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accuracy vs velocity

Posted: Mon Jan 09, 2012 8:37 am
by Tokimini
I've noticed that a lot of members seemed to be very concerned with the velocity of their handloads. On one thread even though the author was pleased with the groups he was getting he said he was still going to up the load to try and get more speed. I don't own a cronograph and have no plans to get one. My sole concern is accuracy, but I'm interested in what other handloaders priorities are. What is most important to you, accuracy or muzzle velocity?

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 8:43 am
by Rick in Oregon
#1: Accuracy

#2: Velocity (but not at the expense of accuracy).

You really should consider a chronograph. Without one, you're just whistling Dixie, not knowing the velocity limits your knowledge of your pet load, and also makes it impossible to produce "come-up" charts for the load if it's paired with a ballistics program. You'll also never know the SD, ES to get your long range loads tweaked for maximum performance and eliminate vertical stringing. You already own a computer, so making accurate 'come-up' charts will be no effort.

Once I got a chrono many years ago, my handloads just "started to come together" so to speak, LR hits became normal, and I was able to really tweak any pet load to be a screamer load. JMO

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 10:08 am
by bow shot
Accuracy first, velocity second.

I see a chrony as being a great tool for determining whether a load's vertial stringing is recepie or shooter related. Ie., if the shot-to-shot velocity does "not" vary, focus should be on the shooter, not the load. I blew a lot of time ( :D fun!) and money ( :mad: not fun!) trying to eliminate vertical stringing from my load only to realize over time that the stringing was the result of poor recoil control on my part :cry: .

If I had a chrony, and had seen that there was "no" velocity variation shot-to-shot, it would have saved me a ton of time cursing the rifle, the loads, etc... all along the problem was my shooting form :doh: .

No, I don't have a chrony, and wish I did... :cry:

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 10:10 am
by bow shot
Rick, can explain a "come up" chart please..

Also, you detailed your MOA method for distance shooting... I think you charted the turret adjustments and stuck it in you lens cap or something... do you remember what/where that thread was?

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 10:54 am
by RAMOS
Rick, as long as your answering questions........What chrono are you using and do you have a recommendation on the current units?

On Topic: Always accuracy first! It sucks to miss at any speed.

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 11:10 am
by Rick in Oregon
RAMOS wrote:Rick, as long as your answering questions........What chrono are you using and do you have a recommendation on the current units?
Jon, I'm probably not the guy to ask about chronographs. I've used my Shooting Chrony Beta model for almost 20 years, just upgraded it to the new model that has the bench-mounted readout, but without printer.

If I had my druthers, I'd own an Ohler 35P, but everytime I gather funds for such, it gets shanghi'd to a rifle project of some sort. Silly I know, and it's been happening for the full 20 years. Pop over to Saubier and 6mmbr and ask those guys. I'll say this though, for just around a hundred bucks, the little Chrony does an amazing job, and gives me all the data I need for what I do. Can't say a single bad thing about it; it's been a faithful, reliable little unit and is compact enough to go into my range box.

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 12:46 pm
by Glen
Accuracy 1st BUT,, :lol: the whole reason behind getting a 204R was for the accuracy at the high velocities. I wanted both & thru load testing found it.

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 1:49 pm
by Tokimini
Rick, since joining this forum I have saved myself countless time and aggravation by following the recommendations of people much more knowledgeable about reloading than myself, and you are probably at the top of the heap in that department, so I take your opinion very seriously. Over time I have gotten my handload groups (5 shots @ 100 yards) down to sub .5" and my best loads (40gr Vmax with 8208XBR) are getting close to .25". You mentioned some terms I not familiar with like SD and ES so forgive me if this is a stupid question but how would getting a chronograph tighten my groups up?

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 1:59 pm
by Ol` Joe
I consider my crony an important tool in my load development, but will never put an extra 100 fps over top accuracy.
The price of chronograph today puts them within anyones reach, and is something every serious reloader should strongly considerer owning

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 2:47 pm
by Sth Oz Dan
You wanna know what's happening with each shot - get a chrono. It's not about bragging rights on fps, just a great analysis tool. ES = extreme spread (between slowest and fastest speeds in a string), and SD = standard deviation in a string of shots. No long range target experience for me yet, but from what I've read - if a load has low SD and ES, ie velocity very similar from each shot, then long range accuracy is much better.
Definitely load for accuracy. Critters won't argue with a slower load.
Even if a faster load shoots flatter at long range, it's useless unless it's POI is consistent.

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 3:50 pm
by Rick in Oregon
Tokimini wrote:You mentioned some terms I not familiar with like SD and ES so forgive me if this is a stupid question but how would getting a chronograph tighten my groups up?
Tokimini: Answer: Maybe nothing. However with a chrono, one example is that you can see which loads produce the most consistent velocity, thereby the most overall consistency. In most cases, the more consistency, the more accurate the load. If nothing else, you soon learn how much powder increases velocity for a given case so you can see the relationship between powder increases vs. actual velocity gained. Also, knowing the actual velocity gives you the opportunity to make "come-up" charts for your given rifle and load and make first shot hits at ranges not possible previously.

The abbreviations 'ES' and 'SD' refer to Extreme Spread and Standard Deviation. It would be best to research these two terms properly, lest I not explain it in the best terms. I'm sure you can see right away the immediate effect on accuracy just by their titles.

Let me just say that overall, all my rifles are shooting better/tighter groups once I gained the advantage of a chronograph and learned how to use it.

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 5:01 pm
by Sth Oz Dan
Rick in Oregon wrote:
Tokimini wrote:You mentioned some terms I not familiar with like SD and ES so forgive me if this is a stupid question but how would getting a chronograph tighten my groups up?
It would be best to research these two terms properly, lest I not explain it in the best terms.
Well put Rick.
There is a lot of experience on this site, not much of which is mine.
Don't limit your research to this forum.
But do tell us what you learn :D

Re: accuracy vs velocity

Posted: Mon Jan 09, 2012 5:23 pm
by Fred_C_Dobbs
Tokimini wrote:...how would getting a chronograph tighten my groups up?
The higher your load's SD, the more disproportionally your groups will open up as range increases.

Because gravity affects everything exponentially with respect to time, unless two bullets have exactly the same Time of Flight (meaning they began with the same MV), the difference in the distance they drop will increase dramatically as Time of Flight increases. In 0.2 secs ToF, the difference will be 4x what it was after 0.1 secs. In 0.5 secs ToF, the difference will be 25x what it was after 0.1 secs ToF.

You can have a 39-gr SMK load that's shooting bugholes @100yards, but with a 3800 fps avg MV, @500 yards an SD of 50 fps will increase your groups' sizes by an additional 1.3" on average. That's a deterministic error you could have eliminated if you had chronographed your loads, recognized the high SD and taken steps to correct it.

The difference is less pronounced in the .204 because it's an uncommonly fast round and generally only is fired at relatively short ranges. With slower rounds employed at longer ranges, because that necessarily means a longer ToF, it also means a low SD is more critical to small groups. Shooting a .308 @1000 yards, an SD of 50 produces an additional 20" average error.

If you're shooting competitively @600 yards or more, unless your SD is in the single digits, you'd better be facing weak competition or you're going to get your clock cleaned.

Without chronograph data, you can't know whether your SD is excessive, or whether the steps you've taken to lower it have been effective.