Trueing muzzle velocity vs BC

[XLR]

This seems like the time of the year when guys start getting the long-range shooting urge. It is the best time to start practicing and brushing up on your wind calling skills! One common thing that I get asked a lot is whether to true the BC or Velocity? What is your preffered method for dialing in your long range rifle? Do you trust what the chronograph says and true BC from there? Do you true velocity to 600 and then BC after that? Or do you strictly true velocity because BC is a measurement that has been taken by a multiple $1000 tool by the big bullet companies?

 

[MTNHUNTER76]

Typically true velocity to 500, then b.c. further out. My chrono just sits in the drawer, never use it. I will adjust velocity past 500 if needed to get the curve as close as possible to real time data.

 

[Justin Crossley]

For my shooting (typically about 1,200 yards or less), I only adjust velocity in my solver. I used to adjust BC at longer ranges but now I always use Applied Ballistic custom curves and have had very good results.

It seems that since I've started using the custom curves, a Magnetospeed or Labradar, and Nightforce scopes, I rarely have to make any adjustments from what my solver tells me......

 

[carsonkeys]

For my shooting (typically about 1,200 yards or less), I only adjust velocity in my solver. I used to adjust BC at longer ranges but now I always use Applied Ballistic custom curves and have had very good results.

It seems that since I've started using the custom curves, a Magnetospeed or Labradar, and Nightforce scopes, I rarely have to make any adjustments from what my solver tells me......

This makes me happy to hear. I just bought a vortex fury AB and hesitantly used the AB custom curves, but haven't had a chance to test it yet. Sounds like that was the right move.

 

[XLR]

For my shooting (typically about 1,200 yards or less), I only adjust velocity in my solver. I used to adjust BC at longer ranges but now I always use Applied Ballistic custom curves and have had very good results.

It seems that since I've started using the custom curves, a Magnetospeed or Labradar, and Nightforce scopes, I rarely have to make any adjustments from what my solver tells me......

I wish we could get some of the AB guys on here to explain the difference they see from different barrels! Whether guys are shooting a 5R bartlein or a 4 grove benchmark. Also bore diameter and whether they are shooting a .237 or .236 6mm barrel. I am sure that they affect the BC but is it a measurable difference that we will see on target?

 

[carsonkeys]

I wish we could get some of the AB guys on here to explain the difference they see from different barrels! Whether guys are shooting a 5R bartlein or a 4 grove benchmark. Also bore diameter and whether they are shooting a .237 or .236 6mm barrel. I am sure that they affect the BC but is it a measurable difference that we will see on target?

In addition, I'd selfishly like to see barrel lengths discussed. I've cut my barrels down to 18.5" for use with a can.

 

[Justin Crossley]

I wish we could get some of the AB guys on here to explain the difference they see from different barrels! Whether guys are shooting a 5R bartlein or a 4 grove benchmark. Also bore diameter and whether they are shooting a .237 or .236 6mm barrel. I am sure that they affect the BC but is it a measurable difference that we will see on target?

I don't know how those things affect bc or at what range you can actually see it but I've had very good results whenever I've used the custom curves.

G7 and G1 BC's always required some amount of fine-tuning for me.

 

[XLR]

I don't know how those things affect bc or at what range you can actually see it but I've had very good results whenever I've used the custom curves.

G7 and G1 BC's always required some amount of fine-tuning for me.

For sure! Lately, I have been trying to stick with the muzzle velocity that I get from the chrono and then changing the BC. Typically I will zero and then go to 1200 to true BC. Then I will put it on steel at 800 and 500 with a waterline mark and they have been uber accurate for both my 6 BRA and 6.5 Creed! I am sure that there could be some variation with chronographs but that method has been great. I am also running Vapor Trail Bullets so my access to custom curves has been pretty limited. That is my go-to right now but I have seen a lot of guys go the other way and have great success! It would also be cool to test how much barrel wear changes BC!

 

[XLR]

I have been seeing a few people discussing this lately so I wanted to revamp this thread. I also wrote an article a while ago discussing how I like to true data with different tools. I think its the time of the year where a lot of rifles are coming out of the safe so this is an important topic to same some hassle and money.

Truing Rifle Data

This is the time of the year when shooters start getting the itch. It is the best time to start brushing up on your wind calls and making sure that your rifle is shooting well! One common question that we get asked is how we true our data when we gather dope. This is a great question because...

xlrindustries.com

 

[hawgchaser]

This makes me happy to hear. I just bought a vortex fury AB and hesitantly used the AB custom curves, but haven't had a chance to test it yet. Sounds like that was the right move.

Could you give an update about the fury and how well the AB works for you?

 

[XLR]

Could you give an update about the fury and how well the AB works for you?

I cant comment for him but all of the Fury ABs I have been around have worked pretty well! Seems like the custom curves line up pretty well too. Just double check all your inputs are correct.

 

[hawgchaser]

I cant comment for him but all of the Fury ABs I have been around have worked pretty well! Seems like the custom curves line up pretty well too. Just double check all your inputs are correct.

Thanks for the reply. They seem to be the most affordable AB rangefinding binoculars.

 

[carsonkeys]

Thanks for the reply. They seem to be the most affordable AB rangefinding binoculars.

I like them a lot. You have to put good data in to get good data out, and it took me a while to fully trust them. Though, that hesitancy waned after a few rock shooting sessions in the hills.

My wife just killed a billy at nearly 500 yards and the come up came straight from the fury.

 

[hawgchaser]

I like them a lot. You have to put good data in to get good data out, and it took me a while to fully trust them. Though, that hesitancy waned after a few rock shooting sessions in the hills.

My wife just killed a billy at nearly 500 yards and the come up came straight from the fury.

Thanks for the update. I think I'll have to give them a try.

 

[wind gypsy]

My experience is similar to @Justin Crossley. If you get a good velocity from magnetospeed or labradar and use AB custom curve, things seem to align pretty dang close. It has been a number of years since I've shot over 1k yards though.

There have been times where i chronoed a load within a week and found myself off on elevation at 700+ yards and wonder WTF, busted out the lab-radar and see i'm up 35 FPS due to temp or bore condition or something.

I've heard Pynch on his podcast and others mention truing BC of known bullets for different barrels or twist rates. With my capabilities/experience and at the ranges I shoot, I'm not sure I can discern that level of detail when mixed with possible contributions like mirage conditions or aerodynamic jump impacts. It just seems that with the custom curve, elevation errors seem to track to MV error more than anything else. Again, that is shooting less than 1000 yards mostly.

 

[StopMakingSense]

@Formidilosus any thoughts on here for your true up out to 1000m?

 

[philcox]

For my shooting (typically about 1,200 yards or less), I only adjust velocity in my solver. I used to adjust BC at longer ranges but now I always use Applied Ballistic custom curves and have had very good results.

It seems that since I've started using the custom curves, a Magnetospeed or Labradar, and Nightforce scopes, I rarely have to make any adjustments from what my solver tells me......

I know this is old, but have a bit better description? I just got the Revic RF Binos, so now think I need to know about this more

 

[Justin Crossley]

I know this is old, but have a bit better description? I just got the Revic RF Binos, so now think I need to know about this more

In Applied Ballistics app I use custom curves. I input the velocity from my Garmin Xero chronograph. Use DA and temp for atmosphere. Very rarely does that result in an incorrect solution.

Does that answer what you want to know?

 

[philcox]

In Applied Ballistics app I use custom curves. I input the velocity from my Garmin Xero chronograph. Use DA and temp for atmosphere. Very rarely does that result in an incorrect solution.

Does that answer what you want to know?

Yep, thanks. You’re using the AB app. I’ll have to see if the Revic app has that. Thx

 

[huntnful]

Yep, thanks. You’re using the AB app. I’ll have to see if the Revic app has that. Thx

The Revic doesn’t. But it has an excellent on board solver and sensor for environmental conditions. Put legit, good info, into it and you’ll get the proper corrections