Daystate built in Chrono vs. Labradar

[GA_LeadHead]

My new Daystate Alpha Wolf Safari arrived today. After initial setup, sighting in, I wanted to compare the results from the built in chronograph vs. my LabRadar.
Very different results in muzzle velocity, but the math works out that the extreme spread and standard deviations are within 1 fps of each other so the rifle is consistent.
What is puzzling is the average difference of 12.45 fps between the two measurements. So which one do I trust? Any ideas on what is causing the difference. I have my Lab radar just in front of the muzzle. Very close.
Here are the results from one mag of .22 JSB 25.39gr Redesigns. Note. This is out of the box. I have not adjusted anything on the rifle.

Shots	Labradar	Alpha Wolf	Diff
1​	951​	938​	13​
2​	950​	938​	12​
3​	956​	945​	11​
4​	954​	942​	12​
5​	955​	942​	13​
6​	959​	947​	12​
7​	954​	944​	10​
8​	956​	939​	17​
9​	960​	947​	13​
10​	955​	944​	11​
11​	958​	945​	13​
AVG	955.27​	942.82​	12.45​
EXT SPR	10​	9​
STD DEV	3.07​	3.31​
JBM B.C. *Only from Labradar shots	0.041​

 

[nervoustrig]

A difference of a bit over 1%. In the gambling world, that's what's called a pick 'em.

 

[GA_LeadHead]

A difference of a bit over 1%. In the gambling world, that's what's called a pick 'em.

Ha! I didn't think about it that way.
Reminds me of the old saying that sometimes you have to step back and look at the whole elephant to describe it. Instead of wearing a blindfold and only touching it's tail.

 

[Richieg]

I would tend to trust the Lab Radar.

 

[GA_LeadHead]

I would tend to trust the Lab Radar.

My thoughts as well.

 

[Richieg]

I shot my Alpha over my Lab Radar when I first got it and they were within a few fps. of each other. I will do it tomorrow again to check it out.

 

[davecole]

I did a quick drop calculation using a BC of .0412 which is the calculated and proven BC for the MRD in my rifle shooting at a slightly faster speed.
Using the greatest variance measured between the Labradar and the guns' chrony of 17fps, I came up with a POI difference of 0.54" @ 100 yards or about one click.

 

[AlanMcD]

The good news is that the difference is basically all just a mean shift and not in variance, and has been pointed out, it is a small percentage - and it is probably within the specifications of any one chronograph's level of accuracy, let alone two . . .

Bottom line, pick one to use and be happy with it. Since the Delta Wolf's chrony is built in and thus always with the gun, I'd use that one. But I would use the data from the other features of the Lab Radar like BC as shot . . .

 

[Richieg]

Shot my Alpha today here are some velocity comparisons between mine and my Lab Radar

 

[Arzrover]

The Daystate chrono can be calibrated and are usually dependably close from my experience. It's optically derived vs echo from a radar signal on the LR. Setup is important and environment are important with the LR. Even though it has "Lab" in the name, I'm not so convinced of its absolute accuracy. The DS will be more consistent, period, but will depend on the cal number for absolute accuracy.

With all the trials I've had with mine,I trust the Daystate more.

Bob

 

[shambozzie]

The fx chrony and chrony in Daystate grand prix is +-5 fps .