Home Forums Hunting & Shooting Ask The Gunwriters SD and ES

CumGargler, how's ES/SD on this ammo? Does it over penetrate or not offer enough penetration on the thick armor cockroaches wear? Is it worth the cost, or going through as much as you do to keep the hoards of roaches in your restaurant at bay, you find regular table salt more cost effective?

No dumbazz, that's not what I'm saying. I understand that velocity is a variable and that the barrel is in constant motion. You want to time your muzzle exit when the muzzle movement slows down and is just before it's peak. I've played with a chronograph, quick load AND pressure trace, have seen how velocity changes exit time...

Great post. I can tell some stories about newbie handloaders shooting schidt for groups and coming up to me at the range and telling me their sd and es numbers were low. I finally got tired of one guy bugging me, as he was having issues with his "precision" rifle and loads and only relying on the chronograph. I told him to "throw the fu cking chrono away or leave it at home. Shoot your rifle and let it tell you what it likes". I know that sounds harsh, but don't ask me stupid questions more than about 2 times. You may not like the answer I give you!!! That goes for anyone.

I don't use a chrono that gives me es and sd numbers, as I could really care less. I know what my ammo and rifles do at just about any distance because I test them. I have the hard numbers on paper. The lazy fu cks don't want to do that and are looking for an easy way out. There is no replacement for actually getting out there and doing the shooting.

The only time my loads were tested, was when I was at a range/rock quarry in the national forest and a guy wanted to see what es sd numbers my loads were producing. He kept eyeballing my groups and was struggling big time with his loads and rifle. The funny thing about that was it was a Tikka. One of the early superlight 223's with the fast twist barrel. I was shooting one of my Winchesters, before I even owned a Tikka (around 2009-2011). Actually my competition rifle at the time. A souped up Winchester (FN PBR XP), that a lot of SWAT/police guys used back in the day. When he had me run my loads across his chrono, I fired 10 shots into a cluster of about .6" on paper. The sd was 7 or 9, and the extreme spread was small as well. He asked, "what is it exactly you do again". I said, what do you mean? He said, "what do you do for a living". I said I'm a "welder". He shook his head and said, "well you just made an aeronautical engineer look pretty bad!!". Are the sd/es numbers of my other loads pretty small?? I don't know, but I know they shoot good:


That guy is actually a friend of mine now. Funny, the people you meet out in the national forest, or at ranges. Some get it, some don't..

I always use the high performance stuff.

It’s like a Nosler Partition for them tough bastids

Not just drop though.. the slower bullet also spends more time in the wind.. correct? In theory you should pick up more horizontal dispersion also, say with a 3 or 9 o'clock with the slower bullet.

And the way I learned it, the lower velocity exiting at a higher point in the barrels recoil, really had a greater effect when it comes to handgun velocities.

I don't think anybody has said that "good numbers trump accuracy", just that some want both.

Well played, you're nearly tolerable when Burns isn't around.

If you don't intend to shoot long range, mostly, it doesn't matter much.

Flight time differences would probably be measured in 1/100ths or 1/1000’s of a second, so time exposed to wind wouldn’t make any significant difference for horizontal dispersion

Thanks all for the conversation, it's been....interesting.

I realize, I've probably not been as clear as I wanted and that's ok, sparked some interesting conversation and that's the point of this.

If things stack up right this summer, hope to get some time out at Lodi for shooting longer than I typically can.

Just for conversation sake I ran the numbers with Strelok Pro using my 6mm SLR data (think 6mmC +P) Berger 105 Hybrid (fictional load, my load has an SD of 7) and a 10MPH cross wind, same conditions. I used the high and low MVs for the fictional load.



So at 600 you're looking at 2.3" delta in drop and .5" less wind.

at 1000 you're looking at 8.8" delta in drop and 1.4" in wind delta.

Again, I don't think anybody has said that stats trump accuracy, just that for the longer distances it's better to have both good accuracy and stats.

50 fps between shots is a pretty big spread. I would put that load in the “poor” column

Nevertheless, even with that load, you can see that windage isn’t significant unless you think you can actually hold your POA to the accuracy of 1/2” at 600 yards or 1.4” at 1000 yards

And that’s saying nothing about your ability to read the wind accurately to .5” at 600 or 1.4” at 1000

Which I submit is a pipe dream

I agree..

But even with a prefect wind call, all other things being equal, the higher SD load will most often have more dispersion. In my extreme example; 8.8"x 1.4" at 1000 between the fast and slow rounds in that group, IF everything else went perfectly.

So again, why not try for accuracy and good stats when shooting the longer distances?

BTW, during load development for this rifle I had serval loads that were over 50 FPS spreads and with the same brass prep OAL etc. :

Stats - Average 3005.55 fps
Stats - Highest 3036.58 fps
Stats - Lowest 2983.59 fps
Stats - Ext. Spread 52.99 fps
Stats - Std. Dev 25.67 fps

Stats - Average 3047.84 fps
Stats - Highest 3074.99 fps
Stats - Lowest 3016.53 fps
Stats - Ext. Spread 58.46 fps
Stats - Std. Dev 24.09 fps

And all were sub MOA at 100yds. So IF I stopped when I achieved good accuracy, without looking at stats...

Which rules…

In my experience, where the muzzle is at in it's cycle when the base of the bullet clears is worth far more than SD/ES numbers.

I shot this yesterday with a new gun. At the lowest charge weight tried (pictured), the group impacted a full 1/4" above the next 5 groups, each increasing .3 gr. more powder, moved progressively downward. Five incrementally higher charge weight groups later, the muzzle bottomed out in it's cycle and the gun shot small again. One more charge increase and the group started to climb.

With a larger target and moderate accuracy requirements, several types of load development seem to work. As the target gets smaller and the accuracy demands increase, many of the 'truths' that people think they're seeing 'on target' are simply proven not to be reliable.

Good shootin' -Al

Thanks Al, good info.

Guy