Some Labradar velocity measurements

H

Harry Fuller

Guest
Rough worksheet.
Velocities for 10 shots 10.34 gr JSB from TM 1000

BCs worked from Dave's Chairgun calculator.
Each shot's velocity measured at V0, V6, V10, V14, V18, V20 yards (operator selected).



Working through some of the other range spacings eg., V6 yd to V18 yd etc gave very good BC coincidence.

Lifting the power/velocity from 14.6 fpe/797 fps to 16.7/852 seemed to lower BC at the same temperature and atP from average 0.0263 to 0.0252 for a similar string.
One rifle, one set of conditions, so no great conclusions. Just thought some may find some interest. (8.44 gr JSB are consistently giving me BC of 0.022 or a tad lower to 20 yards from this barrel (which is pretty much what others have found).

I'm looking forward to getting to my farm range shortly to find the range limitations of the Labradar with the various calibre pellets.
The diagnostic downloads seem to give an average of two readings per yard of range. When I can combine the Labradar data with slow motion through-the-scope video from say ten yards, to whatever the limits are, then some interesting correlations may appear; like what is the velocity, and at what actual range do some pellets, that have seemingly traveled with stability, begin a reverse spiral. eg., is it when G acceleration changes from - to + at/after the trajectory apogee (as I have long suspected).

Edit: the BC using just the 10 V0 and 10 V20 yd data gives 0.0270
Stats - Average 797.01 fps
Stats - Highest 801.75 fps
Stats - Lowest 790.31 fps
Stats - Ext. Spread 11.44 fps
Stats - Std. Dev 3.38 fps

Shot ID V0 V6 V10 V14 V18 V20
1 795 774 760 748.4 732 727
2 799 778 764 749 735 727
3 790 770 756 742 728 721
4 796 775 762 748 734 730
5 799 779 765 751 736 729
6 794 773 760 746 733 727
7 798 777 763 749 735 727
8 797 776 762 749 735 729
9 800 779 765 751 737 731
10 802 781 767 753 739 733
797 776.2 762.4 748.64 734.4 728.1


0.027 Av BC


The Labradar cost me USA$559.95 plus USA$81.74 freight to Australia. ... Regards, Harry.
 
Last edited by a moderator:
21grains said:
nt.
Click to expand...

In the menu you select the ranges you want results displayed. The radar is constantly sending out and receiving from the pellet/bullet. Five ranges can be selected for velocity display. But the download to a computer will show approx two velocities per yard travel.
Collecting data for BC is that simple. So far I know it will reliably collect .177 data from my TM 1000 to 30 yards and abot 50% of shots to 40 yards on a club range with rimfires going off all around me. This coming week at the farm I am hoping to get time to see its ultimate range for my .25 cal pellets. I'm hoping for 50 yd perhaps 75 or further as I want to see what the BC profile is to at least that far. ... I can put the CED M2 chronograph out further at 100 to 200 yards eventually to get the rest of the picture with these new pellets. I have done it to 200 yards with the normal JSB Kings..

Here is a comparison I did today. Just shows the averages for 0 to 5, 10, 15, and 20 yards:
Conditions were : 17.5dC; 53% H; 1022 hPa.
FX Elite with tight BSA barrel, pellets sized to 0.2500" which is the best for accuracy and consistency from this barrel (.246" grooves, about .243 lands tapered hammer forged barrel).
One shot only each pellet recorded at 4 down-range distances. The MVs were as for the rifle in present tune for normal Kings at around 900 fps.

Average BCs for Velocities at V0-V5; V0- V10; V0-V15; V0-V20 yards:
Heavy King 34 gr – 0.0542 MV 787 fps 47.94 fpe
Barracuda 31 gr – 0.0456 MV 840 fps 48.56 fpe
King 24.4 gr – 0.0342 MV 897 fps 45.42 fpe
PAX Ext 30 gr – 0.0332 MV 849 fps 48.00 fpe

As per Chairgun calculator. The normal Kings do give Better BC (around 0.0372 at lower 880 fps velocity from these barrels ).
The "Heavy King " is the new pellet I have pestered Pavel at JSB to make since 2010/11. The .303 and .357s got it held up.
I will be seeing what it can do this coming week at the farm as work time permits.

Will also be putting the Premium 8.44 gr Exacts through their paces with the TM 1000 and FWB barrel.
Their BC will be lower than the longer 8.44 pellet I suspect but their wt consistency is extremely good.
Kind regards, Harry.
 
How well does it perform reading .177 pellets

Just curious, after setting up mainly to read velocity at muzzle does it read every shot? I have a CED M2 with infrared screens and constantly have to move the chronograph to try and get reads. Always get error messages. It is a pain if I go to my range when a range master is controlling shooting as I have to wait for a cease fire to re-adjust. I am only shooting up to 25 meters and am mainly interested in seeing the velocity right out of the muzzle.
 
You must log in or register to reply here.
Back
Top