I was a skeptic until l tried it. It's right on. No need to pull the tape for all of the yardages.
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Field Target is an arms race.
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What I described is "after" I've already fudged scope height, velocity, BC, and put in DA to get the dope to line up as perfectly as possible. However my app only does G1 so that's what I have to work with and this could be the difference vs a better drag curve. I haven't tried any other apps. Be that as it may it's usually wind, mental mistakes, or positionals that get me.
I can't remember missing a close KZ in FT in years, even the 3/8th. 3/8th in UFT using 22 cal well that's a different story but I blame that on me. It's a little tough hitting one of those especially that 20+ yarder.
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You shouldn't need to fudge velocity or anythIng but bc and scope height.
The values that you may end up with as BC and scope height may be completely ridiculous and nothing close to what you actually have...., but as long as you have your shortest distance, exact and your longest distance exact along with a proper zero at the Apex… Everything else will line up
The values that you may end up with as BC and scope height may be completely ridiculous and nothing close to what you actually have...., but as long as you have your shortest distance, exact and your longest distance exact along with a proper zero at the Apex… Everything else will line up
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I do the same. Zero (25 to 27 yards roughly), 10 yards and 55 yards, Chairgun to fill in the rest, preferably off a bench and indoors. If i'm feeling frisky i'll grab some in between numbers to 'verify' with CG. Once I broke 10 to zero and zero to 55 into two separate CG profiles, I wasn't getting exactly what I wanted with the whole spread in a single profile.
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If we have good velocity, BC, scope height, and distance measurements, we should not need to “fudge” anything.
Except, a bent up/down barrel will require you to fudge the scope height.
Scope height and target distance measurements should be taken from the scope’s erector tube gimbal. That is especially true for close targets. If you use anything else (muzzle, scope objective, etc) you will be off and that is why you would need to “fudge” at 10yds.
The scope does not “know” where the muzzle is. Sure, drop is calculated from the muzzle, but clicks and reticle holdovers are angles with the vertex being at the scope gimbal. That is the only point where you can expect consistency.
Except, a bent up/down barrel will require you to fudge the scope height.
Scope height and target distance measurements should be taken from the scope’s erector tube gimbal. That is especially true for close targets. If you use anything else (muzzle, scope objective, etc) you will be off and that is why you would need to “fudge” at 10yds.
The scope does not “know” where the muzzle is. Sure, drop is calculated from the muzzle, but clicks and reticle holdovers are angles with the vertex being at the scope gimbal. That is the only point where you can expect consistency.
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Assuming the chrono is giving the actual velocity can and has been a problem for me, others, and I'm pretty sure you as well. That's why I say "fudge" because I'm putting in the velocity that works to get the dope as close as possible. Hopefully my new-ish Garmin chrono is pretty close. My Oehler wouldn't pick up 17 cal pellets so I had to do a best guess of velocity, however I must be close, like within a few fps. The other chrony's I had years ago were off because I compared them to my Oehler P35 with projectiles they both would pick up.
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I'm curious! Do some math for me please to compare the 8 inches from the middle of my barrel to the scope gimbal and how much it'll change the dope on a typical FT rifle and scope.
Thanks Scott
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At 10yds, your clicks will result in about 2.2% more correction at the target than you expect. So you’ll likely be off by a click or two.
8in/(10yds x 36in/yd)=0.022 or 2.2%
That’s just the subtensions. Your apparent scope height will also be less as you move away from the gimbal. So you’ll have that cumulative error as well. How much error will depend on the actual scope height.
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Phew, ill look at this but I just go shoot. Helps me confirm my ranging and confirms my dope. Just shows multiple ways to do things! I wasn't aware of this method previously.
Im curious now to try this and then go confirm it and see how it plays out.
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don't we all.. but Mike is right, BC and Scope height fiddling have been key to "improving" my scores.
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I have to redo all my FT guns this spring so Ill be looking into this along with the traditional method. This method may be more conducive to WFTF?
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I used that method because I usually shot a new rifle every GP. In my last serious year of FT...that was at least 7 or 8 different rifles. I didn't have time to get my numbers every time by shooting. A couple times I got my numbers at the sight in before the match began. It takes about 10 minutes compared to hours. If I thought there was a disadvantage to the method I would not have used it.
The reality of FT at advanced levels is that the game is won on the 45-55y targets and the offhand lane. Before I knew how to properly align my reticle to the bore...I could miss short small kz shots. Once I figured that out anything under 45y was pretty easy in most wind.
If my scope is off a few clicks at 25 y...I couldn't care less. The kzs are so big and the wind is so easy at those distances that it makes virtually no difference. You can be off a country mile and the target will still fall if you have a good hold. In the deadman position I can hold the crosshairs on an aspirin at 55y nearly indefinitely with no coat. If I have to shoot from a traditional position...I need a coat to do that and I'm only gonna be able to hold it for 10-15 seconds at most.
The 45-55y targets require exact numbers and that is super easy with this abbreviated method. If the other numbers are off a click I don't care.
Mike
The reality of FT at advanced levels is that the game is won on the 45-55y targets and the offhand lane. Before I knew how to properly align my reticle to the bore...I could miss short small kz shots. Once I figured that out anything under 45y was pretty easy in most wind.
If my scope is off a few clicks at 25 y...I couldn't care less. The kzs are so big and the wind is so easy at those distances that it makes virtually no difference. You can be off a country mile and the target will still fall if you have a good hold. In the deadman position I can hold the crosshairs on an aspirin at 55y nearly indefinitely with no coat. If I have to shoot from a traditional position...I need a coat to do that and I'm only gonna be able to hold it for 10-15 seconds at most.
The 45-55y targets require exact numbers and that is super easy with this abbreviated method. If the other numbers are off a click I don't care.
Mike
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This must be specific to WFTF?
For the American classes of field target (sub 20fpe). If you're 19ish fpe, calling it 50 or 55 won't make you miss. Ie trajectory isn't so loopy that it puts you out of the 1.5" kill zone. Wind reads are a different story.
Can check actual some time, but working from memory I think my 50 and 55 is a 0.2mil holdover difference on that last gun I used in a match. Not positive, but wanna say it was 0.8 mil for 55 and 0.6 mil for 50. At least at my home elevation, going down 5000 feet to that match required me to hold over more. But the difference between 50 and 55 was still only something like 0.2-0.3 mil.
Edit: yeah I checked my Strelok profile for this gun, which as previously mentioned is "close" but not perfect. 0.3 mil difference between 50 and 55 yards.
I imagine it's much more critical with a low BC 8gr and/or a pellet moving 100fps slower.
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The 45-55y targets in wftf need exact numbers BECAUSE of the wind. You cannot afford to shrink the width of the kill zone because you are off a little in vertical. If there was no wind to worry about..... +/- 5y would probably be fine if you had a good hold.
Mike
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I don't think CG can adjust for canted rails/mounts, if it can i've never found where to do it.
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At 20 ft-lbs, if your group size at 55 yards is larger than 3/4" your long distance clicks start to matter more in the wind.
Take a dime and put its center towards the top edge of a quarter (head wind), now substitute a penny then nickel (keeping the center in the same location) and you can see how larger groups sizes will create more misses at distance when you can't just aim/hit dead center.
Mike has a great wind charting article that I took a step further and created full charts of wind constants that work with mil/moa reticles and at any rifle power or scope mag level (shoot in a known wind and count the hold off then select the proper chart). I've been using this for a bunch of years now, but more to the point this was a tremendous help at the Worlds and allowed me to basically hit every pure cross wind shot without any real wind practice.
Take a dime and put its center towards the top edge of a quarter (head wind), now substitute a penny then nickel (keeping the center in the same location) and you can see how larger groups sizes will create more misses at distance when you can't just aim/hit dead center.
Mike has a great wind charting article that I took a step further and created full charts of wind constants that work with mil/moa reticles and at any rifle power or scope mag level (shoot in a known wind and count the hold off then select the proper chart). I've been using this for a bunch of years now, but more to the point this was a tremendous help at the Worlds and allowed me to basically hit every pure cross wind shot without any real wind practice.
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55yd groups larger than 3/4"? Sounds like time to join the arms race and buy something better.
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truth! I personally struggle with anything worse than MOA. I feel at MOA accuracy its one less variable I have to worry about.55yd groups later than 3/4"? Sounds like time to join the arms race and buy something better.
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