My way of evaluating and testing is simple. When I can I keep 2-3 rifles that I shoot/hunt with the most stashed in my truck. Whenever I get the chance I stop at a range, put up target, rifle on bipod w/no sandbag for rear, basically as if making a shot during a hunt, 1 shot is taken and check impact point. Depending on my work schedule I can do this a few times a week, sometimes might not be able to for a couple weeks. Never know what time of day or weather conditions will prevail, so for me I know how my rifles/loads will perform doing it this way.
Hope I explained it well.

Just an update on the test. It really helped find, diagnose, and fix a problem with one of the rifles I tested.




The target on top was for a 7 RUM that was shooting pretty well but lately has opened up. I shot a few more that day and they were all over the place; about a 2 MOA load/gun combo.

I went back to the drawing board and did some more development. I dropped the charge weight considerably from that load and found a somewhat accurate load at 1.5 grains under it. It printed a group that was about MOA but more importantly, a group that had little vertical dispersion only measuring about 1/2 MOA.

Today I went to the range with 14 cartridges of the new load for more testing on the sillhouette range. Here's how it went.

I started with a pristine clean cold barrel and fired three shots over a chronograph at 100 yards with some cooling in between to sight in. The group had no vertical dispersion but started left and with each shot moved to the right till the last shot was about 1/2" right and still high. I only moved the scope down 1/2 MOA believing that the center of the group was OK as far as L and R. The velocities were remarkably close; 3209, 3210, 3215 fps.

I plugged 3200 into my hand held ballistic program and commenced shooting steel plates out to 760 yards to nail down the data. First round hit on the 330 yard plate, center. First round hit on the 430 yard plate, HIGH. Fired a shot at the 560 yard plate and my spotter called it 10" high! I adjusted the scope down 2 MOA and made a center punch hit on the plate.

I went back into the ballistic program and adjusted the velocity input till the read out matched what I dialed to make that hit. I had to increase the input to 3500 fps!!!!

I then continued shooting the rest of the longer plates with the new data table. Made a first round hit on the 650 yard plate, first round hit on the 700 yard plate and finished with a first round hit on the 760 yard plate.


The descrepancy between the actual measured velocity and the velocity that I had to use in the program was enormous and the only thing I can attribute it to is the actual BC of the bullet. The actual BC must be higher
than the program is getting from its Nosler data base.

I had two shells left, dialed back to the 100 yard -0- and fired them. They went into the same hole but 1/2 MOA right of the bull.

I have concluded that as the barrel warms, the POI moves right. Also this barrel shoots better when it is fouled like HC's pants

The rifle has earned a safe spot in my safe....

quote:

Originally posted by rcamuglia:
...this barrel shoots better when it is fouled like HC's pants ...

Then it might be time for a New Barrel(and maybe New Pants)!

Does your particular Ballistics Program have the ability to adjust for Elevation and Barometric Pressure?

quote:

Originally posted by Hot Core:

quote:

Originally posted by rcamuglia:
...this barrel shoots better when it is fouled like HC's pants ...

Then it might be time for a New Barrel(and maybe New Pants)!

Does your particular Ballistics Program have the ability to adjust for Elevation and Barometric Pressure?

Yes it has input areas for all pertinent atmospheric conditions. It's called BulletFlight and it runs on my iPhone. It was only $30 and works great. I use a Kestrel 4000 to obtain atmospheric conditions. This is the first time I've had such a discrepancy with actual velocity and what needed to bet input to make it match the actual drop. It has to be a BC value problem (ie. I could have tweaked that value and still may to make the drop output match actual)

Edit: I had to drop the charge 2 1/2 grains not 1 1/2. I can't subtract or spell

Hey R, You may have gleened off the Board that I'm not a real fan of knowing the actual Velocity, because it doesn't really tell a person anything worthwhile. And adjusting it to get the Trajectory on-track is a relatively good way to resolve the inconsistency.

But, it could be the actual B.C. is different than what the Manufacturer says it is, or..., perhaps that particular Software Program is not as good as a person would initially expect it to be.

But, as long as you can Fudge Factor it into duplicating reality, then it is still(somewhat - maybe) useful.

Good to see you recognized the difference between Calculated and Reality.
-----

Surely Mr. Woods has a special Super Wham-O Dyne THINGY to adjust the Bullets B.C. to make it match your Software though.

quote:

Originally posted by Hot Core:
Hey R, You may have gleened off the Board that I'm not a real fan of knowing the actual Velocity, because it doesn't really tell a person anything worthwhile. And adjusting it to get the Trajectory on-track is a relatively good way to resolve the inconsistency.

But, it could be the actual B.C. is different than what the Manufacturer says it is, or..., perhaps that particular Software Program is not as good as a person would initially expect it to be.

But, as long as you can Fudge Factor it into duplicating reality, then it is still(somewhat - maybe) useful.

Good to see you recognized the difference between Calculated and Reality.
-----

Surely Mr. Woods has a special Super Wham-O Dyne THINGY to adjust the Bullets B.C. to make it match your Software though.

Don't laugh!

This program is sophisticated!

It has a "utilities" section where BC CAN be calculated either from actual drop downrange or a second velocity reading/time of flight downrange.

A couple of buddies were actually doing the latter on Sunday at the range. They had a second chronograph set up in front of their target at 330 to get the reading.

As far as reality vr read out, you always have to do the actual shooting to confirm drop. Too many factors including individual rifle differences to trust a computer as the be all/end all!

quote:

Originally posted by Hot Core:
But, it could be the actual B.C. is different than what the Manufacturer says it is, or..., perhaps that particular Software Program is not as good as a person would initially expect it to be.

Went back into the program and checked the bullet I selected. Again, a loose nut on the handle was the problem (me). I had selected a bullet that had a BC of .290???? instead of the 160 gr Accubond with a BC of .531!!!!

The program is correct at the actual measured velocity of 3200 fps when you are smart enough to choose the right bullet from the library!