Heavy vs light bullet Wind drift

[284winner]

Hello all,

Like many I spend too much time looking at ballistic calculators and plugging numbers.

I’ve been kicking around the idea picking up another barrel and would like something to cheat the wind a little.

I shoot a 6 creed now but would like to play with the saum/wsm case.

I’m just not seeing a wind drift advantage with a 300 wsm vs a 6 creed at 1000yds like I had thought I would.

Reference to a 208gr bullet vs 115gr.


My question: 2 bullets with the same bc at the same velocity but bullet A weighs 100 grains more than bullet B. Shouldn’t the wind have less influence over the heavy bullet?


Thanks,
RR

Going to get alot of feedback on this but... Oh Well, here goes.
IMO...Stick with the 208 eld. Sounds like that's what your referring too. Recoil enters into that formula as well. Just something to consider.

 

[284winner]

All things being equal, go heavier in wind. Just what tends to prove itself again and again.

 

[Laurie]

I have no findings. I was just suggesting a test that goes directly to the point of what the real world results are. Generally we know that there are trade offs. Higher recoiling (larger caliber, heavy bullet, big case) combinations tend to shine as the wind becomes more challenging, but it would not be a good idea to bet against a good Dasher or 6BRA on a day when the wind is more moderate.

Oddly enough, I've just mentioned shooting a 7mm-08 F-Class rifle in 600/1,000 yard BR in another live thread in the Big Stuff section:

http://forum.accurateshooter.com/threads/7mm08-used-in-100yd-benchrest.3947010/#post-37171269

The 7mm 160 gn Sierra TMK only has a slightly higher BC than the better 105-108 gn 243s and my MVs are comparable with 6BR at 2,830 fps. Competitive against a proper 6BR or Dasher 'Heavy Gun'? No way!

An F-Class shooting friend did such a test some years back when he lived in New Zealand, in this case two good prone shooters firing 6.5X47 Lapuas with known good precision at 1,000 from the prone position in varying wind conditions. The butts crew recorded the lateral distance from the target centre for each shot on the two targets. He was testing the 140gn Berger VLD against a competing bullet at the same MV more or less. Bergers were available in the country but its the 6mm VLDs were nearly double the price of the other bullet. In this case, the VLDs lived up to the BC claims, the reduced drift being very close to what the ballistic program predicted.

 

[mysticplayer]

For those of you for whom seeing is more convincing than calculating I suggest a test. This was actually done at my suggestion by some short range shooters. On a day when the wind is varied and relatively steady for periods of time, when both left and right are seen, put two shooters on adjacent benches firing at targets that are side by side at the same distance. With both holding center, shooting the loads that they would be in competition with a particular bullet/caliber combination, have both shooters fire at the same time choosing wind conditions that will show the most deflection both left and right. Since muzzle brakes are allowed for long range benchrest it may be desirable to skip a bench between shooters to make sure that muzzle blast from one rifle does not affect the bullet from the other. Since both shooters will be shooting at the exact same instant, comparing the width of their groups should either verify or disprove what ballistics software has predicted. For this test, the velocities do not have to be the same because what is important is the real world effects of the wind at the velocities that have proven to be the most accurate for those particular combinations, the velocities that would actually be used in competition.

This is called Volley fire testing and works very very well at giving real world results to complicated questions.

For team shooting, it allows a quick comparison to confirm zeros, ballistics and rifle set up.

For testing, it is a dead simple way to get past all the assumptions and math.

In this case, create 2 ballistic twins but with varying weights and cals. The biggest extreme and likely, easiest to create would be a 223 and a 308. Run the numbers on whatever combo is equal. Set the zeros (POI) to be the same at distance... the further the better for this test.

Obviously, the accuracy of both rifles should be similar and confirmed in no wind conditions.

On a day with winds (gusty, strong, nasty stuff), get both shooters to fire at the same time but keep the center hold. All you are doing is a real time, real world comparison between two bullets flying to the target.

Plot where the bullet lands from each rifle. If you have scoring pits, this is easy but can also be charted with remote camera.

See what happens and decide for yourself.

FYI, in mid range FTR (out to 600yds), there are a number of shooters using 223 and competing very well against the 308. In open, the 6mms and 6.5's give the 7mms a real run.

however at LR (out to 1000yds), I was one of the very few using a 223 and it wasn't even a close race vs the 185's of the day. On paper, my 223/90 set up held an advantage.

In open at 1000yds, it is a 7mm world.... the 6mm, 6.5mm were all tried and couldn't keep up (maybe new heavies might change that???). The 30cals worked great but recoil and fatigue became too big a negative.

Jerry

 

[RampedRaptor]

I’m still here. Appreciate the comments and first hand experiences thus far!

 

[243Mendoza]

This is called Volley fire testing and works very very well at giving real world results to complicated questions.

For team shooting, it allows a quick comparison to confirm zeros, ballistics and rifle set up.

For testing, it is a dead simple way to get past all the assumptions and math.

In this case, create 2 ballistic twins but with varying weights and cals. The biggest extreme and likely, easiest to create would be a 223 and a 308. Run the numbers on whatever combo is equal. Set the zeros (POI) to be the same at distance... the further the better for this test.

Obviously, the accuracy of both rifles should be similar and confirmed in no wind conditions.

On a day with winds (gusty, strong, nasty stuff), get both shooters to fire at the same time but keep the center hold. All you are doing is a real time, real world comparison between two bullets flying to the target.

Plot where the bullet lands from each rifle. If you have scoring pits, this is easy but can also be charted with remote camera.

See what happens and decide for yourself.

FYI, in mid range FTR (out to 600yds), there are a number of shooters using 223 and competing very well against the 308. In open, the 6mms and 6.5's give the 7mms a real run.

however at LR (out to 1000yds), I was one of the very few using a 223 and it wasn't even a close race vs the 185's of the day. On paper, my 223/90 set up held an advantage.

In open at 1000yds, it is a 7mm world.... the 6mm, 6.5mm were all tried and couldn't keep up (maybe new heavies might change that???). The 30cals worked great but recoil and fatigue became too big a negative.

Jerry

Were the theoretical (on paper) predictions for the 6mm and 6.5mm wrong when compared to the 7mm? Could it be that your suggestion of inertia effects in varying winds be a factor?

 

[mysticplayer]

Over the last 6yrs, many shooters have tried various combos in F Open out to 1000yds. The end result is nothing has been able to outscore the 284/180gr combo on a consistent basis over many many shooters all around the world.

The only ones that came close were a few brave souls that were shooting big 30cals. Not sure how many are still as most complained about recoil and fatigue.

On paper, the ballistics of a fast 6mm and 6.5 should be right up there with the "slow" 284 but scores don't lie.

I think the biggest comparison happened years back when the US team got beat by the Scotts (or Brits?). The US team was using 6.5-284's... the Scotts were using 284's. That moved the posts towards the 7mm. And Mr. Ballard put the icing on the cake by taking the US Nationals with the 284

Since then, I am unsure how many big US LR F Open matches have been won by anything other then a 7mm of some sort.

Jerry

 

[Milo 2.0]

Over the last 6yrs, many shooters have tried various combos in F Open out to 1000yds. The end result is nothing has been able to outscore the 284/180gr combo on a consistent basis over many many shooters all around the world.

The only ones that came close were a few brave souls that were shooting big 30cals. Not sure how many are still as most complained about recoil and fatigue.

On paper, the ballistics of a fast 6mm and 6.5 should be right up there with the "slow" 284 but scores don't lie.

I think the biggest comparison happened years back when the US team got beat by the Scotts (or Brits?). The US team was using 6.5-284's... the Scotts were using 284's. That moved the posts towards the 7mm. And Mr. Ballard put the icing on the cake by taking the US Nationals with the 284

Since then, I am unsure how many big US LR F Open matches have been won by anything other then a 7mm of some sort.

Jerry

This post doesn't address the op's question, until the 6.5 150gr Sierra there hasn't been a 6mm or 6.5 bullet that came close to the BC of a 7mm 180gr Berger hybrid.
A true test here would be a 308 cal 208 amax vs a Berger 6.5mm 140 hybrid traveling the same speed.

 

[RampedRaptor]

This post doesn't address the op's question, until the 6.5 150gr Sierra there hasn't been a 6mm or 6.5 bullet that came close to the BC of a 7mm 180gr Berger hybrid.
A true test here would be a 308 cal 208 amax vs a Berger 6.5mm 140 hybrid traveling the same speed.

That would be a great test if someone had both calibers and was willing to spend a couple dollars and some time to conduct the test.

I’ve been leaning towards the 7-300 as the best of both worlds. Whichever caliber I choose, I want it to be easy to tune. Life’s to short for temperamental cartridges.

 

[Milo 2.0]

That would be a great test if someone had both calibers and was willing to spend a couple dollars and some time to conduct the test.

I’ve been leaning towards the 7-300 as the best of both worlds. Whichever caliber I choose, I want it to be easy to tune. Life’s to short for temperamental cartridges.

People run tests all the time, question is, do you believe them. What prompted the test in the first place, people skew results in favor of their desired results.
Boils down to, what ever you build, depending on the degree of accuracy you're trying to achieve, wind will be a factor to overcome. Every minute of every hour for the whole day.

 

[Bob Sebold]

A little story: I was shooting a match with 180 gr bullets going a little faster than Danny Biggs and Jim Murphy's Maganums. We are all shooting fast, pounding x's, not looking at flags...Their 215 or 230 gr bullets hit liner 9's, my 180 hit a liner 8. That is all you get out of heavier bullets. About a half inch. We all stopped and looked at that for a long time. Is that enough to spend the money? Up to you, this game is not cheap, but I need every point I can get. That's why I got a magnum now too! Better to let Bryan Litz do the math, he's better at it anyway. Shoot more, and learn the wind better. Have more than one rifle. I find three not enough sometimes. If you can not read flags, or mirage, you would be doomed with a 50 BMG. Heavier bullets will give a few more pts in a day on windy days. Will not help in a trigger pulling contest. Bring back the 6 for that.

 

[mysticplayer]

This post doesn't address the op's question, until the 6.5 150gr Sierra there hasn't been a 6mm or 6.5 bullet that came close to the BC of a 7mm 180gr Berger hybrid.
A true test here would be a 308 cal 208 amax vs a Berger 6.5mm 140 hybrid traveling the same speed.

But the smaller cals have been shoot much faster... for the same level of recoil. 6.5-284's were going how fast with the 140's back in the day?

What Bob Sebold is describing is exactly what I am talking about.... Far 10 vs a just out 9

In bumpy air, you can see the 9's in the corners with the smaller lighter bullets vs wide 10's for the heavier slugs.

It is not much, but it is enough to not be competitive in this game.... and that is based on an enormous sample size by dozens of shooters all around the world.

YMMV
Jerry

 

[Laurie]

Agree completely Jerry - just as long as you can get to grips with the extra recoil and torque of the heavier bullets. I myself have had many of my best 800-1,000 yard match results with the 168gn Berger Hybrid driven fast, but that's an exception to the norm, and I don't shoot FTR seriously these days anyway. In F-Open, I shoot high BC 7mm 175s and 180s like everybody else, and I have no real problems keeping them under control in a 22lb rifle.

 

[KenOath]

A little story: I was shooting a match with 180 gr bullets going a little faster than Danny Biggs and Jim Murphy's Maganums. We are all shooting fast, pounding x's, not looking at flags...Their 215 or 230 gr bullets hit liner 9's, my 180 hit a liner 8. That is all you get out of heavier bullets. About a half inch. We all stopped and looked at that for a long time. Is that enough to spend the money? Up to you, this game is not cheap, but I need every point I can get. That's why I got a magnum now too! Better to let Bryan Litz do the math, he's better at it anyway. Shoot more, and learn the wind better. Have more than one rifle. I find three not enough sometimes. If you can not read flags, or mirage, you would be doomed with a 50 BMG. Heavier bullets will give a few more pts in a day on windy days. Will not help in a trigger pulling contest. Bring back the 6 for that.

Hi Bob,

Just curious to know have you gone from straight .284 shooting 180s to a 7SAUM shooting 180s or a WSM?

Cheers Rushty

 

[mysticplayer]

Agree completely Jerry - just as long as you can get to grips with the extra recoil and torque of the heavier bullets. I myself have had many of my best 800-1,000 yard match results with the 168gn Berger Hybrid driven fast, but that's an exception to the norm, and I don't shoot FTR seriously these days anyway. In F-Open, I shoot high BC 7mm 175s and 180s like everybody else, and I have no real problems keeping them under control in a 22lb rifle.

Why I like the rifle weight caps and forend restrictions... otherwise, this would be a runaway sport. Now you have to balance ballistics with what you can drive for multi day matches and put that last shot into the X/V bull regardless.

At some point, ENOUGH is what we end up using. Spend more time learning the winds. Spend more money keeping the gear in peak form. Stop chasing the ballistic genie.

Until a new mousetrap comes along...

Jerry

 

[Keith Glasscock]

I'm not Bob, but I agree with him completely. I'm just now in the process of adding another club to the bag. It'll be a big one, for those days when the wind doesn't want to play nice.

 

[Mulligan]

I'm not Bob, but I agree with him completely. I'm just now in the process of adding another club to the bag. It'll be a big one, for those days when the wind doesn't want to play nice.

Whatcha building Keith?
Inquiring minds want to know....... OK at least, I want to know.
CW

 

[Keith Glasscock]

I'm going to try 7/270 WSM first. I'm not original and think I can take advantage of the large well of knowledge there is about that one.

If that doesn't work, it's a toss-up which way I'll go.

 

[Homerange]

I'm going to try 7/270 WSM first. I'm not original and think I can take advantage of the large well of knowledge there is about that one.

If that doesn't work, it's a toss-up which way I'll go.

A buddy built a 7mm Practical that's been surprising accurate and it shoots ~3" @ 1k.
Quite a bitser of a rifle with custom this and that but by gawd it shoots.

 

[Bob Sebold]

I built a 300 WSM. Shooting 230's at about 2790 fps. Nothing to special, but I shot it in Canada with great results, over what I thought I would get with the 284 and 180's at 2850 fps. You do get kicked around a little more, so if you are recoil sensitive it might not be the way to go. It doesn't bother me. I do notice I shoot fewer x's, however, fewer 9's also. I think that is because I only shoot it in bad conditions. I shot the 284 at Berger SW, both days, but had the 300 ready for the last day. Then they canceled the match due to too much wind. That would have been an interesting shoot, but I was happy with where I ended up. Get on top and stay there!