50s 52s 53s 55s vs wind

[Ozshot]

So just after some honest opinions, is ther really that much difference in wind drift between the 50s-55 range, now I obviously know that distance will play a factor so let me give you a scenario. Say I’ve loaded a 223AI or even a standard 223 with an accuracy round in the same projectile in both 50 & 55gn let’s just say nosler BT. Say you have a constant steady crosswind at 20mph (30kmph) over a 250 yard shot… how
Much difference in drift would you expect? 1”? 2”? 6”? A foot??.

 

[GLShooter]

JBM ballistics program is your mentor on this. Just plug in the specs and you can play what if till the cows come home. Lots of information and it's free.

JBM

Greg

 

[Chuckhunter]

Generally speaking, it's more about the bullet's design and BC than it is about slight weight variations.

 

[Matt_3479]

Velocity and bc play a major role here. You’d loose bc on a lighter bullet, but with higher velocities it can sometimes over come the difference. Now I’m this case when your talking bullets weights so close together you generally will not pump the velocity high enough on the lighter bullet to over come the heavier bullets bc and weight in the ballistics but that’s for a ballistics calculator to decide.

just for example for you though, a 50gr nosler ballistic tip and a 55gr nosler ballistic tip have 1” of wind difference at equal velocities at 250 yards. Not enough to worry about in my opinion. With the slight added velocity of the 50 gr it will minimize the difference even more

 

[natdscott]

Velocity and bc play a major role here. You’d loose bc on a lighter bullet, but with higher velocities it can sometimes over come the difference. Now I’m this case when your talking bullets weights so close together you generally will not pump the velocity high enough on the lighter bullet to over come the heavier bullets bc and weight in the wind but that’s for a ballistics calculator to decide.

just for example for you though, a 50gr nosler ballistic tip and a 55gr nosler ballistic tip have 1” of wind difference at equal velocities at 250 yards. Not enough to worry about in my opinion. With the slight added velocity of the 50 gr it will minimize the difference even more

More hypothetical speed from a lighter bullet will not improve or “over come” the lower BC as far as wind drift in concerned, except inasmuch as the BC of the bullet changes with the speed.

Elevation can be helped though.

As far as the windage difference is concerned, I would say the difference depends on what a shooter is trying to accomplish. Higher BC = lower penalty per mph of a missed call, both having dialed too much, or not enough.
The lower end of what he’s asked is in the 0.210-220 G1 range, where the top end is almost 0.275 G1. That’s quite a bit, in some circles.

So, shooter @Ozshot, what are you trying to do?

 

[DaveTooley]

If it's not accurate then weight and BC doesn't matter. Shoot the most accurate bullet.

 

[Gary in MD]

For busting a “Roo” in the head, I’d pick the 55 every time. With the 50 and 55 both loaded to their potential, the advantage will always be with the 55s, especially out at a couple hundred yards.
This opinion based on shooting zero kangaroos but many hundreds of varmints here in the US of A.
YMMV
Gary

 

[Homerange]

So, shooter @Ozshot, what are you trying to do?

Ozshot is a commercial roo shooter and has recently discovered Speer 52gr garbage cans are shooting well for him and they are more readily available than his preferred 55gr BT's.
Long range head shots are mandatory so precise hold over and windage need be known.

Like others say a ballistics calculator is what's needed until a projectiles behavior becomes 2nd nature to the shooter.

 

[natdscott]

Ozshot is a commercial roo shooter and has recently discovered Speer 52gr garbage cans are shooting well for him and they are more readily available than his preferred 55gr BT's.
Long range head shots are mandatory so precise hold over and windage need be known.

Like others say a ballistics calculator is what's needed until a projectiles behavior becomes 2nd nature to the shooter.

Then why not upgrade to a 65 Gameking, 69 SMK, 60 TMK… things like that?

 

[Matt_3479]

More hypothetical speed from a lighter bullet will not improve or “over come” the lower BC as far as wind drift in concerned, except inasmuch as the BC of the bullet changes with the speed.

Elevation can be helped though.

As far as the windage difference is concerned, I would say the difference depends on what a shooter is trying to accomplish. Higher BC = lower penalty per mph of a missed call, both having dialed too much, or not enough.
The lower end of what he’s asked is in the 0.210-220 G1 range, where the top end is almost 0.275 G1. That’s quite a bit, in some circles.

So, shooter @Ozshot, what are you trying to do?

sorry I meant to put that. I was talking elevation for speed and bc related. I didn’t state that correctly but it was what I was meaning to say.

 

[Ozshot]

Ozshot is a commercial roo shooter and has recently discovered Speer 52gr garbage cans are shooting well for him and they are more readily available than his preferred 55gr BT's.
Long range head shots are mandatory so precise hold over and windage need be known.

Like others say a ballistics calculator is what's needed until a projectiles behavior becomes 2nd nature to the shooter.

Thanks homerange, nailed the reasoning. Whilst I’ve been reloading for quite a few years I’ve really only just started delving into the ballistics side or even started playing with different setups with the availability and shortage issues we are all facing. I have never tried a ballistics program and didn’t even realize free programs existed but could be a real help. In terms of why I don’t go heavy projectiles to be honest I haven’t tried that way yet but from the information I’d received from other shooters the drops on the larger projectiles become pronounced quite quickly. I don’t have time to adjust turrets for each shot and have to aim with the adjustment for wind/distance already incorporated. Hence my quest for the perfect projectile/powder setup to give me the lowest holdover/drop in the less then 300yard range for the 223/223AI cartridge whilst still having instant kill ability on head shots and be consistently an accurate round in my rifle…… I’m not asking for much am I

 

[Ozshot]

Also as homerange said once you have an extended time with a certain setup it will become second nature and it won’t matter

 

[Jeff Porter]

If you learn your way around the JBM program you can do some valid comparisons. In your case, shooting 52-55 gr varmint bullets at AI velocities (3600-3700fps) from a bolt gun with sights closer to the bore your point blank range on a 4" (10cm) object like a Roo head ( hold center of the ear hole and shoot, no dialing or reticle reading) will be 280-300 yards depending on the bullet and the velocities you actually run. Wind drift between 53 and 55 gr at 250 yards will not be discernable with both needing 1/4 moa per 1 mph of wind value.

Edit to add - I ran my numbers using 53Vmax at 3700 and 55 Vmax at 3600 for the 52 Speer at 3700 you may need a touch more wind (0.3 moa per mph) than a BT or a Vmax but the point blank range is still 280 yards.

 

[Homerange]

Also as homerange said once you have an extended time with a certain setup it will become second nature and it won’t matter

What are your minimum ranges for roos ?
Would a 200yd zero work for you with a holdover for the longer shots. What zero are you using currently ?

Sorta like what JP is pointing to above.

 

[Darwin]

Applied Balistics bc’s for the 50,53,55 Vmax is .11, .13, .12 G7. OR .215, .254, .234 G1.
You’ll want to enter altitude and temp into JBM as well. Have fun.

 

[Ozshot]

If you learn your way around the JBM program you can do some valid comparisons. In your case, shooting 52-55 gr varmint bullets at AI velocities (3600-3700fps) from a bolt gun with sights closer to the bore your point blank range on a 4" (10cm) object like a Roo head ( hold center of the ear hole and shoot, no dialing or reticle reading) will be 280-300 yards depending on the bullet and the velocities you actually run. Wind drift between 53 and 55 gr at 250 yards will not be discernable with both needing 1/4 moa per 1 mph of wind value.

Edit to add - I ran my numbers using 53Vmax at 3700 and 55 Vmax at 3600 for the 52 Speer at 3700 you may need a touch more wind (0.3 moa per mph) than a BT or a Vmax but the point blank range is still 280 yards.

Thanks Jeff sorry about the slow reply I’ve had a busy few nights. That’s really helpful and will save me a a lot of playing around between the 50-55s. Can you please clarify what you mean by the point blank range is 280 yards? Do you mean the bullet will shoot flat or too it’s zero at 280 without holdover?. Thanks again cheers Lindsay

 

[Ozshot]

What are your minimum ranges for roos ?
Would a 200yd zero work for you with a holdover for the longer shots. What zero are you using currently ?

Sorta like what JP is pointing to above.

I’m currently shooting in at 1” to 1-1-/2” high at 100 yards and then adjusting up or down when I’m in the field till it’s where I want then I don’t adjust till it requires it… could be weeks. I think from what I worked out years ago when I started the 1-1/2” at 100 works out around a 220 yard zero buy I could be completely wrong. My though is if I’m closer I aim at the jaw and if I’m round that 220 I aim straight on and if it heaps further out I’ll aim top of skull. I’ve worked it that way so that it’s the best outcome for a kill shot if I misjudge the distance. Got my first semi windy night done with the speers and really didn’t have the issue of huge hold overs so people were suggesting, just standard as normal, I fell like they are getting out there so fast the wind seems to have less chance to act on it!!. Admittedly it was only 15 mph or so

 

[Jeff Porter]

Thanks Jeff sorry about the slow reply I’ve had a busy few nights. That’s really helpful and will save me a a lot of playing around between the 50-55s. Can you please clarify what you mean by the point blank range is 280 yards? Do you mean the bullet will shoot flat or too it’s zero at 280 without holdover?. Thanks again cheers Lindsay

Lindsay - yes. The concept of a point blank zero is just that. You hold middle of fur from the muzzle to the calculated distance and do not hold over. You have to know the height of your sights above the bore and the diameter of your target in addition to the muzzle velocity and BC of the bullet. The theory is you set the zero such that the flight path of the bullet does not rise above 1/2 the diameter of your target or fall below 1/2 the diameter until your point blank range. In my case chasing coyotes, I use a 5” diameter for the kill zone. I set the radius in JBM to 2.5” and ask it to zero at point blank zero. With my 243 shooting 58Vmax at 3700 FPS I will zero at 270 yards and hold middle of fur out to 313 yards. It is about 2” high at 200 yards but it is still a double lung shot if aiming right. But as you say, you could hold bottom rib to 200. Center of mass 250-310. Top of the shoulder at 325. Further than that I need to call them closer.

A Roos head may be smaller and your radius would be smaller and the range shorter.

The faster and flatter bullets like 223 AI with optics as close to the bore as possible will give you the best results.

Regards

 

[Ozshot]

Lindsay - yes. The concept of a point blank zero is just that. You hold middle of fur from the muzzle to the calculated distance and do not hold over. You have to know the height of your sights above the bore and the diameter of your target in addition to the muzzle velocity and BC of the bullet. The theory is you set the zero such that the flight path of the bullet does not rise above 1/2 the diameter of your target or fall below 1/2 the diameter until your point blank range. In my case chasing coyotes, I use a 5” diameter for the kill zone. I set the radius in JBM to 2.5” and ask it to zero at point blank zero. With my 243 shooting 58Vmax at 3700 FPS I will zero at 270 yards and hold middle of fur out to 313 yards. It is about 2” high at 200 yards but it is still a double lung shot if aiming right. But as you say, you could hold bottom rib to 200. Center of mass 250-310. Top of the shoulder at 325. Further than that I need to call them closer.

A Roos head may be smaller and your radius would be smaller and the range shorter.

The faster and flatter bullets like 223 AI with optics as close to the bore as possible will give you the best results.

Regards

Thanks Jeff that’s heaps easier for me to
Understand when you put it like that! I’m running a khales helia 2 4-12 x56 on a pic rail, not sure if I could get it closer I’d have to look at the options. Do you shoot coyote to sell the hides? Does it matter where your entry hole is if you do? Or do hide shooters have to head shot on coyotes. I think 4 “ in the right size for an average it can only be an issue if you have a really big one looking front on if your a bit low it will not penetrate through the nose/jaw properly to get to the brain so you have a smaller target unless they turn thier head

 

[Homerange]

I’m running a khales helia 2 4-12 x56 on a pic rail, not sure if I could get it closer I’d have to look at the options.

Depends on how much clearance between the objective lens and the barrel you currently have as to how much you can lower the scope. If you have high rings you might be able to go to a medium height ring however that depends on the rifle stock because if it has a high comb that might limit how low you can go.
If the setup shoulders nicely and you have a good cheek weld sometimes it's better not to mess with something that's already working good.
If you know any good shot gunners they might be able to help with gun mount tuning.

A trick we use is to focus on an imaginary target, close eyes, mount rifle, open eyes and cross hairs need be close to bang on the imaginary target. This simple test is excellent for offhand shooting whereas I imagine most of your LR Roo headshots are taken with a rest.