This is a method I’ve came up with for calculating the muzzle velocity of a given round and rifle without having a chronograph, using a ballistics calculator and multiple shooting distances at the range. I will also leave a note at the end on how this can be done at a single range but it may not be as accurate.
Requirements
1 – A rifle and shooter that can shoot at least 1 MOA groups, the tighter the better. The scope on the rifle must be able to shoot a good box, i.e. 1 click or adjustment on the scope knobs must equal what they state it to be and it must return to the same alignment if moved back to a previous setting
2 – A range that offers multiple distances, the further spread between distances, the better
3 – A good ballistics calculation tool. There are many out there, via apps for phones, Excel spreadsheets, web sites. It should have a complete variable input capability including weather, elevation, and bullet ballistics. I use “Strelok” for the Android phone.
4 - A calm day, wind wise, is a big plus
1st - Zero your rifle at the shortest distance. I will use 100 yards
My setup and 100 yard zero (It might not be the fanciest but I prefer function over style. Anything more is just showing off... LOL)
DPMS LR-308
Vortex Viper PA - 6.5-20 x 44
Timney Trigger
Winchester Bipod
Wedgey Sandbag sitting on a 2x4 for rear support (Ghetto looking but effective)
I put 1 click (1/4 MOA) up in the scope after this and called it good.
Enter the round's manufacturer stated ballistics that you are firing, along with your rifle setup, weather, scope height, and any other inputs that your ballistics calculator has to offer. The more accurate these inputs are, the better this calculation will be. If you are using a hand load, enter the manufacturers ballistic coefficient and enter an estimated muzzle velocity. We will correct it later. Enter the scope Zero at whatever distance you zeroed the rifle.
I entered the stated data for Federal SMK 168 grn BTHP (Which just so happens to be the #1 default round… lol) as BC 0.447, weight 168, and I decreased the default MV of 2650 to 2600 assuming that I would lose a little bit from the gas system of my rifle.
Go to your longest range available. My range offers 600 yards.
Enter in the new distance into your ballistics calculator and adjust your scope to whatever it suggests. Mine suggested 16.5 MOA or 66 clicks of elevation
It was early and pretty calm when I shot the 100 yard group... Between me transporting all my gear to 600 and grabbing a bite for breakfast... This happened...
I picked an average and dialed that in for windage but the wind was literally in the middle of random gusts and changing direction so I’d be on target sometimes and high & left others… so I gave up on 600 as I’m trying to calibrate here… not win an extreme conditions competition… rofl…
So I moved it to my next shortest range which was 400 yards and dialed in the suggested correction of 8 MOA or 32 clicks. I adjusted another average for the wind and shot a group…
As you can see, the group was a tad high and left. I misjudged the wind just a bit and it was pushing the round a bit but the elevation was consistent and that’s what’s important here. Since the group was high, I can safely assume that the muzzle velocity that I entered was too low. So I called the overall elevation offset 1.5” and then went back into the ballistics calculator and increased the muzzle velocity until the suggested correction was 1.5” lower than the previous correction. Low & behold… The MV for a perfect 1.5” turned out to be 2648 fps… lol… Pretty much as the box says of 2650… go figure…
So now, I put 1 click down (Right at 1” at 400 yards) on the scope and changed my zero to 400 yards in the ballistics calculator. This would put me shooting a ½” high at 400 buts whats a ½” between friends….
With everything all calibrated, you should be able to punch up any distance, and dial in the suggested correction and you should be right on target. I decided to test at 200 yards…. From 400 yards, the ballistics calculator suggests -5.5 MOA or 22 clicks so I dialed that in and headed over to the 200 yard range, and there she blows… Don’t laugh at the group ROFL… Me and the bullet are getting blown all over like crazy and I’m a little shooter fatigued at this point…. I was actually doing 2 different rounds on this day and shooting quite a bit more… I just extracted the info pertinent to this post *excuse*
The alternate method of doing this from a single distance would be to shoot a group at 100 yards. 100 yards because 1 MOA is 1.084" at 100 yards so we can just say 1". Shoot it low on the target, near the bottom. On my setup, a 600 yard shot would require a 15.7 moa correction. Set the calculator for zeroed at 100 yards. then just as above, enter a far distance and adjust the scope accordingly. Shoot another group at the same target, using the same aiming point. The next shot group should come in high. As in my case, the 2nd group should come in at 15.7" high. Measure the actual distance with a ruler and correct the muzzle velocity until the suggested correction matches the measurement. Correct your scope for the newly calculated correction and shoot another group, aiming at the original aiming point. The new group should match the suggested correction.
Requirements
1 – A rifle and shooter that can shoot at least 1 MOA groups, the tighter the better. The scope on the rifle must be able to shoot a good box, i.e. 1 click or adjustment on the scope knobs must equal what they state it to be and it must return to the same alignment if moved back to a previous setting
2 – A range that offers multiple distances, the further spread between distances, the better
3 – A good ballistics calculation tool. There are many out there, via apps for phones, Excel spreadsheets, web sites. It should have a complete variable input capability including weather, elevation, and bullet ballistics. I use “Strelok” for the Android phone.
4 - A calm day, wind wise, is a big plus
1st - Zero your rifle at the shortest distance. I will use 100 yards
My setup and 100 yard zero (It might not be the fanciest but I prefer function over style. Anything more is just showing off... LOL)
DPMS LR-308
Vortex Viper PA - 6.5-20 x 44
Timney Trigger
Winchester Bipod
Wedgey Sandbag sitting on a 2x4 for rear support (Ghetto looking but effective)
I put 1 click (1/4 MOA) up in the scope after this and called it good.
Enter the round's manufacturer stated ballistics that you are firing, along with your rifle setup, weather, scope height, and any other inputs that your ballistics calculator has to offer. The more accurate these inputs are, the better this calculation will be. If you are using a hand load, enter the manufacturers ballistic coefficient and enter an estimated muzzle velocity. We will correct it later. Enter the scope Zero at whatever distance you zeroed the rifle.
I entered the stated data for Federal SMK 168 grn BTHP (Which just so happens to be the #1 default round… lol) as BC 0.447, weight 168, and I decreased the default MV of 2650 to 2600 assuming that I would lose a little bit from the gas system of my rifle.
Go to your longest range available. My range offers 600 yards.
Enter in the new distance into your ballistics calculator and adjust your scope to whatever it suggests. Mine suggested 16.5 MOA or 66 clicks of elevation
It was early and pretty calm when I shot the 100 yard group... Between me transporting all my gear to 600 and grabbing a bite for breakfast... This happened...
I picked an average and dialed that in for windage but the wind was literally in the middle of random gusts and changing direction so I’d be on target sometimes and high & left others… so I gave up on 600 as I’m trying to calibrate here… not win an extreme conditions competition… rofl…
So I moved it to my next shortest range which was 400 yards and dialed in the suggested correction of 8 MOA or 32 clicks. I adjusted another average for the wind and shot a group…
As you can see, the group was a tad high and left. I misjudged the wind just a bit and it was pushing the round a bit but the elevation was consistent and that’s what’s important here. Since the group was high, I can safely assume that the muzzle velocity that I entered was too low. So I called the overall elevation offset 1.5” and then went back into the ballistics calculator and increased the muzzle velocity until the suggested correction was 1.5” lower than the previous correction. Low & behold… The MV for a perfect 1.5” turned out to be 2648 fps… lol… Pretty much as the box says of 2650… go figure…
So now, I put 1 click down (Right at 1” at 400 yards) on the scope and changed my zero to 400 yards in the ballistics calculator. This would put me shooting a ½” high at 400 buts whats a ½” between friends….
With everything all calibrated, you should be able to punch up any distance, and dial in the suggested correction and you should be right on target. I decided to test at 200 yards…. From 400 yards, the ballistics calculator suggests -5.5 MOA or 22 clicks so I dialed that in and headed over to the 200 yard range, and there she blows… Don’t laugh at the group ROFL… Me and the bullet are getting blown all over like crazy and I’m a little shooter fatigued at this point…. I was actually doing 2 different rounds on this day and shooting quite a bit more… I just extracted the info pertinent to this post *excuse*
The alternate method of doing this from a single distance would be to shoot a group at 100 yards. 100 yards because 1 MOA is 1.084" at 100 yards so we can just say 1". Shoot it low on the target, near the bottom. On my setup, a 600 yard shot would require a 15.7 moa correction. Set the calculator for zeroed at 100 yards. then just as above, enter a far distance and adjust the scope accordingly. Shoot another group at the same target, using the same aiming point. The next shot group should come in high. As in my case, the 2nd group should come in at 15.7" high. Measure the actual distance with a ruler and correct the muzzle velocity until the suggested correction matches the measurement. Correct your scope for the newly calculated correction and shoot another group, aiming at the original aiming point. The new group should match the suggested correction.
