BP substitutes consistency

[JDL in NC]

Has anyone tested or compared BlackMag3 and 777 for consistency?  I recently chronographed both and found that BlackMag3 produced extreme spreads by over 100 fps with weighed charges (777 would consistently produce extreme spreads by only 5-20 fps).  I also had read that BlackMag3 would give higher velocities volume to volume compared to 777.  In my powder measure set to 100grs the measure would hold 99.8grs of BlackMag3 compared to 84.5grs of 77 (some 15% difference) which probably explains why BlackMag3 produces more velocity vol to vol with 777. I found that with same weight charges both produced close to same velocities.  It seemed that BlackMag3 was sensitive to seating pressure of bullet, (more so than 777) but I've not tested this.  BlackMag3, no doubt is a cleaner burning powder, but if it lacks consistency I will continue to use 777.  The reason for this posting is that I haven't really shot enough of BlackMag3 yet to come to a conclusion which powder is more consistent and thought that someone might have done some extensive testing with BlackMag3, as I have not.  I would love to use BlackMag3 but I will not trade consistency for cleaner burning.  Any input would be appreciated.

Thanks, JD in NC

[Redhawk1]

You post is very informative. But the thing about volume measures, you will not get consistency. That is why some of use take a volume charge and weigh it. I weigh 10 each 90 gr. charges. I get the average and that is what I use as a weighed charge. That is the best way to get consistency.
I do this for my Muzzleloaders and my Black powder cartridges.  

Also Welcome to Graybeard.

[JDL in NC]

Redhawk1,

Thanks for the reply.  I understand the inconsistencies with the volume measures,  I just found that BlackMag3 was very inconsistent in velocity with weighed charges (what few I chronographed).  I found T7 to be very consistent in velocity (even with measured charges).  I have always tried to be consistent with seating pressure also, but I feel that the BlackMag3 powder may be sensitive to pressure.  I haven't tested enough of BlackMag3 to know if this is true so my testing is inconclusive.

My brother advised me that he found in the past that the powder that was once made by the same company that makes American Pioneer (maybe cleanshot?) was so sensitive to bullet seating pressure and produced such inconsistent velocities he stopped using it.  When I told him that I had purchased some BlackMag3 to try he advised me that I might find the same problem and I should chronograph some loads to compare with T7.  I was hoping someone might have already tested the powders and that would save me some time and money.

[Redhawk1]

I am surprised Keith Lewis has not posted yet. He has been shooting the BlackMag3 and reports very good success. Me, I will stick to the triple7.

But keep us undated with your findings.

[Stan M.]

JDL,
 Thanks for the information. I have been wanting to shoot through a chronogragh to see what my velocities were. I have been shooting BM3 and T7 in my Encore but decided to use the BM3 because it cleaner, slightly more accurate (in my rifle) and produces less mess.
Take care,
Stan