Speed VS accuracy

[dragman]

I know the saying is always been who cares how fast it is as long as it's accurate. this is my dilema of sorts. I have almost completed load development on my bench gun that I shoot 850-1000 with and I shoot silhouette with and I have a choice and don't know which is the right one?
load A. shoots 2900.2 FPS with a extreme spread over 5 shots of 16fps and @ 100 yards it shoots .1ish center to center. It really looks like one hole just a little egg shaped.
load B. shoots 2975.4 FPS with an extreme spread over 5 shots of 13fps and @ 100 yards it shoots .215 center to center. a makes a nice bug hole.

Now at that distance is the slightly tighter extreme spread and the 75fps going to make up for the size of the group??? I am thinking with wind, rain, mother nature in general the faster load since it shoots decently well might out perform the "better" load. What does everyone else think???

 

[Nomad47]

I wish I had a tough decision like that to make.

I would shoot both loads at side by side targets at 600 yards alternating shots so both loads get the same conditions. Then I would choose the best group with a little extra emphasis on vertical.

 

[dragman]

I don't have a 600 yard spot regularly availible, but I am gonna reload them both 20 shots a piece and do 4 5 shot groups each @ 300.
question is if the results are similar what direction is the " correct one "

 

[Keith Glasscock]

I'd take a 1 over a 2 any day, all else being equal.

I make load choices a little differently. I look at each load's tolerance to variation in conditions. One of those two loads is likely to be a bit touchy about ammunition assembly, neck tension, etc.. The other load will likely be much more tolerant. Since I shoot F-class, I want all the tolerance I can get. Both are more than adequate for what I need.

 

[halfmoanut]

JMTC here, I shoot 600yd benchrest competition and do all of my load developement @ 200. When I find 2 loads that will be competitive @ 200 for 600 yrds I take them both to a 600yd range and test them and every time one of those groups will have more vertical than the other. The one with the least amount of vertical will go to the match with me,however it may not be the smallest @ 200. Speed will never thrump accuracy @ least in my book.

 

[dragman]

that is the question. at some point for a long shot speed IMHO does trump accuracy. I am not saying just see what shoots fast and go with it but in a case were two loads are close but one is a lot faster doesn't that equate into down range accuracy since the elements are effecting it less??
with perfect conditions the more accurate round always wins. but with wind rain and changing conditions does the flatter faster bullet retain it's original accuracy were the slower one may go from great to horrible???

 

[halfmoanut]

A fellow at a shoot whom was 10th overall at nationals 100-200yds told me he won shooting his 6ppc @ 2700fps this past year. I would have to say for myself I'll take accuracy over speed anytime. When shooting in competition you shoot for the size of a group (agg) and for the best score, if the size of a group is small it will fit into the 10 ring for a better score and also be a better (agg) for the average of how many targets are being shot.The name of the game is accuracy.But here again,JMTC'S!!!!!

 

[Outrider27]

that is the question. at some point for a long shot speed IMHO does trump accuracy. I am not saying just see what shoots fast and go with it but in a case were two loads are close but one is a lot faster doesn't that equate into down range accuracy since the elements are effecting it less??

Doubtful, where the usual biggest uncertainty is wind deflection. Wind deflection is not a function of the time of flight, but a function of lag time, which is the difference, at a given range (say 1000 yards) between the bullet's actual time of flight at that distance and the bullet's time of flight at the same distance in a vacuum. Therefore, the important factor isn't the difference in velocity, it's the difference between the two velocities and their respective times of flight in a vacuum. If one of the loads goes from great to horrible under changing conditions, I wouldn't automatically conclude that more velocity will improve the situation. In the case of the two loads you cite (it's nice to have two choices that good, isn't it?), my impulse would be to go with the slightly more accurate load, which, this time, is the lower velocity load. But remember, in the end, obsessing over possible technical reasons to make a choice like this is often to little avail; in the end, IF you have good wind data and the ability to adjust for it, your rifle will tell you which is best, or if your wind judging ability is on a par with mine, it won't matter which of those loads you use..... ;D

 

[rcw3]

dragman

I would always go with the more accurate load for a few reasons:

1. Shot dispersion seems to get progressively worse the further out you go, so at distance I think you will find the .2 load spreads out more than the .1 load will; and

2. I find that the tighter shooting loads run better in the wind and are less affected by the wind.

Just my views and opinions on the subject FWIW.

Robert

 

[dragman]

Great info
Thanks all

 

[M14AMU]

Whichever one gives you the most CONFIDENCE!! It's a 'mental game'....of sorts!!

 

[lukehalee]

Here's a thought. Dump the chrony and tune for the load that holds up best to the wind. Unfortunately this changes with conditions.

 

[mgx1138]

Did I miss something? What caliber is this rifle that you are shooting for benchrest and for silhouette? What discipline are you planning to shoot with it at 850 - 1000 yards? What king of rifle is it? How many groups did you shoot that were ".1" ish" at 100 yards? How many that were .215" ? What bullet? What BC?

For my long range loads, I always have a bullet and target velocity in mind... some mix of bullet weight, BC and muzzle velocity that I know will give me a flat trajectory and competitive wind bucking at my intended range (like the Berger 140 hybrid @ 2900 - 3000 fps). Then I test to find the most accurate powder and load with that bullet and that target MV range.

Did I miss a bunch of information somehow? Best Regards.

 

[dragman]

Gun - Bat model B with a Bartline 30.5" barrel 9 twist shooting 180 bergers for all the loads.

I shoot 850-1000 and I shoot silhouette

 

[mgx1138]

So I would probably make a very different decision for benchrest vs. silhouette shooting. The small increase in accuracy is going to be meaningless when shooting offhand; I'd go with the higher velocity load. Maybe I'd make the opposite decision for shooting LR benchrest, where you can watch the wind carefully and shoot your 5 rounds in 30 seconds if you like.

So is this a 7mm? the only 180 grain Berger target bullets are for 7mm... are you shooting the VLD or the Hybrid? I find that the VLD shoot more consistently when you push them hard and load them at or into the lands. The hybrid is more length and velocity tolerant.

Best of luck.

 

[dragman]

caliber is a .284
it is silhouette 850-1000 but it's all bench rest style shooting
it's 180Hybrids and they are jammed around .15 thousands into the lands.

 

[savagedasher]

Why not both that the difference between a 6br and a dasher or brx
Good Shooting Larry

 

[dragman]

Why not both that the difference between a 6br and a dasher or brx
Good Shooting Larry

???

 

[savagedasher]

Thanks that what i meant to say . Thats what a dasher or a brx does to 6mm Br . Gives you both.
Good Shooting Larry

 

[Trevor60]

I will be the contrarian in this case for argument shake. When you look at group size; one could be twice as big as the other while only gaining 75fps gaining approx 2.5% in speed. But when i run a 6mm bullet with a .272 g7 i see a .2moa difference in favour of the faster bullet at both the 800 and 1000 yard targets. .2moa at 1,000 yards is 2 inches wind drift against a 1" disadvantage in vertical.

This is not an absolute gain of 2 inches as the 2" group would be larger horizontally as well as vertically and would cut into the horizontal advantage.

Using F class as the reference as i do not know silhouette target dimensions the difference when shooting F class would be a clean 10 vs. an outer 9... 2" is 1 5/8 larger then the difference in the ring diameter. But the difference in vertical would only be 1" of a 5 inch circle at 1,000. percentage wise the .2moa group is 40% of the X ring while the .1moa group is only 20%

I have analyzed the same groupings when picking a load for myself with the 308 but have chosen the higher speed as it had a better drift advantage then i was giving up in vertical, my 2 loads were 150fps appart yet the vertical grouping difference was less then 1.5" at 1,000

everything is relative as you say the .1 group is actually .1ish that could be .12 or .16 the closer to .1 the harder it would be to justify taking the faster round.

As a side note i have taken the tighter shooting bullet when shooting a smaller targets. I was testing BIB's 187 at 300 and they shot outstanding against another bullet with higher BC (matrix bullets) but at 300 because the F class target is actually smaller then .5moa i chose the BIB's as what i gained in a reduced vertical outweight the wind drift advantage.