Ballistic Turrets

[Reloder28]

I finally got my rig to the 600 yard range. With my scope zeroed at 250 yards I cranked it to 600 yards and fired two rounds.

300 WSM 155 Scenar 3285 fps
First shot:
+8" elevation
L6" windage

Second shot:
+11.5" elevation
L4" windage

Total spread 4.25"

This was on a standard 500 yard F Class target. I had no clear aiming point with my scope set on 6X. I simply tried to divide the black into equal quadrants.

What do you make of this? I was pretty pleased as this was my first shot ever beyond 300 yards on a fixed target. Shooting conditions were not optimum. I realize it wasn't near the X. I am open for ways to get it closer to the X.

 

[Greyfox]

I like the Custom Turret tapes mentioned. I order them with the average attitude and temperature for my hunting area for the yardage scale and include an MOA scale at the bottom. For 600 yards and under dialing yardage is very fast, and at this range temperature and altitude variations matter very have little on deer/coyote sized targets. For longer range work and small targets I can use the MOA scale for more technical shots, but have shot deer and antelope out to 1000 yards very successfully using a yardage turret and clicking adjustments for variations in temperature and elevation. It not as problematic as many make it out to be. It generally takes greater than a 15 degree temperature change and a 1500 ft elevation change before I start worrying about fine tuning when shooting yardage turrets out past 600 yards. As mentioned, the G7 RF now makes even this unnecessary.

 

[Canadian Bushman]

I like the Custom Turret tapes mentioned. I order them with the average attitude and temperature for my hunting area for the yardage scale and include an MOA scale at the bottom. For 600 yards and under dialing yardage is very fast, and at this range temperature and altitude variations matter very have little on deer/coyote sized targets. For longer range work and small targets I can use the MOA scale for more technical shots, but have shot deer and antelope out to 1000 yards very successfully using a yardage turret and clicking adjustments for variations in temperature and elevation. It not as problematic as many make it out to be. It generally takes greater than a 15 degree temperature change and a 1500 ft elevation change before I start worrying about fine tuning when shooting yardage turrets out past 600 yards. As mentioned, the G7 RF now makes even this unnecessary.

This is the most practical way to use calibrated turrets. You should also have a clear understanding of the effects reloading has on mv ,realistic ES, SD values, and truing a b.c value. Which greyfox is well versed in, and most beginners are not.
Without this forethought, dialing a yardage and pulling a trigger is assuming a lot.

Even with this in mind, fouled barrels, differently sized brass, and varying bullet lots have a great enough effect on mv to deter me from using any permanently labeled caps.

 

[davkrat]

A thread I started a few years back: http://www.longrangehunting.com/forums/f19/case-bdc-turrets-72754/

I'm sure this dead horse has been beat plenty of times! I was running the numbers today to try and figure out which BDC settings to order my turret. The load is .308 Win, 150 gr ETips at 2850 fps. I decided to graph the click settings for a bunch of different altitude and temps.

I've always thought it was funny when people complain about the slight differences you get when you change conditions. In reality out to 600 yards (many may call this medium range but I personally consider it my max) the differences for the various conditions are within a click up or down on a 1/4 MOA click scope. I even added an extreme condition of 10,000' at 60 degrees (not likely anywhere I hunt during deer season!) Don't know if this pic will show but looking at the data you'll see a BDC for 5,000' at 60 will theoretically work for 2,000' at 90 degrees and 8,000' at 30. You're within the one click zone for all those ranges and conditions.

In other words a turret for 5,000' at 60 degrees needs 68.7" at 600 yards. That is just above the 68.6" for -1 click from the 2,000' @ 90 setting and below the 69.1" for +1 click from the 8,000' @ 30 setting. For all these conditions you should be within 1 click off which at 600 yards is less than 1.5" For big game hunting that seems like nothing to worry about. and having MOA comeups probably won't get you much closer due to the coarseness of the 1/4 MOA adjustment.

 

[Greyfox]

If you consider that Davkrats study is using a 150gr 30caliber bullet, the variation is even less if a high BC/velocity cartridge is used. The requirement when using turrets is thst you MUST make sure you have a consistent load and riflle, especially as the range increases. I think this is the biggest issue shooters have with yardage turrets. With a consistent set up, tuning adjustments for compensating yardage turrets for variations in temperature and altitude are very definable, with adjustments easy to make with a simple mental calculation. The major benefit of using yardage turrets is speed, readability, and error reduction, particularly in the low light conditions at dusk and dawn when MOA graduations can be difficult to view. IMO.

 

[Canadian Bushman]

A thread I started a few years back: http://www.longrangehunting.com/forums/f19/case-bdc-turrets-72754/

I'm sure this dead horse has been beat plenty of times! I was running the numbers today to try and figure out which BDC settings to order my turret. The load is .308 Win, 150 gr ETips at 2850 fps. I decided to graph the click settings for a bunch of different altitude and temps.

I've always thought it was funny when people complain about the slight differences you get when you change conditions. In reality out to 600 yards (many may call this medium range but I personally consider it my max) the differences for the various conditions are within a click up or down on a 1/4 MOA click scope. I even added an extreme condition of 10,000' at 60 degrees (not likely anywhere I hunt during deer season!) Don't know if this pic will show but looking at the data you'll see a BDC for 5,000' at 60 will theoretically work for 2,000' at 90 degrees and 8,000' at 30. You're within the one click zone for all those ranges and conditions.

In other words a turret for 5,000' at 60 degrees needs 68.7" at 600 yards. That is just above the 68.6" for -1 click from the 2,000' @ 90 setting and below the 69.1" for +1 click from the 8,000' @ 30 setting. For all these conditions you should be within 1 click off which at 600 yards is less than 1.5" For big game hunting that seems like nothing to worry about. and having MOA comeups probably won't get you much closer due to the coarseness of the 1/4 MOA adjustment.

Thats strange because when i run some numbers in shooter a 40* temp swing with a .2 in/hg, it puts me an entire 1/2 moa off.

This is just considering atmospherics, if i change the value of the powder temp its even more. Which i feel i have that value nailed down i left it off to isolate weather changes.

Where i hunt i see pressure changes from 29.6-30.2 and temp swings from 30-100. This can easily account for a .7 moa (4.4") difference in elevation at 600 yards with simply atmospherics. The powder temp value witch plays a big part in transitioning seasons is still not on.

All numbers were done with shooter for a 215gr 30 cal at 2650 and a 105gr 6mm at 2830.

 

[davkrat]

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[davkrat]

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[davkrat]

I honestly don't recall what program I used to come up with those numbers. Like I said I did that years ago. Perhaps I'll do it again with some of the newer programs. I believe though at the 300-600 yard ranges where most "longrange" big game is taken the error for average conditions is likely to be less than the 1/4 MOA adjustments of your scope. If it's freezing cold or super hot then it's a simple mental trick to add/remove a click or two. No batteries. No lost cards. No fumbling to find either in your pack. I'd say they're worth it just as backup, always attached to your rifle. Nothing stops you from using the MOA hashes while having yard ashes above.

Like Greyfix said too I've been working on developing s consistant load and never actually ordered a turret. I intend to very soon though. I have used the Custom Turret tape on my .308 and it's worked out fine for plinking rocks at various ranges.

I finally got my rig to the 600 yard range. With my scope zeroed at 250 yards I cranked it to 600 yards and fired two rounds.

300 WSM 155 Scenar 3285 fps
First shot:
+8" elevation
L6" windage

Second shot:
+11.5" elevation
L4" windage

Total spread 4.25"

First off you need to shoot a few more shots. Your "group" is around 1.5 MOA high. Things I've found is how zeroed am I at zero. How accurate is the velocity I plugged in. How inflated were the manufacturers BC. I've started recording my true trajectory for my loads to try and develop an accurate BC and velocity to order my turret from. Once you get a turret or tape you should "zero" it at the middle yardage it covers. Usually 400-450 yards. That way any error in your zero is averaged out at 200 or 600-700 yards, whatever ranges your turret covers.

 

[Canadian Bushman]

I honestly don't recall what program I used to come up with those numbers. Like I said I did that years ago. Perhaps I'll do it again with some of the newer programs. I believe though at the 300-600 yard ranges where most "longrange" big game is taken the error for average conditions is likely to be less than the 1/4 MOA adjustments of your scope. If it's freezing cold or super hot then it's a simple mental trick to add/remove a click or two. No batteries. No lost cards. No fumbling to find either in your pack. I'd say they're worth it just as backup, always attached to your rifle. Nothing stops you from using the MOA hashes while having yard ashes above.

Like Greyfix said too I've been working on developing s consistant load and never actually ordered a turret. I intend to very soon though. I have used the Custom Turret tape on my .308 and it's worked out fine for plinking rocks at various ranges.

If you have this mindset and understand its limitations you wont have any problems.
I would also second the turret tape because it can easily be updated as barrels wear and a shooter develops his load and practices.

P.S. 300 yards my drop is always the same regardless of conditions. 350-400 is where effects start to take place and usually never change more than .25 moa. I would not hesitate dialing to a given drop for these ranges.

 

[Reloder28]

I am very much a novice at this long range shooting. My first time to try it was Friday, June 12, 2015. I fired two shots. I am happy it "grouped" 4.25" @ 600 yards. I was using an F Class 500 yard target.


What should my sight picture look like? Should I be able to see the X?

 

[cohunter14]

I am very much a novice at this long range shooting. My first time to try it was Friday, June 12, 2015. I fired two shots. I am happy it "grouped" 4.25" @ 600 yards. I was using an F Class 500 yard target.


What should my sight picture look like? Should I be able to see the X?

The grouping doesn't matter if you are 11" high. To answer your question, you should have some point of aim that you can see. If you can't see the X, make some sort of mark so you know you are aiming at the same point every time.

Seeing this is the first time you have shot past 300 yards, your turret might not match your load. If you are getting a turret, you should double check to make sure your ballistic chart matches what your gun is actually shooting. Otherwise you end up with a turret that has yardages on it which are incorrect.

If your zero is correct, it sounds to me like you might need to verify your drops and potentially get a new turret. Unless you think your point of aim could have been 11" off, which I doubt.

 

[lancetkenyon]

With an 18X scope, you should easily be able to identify the "X" at 600 yards on a 37"x37" 500 yard F Class target.

With an 11" high POI at 600 yards, you are between 1.75-2 MOA high. That is a miss on a deer, or worse, a high non-fatal wound. A decent group of 4.25", but you need to check your drop data and correct it.

 

[Reloder28]

My turret is etched to be zeroed at 100 yards. But, I don't use that setting. My scope is actually set for 2" high @ 100 which gives me a 250 yard zero. I also set my zero stop at 250 yards. When I crank it to 600 I should still be hitting near the X Ring at 600 yards, right? The 2" high setting at 100 does not carry over beyond that zero distance, right?

Can you tell I'm new at this?