Why do people obsess over velocity?


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layusn1
June 19, 2007, 12:28 PM
Why do people seem to obsess over velocity when they are developing their loads? It often seems like they are more concerned with that then with the groups they are getting with the loads. I notice that to be more the case with 223 loads than with handgun loads but I do still notice it with both. Is there a particular reason for that?

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ocabj
June 19, 2007, 12:48 PM
I don't really see this, myself.

For the most part, most people I know will work up a load for group size and then chronograph the load after they find one that groups well.

Depending on what the load will be used for, will a shooter decide if the load needs to be changed. For example, if a shooter is working up a load for use in competition, then velocity will be critical. It is important for the competitive shooter to know if the load will make the distance required, and how much wind drift to expect based on the muzzle velocity (and BC).

JDGray
June 19, 2007, 02:27 PM
Getting good velocity with a powder, without pressure signs, and duplicating factory velocities, is what its all about. Oh, and accuracy;) I dont shoot for the moon, but like to keep it close to factory as possible. Good expansion is only done with good velocity.

layusn1
June 19, 2007, 02:58 PM
Is velocity really important in your handloads if your just punching paper for groups at 25 yrds or less? I keep Federal Hydra Shock for Self defense in my CZ75 and my wife's Sig.

jwr_747
June 19, 2007, 03:20 PM
all my rifle loads are for shooting paper and gongs.don't care about speed,smallest group is my goal.most of my pistol loads,same as rifle,paper and gongs.HP defense loads need the speed ( in theory ) for a JHP to function as designed,expand. and than you really not looking at speed but pressure. if you start seeing hi press signs,you've gone as far as necessary,it gust happens that higher press,usually produces higher velocity. jwr

cheygriz
June 19, 2007, 03:44 PM
Obsessing over velocity makes no sense. However, velocity does determine flatness of trajectory, and kinetic energy.

Increasing bullet weight only increases Ke by direct proportion. Increasing velocity increases Ke by the square.

Ke= mv2. Kinetic energy equals mass times velocity squared.

jfh
June 19, 2007, 03:52 PM
for low Standard Deviations are what I found most correlated with accuracy at a given load in my pistols (.45 ACP, 10mm).

It didn't always correlate, but I had rounds in both calibers that used 200 gr SWC and 4.8 gr. of 231 that provided remarkably consistent velocities--SDs under 10, IIRC. They were both the most accurate loads out of either 1911.

I've started reloading again--this time with .38 /.357, in my j-frames. I've got some basic 231 loads done, and it's time to break out the chrono again.
I'm thinking that the sweet spot for each bullet will be the load / LOA / crimp settings that produce the best SD.

Then I'll take a look at velocity. Otherwise, velocity is like penis-measuring, I think.

Jim H.

Walkalong
June 19, 2007, 04:27 PM
I obsess with putting every bullet through the same hole. I am constantly dissapointed, but I keep trying. :)

layusn1
June 19, 2007, 04:30 PM
OK, so its not necessarily obsessing over velocity but highest velocity with the lowest standard deviation over a sting of shots equals accuracy over varying distances?

Does this basically translate to people talking about a specific bullet/caliber shooting flat?

The Bushmaster
June 19, 2007, 05:02 PM
By golly...I think he's got it...:D

ocabj
June 19, 2007, 05:35 PM
I don't know about making a load that shoots *flat*. There's no such thing in my opinion.

I'm sure there are very, very specific situations where you can make a load that shoots *flat* (maybe less than 1MOA drop) between two short distances. But for the most part, the second a bullet exits the barrel, it's subject to gravity. We're simply lobbing bullets, but very fast.

The only competitive shooting I'm really into is Service Rifle High Power. I've basically tried to keep my match loads (.223) between 2700 and 2800 fps. I'll find a good 'pulse' in the pressure/burn curve for the powder I'm using within the 2700 and 2800 fps points that results in a good group. Is that obsessing over velocity? Maybe. I'm not concerned about drop. I'm concerned about wind drift. I figure pushing a 77gr BTHP at 2750fps gives me enough leeway in 200 and 300 yard rapids such that a 5mph wind change in the middle of the string won't cost me the 10-ring.

ftierson
June 19, 2007, 11:10 PM
Speed kills...

Forrest

Stinger
June 20, 2007, 01:48 AM
By flat he means flatter trajectory. Knowing velocity makes mapping trajectory possible (trust but verify,) and on those long shots you're still in the game.

We can't measure pressure. We can look for pressure signs, but in and of themselves (short of serious problems) they don't mean much. Apply a velocity figure to that and things begin to change.

Say you've got a load that shoots great groups, shows no pressure signs, is 1-2g below max, but when you run it over a chrony you are getting 2-300fps more than what the books tell you on a max load. Guess what? You probably have a load with too much pressure.

Zeke Menuar
June 20, 2007, 03:20 AM
I care about how fast my 300 Weatherby goes. I have some relatives that like to brag and play one-up. 3300 fps from the chronograph gets some really dumbfounded looks and has cost one idiot cousin $50.

In reality my hunting loads for the Weatherby are around 3100 fps. The speedburner loads are for show and bragging rights.

I check the speed of my loads to make sure my loads are uniform. If I load up 20 rounds. I like those 20 rounds to be as close together as possible speedwise. If they aren't, I have a problem.

I don't chase velocity. I chase accuracy. Top speed doesn't always mean top accuracy.

ZM

Crazy4nitro
June 20, 2007, 10:35 AM
But Hey if some can Put 3 extra grains of powder to get the magical 00's at the end of the number,who cares about wear on the gun.....

This isnt me,but some are too ate up with it..

C4N

rdhood
June 20, 2007, 11:24 AM
I have just started reloading. I am currently reloading only .40 S&W. My obsession is the lowest charge load that will accomplish three things: cycle my pistol (Hi Point .40 S&W), give low recoil, give decent accuracy.

I recently ran across this article:

http://www.handgunsmag.com/ammunition/40lite_091806/index1.html

and tried what it suggested as my first bunch of rounds I ever produced. They failed to cycle/feed on about 5 out of 100 cartridges. Other than that, my SO/fiance was able to handle the recoil quite well and we both shot better groups than retail loads. For my next 200 (to be shot this weekend), I bumped from 3.5 to 3.7gr of WW231. The minimum suggested by Hodgdon is 4gr, and I suspect that it will require 4gr to properly cycle/feed this particular pistol.

As you can see, hot loads and velocity are not everyone's game. Accuracy and expense (and for me, recoil) often outweigh velocity when it comes to reloading.

30Cal
June 20, 2007, 12:57 PM
A lot of people just make the assumption that more velocity is better but never ask the question "how much better." Furthermore, most people wouldn't know how to come up with a meaningful answer to the "how much" question.

If you run a set of comparisons, a 100fps boost makes a very miniscule difference.

Ty

snuffy
June 20, 2007, 01:50 PM
It's ALL about velocity. By that I mean the creation of "new" cartridges, or wildcatting existing shells. The magnum craze that brought about the 7 mag and a few others were all about pushing for high velocity.

One point not made by anybody yet, is the term "Point Blank Range." PBR is being able to put the cross-hairs of a scope on the center of a rib cage of an average sized deer, and be assured a bullet will hit inside of a 9 inch square on those ribs. It is dependant on velocity, the higher the velocity the further the PBR is. It is usually stated as 0 out to say 375 yards. The critical measurement is the high point of the arc or trajectory can't go above the top of the 9 inch square. The final figure is when the bullet drops far enough to go under the bottom of that square.

IIRC when the 7mm STW was first wildcatted, it's main selling point was it could toss a 140 grain 7mm boat tail bullet out to 400 yds, with the mid-point being only 5 inches! In order to do that the velocity, (again IIRC) had to be 3600 fps.

If you're more interested in accuracy,(small groups), fine. If those small groups happen BEFORE the max powder charge, fine again. But most will agree that for long distance match shooting, you want both highest velocity AND best groups. It can be done!

As far as the highest velocity wearing a rifle out, the action is made to take 200% above it's working pressure. The barrel however, will wear out faster if all you shoot is the max charges.

Clark
June 20, 2007, 07:39 PM
I can get 4200 fps in .223 with Blue Dot and higher with H110, but the practical limit for keeping the bore clean for 100+ rounds and stay sub moa is 3600 fps.

I only measure that 4200 fps for bragging, and something tangible over the internet.

Stinger
June 20, 2007, 08:21 PM
Clark,

You're definitely one in a million :)

kidcoltoutlaw
June 21, 2007, 10:55 AM
Without velocity a 30-30 and a 300 RUM are the same round.

SSN Vet
June 22, 2007, 09:26 PM
I feel the need for speed! :)

then I can brag that I'm faster :neener:

or was that supposed to be bigger :rolleyes:

Alphazulu6
June 22, 2007, 09:32 PM
Ok anyone who shoots Camp Perry would know that a little heavier and a little faster is what beats the wind. As far as how much and how fast? Rule of thumb is that you better be super sonic at the distances your target is if you are going to compete with the 6mm BR and 6.5s....

P-32
June 23, 2007, 02:48 AM
Ok anyone who shoots Camp Perry would know that a little heavier and a little faster is what beats the wind. As far as how much and how fast? Rule of thumb is that you better be super sonic at the distances your target is if you are going to compete with the 6mm BR and 6.5s....

Might be true at 600 & a 1000 yards but the deer/elk is never going to know my bullet could have been going another 200 FPS.

Fly320s
June 23, 2007, 03:18 AM
Speed is life.

Peter M. Eick
June 23, 2007, 07:27 AM
Also, speed is one of the easiest things for the reloader to measure. Most of us don't have pressure gear so we use speed as a proxy for pressure.

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