Ballistics program vs Real life

[scottyd2506]

I have a Rem 700 long action 284 win, 317 neck, .212 freebore. Been shooting 195's and mostly 180 Hybrids. loaded to 3.240 & 3.250 oal.
Have a Bartlin 30 inch 5R 1:8.0 tw barrel with a small RAS tunable (birdcage style) brake. 2.0 inch scope height.

Main load is a 180 Hybrid @ 2820 fps, or sometimes if I fiddle w newer brass and get the donut reamed out 195's @ 2605 fps.

Scope is a Sightron SIII 8-32x56 MOA-H 1/4 moa clicks, w 20 moa base and less rind with 20 moa incerts (total 40 moa)
Scope bottoms out at a 200 yd zero with 180's or just one click up. (I wanted to have enough clicks up to go a mile if I wanted someday)

Adding 10 fps for 7 yards to chrono, load in Strelok pro are 180@2830 and 195@2615, last time I shot, 70 deg tempo, 70 deg powder temp, 75 humidity, 29.9 pressure inHG 500 ft alt. shooting at 244 deg wsw. with spin drift and coriolis effect, it says I need 99.5 clicks from a 200y zero. We change for atmospheric conditions and even ammo temp.

This has always worked for me.

Here is where the problem is, so I get in new lot of powder, so I re Chrono my loads...
The same load of 55.0g H4831 used to show 2820 fps 7 yds from muzzle on a chrono, and the 195s w 52.1g showed 2605 fps.
Now 900 rnds later, it's showing 2548 fps for the 195's and 2760's fps for the 180's same charge. So I load older 195.s, they show 2540's now instead of 2605 fps.

I adjust the powder charge to get back to 2820-30 fps, takes 56.0g now. Go out and shoot.. now I'm 2-3 clicks off at 1000 yards, if load up quickload, it's got me around 2825 fps with 55.0g and 2870 fps with 56.0g load.. if I enter the 2870 fps data in, I'm right on the money at 96 clicks. if I use the loads that now chono 2760's and use 2825 fps, it's right on the money at 99.0 clicks. I

The Crono is saying the powder lot is slower, another older can of H4831 (with a few loads left) shows its just as slow as the new. So I figure my chrono is off maybe, bought new battery, shooting strait through it.. still off by 60 fps avg... I try my buddies Chrono (dif brand), his reads the same as mine. We try his ballistic program Kestrol 5700 he just got, about same as my Strelok pro. My AR-10 also using Varget is like 4 clicks off. I've tried chrono on several dif days, sunny, cloudy etc, same 60 fps low.

I know this sounds confusing Ill break it down.
180 Hybrid 2832 fps .345 bc G7 200yd zero shows I need 99 clicks to get to 1000 yards.

somehow 55.0 is only getting 2760's now avg, So I slowly bump it up to 56.0g to get same vel of 2830 fps.
But now under same type weather, I only need 96 clicks to get 1000yds using 2830 fps muzzle vel.

Either my MV is more or my bullet BC is much moire than G7 of .345

When I enter in 2865-70 fps muzzle vel in program, all is good.
But Chrono is showing 2823 fps 7yds from muzzle.

I thought at 1st, a slow lot of power, it's why I loaded 56.0g H4831 to get back to org speed. I don't really want to go 2870 fps as I don't want to tear up my Lapua brass I worked on.
Then After remembering my 2605 fps 195 loads measured 2540's or 60 fps less. I thought bad Chronograph.. but I backed it up with a friends chrono and loads are the same ..180's show 2770's or so ips.. What are the odds both our chronos are bad???

 

[dfanonymous]

So basically you had a load, you rechrono'd a new load, got a different MV, used it, it didn't work, and your new loads dope is the same but both chrono's are saying the MV is slower but the 1000y dope is still the same?

 

[scottyd2506]

Sorry guy, I know it sounds confusing, not the greatest paragraph writer.

Basically, yes, after changing lots I re- chronoed, thought I had a slow lot, but after chronoing other older loads, everything is down in 50-60 fps FPS

But using my old data of 180@2820-2830 fps I'm spot on, but chrono read like 2760 fps to 2780 fps (depending on temp). if I put in say 2780 fps like Chronos shows, my poi is higher like 5-7 inches at 1000.
If I go up in powder charge, say to get back my vel to 2825 fps... I hit 4-7 inches high again.

Strelok pro, and Kestrol 5700 with applied ballistics all show the same... 180@2832 fps, .345bc G7, 29.9 Barametric, 70 temp, 70 humidity.. shows I need 99 clicks from a 200 yd zero..
The new loads that chrono 2780 fps still work dead on... on the 2832 fps in programs.
because I 1st thought I had a slow lot, I loaded up to 56.0g to get back to 2830 fps (or so), I was hitting dead on a 96 clicks and 7 or so inches high at 99 clicks.
When I entered 2870 fps in the program for the 56.0g loads, it showed 96 clicks and is dead on.
Quickload shows going from 55.0g H4831 and 2830 fps to 56.0g yealds 2872 fps.

Everyone else with this setup gets around 2820-2840 fps using 180 Hybrid 54.5 to 55.0g H4831 30 inch barrel. 3.20+ oal.

Everything is adding up but the chrono reading seems off, yet my buddy who has a dif chrono, I used his and got the same reading as my chrono, 2772-2778 fps or so.. so how can my chrono be bad?

Loading the 180 Hybrid at 2777 fps for example 55.0g H4831 shows I need 103.3 clicks using a .345 bc, and 102.7 using a .349bc. but in the real world I need around 99 clicks 80 temp.
Either I have to enter my old 2830 fps reading or enter in a G7 of .375 to get 99 clicks, and I'm pinging my 24 inch steel, if wind isn't bad i'm pinging a 10in round plate at 1k most often.

Ive done a tracking test for vertical before and all turned out good.
maybe I need to do another

 

[dfanonymous]

I feel this is suppose to be a long series of guesses to help trouble shoot, but what I found to be true is the bullet never lies. If you're 10.5 mils or whatever your using and that's where the bullet is going then that's what it is. As long as the rest of your dope; 600-900 is still in-line, then your mv is correct despite what the chrono says. If you're 1000y dope is correct but 600-900 is off, then your using the incorrect BC.

 

[Buster Hemlock]

Out of curiosity what chronograph do you have and what does your buddy have? The bullet doesn't lie but some chronos do/aren't the best. Not insulting your equipment either just so that is clear

 

[scottyd2506]

Out of curiosity what chronograph do you have and what does your buddy have? The bullet doesn't lie but some chronos do/aren't the best. Not insulting your equipment either just so that is clear

Thanks, no problem insulting equipment, it is what it is. Thanks for the kind help also!!!

my Chrono is a Competition Electronics, Prochrono digital. it's a $99 one
My buddies is a Shooting Chrony F1.. same cheap price.

Reading low. his read like 2772, 2772 and 2701 fps (last one I threw out).
I was sure my Chrono was bad after battery replacement, then his backed it up.

What is the chance they both go bad and read low at the same time? guess i'm in the market for another chrono, the$600 Ohlner 35p not gonna happen, maybe a Magnetto. but I like to at least chrono my semi auto pistols.

 

[Buster Hemlock]

I had the same chrono as you guys, still have it sitting out in the garage. They can be extremely temperamental, lighting will mess with them, having the screens move in the wind because there is some play in the posts will mess with your readings as well. I used a buddies Magneto speed for a while before using another buddies Labradar and then bought my own Labradar. The labradar will work with pistols as well, I even have a trigger that they sell that works with my bow. Setup is easy and it's not attached to your barrel so won't mess with zero or barrel harmonics and you don't have to worry about shooting it either which is nice! If you get a Labradar spend $20 on a lithium battery pack because it eats through batteries which gets expensive quick

 

[scottyd2506]

I feel this is suppose to be a long series of guesses to help trouble shoot, but what I found to be true is the bullet never lies. If you're 10.5 mils or whatever your using and that's where the bullet is going then that's what it is. As long as the rest of your dope; 600-900 is still in-line, then your mv is correct despite what the chrono says. If you're 1000y dope is correct but 600-900 is off, then your using the incorrect BC.

I was kinda thinking the same, the bullet doesn't lie. But I expect a chrono is a tool and there to help.

As I said before, on my Chrono, the 56.0g load shows 2824 fps 7 yards from muzzle, actual 2835 fps.@ zero yards. but like I said in actual shooting with me 1.5 inch high at 100 and dead on at 200, using 93 clicks I was hitting 5-6 inch low at 1000 yards on the 24in sq steel plate at 93 clicks, went up to 95-96 clicks, hit center or just barely high from center at 96 clicks. (1/4 moa) maybe 10 in from the top. Stelok at 180@2830 fps shows 99 clicks, but had me nipping the top of the 24in plate or missing 1/2 the time.
96 clicks on the program shows im around 2870 fps, 56.0g on quickload shows I'm round 2870 fps 62k psi.

Thats a workable load, and shoots ok, it extracts easy, etc -- but I don't want to kill my brass.. $125 on sale for 100 and all the prep and work. I'd rather not beat it up. Thanks for the advice. I'll prob go back to the 55.0 load, just enter

Thanks for your advice. I will just go with what the REAL world shows vs what the 2 chronos show.

I'm not sure what BC to use, Berger Website used .349 G7, buddies Kestrel 5700 uses .345 G7 for my bullet. But it's "applied ballistics" Bryan Litz program, but he also works for Berger, so what BC is it?

 

[dfanonymous]

I was kinda thinking the same, the bullet doesn't lie. But I expect a chrono is a tool and there to help.

As I said before, on my Chrono, the 56.0g load shows 2824 fps 7 yards from muzzle, actual 2835 fps.@ zero yards. but like I said in actual shooting with me 1.5 inch high at 100 and dead on at 200, using 93 clicks I was hitting 5-6 inch low at 1000 yards on the 24in sq steel plate at 93 clicks, went up to 95-96 clicks, hit center or just barely high from center at 96 clicks. (1/4 moa) maybe 10 in from the top. Stelok at 180@2830 fps shows 99 clicks, but had me nipping the top of the 24in plate or missing 1/2 the time.
96 clicks on the program shows im around 2870 fps, 56.0g on quickload shows I'm round 2870 fps 62k psi.

Thats a workable load, and shoots ok, it extracts easy, etc -- but I don't want to kill my brass.. $125 on sale for 100 and all the prep and work. I'd rather not beat it up. Thanks for the advice. I'll prob go back to the 55.0 load, just enter

Thanks for your advice. I will just go with what the REAL world shows vs what the 2 chronos show.

I'm not sure what BC to use, Berger Website used .349 G7, buddies Kestrel 5700 uses .345 G7 for my bullet. But it's "applied ballistics" Bryan Litz program, but he also works for Berger, so what BC is it?

For the BC, I said "IF" you're dope isn't correct at 600 thru 900y. If you're dope is fine then your BC isn't an issue.

 

[Horse1]

I have one of those green fold in half $99 Chronos as well. I find the most consistent results of displayed velocity vs. what a ballistic table says when shooting on a clear morning from 15min before sunrise to ~45-60min after the sun has risen and shooting from E to W with the rising sun @ my back. Under those conditions I rarely use the screens, just shoot.

I'm also an early adopter of the LabRadar and haven't set up my green Chrono since buying the LR.

 

[TRG65]

I used to use shooting Chrono's, but when I got access to a 1k range I quit and got rid of it, and just believed the bullet. It was incredibly temperamental like has been stated before. When I moved and didn't have a 1k range, I got a magentospeed on a sweet Black Friday deal. I've been using that since. It is not temperamental, and accurate and I don't need a 1k range now. I like to shoot the 1k range every so often just to confirm, but I now believe the magentospeed. When this breaks, I'll get a lab radar. At the end of the day. If you are sure of the conditions, ie there was no wind on a hill lifting your bullet or pushing it down, believe the bullet.

 

[CaptnC]

I've been using JBM ballistic program to create a dope card that has been about as accurate as anything else that I've tried.

We were set up shooting steel at 600 yards.

I plugged In all the same data into the Strelok program Sunday as well as the JBM program. Strelok called for 6.8 MOA dial up. The JBM card said 9.1...I dialed up 9.0 and rang steel as small as 6".

The only difference was I didn't have any wind plugged into the JBM program. It was about 12mph from my back, just over the right shoulder.

I played with the wind in the Strelok program the time before my last trip. Their data output changed a lot at 600yds, especially a tail wind and head wind.

At 600 yards I just don't see much...MUCH effect from those two wind directions. That's why I seldom input the wind in the JBM in those two wind directions. I dropped the wind out of the Strelok and it was still call for less than 7MOA at 600...

Which means I would have missed all my shots!

 

[scottyd2506]

I've been using JBM ballistic program to create a dope card that has been about as accurate as anything else that I've tried.

We were set up shooting steel at 600 yards.

I plugged In all the same data into the Strelok program Sunday as well as the JBM program. Strelok called for 6.8 MOA dial up. The JBM card said 9.1...I dialed up 9.0 and rang steel as small as 6".

The only difference was I didn't have any wind plugged into the JBM program. It was about 12mph from my back, just over the right shoulder.

I played with the wind in the Strelok program the time before my last trip. Their data output changed a lot at 600yds, especially a tail wind and head wind.

At 600 yards I just don't see much...MUCH effect from those two wind directions. That's why I seldom input the wind in the JBM in those two wind directions. I dropped the wind out of the Strelok and it was still call for less than 7MOA at 600...

Which means I would have missed all my shots!

Yes Strelok pro may not be the best to use, and there could be much better.

Nice, yeah, that a difference of 10.6 inches and 14.2 inches at 600 yards.

My buddy entered in my data on his Kestel 5700 that has applied ballistics on it and we both came out very close in drop. something like 98.4 vs 98.9 clicks, but he's still learning it, so accuracy could be worse or better. entering in data like Amb Temp, humidity, Barometric pressure, ammo temp can all have effect at 1k, We got it as close a possible, but who knows.
It's been a few years since I test much loads.. I noticed like I said before. my 195s was going 2605 fps, just for reference I measured them they was lower. like mid 2700's 2748 etc fps.

Not sure exactly before don't remember what temp I org chronoed the 195's.. but H4831 extreme pretty temp stable.

Owell, I plan to get a Magnettospeed sporter to play with. optical chronos are good if you get a expensive one. But you take a chance with the $100 units...

 

[CaptnC]

I think you will be very pleased with the Magnetospeed.

I guess my barrels are heavy enough that having the Magnetospeed on the barrel I dont have any change in POI.

I've shot at 200 yards, pulled it off and went right to 600...dialed up the shots without issue with several rifles. The lightest contour is a varmint contour.