Effect of wind on the bullet size?

jesheba

Whoa!!! I started an argument with some people! What's your thoughts on the different effects of wind on a 55grain,50 grain and a 40grain bullet out of a 22-250.Taking into consideration the lighter bullets will travel faster. Seems to me the faster bullet will be affected for less time and have less surface area to be affected by the wind and therefore be affected less. What do I know? Anybody actually witness the effects? Many I speak to swear the big bullet will buck the wind.

Randy Summers

MIKE WISKEY

WIND DIFT HAS NOTHING TO DO WITH BULLET WEIGHT, THE HIGHER THE B.C. (BALLISTIC COEFFICIENT) THE LESS WIND DRIFT. A .22 CAL 69 GN BULLET WITH A B.C. OF .4OO (THESE ARE FIGURES OUT OF THIN AIR) WILL HAVE LES WIND DRIFT UNDER THE SAME CONDITIONS THAN A .45 CAL 300 GN BULLET WITH A B.C OF .200 REGUARDLESS OF INITIAL VELOCITY (ASSUMING SAME VEL. FOR BOTH). USUALY HEAVEYER BULLETS OF THE SAME CAL. HAVE A HIGHER B.C. BUT NOT ALWAYS (I.E. 30 CAL 169 GN MATCH VS 200 GN R.N.).

JustC

I beleive it is more a length issue, correct?

Isn't that why the 70-75gr bullets are LOOOONGGG and called Very Low Drag?



A great rifle with a junk scope,....is junk.

Guns & Glass

BC, AND bullet weight both affect deviation by wind.
When comparing bullets that are same in profile, and close in weight, using the same powder charge the travel time is so very close it is hardly a discussion point.
Generally the heavier of the two will have less deviation.
This is even more apparent in ultra long range (1,000 yds) where the heavier bullet will group better.
Remember,in working up pet loads, only ONE thing at a time can be changed for accurate analysis.

Happy Bullet Holes!

jesheba

How does one compute the B.C.? This is a new concept to me.

Randy Summers

gruntled

An object in motion tends to remain in motion unless acted on by another force. In this case we are talking about momentum & that is a function of mass times velosity. The greater the mass or velosity
the more it will require to change the direction. The problem with this question is that the heavier bullet will have greater mass but less velosity. The slower bullet will also have the wind acting on it for a longer time & on a greater area.
So the final answer is.... I haven't got a clue.

Tailgunner1954

Jesheba
It takes a chronograph that can give you the FPS at the muzzle and again at longer range (say 100 and 300 yd) and you than compair the drop in speed to a "standard" bullet with a BC of 1.
To (try) put it simply, BC is a (inverse) measure of wind resistance, the higher the number the lower the wind resistance.

The 40gr bullet in your qustion will slow faster than the 55gr will (assumming a similar profile). To see this more clearly look at the downrange retained velocity of different bullets is a manufactures balistic chart.

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Some guys like a mag full of lead, I still prefer one round to the head.

He Dog

Jesheba, see if this helps: http://home.pdq.net/lfdw/BC_Calcs.htm

Piadea

Been thinking about this one. BC is a measure of bullet efficiency and certainly impacts it's ability to overcome drag (air resistance) which affects its ability to retain velocity and therefore affects drop, but has no affect on wind drift. Everything being equal ie BC and muzzle velocity the heavier bullet will drift less because it's momentum is greater. Let's say you start a 50 gr. bullet at 3000 FPS. To overcome it's weight disadvantage (20%) a 40 gr. bullet would have to be pushed AT LEAST 3750 FPS just to keep even in terms of momentum (Velocity X Mass) Of couse this is in a vacuum. So the velocity would have to be even higher. As stated above there are several variables at work here but mass (weight of the bullet) is by far the controling factor.

rg666

Jesheba, BC's are provided by the bullet manufacturers. You can look at any bulletsmith's web site (ie Sierra) & they will list the BC with all the other basic data. RG