Wind number and caliber/cartridge

[Marbles]

Short version:
What caliber, cartridge, bullet, and velocity gets the best wind performance? How does this change when recoil is considered?

I was scouting for goats the other day in an area I have a tag for when season starts. I glassed up a Billy in a saddle, at that point in time winds were 15-20 mph running almost exactly left to right. The goat was at 600 yards, assuming I stocked to 300 yards, the conditions that day would have given me a 16 inch drift (4 mph 223 with 77 TMK at 2700 fps). The day before I had 20 mph sustained winds with gusts of 35 mph on an exposed ridge, saddles felt worse, but I did not pull the Kestrel out. This means a wind gust could have moved my shot by almost 13 inches if I was holding for a 20 mph wind.

This has me certain I will be bringing my 243 come August. However, even with 108 ELD-Ms the 243 is only a 5 mph gun (expected velocity 2900 fps), 11 inches of drift at 300 yards with a 20 mph wind, 19 inches in a 35 mph wind. This is much better. However, even if I can launch a 108 ELD-M at 3200 fps from something like a 6 UM it is still only a 6 mph gun.

Playing in AB it looks like a 7mm is were BC starts to really improve wind performance with a 180 ELD-M at 2600 fps being a hair better than a 6 mph gun (I think that is a reasonable short barreled 7mm-08 velocity?, though it might be optimistic). Same bullet gets a 7 mph gun if one steps up to something that pushes it to 2800 fps. It looks like a big 300 does not really get better wind performance, for example, a 225 ELD-M thrown at 2800 fps (300 PRC) is still a 7 mph gun and brings a lot more recoil.

I will be shooting my 243 barrel out before getting any new cartridge, however I'm questioning if I will stay with a 6mm. However, based on my ability with a suppressed 308 slinging 178 gr bullets, at present recoil is a clear issue for my shooting ability, and trading poor shooting all the time for better edge case scenarios is fullish. So not saying I will go bigger either.

Given that @B_Reynolds_AK uses a 6mm, I'm probably wasting my time (but I'm watching the kids today, so not like I could be in the field or actually shooting with the time).

 

[B_Reynolds_AK]

Well I’ve certainly gone through the same thought process in the past. As you referenced, I’ve switched from a 6.5 to a 6 CM recently in order to benefit from the increased wind number with less recoil.

I’m literally out in the mountains shooting rocks right now. I hiked up 3,000 ft last night and shot at midnight and then this morning as well, in differing wind conditions. From 450 to consistent hits in the 900’s and walking impacts in after 1-2 shots out to 1550. With the 6 mph gun and ability to easily spot impacts, I think I’ve found a sweet spot for myself. To get to a 7 mph gun, you really need to bump up in velocity, which equals more powder and recoil. We ARE going to screw up wind calls, and shooting/hunting solo as I often am, if you cannot spot and correct for the miss, you are greatly disadvantaged.

Of course calling the wind accurately is more important than a 1 mph increased wind number on a gun, so practicing in real world conditions like this is so vital.

I’m shooting the Barnes Match Burner 112’s with a confirmed G7 B.C. of .286 at 2940 fps from this 20” barrel.

The only other cartridge that I would consider right now that may give me a slight advantage is the 22 CM w/ 88 ELD-M’s, but it’s not significant enough for me to change after investing in the 6.

 

[Marbles]

Well I’ve certainly gone through the same thought process in the past. As you referenced, I’ve switched from a 6.5 to a 6 CM recently in order to benefit from the increased wind number with less recoil.

I’m literally out in the mountains shooting rocks right now. I hiked up 3,000 ft last night and shot at midnight and then this morning as well, in differing wind conditions. From 450 to consistent hits in the 900’s and walking impacts in after 1-2 shots out to 1550. With the 6 mph gun and ability to easily spot impacts, I think I’ve found a sweet spot for myself. To get to a 7 mph gun, you really need to bump up in velocity, which equals more powder and recoil. We ARE going to screw up wind calls, and shooting/hunting solo as I often am, if you cannot spot and correct for the miss, you are greatly disadvantaged.

Of course calling the wind accurately is more important than a 1 mph increased wind number on a gun, so practicing in real world conditions like this is so vital.

I’m shooting the Barnes Match Burner 112’s with a confirmed G7 B.C. of .286 at 2940 fps from this 20” barrel.

The only other cartridge that I would consider right now that may give me a slight advantage is the 22 CM w/ 88 ELD-M’s, but it’s not significant enough for me to change after investing in the 6.
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That looks like great weather.

Agree on the practice bit, and will probably focus on 223 practice because it will do less to cover up my lack of skill. Once I burn out the 243 barrel, I will probably go with a different chambering (such as 6 Creedmoor). Before I would go heavier, I would screw my 308 barrel back on and see how I shoot with the increased recoil.

Between the 223 and the 243, I probably have 5000 rounds of practice before I actually have to make a decision.

 

[khuber84]

A velocity above 3000 fps, with the bullets per caliber that are in the top 10% of available BC. So 6mm cm with say 112 match burner at 3000 fps, 25 prc with 134 at 3100 fps is prob similar to a 6um with 115s around 3200/3300, within a tenth of wind. Then you step up to 65prc/Saum with 147/156 at 3000-3100fps. Above thay you get into 270wsm and Weatherby with 170/175 2950-3000fps. To get above 3000 in a 7mm with 175gr or heavier, you need a big case, 7mag 7lrm, stw, 28 nosler, recoil jumps a lot. Then with 30 cals, 200+ gr bullets at 3k the recoil is getting stout with bare muzzle, even with a brake there is a LOT of energy in the rifle, recoil and braking energy, very hard on optics and mounts.

Granted a 6cm VS say a 300 rum, the rum out classes it in the wind by at least 1mph, maybe two on the gun number. I know my 338 rum with 300otm is a 10-11mph gun depending on DA, my 6cm is 8mph gun. You still have to be efficient at reading wind/terrain to apply the gun number to your shooting situation.

 

[wind gypsy]

20+ mph wind is a handful, no way around that.

 

[Marbles]

I might be using mph gun wrong; I'm bassing it off of roughly 0.1 mil per hundred yards. If I have the terminology wrong, someone please correct my ignorance.

20+ mph wind is a handful, no way around that.

I had just told myself I had no business shooting past 400 on an animal, so wind was a minimal concern, those conditions made me realize it can be a problem at closer ranges.

 

[khuber84]

To calculate this properly(to my knowledge) choose a DA. Turn off spin drift, use a 9 o'clock wind direction. Find the wind value that gives you 0.5 mil at 500y, 0.6 at 600y, 0.7 at 700y. Likely at 800y it'll be 0.9 but maybe not.
You're seeking the full value wind number that equates to the above drift figures. This is how it was taught by modern day sniper several years back when I first heard it. The simple quick wind concepts cost me a shit ton of money swapping everything over from moa to mils bout 5 yrs ago.

 

[B_Reynolds_AK]

No, you’re correct on the wind number, being that you dial to the same number as the range in hundreds of yards. Ie. .4 = 400 .5 = 500 etc. for the given wind speed that corresponds to the mph number of your rifle, referenced by looking at your ballistic calculator.

 

[Rippey715]

25CM running 134 ELDMs at 2765fps; 7.5mph wind number to 900yds. Slightly less recoil than a 6.5. Slower speed makes it easier to spot shots beyond 400.

 

[wind gypsy]

I had just told myself I had no business shooting past 400 on an animal, so wind was a minimal concern, those conditions made me realize it can be a problem at closer ranges.

Yeah, unless max range is like 150 yards, 20-30+ MPH winds are going to take some consideration.

 

[Lawnboi]

One thing I consider is the weight of the gun compared to the bullet. For example the 223 is easy to shoot and spot in fairly light package. That changes when you move up in cartridge bullet. A higher wind number is awesome but it’s a give and take, especially on awe site like this where everyone needing an 8 pound rifle.

Something bigger becomes much more manageable in a 12-14 pound package.

When considering rifles in the future, that’s something I’ll take into account. If the area determines I need better ballistics, and can take advantage of those, it’s going to come with a weight penalty.

Re the 223. They suck in the wind, no way about it. 4mph rifle, at 400 yards, 1 mph is a tenth of wind. Those 20mph gusts ranging from 15-20mph are now pushing my bullet half mil. I find when shooting rifles wind number at that mark where 1mph is one tenth it begins getting a lot harder to hit reasonable targets.

350ish is already sporty enough for me with the 223 in manageable winds. Personally that’s why I carry a 22 creed if I want no recoil and a 6mph rifle.

 

[Formidilosus]

Short version:
What caliber, cartridge, bullet, and velocity gets the best wind performance? How does this change when recoil is considered?

Recoil above 12-15ft-lbs nearly wipes out any advantage of wind number for field shooting.

I was scouting for goats the other day in an area I have a tag for when season starts. I glassed up a Billy in a saddle, at that point in time winds were 15-20 mph running almost exactly left to right. The goat was at 600 yards, assuming I stocked to 300 yards, the conditions that day would have given me a 16 inch drift (4 mph 223 with 77 TMK at 2700 fps). The day before I had 20 mph sustained winds with gusts of 35 mph on an exposed ridge, saddles felt worse, but I did not pull the Kestrel out. This means a wind gust could have moved my shot by almost 13 inches if I was holding for a 20 mph wind.

This has me certain I will be bringing my 243 come August. However, even with 108 ELD-Ms the 243 is only a 5 mph gun (expected velocity 2900 fps), 11 inches of drift at 300 yards with a 20 mph wind, 19 inches in a 35 mph wind. This is much better.

Taking shots on animals in 30+ mph winds… don’t do it regardless of cartridge or bullet. You will eventually, and at a relatively high rate- miss call badly.

However, even if I can launch a 108 ELD-M at 3200 fps from something like a 6 UM it is still only a 6 mph gun.

Are you figuring the wind brackets at sea level? At 5k DA which is average to low for western hunting, the 6UM on the slow side (3,250fps MV), is between a 7 and 8 mph gun with 108’s. A 6CM is a 7mph gun with same. The 6 UM with 112gr MatchBurners is between a 9 and 10mph gun.

Playing in AB it looks like a 7mm is were BC starts to really improve wind performance with a 180 ELD-M at 2600 fps being a hair better than a 6 mph gun (I think that is a reasonable short barreled 7mm-08 velocity?, though it might be optimistic). Same bullet gets a 7 mph gun if one steps up to something that pushes it to 2800 fps. It looks like a big 300 does not really get better wind performance, for example, a 225 ELD-M thrown at 2800 fps (300 PRC) is still a 7 mph gun and brings a lot more recoil.

Don’t go chasing the rabbit. Either you can make solid wind calls and correct off hits/misses correctly and quickly, or you can’t.

We just spent 6 days shooting in really broken terrain with 17 people, and the hit rates were all based on the shooter. From 223’s to 7 PRC and lots of things in the middle. The best performer as a cartridge/bullet combo to 1,022 yards was a 22CM with 88’s. There were also people really close/right there with a 6.5 PRC with a hot 147gr load, 6cm with 108gr factory, and out to 550 yards or so multiple 223’s even with 69gr SMK’s. One shooter was also right there with the top guys with a 308win and 168gr Good Medal match to about 600 yards.

While there are differences in bullets and cartridges, Individual skill makes the difference, not buying your way into.

 

[JollyRoger]

I figured my 6CM with factory 108s at 6mph which might be slightly conservative.

20” barrel with suppressor and my MV is 2860.

 

[Marbles]

Are you figuring the wind brackets at sea level? At 5k DA which is average to low for western hunting, the 6UM on the slow side (3,250fps MV), is between a 7 and 8 mph gun with 108’s. A 6CM is a 7mph gun with same. The 6 UM with 112gr MatchBurners is between a 9 and 10mph gun.

I'm using standard atmospherics, so yes, sea level. At 2000 feet above sea level DA was 1600 feet the other day. I have not been paying attention long enough to be certain, but it looks like most of my hunting will take place between -1000 and 5000 density altitude.

Do you adjust wind numbers for DA? Are fractional wind numbers worth it?

My assumption is fractional wind numbers advantage is overshadowed by wind call error and changes in DA.

Going for whole numbers only, and pushing out my current maximum engagement range to what I expect it is (must confirm in hunting country on rocks, current high confidence range is 300 yards) to 400 yards, changing from 0 to 5000 feet in DA looks to make no functional difference and I still get a 5 mph gun with my expected velocity and 108 ELDMs (looks to be more significant at longer ranges, but I have not payed much attention to these longer ranges yet).

Recoil above 12-15ft-lbs nearly wipes out any advantage of wind number for field shooting.

My current shooting has me thinking recoil above 12ish ft-lbs degrades my shooting notably. Taking a permanent handicap for an edge case advantage would be foolish, and despite my hopes fairy dust doesn't exist. Well, no better than a 22 creed or 115 DTAC with deep nose ring is what it sounds like.

Taking shots on animals in 30+ mph winds… don’t do it regardless of cartridge or bullet. You will eventually, and at a relatively high rate- miss call badly.

Before looking at my Kestrel, I badly over called the windspeed at my location. I had not considered it (which shows the conditions are not common), but guess I should treat it like max engagement ranges, don't fudge and get closer, or don't shoot. Better to let a healthy animal walk than loose a wound one.

Don’t go chasing the rabbit. Either you can make solid wind calls and correct off hits/misses correctly and quickly, or you can’t.

Roger.

We just spent 6 days shooting in really broken terrain with 17 people, and the hit rates were all based on the shooter. From 223’s to 7 PRC and lots of things in the middle. The best performer as a cartridge/bullet combo to 1,022 yards was a 22CM with 88’s. There were also people really close/right there with a 6.5 PRC with a hot 147gr load, 6cm with 108gr factory, and out to 550 yards or so multiple 223’s even with 69gr SMK’s. One shooter was also right there with the top guys with a 308win and 168gr Good Medal match to about 600 yards.

While there are differences in bullets and cartridges, Individual skill makes the difference, not buying your way into.

My current plan is to buy skill in the form of expended rounds, primarily 223. So far it is working well, but still needs a lot of investment.

 

[croben]

Well I’ve certainly gone through the same thought process in the past. As you referenced, I’ve switched from a 6.5 to a 6 CM recently in order to benefit from the increased wind number with less recoil.

I’m literally out in the mountains shooting rocks right now. I hiked up 3,000 ft last night and shot at midnight and then this morning as well, in differing wind conditions. From 450 to consistent hits in the 900’s and walking impacts in after 1-2 shots out to 1550. With the 6 mph gun and ability to easily spot impacts, I think I’ve found a sweet spot for myself. To get to a 7 mph gun, you really need to bump up in velocity, which equals more powder and recoil. We ARE going to screw up wind calls, and shooting/hunting solo as I often am, if you cannot spot and correct for the miss, you are greatly disadvantaged.

Of course calling the wind accurately is more important than a 1 mph increased wind number on a gun, so practicing in real world conditions like this is so vital.

I’m shooting the Barnes Match Burner 112’s with a confirmed G7 B.C. of .286 at 2940 fps from this 20” barrel.

The only other cartridge that I would consider right now that may give me a slight advantage is the 22 CM w/ 88 ELD-M’s, but it’s not significant enough for me to change after investing in the 6.
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Not to hijack the thread, but what pack is this?

 

[Marbles]

One thing I consider is the weight of the gun compared to the bullet. For example the 223 is easy to shoot and spot in fairly light package. That changes when you move up in cartridge bullet. A higher wind number is awesome but it’s a give and take, especially on awe site like this where everyone needing an 8 pound rifle.

Something bigger becomes much more manageable in a 12-14 pound package.

When considering rifles in the future, that’s something I’ll take into account. If the area determines I need better ballistics, and can take advantage of those, it’s going to come with a weight penalty.

Re the 223. They suck in the wind, no way about it. 4mph rifle, at 400 yards, 1 mph is a tenth of wind. Those 20mph gusts ranging from 15-20mph are now pushing my bullet half mil. I find when shooting rifles wind number at that mark where 1mph is one tenth it begins getting a lot harder to hit reasonable targets.

350ish is already sporty enough for me with the 223 in manageable winds. Personally that’s why I carry a 22 creed if I want no recoil and a 6mph rifle.

My current 8.5 pound set up as already on the heavy side, so I would rather take a wind handicap than add several pounds. I certainly will not be going back a the recoil of a 7 pound 30-06.

 

[willfrye027]

Great discussion! I am still “tempted” with ballistic masturbation. When I started shooting long range my plan was to buy my way into getting hits at long range..

Realistically I could/should have started with a 223 and a 6.5 creedmoor and ended up at the same place I am now, for much cheaper and probably faster.

Forms recoil consideration is pretty much spot on for me. I tried a bunch of different stuff and pretty much decided that 12ft/lbs is as much as I can comfortably shoot.

These days I try to shoot my 223 as much as possible—crappy wind number but has significantly improved my shooting even though I’m only 800 rounds in with it.

For my “hunting” rifle it’s been a 25 creedmoor at 9.5lbs all in…great wind number/recoil but not dramatically better than 6.5 creedmoor loaded super hot.

I’ve been experimenting with 22 creedmoor and 88eld. Probably shot around 1200 of those bullets. At 1000 yards my hit rates are slightly better with the 25 creedmoor…but im starting to think it’s more a function of rifle weight (9.5lbs vs 8lb IIRC).

Definitely, the lower recoil of the 22 creedmoor I shoot better in the field and am less likely to anticipate recoil or otherwise screw up the shot process.

Considering how effective 22 and 6mm bullets are proving…my journey is taking me to smaller and smaller cartridges/bullets and giving up a tiny bit of wind number in the process.

 

[Lawnboi]

I really agree with a lot that’s said above.

If I could go back I’d own a 223 and a 6.5 creedmoor and stick with that. I’d build both to be ~10 pounds suppressed and be happy. I plan on buying a 6.5 cm barrel here soon to satisfy 6mm minimum states and have something that I’m not afraid to shoot without fear of losing a barrel by fall.

The 22 and 6 creed are very appealing but you get to the point where if you shoot a decent amount barrels fry pretty quick.

 

[Wrench]

Shooting in static wind is hard enough, Shooting long shots on game in gusty conditions is reckless to me.

I was lucky enough to be able to shoot in a 20mph blow yesterday and as a storm front passed by my impacts changed by almost 2 mils in 2 minutes. Big temp swing and wind shift.....that stuff happens in the wild often.

 

[Lawnboi]

My current 8.5 pound set up as already on the heavy side, so I would rather take a wind handicap than add several pounds. I certainly will not be going back a the recoil of a 7 pound 30-06.

Then the answer is easy, a 22 or 6 with a more efficient bullet is probably the answer. The 108 is also not the hottest 6mm bullet.

In high, gusty winds you need to know when not to shoot. When your talking that much wind, or variable winds, your not going to out BC it. A more efficient bullet surely helps a little though.