Is a Chronograph needed? Dope chart

76Aaron · Mar 8, 2023

I am working on a 7mm-08 load for an 18" barrel set up. Using the reloading manual velocity, and the Hornaday calculator, I have an estimated FPS but need to get a dope chart dialed in. If a Chronograph is a must have for this (and nice to have for reloading), any recommendations on brand? if there is another way using the data from the book and calculator, please let me know and I'll try that. Thank you.

NobullSKS · Mar 9, 2023

76Aaron said:
I am working on a 7mm-08 load for an 18" barrel set up. Using the reloading manual velocity, and the Hornaday calculator, I have an estimated FPS but need to get a dope chart dialed in. If a Chronograph is a must have for this (and nice to have for reloading), any recommendations on brand? if there is another way using the data from the book and calculator, please let me know and I'll try that. Thank you.

I would/do….

If you shoot at a range…. Ask if they have one to borrow.
Magnetospeed…. Load extra rounds for velocity…. Attaching anything to barrel will affect POI.
I've seen folks use them mounted to arca rail on free float hand guards but…

Hueco · Mar 9, 2023

If you can shoot at known distances, you can calculate the speed by measuring the drop. Instead of taking speed at the muzzle and then calculating drop at 100 and then shooting to verify…you are shooting at 100 and and using the drop to calculate the speed at the muzzle.

It's just math - it goes both ways. Up until recently (bought a chrono off a member here), I was doing that exercise for establishing dope for .22LR for NRL.

arrowshooter · Mar 9, 2023

If this is going to be a one and done project for you then find what groups best at 100 yds then see what your drop is at 200 yds. Per Hueco it is just math from there. Having a chrono though does a whole lot more for you when it comes to load development than just help you with your "dope". They can actually help you become a better reloader. I have always used Competition Electronics Chronographs and recently upgraded to the DLX. It's nice to hear and see what is going on while sitting at the shooting bench instead of trying to see the numbers on the chrono. It is also not that expensive compared to other chronos on the market.

thorborg · Mar 9, 2023

I stuffed a lot of different calibers, shot a lot of targets having great fun, and hunted successfully with my efforts for over 30 years without one, and without a press too for that matter. But my first, a 20 dollar optical chronograph, changed the game on accuracy some, but more so in optimizing powders, perceived safety, economy and consistency not to mention upped the excitement in the arena of handloading for me. While the low cost optical device provided the essentials for almost ten years it some what frustrated vial finicky environmental requirements needed to operate wasting some outings and components.
I added the magnetic device. it was simple and efficient for speed info but did little for real world precision and repeatable hit determination, but mainly left me wanting for handguns, it was basically useless.
The Doppler won the day, especially with a remote trigger added, albeit not a device I would want to have splurged on my first 30 years of my handloading life and in my mind, essentially unneeded until I had acquired a higher level knowledge, ability, experience, in handloading.

I think one is best served in learning to drive well and fix hot rods, sticking with a torque wrench, tac and dwell meter, before investing in a Sun diagnostic center and race car. (or what ever todays equivalent is)

kopcicle · Mar 9, 2023

Now I wouldn't consider working up a load without a chrono.
Then it was all waterline, looking for a node.

TLDR warning.

18" isn't in most of the tables and can be a bit of a touchy subject.
Learn SD and ES. Build a table or spreadsheet and get to work.

What is your intended use?
As a for instance, medium game. I use a 5" Maximum Point Blank Range.
That is, the round is never 2.5 inches above or below line of sight out to whatever range.
This is difficult to determine experimentally without an accurate foot per second.
It's best to first get a consistent foot per second and then waterline while adjusting seating depth.
At that point there are several ballistic calculators that are reasonably accurate for G1 or G7 that will save you time and ammunition by being in the neighborhood while you verify by shooting.
My .308's and the .270 have some wacky zero ranges. I'm fortunate that the calculator I use resolves to 4 decimal places.
The 140gr .270 for instance, found a node at 2925 ft/sec. At 100 yards that puts it at plus 2.2936" above center. The resulting MPBR is about 262 yards.
This simplifies things a bunch. Anything I dead hold on that is 5" in diameter, out to 262 yards, I'm going to hit.
Note, the zero was 225 yards.

TLDR
yes get a chrono
Work on the SD and the waterline
play with seating depth
MPBR for intended use

arrowshooter · Mar 9, 2023

Yep

One thing I played with when working up my new -06 was sighting in at I believe it was 26 yard and it put me at 4.75" out to 300yds, on paper anyway. I tested it at 100yds and it matched the calculations.

DizzyJ · Mar 9, 2023

They're good to get an idea of actual speed. From that you can create your dope charts. Those dope charts will probably need to be tweaked to be accurate.

A chrono will also tell you if you're pushing the limits load wise. Speed doesn't come free. The faster you're pushing that bullet the more pressure you're creating in your chamber. If you're going over published speeds, you may very well be on the ragged edge of catastrophe.

Lastly, get a chrono that's reliable. There are lots of versions out there and some can't be trusted which means your data is crap. I'll let you do your own research on the pros and cons of each type. The better they get, the more they cost.

titsonritz · Mar 9, 2023

Hueco said:
If you can shoot at known distances, you can calculate the speed by measuring the drop. Instead of taking speed at the muzzle and then calculating drop at 100 and then shooting to verify…you are shooting at 100 and and using the drop to calculate the speed at the muzzle.

It's just math - it goes both ways. Up until recently (bought a chrono off a member here), I was doing that exercise for establishing dope for .22LR for NRL.

Maph is racist, I don't want to have to work at it I just want the bullet to hit the damn target. :s0108:

DizzyJ · Mar 9, 2023

titsonritz said:
Maph is racist, I don't want to have to work at it I just want the bullet to hit the damn target.

Bigger target.

76Aaron · Mar 9, 2023

Thank you all for the info. This is a youth model rifle (hence the 18"), and I am working up a load for spring bear. Ideal shot would be no longer than 300, max 400 if I am confident in the load. Looking at using 150 gn ELD-X. My dear loads in 139gn have all worked out but have been under 200 yards. This is something that I am trying to improve my knowledge on. Thank you again for the input.