New here... Dope card assistance please, MK12 mod 0 inside

[dingo88]

Hey all, new here. Just getting into more precision rifle work. I've shot a lot of 3 gun 2 gun etc.

Anyway.

I cannot get my dope card to line up basically at all with strelok, no idea what I'm doing wrong here.

Cartridge
69gr RMR BTHP
~2795FPS @Muzzle from 18" Douglas barrel. (2770-2820FPS)
Tested at 100' above sea level 59°F
G1 .305 (I have no idea what to put here or how to measure this, so I just used some SMK number I found)
Scope NXS 2.5-10x24 mil-r reticle
HOB measured at 2.7"



The Table....

Distance, yards​	Bullet speed, f/s​	Time of Flight, sec​	Vert. correction, MRAD​	Hor. correction, MRAD​
100.0​	2455.4​	0.12​	0.0​	0.00​
150.0​	2315.9​	0.18​	0.1​	0.00​
200.0​	2181.4​	0.25​	0.4​	0.00​
250.0​	2052.2​	0.32​	0.8​	0.00​
300.0​	1927.8​	0.40​	1.2​	0.00​
350.0​	1808.1​	0.48​	1.7​	0.00​
400.0​	1693.2​	0.56​	2.3​	0.00​
450.0​	1583.3​	0.65​	2.9​	0.00​
500.0​	1477.7​	0.75​	3.6​	0.00​
550.0​	1377.0​	0.86​	4.4​	0.00​
600.0​	1280.5​	0.97​	5.2​	0.00​
650.0​	1188.3​	1.09​	6.2​	0.00​
700.0​	1100.7​	1.22​	7.2​	0.00​
750.0​	1017.1​	1.37​	8.4​	0.00​
800.0​	937.3​	1.52​	9.7​	0.00​

Reality checks...

300ft above sea level
78°F ambient
496yd 3.1MRAD +angle but slight
633yd 5.1MRAD +angle but slight
696yd 5.9MRAD +high angle shot
Hits made predictably on a 10" plate at these distances using these holdovers.

Is this just how it is? Is there any way to make a table more true to life?

The rifle

 

[Wild_Bill148]

Make sure you're as accurate as you can be with your input values in strelok. Then when you go to the range, record your real world dope and true your Software to your live fire results. If I remember correctly, you adjust your MV inside 5 or 600 yards and BC beyond that. There's an article on how to do this on the hide somewhere.

I think Frank says something like "Believe the bullet"

 

[dingo88]

Make sure you're as accurate as you can be with your input values in strelok. Then when you go to the range, record your real world dope and true your Software to your live fire results. If I remember correctly, you adjust your MV inside 5 or 600 yards and BC beyond that. There's an article on how to do this on the hide somewhere.

I think Frank says something like "Believe the bullet"

Appreciate the input man, thank you.

 

[6.5SH]

From RMR's page:
"We haven’t yet done extensive testing on the BC but you should expect about .320-.335 depending on the velocity you shoot it at. We would love to get your feedback on long distance BC."

.224 RMR 69 Gr. BTHP 3GH *NEW* (Read Description Before Ordering) | RMR Bullets

We make this bullet ourselves. It is still in development so there may be some variances from lot to lot. We have pretty much gotten this bullet to where we want it. It is nearly perfect. I say nearly because city wastewater requirements mean we don’t currently have a way to polish/degrease this...

www.rmrbullets.com

I've not shot these yet so no first hand with them, but assuming your velocity and distances are accurate is a place to start given you seem to have over performed at each distance.

The other things to watch is the environmental data, you are only mentioning some of the needed values. The other one is the angle, Strelok does have the ability to measure and adjust for it.

ETA:
G1 of .335 puts me within .1 of your first two distances, and .4 of your 696 yds with 0 slope. A +/-20 degree slope puts it back within .1 at 5.8 mils.
This is with a guess of 78' F and a DA of 500 using the rest of your info.

 

[Conaso]

To start, ensure you turn off "Consider powder temperature" in main settings. And do not use DA; if using only DA instead of temperature, pressure, and humidity, the Strelok won't be able to account for the effect of temperature on the speed of sound - unless you input temperature and DA (not available in Stelok).

Although not provided, G7 BC model is meant for boat-tailed bullets; to begin I'd try G7 .172. Second, if using Strelok, use the 'trajectory validation" feature, 'speed" option at distances up to 600 yards. If re-zeroing, ensure each time you record your zero temperature, pressure, and humidity at the correct distance (100 yards?); and when you step out further, ensure the current ambient temp is entered manually or with a weather meter.

 

[dingo88]

Guys seriously thank you so much. I'm stoked to redo my dope cards given all this info

 

[dingo88]

What is "DA?"

 

[6.5SH]

What is "DA?"

Density Altitude. If you don't have a Kestrel or other device that offers it use the normal environmental data from your phone or other device.

 

[dingo88]

Density Altitude. If you don't have a Kestrel or other device that offers it use the normal environmental data from your phone or other device.

Seriously guys thank you

 

[DocRDS]

Dunno if anyone explained, yes you have measured Muzzle Velocity and BC. However, when doing a dope card you "tweak" those numbers to match your real world data. The rules of thumb are:
For Data < 800 Yards: Adjust Muzzle Velocity
For Data > 800 Yards: Adjust the BC

Some people say 800, others 900.
Bottom line: match the predictions to your real world dope. And keep tweaking as you get more and more data.

DOPE is a process not an event. Someone said that somewhere around here.