I purchased a jug of Precision Rifle and tried it this weekend. I am shooting a 20" AR15. Load is 25.3gr PR behind a 69 gr SMK with a CCI 450 in LC cases.
First, the powder meters very well through my Uniflow measure and the loads I shot were measured not weighed. This charge filled the cases just above the base of the neck, so they were slightly compressed. The shooting weather was breezy and sunny 68*. I shot 10 rounds through the chrono with an average velocity of 2809 fps and ES of 36 fps.
I next shot a 10 shot group at 100 yds, prone position with a sling and iron sights. Eight rounds went into 1.25" with two fliers out to 2" (ugh), this is about as good as this old man can do.
As a preliminary test goes, this looks reasonably promising. I will chrono again in the winter to see how the load holds up in cold weather.
405wcf
Today I'm following up in cold weather. Temp this morning is 14*, sunny with no wind. Prior to shooting, rifle and ammo were placed outside for 2 hours to cool. I'm shooting the same rifle and load. I'm using the same CED chronograph with it sitting in the shade. I first shot just for chrono data. Each shot was single loaded to limit warming in the rifle prior to firing. The first three shots resulted in "ERROR" message. I may have been too close to the screens. Backed up to about 12' and got the following velocities: 2754, 2735,2714,2722,2749,2759,2776,2778, ERROR, and ERROR.
Hmm....that pattern looks abnormal to me. For what it is worth the average is 2747 with and extreme spread of 64. If the data can be trusted, I lost an average of 62 fps over 54*, or more than 1.14 fps per degree. The label on the jug states "Better temperature performance....than Varget". I'm not sure about that.
I next shot a ten shot string at 100yds using the same type of 100 yd reduced target as above. I shot prone position with sling and iron sights. I got a nice horizontal group, 3 1/2" wide x 1 1/2" high. This looks to me like poor shooting on my part.
My conclusion is that I am not confident in the velocity data I generated (gotta take the plunge for the Lab Radar). However, I do suspect that SW Precision Rifle powder is more temperature sensitive (at least in this application) than the manufacturer suggests. Shooters World tends to emphasize the use of PR rifle powder for the heavier bullets in 5.56 such as the 77gr which may result in better ES.
I will keep working with it to see what I can learn.
405wcf
