How important is velocity

D

Dre_sa

New member
Greetings all,

A quick question to rile up the masses and maybe some knowledge from the local grey beards.

When hand loading, how important is it to keep track of the exact velocities of your loads?
Does one really need to know the extreme spread, standard deviation, averages and all such mathematical bothering?

I understand that inconsistent velocities will result in increased vertical stringing of groups, but surely with projectiles of the same weight and powder charges of the same weight, you've done all you can to make the velocities as consistent as possible.

If the groups are consistent, predictable, and tiny, what use then, is knowing the velocity? Aside from additional calculations for energy and such.

Is it even possible to get those tiny groups without that information?

Thanks for the help all.

Sent from my Pixel 2 XL using Tapatalk
 
I don't own a chronograph, and have only shot through one five times to get velocity in a class I took on long range shooting. Used the velocity to figure bullet drop at 1000 yards. The rifle I was using was zeroed at 300 yards. Knowing the true velocity then figuring the "come up" got me on paper at 1000 yards first try. Matter of fact, it got me in the black at 1000 yards. Other than that, I don't see a real need for a chronograph. A hole in the X-ring doesn't care how fast the bullet was traveling.
 
go to a ballistics computer such as the JBM calculator and plug in your bullet weight, diameter, and BC then try different velocities and see for yourself how much drop is involved on your loads at the distances you will be shooting

For my current load going from 2950 FPS to 2975 FPS I have .3 inch difference at 300, 3.3 inch difference at 800, and 7 inches at 1000. That is with a hot load on a high BC bullet
 
Being able to keep track of the exact velocities of your loads is a relatively new thing. Chronographs becoming less expensive(And Internet forums thinking they're necessary.) have made it possible. Accuracy is far more important.
Ballistics computers and programs are just that. Computer programs that cannot consider every single variation that's possible. Not to mention they're written by a programmer who likely have never seen a real firearm. Just like computer 1st person shooting games.
 
well I can shoot a round across my $100 chronograph, jump on my ballistics calculator on my cell phone, plug the numbers in and go from a 100 yard sero to 800 yards and be within a MOA at 800 on the first shot. I guess accuracy is in the eye of the beholder. At medium and long ranges consistent velocity is necessary for accuracy unless you want to shoot the target in the knee

Now if all I did was shoot 75 and 100 year old antiques at 50 and 100 and hope for a 2 inch group on a good day I doubt I would bother with either the chrono or the balistics calculator
 
Last edited:
Dre_sa said:
Greetings all,

A quick question to rile up the masses and maybe some knowledge from the local grey beards.

When hand loading, how important is it to keep track of the exact velocities of your loads?
Does one really need to know the extreme spread, standard deviation, averages and all such mathematical bothering?

I understand that inconsistent velocities will result in increased vertical stringing of groups, but surely with projectiles of the same weight and powder charges of the same weight, you've done all you can to make the velocities as consistent as possible.

If the groups are consistent, predictable, and tiny, what use then, is knowing the velocity? Aside from additional calculations for energy and such.

Is it even possible to get those tiny groups without that information?

Thanks for the help all.

Sent from my Pixel 2 XL using Tapatalk
Click to expand...

Rifle or handgun?

Caliber?
 
even with handguns if you are doing competition you have to maintain a power factor level for your loads. Go to any IDPA or USPCA match with a low charge powder puff load to minimize muzzle jump and you will be disqualified
 
At the moment I'm loading for .577-450 and 11mm Mauser. I am considering loading and casting for .308 since I have three rifles in that cartridge and I don't take them out as often as I'd like.

Unfortunately the only ranges available locally are up to 100 yards

Sent from my Pixel 2 XL using Tapatalk
 
I don't NEED a chrony, but have had one for 25 years. They help.

For example. Getting 700 fps for a Hollow Base Wadcutter, or 675, or 750 fps for 200 SWC when I am shooting Bullseye.

Chrony loads to make sure they are near what they are supposed to be.

Building loads for a rifle. I do ladder tests. It works.

I guess its a tool, not necessary, but sure makes things easier if you load for accuracy.

"How much do I lose from a 6" 38 to my 2" 38?" My 5" 45 to my 3.5" 45?"

I load 32-20 for silhouette. They have a 1450 fps limit.

David
 
When hand loading, how important is it to keep track of the exact velocities of your loads?
Does one really need to know the extreme spread, standard deviation, averages and all such mathematical bothering?

I understand that inconsistent velocities will result in increased vertical stringing of groups, but surely with projectiles of the same weight and powder charges of the same weight, you've done all you can to make the velocities as consistent as possible.
Click to expand...

Ahh, but have you? If you have a load that shoots an unusually high SD and you know your projectiles and charges are carefully weighed and checked, then there is something else you can do to bring this down (and theoretically reduce group size). A high SD is typically a sign of something. Minimum charges of slow-for-caliber powders most of the time have high SDs, because there is not enough pressure present for complete (or at least consistent) burn. In this case, the math can tell you to go back to the drawing board with that load. Or it could just mean that switching to magnum primers will help a lot. So those calculations can serve a purpose. I have heard of some loads that showed high SDs still being accurate. I've never seen it though.

If the groups are consistent, predictable, and tiny, what use then, is knowing the velocity? Aside from additional calculations for energy and such.
Click to expand...

Houngdawg answered this quite well. It takes some leg work out of doping your rifle. Although I have used a method to get a very close velocity without a Chrono. I have doped loads at 100 and at 500, then measured the drop. I can then plug that information, along with bullet BC, into a ballistics calculator and get a pretty good estimate of velocity and the trajectory at all ranges in between and greater. This works, and I've done it when I didn't have a chrono.

Is it even possible to get those tiny groups without that information?
Click to expand...

What is tiny? Is 1moa sufficient? 1/2moa? Or do you seek 1/4moa groups? I have developed several loads that were near 1/2moa without a chrono. Just did a mini ladder test and found my load.
 
To me not much. I can see where it could be extremely important for those into competitive shooting or in certain career fields such as professional snipers. I suspect those folks using suppressors want to monitor their subsonic loads.
 
I loaded and shot to about 300 yards for a couple of years without a chrono.
I use mine quite a bit now. For rifle and pistol.
Pistol is mostly for my carry ammo. Because of the short barrels on my carry guns (shorter than what is normally tested for caliber in manuals) i want to make sure i have enough velocity for a HP to expand properly.

As for rifles, it is as Hounddawg has said. I do however shoot 600-800 yards and use the truing function in my ballistics calculator.

Also as for ES/SD, i had a powder bullet combo do ok at 100. Terrible at 300. Found out my ES/SD were way high. Switched powders and grouped much better at all distances.
Cartridge in question was 7mm -08AI with 140gr Berger and CFE 223. Switched to PP2000.
 
I will probably get a Labradar in the near future (my chrono just up and quit a while back)

For me it allows me to get a load in the area of a different powder that the bullet preformed well in before.

Its useful, not a have to.
 
It really depends on you, IMO chronographs are a money and time saver. If you're a competitor I'd say they're invaluable as a shooting tool. I use them to get me on target faster downrange and to tell me if my reloading process is sound. Once you start realizing there is more to be learned than how fast your bullet is leaving the muzzle then you see more benefits to having a chronograph.
 
Personally would not be developing/loading higher pressure pistol or rifle without one. While not an absolute measure of pressure, you're velocities are indicative. If you shoot long enough strings, es and sd might be useful. Some may not shoot long enough strings, but simply look for obvious variations. Am more interested in av velocity, and how temp or other conditions affect it. Chronographs can be relatively inexpensive. Newer ones appear extremely handy and less pia at the range.

As others stated, having your velocity is huge time saver for sight adjustment at longer distance. The programs are that good. Am still checking them, but they are close.
 
even with handguns if you are doing competition you have to maintain a power factor level for your loads. Go to any IDPA or USPCA match with a low charge powder puff load to minimize muzzle jump and you will be disqualified
Click to expand...

Not all disciplines. As long as the bullets completely passes through the cardboard backer, it's fast enough. Bullseye and PPC come to mind. If I'm not mistaking, it's actually in the rules, the bullet must pass through the cardboard backer. And yes, I've seen semi wad cutter bullets stop at the shoulder stuck in the target. Best part about it, the bullet was stuck in the X-ring.
 
We can load with a hammer and a LEE Loader. It goes up from there.

I have an old progressive press and old Crony. This is my second one, I shot the first.

David

Sent from my SM-T900 using Tapatalk
 
When hand loading I use my chronograph to warn me if I'm approaching an overload. If the manuals say that 60 gr of powder is supposed to be 3000 fps I want to know if I'm getting close to 3000 fps with my loads. Most of the time, with most components, and most rifles the manuals will be pretty predictable.

But with some combo's I've seen rifles exceed the expected velocity several grains below the listed max. I might find that 58 gr of powder gives me 3000 fps with certain combo's. Without knowing my speed I might assume that a load 2 gr below max was perfectly safe. And it may not be.

I'm not one to try to push the envelope and develop "hot" loads. But at the same time if I'm shooting a 30-06 I don't want to be loading it to 300 Savage levels either.

I don't worry too much about Standard Deviation or Extreme spread. If you're shooting at 1000 yards then it matters. Even when hunting at 400+ yards 25 fps variance just doesn't matter much. Nor does squeezing the last possible 50 fps out of a round.

Knowing the exact MV can be used to calculate drops and energy downrange. But the fact is that trajectory between all of the common cartridges and bullets is remarkably close. At 300 yards a 30-06 shooting the same bullet 200 fps faster than a 308 only has 2" less drop.
 
You must log in or register to reply here.
Back
Top