GTA
All Springer/NP/PCP Air Gun Discussion General => "Bob and Lloyds Workshop" => Topic started by: Spacebus on April 24, 2022, 05:57:49 PM
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I live on the coast and our winds are variable and can come from any direction. Today the weather folks said the wind was around 10 MPH, but I tried to time shots between gusts/breezes. At what wind speed do lighter slugs start to become inaccurate? I would have assumed a .25 cal 42-FN BBT at 850-900 FPS or .249-39 HP traveling 900-950 FPS would have less wind drift or stability issues, but I saw it first hand. I tried shooting at 50 yard but could not keep a group in a 4" circle. At 25 yards groups were still going from 1/2" up to 2". All of my shots were from a heavy bag under the rifle on a table seated. Unfortunately my chronograph isn't working right now and I'm waiting on a new one, so I can't give 100% accurate data.
Would a 200+ FPE .257 resist wind better? My .457 Challenger shooting 225 grain HP BBT (.458-244-FN) at 960 fps can keep five shots touching at 50 yards.
I suspect my powdercoat skills may have contributed to some of the group size issues on the .249-39 slugs, but the BBT's could group in 1/2" at 25 yards no problem.
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Drift is proportional to the crosswind speed (vector at 90 deg. to bullet path), and to the BC....
Bob
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I have a hard time with it .
Shooting opensighted i shoot dead on to see whete i hit then walk back and apply Kentucky windage the best i can.
Not a clean target but slapped a snuff can lid on a cleaner spot on the cardboard shot and was low right about 4 oclock or so. Then shot about on that scribble in spot the best i could at 11 to clock and was able to at least get in the lid each time ..lol...
Man im sick of this wind here everyday for months now. Like 10+.
Kinda sloppy picture to look at
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I have only 160 fpe .257, but it has less wind drift than a .22lr at 100m. In bad wind conditions groups spread out to 1.5"-2" at 100m.
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I have only 160 fpe .257, but it has less wind drift than a .22lr at 100m. In bad wind conditions groups spread out to 1.5"-2" at 100m.
Do you know how .257 compares to .308 for air guns? That's the kind of performance I am looking for at long range. Are you using cast slugs?
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I have only 160 fpe .257, but it has less wind drift than a .22lr at 100m. In bad wind conditions groups spread out to 1.5"-2" at 100m.
Do you know how .257 compares to .308 for air guns? That's the kind of performance I am looking for at long range. Are you using cast slugs?
.257 is about the sweet spot for good BC bullets shot at reasonable pressure. .308 has better bullets but to get them up to speed means you need more than 3000 psi with 30" barrel. I'm shooting cast 257420BTs from my gun, best 5 shot group so far is 12.5mm at 100M. I was last weekend at range in a bad weather shooting my .257 and Anschutz 54 and .257 did better groups.
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I have only 160 fpe .257, but it has less wind drift than a .22lr at 100m. In bad wind conditions groups spread out to 1.5"-2" at 100m.
Do you know how .257 compares to .308 for air guns? That's the kind of performance I am looking for at long range. Are you using cast slugs?
.257 is about the sweet spot for good BC bullets shot at reasonable pressure. .308 has better bullets but to get them up to speed means you need more than 3000 psi with 30" barrel. I'm shooting cast 257420BTs from my gun, best 5 shot group so far is 12.5mm at 100M. I was last weekend at range in a bad weather shooting my .257 and Anschutz 54 and .257 did better groups.
I appreciate you sharing your experience. I live in such a windy place I'm learning that if I want to shoot past 25 yards my Eagle Claw and Stormrider are not cutting it. On a perfectly calm day I can get good accuracy at 50 yards with both, but we normally have a 13-20 KPH wind. My .45 cal rifle doesn't seem to care about wind at 50 yards, but It's pretty hungry for air.
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