The best range reports will list:
Conditions: Temperature, humidity, wind, altitude. (These are very important)
Type of Ammo: Manufacturer, weight, bullet type (M193/M855 hollow point, boat tail, full metal jacket, etc.), year of manufacture, lot number (lot number is important)
Results: Velocity, size of groups, range of the target. (You'd be surprised how many people report 1" groups and then fail to report that they were shooting at 25 yards). Groups should be at least 5 rounds, preferably 10. If you are using a chronograph, velocity should at least include a list of all the rounds timed and if you have the time, average, high, low and standard deviation.
Try to use the standard chronograph distance: 15 feet from the muzzle. This makes it very easy to compare your results to military and other tests which use 15 feet as a standard. Technically, M855 is measured from 78 feet according to the spec (no, we have no clue why) but it's easy to adjust 15 foot figures to 78 feet and 15 feet is probably much safer for your chrono screens.
Other observations: Excessive flash, slow primers, reliability, any failures or malfunctions.
All these details will permit other shooters to assess the ammunition you tested.
Opinion: A good example range report (courtesy of AR15.COM's own t38tallon):
Here are the results of my testing of Lake City XM193 (Lot-1) ammo.
- Firearm-Bushmaster M4, 14.5" barrel, (1-9")
- Brass Headstamp-00, 01
- Temperature-62-65 deg F
- Altitude Above SL-100'
- Number of shots in test-10
- Target Distance-100Y
- Sights-Open from bench rest
- Velocity Measured with a Chrony @ 10' from muzzle
- High Velocity-3087 fps
- Low Velocity-3030 fps
- Average Velocity-3053 fps (10 shots)
- Accuracy-Good, at approx 2"