Hey, just had a sour experience at the range. I was shooting my 6.5-284 with 107 grain MK's over loads of Varget ranging from a mid load 44.0 grains to a high of 46.5 grains. OAL was 2.99. To say the least, the groups were horrible and the pressure was so high that I only shot one load(44.0 grains)and decided not to press the issue. I think the pressure was more an issue of me having to cam down on the bullets in the chamber, causing excessive pressure. I'll probably bump back the seating to 2.8 OAL. However, the way that my cousin's 7-08, which was also loaded with varget (139gr SST's over 42.0 grains varget) has me questioning the powder. Groups were abismal, so much so they were not worth measuring. I'm thinking that perhaps temperature may have played an issue. I think it got up to around 5 degrees, possibly 10 while shooting. Do you think this could have adversely effected the powder. I don't know, I'm just at a loss here.
I shoot Varget in all my 308 and have never had a problem with temo affecting the pressure and most of my loads are pretty warm to start with.
I have never heard of "cold" causing the pressure to spike , I have seen some loads that were worked up the winter get dangerous when it heated up but that was not with varget. To my knowledge Varget is about one of the most stabil powders out their.
Varget is a Hogdon Extreme powder and is very stable at all temperatures. Varget is awfully fast for the case capacity of your 6.5/284. Did you change primers, seating depth or anything else? Also, with the amount of powder in the case, you could have gotten the "high pressure spike" from not having the powder in the bottom of the case and having your primer flash too far down the powder column? Try a slower powder. Most cases get best accuracy from full cases. Have a friend shooting a 6.5/284 on long range course using WLR primers & H 4350. Just some thoughts.
Thanks for the Advice and the replies,
What I'll probably end up doing is bumping the OAL down to 2.920 for this batch and then try something a little slower. The gun itself was built specifically for 140 grain bullets, so I'm no stranger to slow powders(I usually run 4831 with any 140 grain bullet to produce 1/4"loads). I just wanted to try a lighter bullet, and it looked like varget was a winner for the 107, velocity wise. We'll see, I may get out to the range tommorow and adjust the OAL, and maybe load up some more with some slower powder.
I just thought of something you could try. N150 might just be that magical number that zings those 107's out at velocities unheard of. It is slightly faster than IMR 4831 with similiar load densities, and not as fast as Varget. It is expensive stuff, but you might want to try it! It is also very consistent in varying temps.