Brief history: I bought a Savage 110 FCP in .338 Lapua a few weeks back. Now after compiling some reloading equipment I shot a very nice (in my eyes) group at 200 yards (my zero).
92.0 gr Retumbo
300 gr Berger OTM
Now having said this I shot just under 0.5 MOA (by my calcs, ignore the 0.27 MOA on picture used wrong calculation) with this load and was going to tinker with it a little more but ran out of powder (only bought 1 lb of Retumbo in case it liked the H-1000 better). So I just received another 1 lb bottle of Retumbo and loaded some rounds with 92.0 grains, same bullets, same COL and they shot terrible. It seems this new powder is somewhat hotter as I am getting primer flattening and a sticky bolt which did not happen with the original bottle. I have narrowed it down to the powder solely because nothing else has changed. The only other variable was that the first time I shot the cases were brand new Lapua brass and this time with the new powder they are once fired (trimmed to spec.) brass.
Any advice? Buy 8lb bottle and start load development over, so once load is figured out I should have plenty of powder left? I'm afraid I will get this bottle of Retumbo shooting good once I figure out the load then will be out of powder. This is the first time I have reloaded and I have made sure the process, consistency, tolerances, etc. is the same. I am very frustrated because it took a while to get the load right and if this happens everytime I need more powder it will take a few weekends to get the gun shooting good again.
Yes, it is a very high possibility the new lot of powder is hotter. This is why it is always best to work up the the old charge when changing powder lots. I prefer H-1000 for the 338 LM with 300 Bergers, but if you back off 2 or 3 gr you can probably find your original load again. My last order of H-1000 was 48 lbs all the same lot number. That way I am good for a while.
Thanks for all the replies. I guess I will try backing the Retumbo down 2-3 grains and try 89.0, 89.5, 90.0, 90.5, 91.0 and see if I can find the sweet spot again.
This is my first long range gun and first time really shooting beyond 100 yds.
When originally developing my loads, I had 1 lb of H-1000 and could not produce a group better than the picture above but I will try working that load up again, if others are having better luck.
Also, Broz I noticed you said you bought 48lbs of the same lot. This may be a dumb question but how? Is there a specific retailer or store where you can ask for all the same lot? I bought the powder I am using from Powder Valley. Would they be able to do this and give me several bottles of the same lot?
First, you can not judge a load by shooting one three shot group. Second, yes, powder lots can change. The solution is to get a good chronograph and find the speed of the best loads in the gun. If you change lots of powder, or changer type of powder, and the speed changes, you will know what to do.
While the powders you are using are not very temp sensitive were there any large temp differences in your range conditions?
Just another thing to check... everything still snug with your optics?
In the end you will probably just find out you have a slightly hotter lot of powder, something easily adjusted.
Good luck shooting. Have you run these over a chronograph?