Pressure Signs

[gtk]

I have been reloading for years, but would not call myself an avid reloader by any means.

My .270 load is one that I got from my uncle, and according to his older books, it is a hair over "max". According to my books it is quite a bit over max. Regardless, I have shot it for 30+ years and see no signs of pressure, except for the occasional split neck (which I attribute to wore out brass).

When you folks start with a new load, how far off max (from reloader manual) do you usually start ? I can't see starting at min, just seems like a waste of effort & materials..

Also, when developing a new load, do you tend to find that the closer you get to max, the more accurate ?

 

[markwondi]

I always start at least 3gr below max book value. Two bullets of the same grain weight could have significant differences in bearing surface, which will also have a significant effect on pressure and maximum charge weight in your rifle.

As for accuracy, it depends on the powder used. Alliant Reloder powders seem to work best at max loads in my rifles, while Hodgdon powders like to be a little under.

 

[gtk]

I mainly use IMR for rifles. . 4064 for my 270 & 243 and 4350 for 243 & 300 wsm

 

[7mminatree]

For hunting loads you might find out that some of the starting charges are the most accurate. My 7mag shoots 160 gr Accubonds with 62.5 gr. of IMR 7828 like this. When I first started shooting 7828 I never even considered starting with that low a charge. Now if I was shooting for 600 yards I would be loading around 67. grs. But at 62.5 I'm still pushing close to 2900 fps. The deer don't know the difference.

 

[DaveB]

What 7mminaTree says is money in the bank. The deer cannot tell the difference.

A max load is not necessarily what you want. All the bullets in one hole is the objective.

Lets put it a different way. If you started off at max and had a 1.25 inch group would you stop right there or start making changes, very small ones, but changes?


I never start at max. When I go from one component, like a 150 grain Partition, to a 150 grain Accubond, I STILL start low.

Remember, this hobby can wound, main, and even kill you. I get told all the time I am too cautious. Is okay, I don't mind.

 

[Hunter 257W]

I have no strict % below Max that I use but generally speaking I go about half way between the "book" Min & Max for a starting load. Once the primers start to flatten then I back off a grain or so.

 

[Deer Assassin]

about 2 grains undermax
i see no point at starting at minimum

 

[darn2ten]

I normally start right in the middle and work towards max. Lots of your most accurate loads will be right in the middle somewhere. Not always though, some caliber and or powders seem to like things toward max.