I'm second guessing my load choice for the 300 win mag 150 gr Accubond. Based on the Nosler manual using H1000 powder. I wanted to load 80 gr of powder and wanted to start 10% under so I loaded 72 gr. to start. Planning to work my way up. Now I'm wondering if I should have started at 10% under max of 84gr. instead of 10% under the 80 gr I'm planning to work up to. Did I start too light at 72 gr. or will it be fine? This is still new to me. Thanks for any input.

I'll leave the correct answers to the pros but it does look a little light according to the manual. 180 gr Accubonds shoot really well out of my 300 WM, don't be afraid to try them or even the 165 gr.

The 150 gr. is all I could get ahold of at the time. I was wanting the 165 gr. I guess the upside to the loads I made is I only loaded 5 rounds to see how they performed.

I'm not sure I understand your question.

You are not going to hurt or damage anything by starting that low.

The only downside is that you might have to do a bit more testing than if you had started a bit higher, but that just means more shooting!

Who knows, you might find a sweet spot that is too good to pass up.

I was told to start 10% under and work my way up. So I guess I'm asking, "Should I have started 10% under max or 10% under my target goal?" The manual shows the max at 84 gr. my goal was 80 gr. and I started at 72gr.

You know the more I read my post the dumber I sound.

Not dumb, but rather deliberate and cautious and that's a good thing.

I think you'd benefit by acquiring a chronograph. I've found having it very beneficial as an additional way of evaluating where you're at in terms of pressure because velocity is a direct result of it. When the manual says you should be seeing about 3400 fps but you're getting 3550, you KNOW something's up.

Starting at such a low charge is prudent and doesn't hurt a thing, but I'd suggest loading only two or three rounds of each charge for the purpose of getting an idea what the max charge will be. The thing to remember is that powders like H1000 will work best when you get up into a certain pressure range because progressive-burning powders need that pressure to operate efficiently.

Loading manuals can be so conflicting about minimum and maximum charges that it makes you wonder which one you can trust. I guess that just serves to underscore the idea that as a reloaded, you're really on your own and it's not real hard to get yourself way out on a limb...and I know that because I've been there.

Which brings me back to the chronograph: I had a .243 a few years ago---one on a long series of .243s, but this one supposedly had a match chamber. I'd question the quality of that chamber, but not it's tightness. Having the chronograph available helped mr quickly learn that this particular rifle would not accept anything near a "book" maximum charge. A grain or two over starting charges was max for that rifle, and I didn't have to put life or limb at risk before realizing it. That's just ONE of the benefits of using a chronograph but even if that was the only one, I think it would be sufficient reason to own one.

Sorry for the long-winded pitch. It just seemed like the thing to say at the time.

Your question is very reasonable. First, I'd like to second the comments of RR. Chronographs are inexpensive and take a lot of guesswork out of the equation.

A lot depends on the cartridge and powder charge. In a magnum rifle that burns 90 grains of powder, 10% from maximum is 9 grains, which would equate to a starting load of 81 grains. In this type of cartridge, I would start 10% below maximum if no starting load was available, or maybe a grain or two above the starting load if that exists. In a fast burning pistol load where the maximum load is 7 or 8 grains of powder, I might very well start significantly lower than 10% below maximum, as there's very little room for error.

Does that make sense?

Thanks RiverRider, I only loaded 5 rounds for evaluation so I'm thinking of stepping up in .5 gr. increments to find the sweet spot for my rifle. Do you have a recommended chrony?

Thanks.

This makes perfect sense. I appreciate the advice. Also, do you have a chrony recommendation?

I have a ProChrono digital and am quite happy with it. I don't think it can be beat for the $$$. That said, if you've got a few extra $$ burning a hole in your pocket, you might look at the MagnetoSpeed V1 or V2. The feedback on them is very good, and I'd buy one myself if I didn't already have the ProChrono.

Thanks

Your second guessing is not inappropriate when it comes to reloading IMO. !!! IMO !!! I would like to give you a second guess. H1000 is one of the slowest burning powders and the 150 gr one of the lightest bullets for the 300 WM. If loading that low of a charge with the slow powders with a light bullet you can get hangfires, not good. When I started to work up a similar load 74 or 75 gr of Mag Pro with a 165 gr Speer BT, I got intermittent hang fires. I quit getting the hangfires about 77 gr. The ten percent rule is general. Though you can go way under that (-10% in loadings in many cartridges) with fast powders, you may not want to go that low with the very slowest powders especially with the lighter bullets. Though I will make a "I am not sure note here", I was testing in MI with temps in the 40's and 50's and you texans do a bit of testing in the 80's and 90's, just for a stipulation. Maybe you could ask or do a search on reduced or starting loads with the very slowest powders for a second opinion.

Thanks OnHoPr. The reason I used H1000 was I already had a couple of pounds and was trying to use it up on something. I found load data for the 300 win mag using this powder. So I went down to the local wally world for bullets and all they had in stock for this caliber was the Nosler 150gr. Accubond. I was wanting 165 gr.

Let me ask another question, Should I step up in full 1 gr. increments until I see signs of pressure or am satisfied with accuracy or stay with the .5 gr. increments?

You're dealing with a large case, so I would suggest one-grain increments in search for the limit. You might grt lucky and run right into the results you want, or you could then try .5 or even .3 grain increments once you know you're in the right neighborhood.

Thank you sir.

I would not start at 10% below minimum charge. You are taking a minimum load and reducing it even further. H1000 is a slower burning powder, and you want to keep near max charges with slow powders, especially with lighter bullets. They are not meant to be reduced. I'm showing min is 80 grains and max is 84 or 85 grains of H1000 with that bullet, so call it 84 grains max. If you want a reduced load, then somewhere over 80 would be fine. But I would not go less than that. H1000 will work for your application, but it is not the most ideal powder for the 150 grain bullets. Typically you want to go to a faster burn rate, like a 4350 or 4831 with the 150's in a win mag. I always work backwards from max, somewhere about 2-3 grains less. So I would start there.

Thanks Chad.. I've realized I started a little light. I should have started 10% under max and not 10% under the starting load. My bad. Rookie mistake. I appreciate all of the replies to this thread. I'm am enjoying learning about reloading and all of the different components and various applications of them. This is truly a challenging yet satisfying hobby.