

There's other particulars such as coming into transonic zone downrange and whether you should tweak those numbers or not, but that is well outside of my realm of ballistics knowledge.
 
#6
Ok first off thanks for the help. Got to shoot this afternoon 14in circle stainless steel plate at 745m wind gusting 7 to 10 mph. No spotter fired 3 rds sierra gk 250gr no hits backstop grass and heather. So onto quad to look for strike turned out to be low and left. Back to fp adjust 2 clicks up and 2 right nah decided to make it 3 both ways. Fired annother 3 rds 2 good hits 3rd round I fluffed. Then tryed the hornaday 250gr interlock the horous said two mill more than the gk mmm any way fired 3 rounds same drill as before couldn't find any strike and besides how would I tell if it was them or the gk rounds. So pack up and home adjusted the bc and mv on the kestrel to match the elevation on the scope.
 
#9
Your power charges (assuming from your manuals or Quickload) may say one thing, but there is absolutely no substitute to confirmation over a chronograph. Two barrels from the same maker and chambered by the same reamer can yield a velocity difference with the same load. Some barrels are fast, some are slow...

Get yourself one of these: MagnetoSpeed V2 Ballistic Chronograph | MagnetoSpeed

Before you start tweaking your BC, make sure your MV (and all other for that matter) numbers are accurate. Again, junk in, junk out.
 
#10
I get a good 200 yard zero and then shoot at 900 yards (your 745m is ok, but further would be better). I make scope elevation adjustments until my bullet strikes are at the correct elevation and then adjust the MV in the Kestrel until the meter gives me the elevation reading that matches what's on my scope. Much better than a chrono, however the chrono will get you close to start with.
 
#11
If you have an accurate measurement of your MV from a chronograph, you want to adjust your BC, not your MV. If you don't trust your MV readings from your chronograph, it's time to get yourself a new chronny.
 
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