Subsonic at long range

H

Hammer47

Guest
Since a heavy subsonic bullet is less affected by the wind, has anyone tried subsonics at long range, say 600 to 1000? I know the trajectory would be like a mortar but if the wind drift is less it might be worth looking into. A rub would be a base with enough moa built in but that could be overcome. What do you think? Please, no flames guys, I am too fat and old to fit into my old Nomex suit. Regards...g
 
Hammer47 said:
Since a heavy subsonic bullet is less affected by the wind, has anyone tried subsonics at long range, say 600 to 1000? I know the trajectory would be like a mortar but if the wind drift is less it might be worth looking into. A rub would be a base with enough moa built in but that could be overcome. What do you think? Please, no flames guys, I am too fat and old to fit into my old Nomex suit. Regards...g
Click to expand...

I can't imagine what kind of bullet and weight would be required to start off subsonic and make it 1000 yards downrange with reasonable accuracy. Do you have a suggestion?
 
What makes you think....

That subsonic bullets are less wind sensative...I have helped a friend with the development of loads for 3 subsonic rifles with silencers, and they are all VERY wind sensitive...and would be wothless at 1000 yds..
 
Maybeeeee....

He is a Dentist...they are indeed a strange breed....:D
 
To echo eww1350's sentiment, there's nothing about subsonic projectile flight that is less sensitive to wind deflection.
 
John ---
were on 41-cal MAX rules..... can we swag those puppy's down to 39-cal and re-barrel for 39-120....hehehe

I had a 45-120 a few years back.... sold it to build a 6Dasher... if I'd of only new....hehehe

Happy Shooting
Donovan Moran
 
I think that subsonic all the way is a way of life for the BPCR longrange people. They shoot to 1200 yards, I think. Maybe farther at some of the "buffalo shoots" in MT and WY where they shoot at lifesize Bison targets made of steel.
They are so good that it is scary. All with vernier rear sights that are about 5" tall.
Maybe I'm wrong about the distances, somebody will correct me if that is so.

Jay
 
I have 50 newly formed 7mm/221 and 50x 300/221 cases just made up waiting for the barrels to be chambered. The 7mm will be firing 180gn VLDs at 1040fps and the 300/221 will shoot 240gn matchkings at 1040fps. I am not expecting them to be as good in the wind as a normal 1000yd load. They will just be something to play with. I think their time of flight will be way to long to be realy good in the wind. Their BCs are pretty much as good as you can get, but when fired at 1/3rd of the normal velocity, they will spend a lot of time up in the breeze.
They will be a good mid distance (300-600yd)subsonic (therefore quieter) plinking load, but after that I will run out of scope elevation.
 
Now that it's been alluded to, one of the mighty interesting issue likely to be faced shooting subsonically at great distances is just what the @%#!! the wind is doing all those feet higher up than you're used to doping it. The reason I gave up shooting 220 SMKs in my 1200 yard gun was that it needed 5-8 MOA elevation cranked on the scope than for the 210 SMK or Berger meant that some projectiles were arriving iced up.:rolleyes:
 
Hammer47 said:
Since a heavy subsonic bullet is less affected by the wind, has anyone tried subsonics at long range, say 600 to 1000?
Click to expand...

Many shooters tried that before and during the 1800's when most 1000 yard shots were subsonic by the time they reached the target. If you look at historic records group sizes were in the order of feet, not inches as at todays benchrest matches.

Per unit of time of flight a subsonic bullet is less affected by wind than a supersonic bullet, but per unit distance it's more. Very heavy low drag subsonic bullets (like the 500 Whisper shooting Barnes 750, 800, or AMAX bullets are very efficient at delivering energy to a target at long range but wind deflection is terrible compared to 6.5 to 7.62mm low drag bullet at the same distance shot at 2 to 3 times the velocity. Spend some time with a ballistics computer and prove it to yourself.

As Didion demonstrated in his 1859 publication crosswind deflection is directly proportional to the difference of the time of flight through the atmosphere minus the time of flight if the same bullet is shot at the same muzzle velocity through a vacuum. That's a fact worth remembering.

It's true that lower drag reduces wind deflection but not if it's acchieved by increasing the time of flight. Besides that, the vertical stringing due to variations in muzzle velocity increases with the square of the time of flight. Shooting heavy subsonic bullets ceased to give winning accuracy in the mid 1800's, around the time smokeless powder and spitzer bullets were developed.
Shooters didn't need Didion to tell them that happened, he only showed them why.
 
I heard a great quote from one of the old timers shooting Black Powder Cartridge Rifle in a long range match at Camp Atterbury, IN this summer. After listening to us talk about some problems with high muzzle velocities and bullet failures, he said:

"All this smokeless powder stuff is just a passing fad".

Of course he wasn't serious. Those guys had to build extenders for their target frames to capture the 'hits' at 1000 yards. You could hear the big lead slugs coming for a while before they got there, and they sounded like an automobile crash in the woods behind the targets.

This type of shooting, and the diligent bullet casting that goes on is certainly fascinating, but could never be as precise or accurate as modern high velocity jacketed bullets and smokeless powder, even if they are just a passing fad:)

-Bryan
 
smallbore bullets

I think the idea that subsonic bullets are less sensitive to wind comes from the smallbore crowd where bullets with supersonic muzzle velocities were subsonic 100yd down range and those bullets are supposedly more wind sensitive since they go through the transonic range where shocks are moving and very sensitive to crosswinds.
 
A 45-70 BP shooter at our range told me that at the 1000 yd meets they have allowed a little smokeless powder in their loads to get their velocity up. They were having problems with the rounds dropping into the pits between the berm and the target because the bullet path was so high, think of a mortar shell. With the added velocity the bullets came in with more horizontal component and were able to clear the berm and still go through the target.
 
Hammer47, it is not always true that subsonic bullets will be less deflected by crosswinds. As has been pointed out, the higher deflection forces are compensated by the reduced time of flight.

It is true that when compared to some speeds, subsonic is less affected. This appears to be related somewhat to the drag coefficient (Cd) of the bullet--which is not the same as the ballistic coefficient. The Cd is a maximum near sonic and the low supersonic range. It falls off at higher Mach numbers, but remains higher than that at high subsonic.

Try a trajectory and drift calculator such as found here. Try 200 or 1000 yd with a nominal "G1" BC of .500 (I can't remember what the BC is for the more realistic "G7" profile), about that of a 180 gn .308 Nosler BT. Try this comparing speeds of 3000 or 3500 fps to 1000 fps and then repeat the run starting at 1500 fps.

Compared to 1000 fps, you'll find that drift is less for 3000 fps but higher for 1500 fps. Subsonic may be better for the Schuetzen game (which is what I'm looking into at the moment), but not for 1000 yd benchrest.

For 1000 yd, subsonic trajectories are dramatic, about 50 ft, and as pointed out, this will affect what wind eddies are encountered.

One problem with subsonic will lie with keeping velocities consistent. One percent of 3000 fps is 30 but is only 10 of 1000 fps. The fps spread will need to be kept small, and this when shooting small charge weights, which will require much more accurate charge weighing.
 
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