Can't make heads or tails of my powder

[Quicksilver]

I recently tried some Varget loads (because I was out of H4895) and came up with some interesting results that I wanted to share, because I bet someone knows WHY my data is as follows:

My setup is a 20" .308 AR-10 gas gun- now, I usually shoot 42.8 or 43.2 grains of H4895 depending on summer/winter and get a standard deviation of 11 fps, with an average of 2680 (using a magneto chrony, which by the way I LOVE IT. Money well spent) and my average groups with this setup is 1/2 inch groups at 100 yards, 3/4 to 1" groups at 200 yards.

Well, I worked up a load with Varget using the standard 2.800 length that works so great with my 4895 and I got the following:
Best group and SD was with 42.2 grains of Varget (less than my small load of 4895) but I dropped to 2500 fps average (almost 200 fps less!) with a standard deviation of 4 fps!!! However, my groups at 100 yards at best were 1.5 to 1 3/4 inches!!! What the hell?! At 200 yards, I was lucky to even be near the bullseye, groups opened up to 2 1/2 to 3 1/2 inches, which is just total SHIT.

Whats going on here? I thought Varget was a hotter powder with better consistency? Did I just open a bad jug or what the hell? Also, why did the groups go all to shit from switching powders? I did a ladder test and all the groups were terrible. I honestly don't know whats going on, and with a standard deviation of 4 fps, I would expect fantastic results, but every bullet looks like a flyer! Ideas???

Edit: Bullet is a 175 SMK HPBT.

 

[JGorski]

In a test I did with my 6REM I found a .5grain more of varget equaled the same accuracy as h4895, 40 vs 39.5. That being said, get some RE15 and use what I found to be the most accurate load, 42grs and watch your groups shrink. 43 if you use Win brass.

 

[FLIGHT762]

Varget is a slightly slower burning powder than H-4895. You didn't post what bullet weight you are using. If it's a 168, 44-45 grains of Varget will get you past 2650 FPS.

My two 308 rifles are just not too partial to Varget, I did get a fairly accurate load @ 45 grains W/ a 168 but, I would get occasional flyers. I get better results with RE-15, AR Comp and IMR 8208 XBR in those two rifles. Others have much better results than me.

 

[turbo54]

For any given application, you'll always use a heavier charge of varget than h4895.

Usually quite a bit more.

 

[Quicksilver]

The bullet is a 175 SMK, and I could not load more powder (Varget) than 43 grains, because at ONLY 43 grains I was showing flattened primers, and ripping the lips off my Winchester brass (sticking in the chambers) so theres no way I could shoot 44 or 45 grains of the stuff. Also, I use a FL die the majority of the time, but I went back and used a X die and still stuck em in the chamber above 43 grains. What gives?

 

[Quicksilver]

I was reading something earlier about certain barrel lengths/rifle setups liking a certain FPS (mostly due to barrel harmonics) and while you could have a load with a great SD, the barrel whipping action could make your groups open considerably. Any truth to this? If so, I believe my rifle likes to be just south of the 2700 fps neighborhood.

I just picked up and loaded a small batch of Benchmark and IMR 8208 XBR. Really itching to go chrony them and see whats up.... especially in the accuracy department.

 

[turbo54]

The bullet is a 175 SMK, and I could not load more powder (Varget) than 43 grains, because at ONLY 43 grains I was showing flattened primers, and ripping the lips off my Winchester brass (sticking in the chambers) so theres no way I could shoot 44 or 45 grains of the stuff. Also, I use a FL die the majority of the time, but I went back and used a X die and still stuck em in the chamber above 43 grains. What gives?

Varget is slower, so the pressure is higher with it than h4895 when the bullet passes the gas port. Peak pressure with your varget load is certainly less than with the h4895.

Consider an adjustable gas block or gas tube.

 

[BCP]

The bullet is a 175 SMK, and I could not load more powder (Varget) than 43 grains, because at ONLY 43 grains I was showing flattened primers, and ripping the lips off my Winchester brass (sticking in the chambers) so theres no way I could shoot 44 or 45 grains of the stuff. Also, I use a FL die the majority of the time, but I went back and used a X die and still stuck em in the chamber above 43 grains. What gives?

That doesn't sound right 43varget with a 175 in win brass is NOT a hot load. That was 2400fps in my 18" DPMS and the brass never grew, EVER, over like 10 reloadings. So either you didn't size it enough or you have a weird/bad batch of it.