How much powder over book max is unsafe?

[JGRaider]

The chrono doesn't lie.......use it.

 

[Weldor]

I can say this about published data. I have multiple loading manuals from the 60's 70' 80's up to todays latest. The older manuals have much higher max loads than todays manuals. Use with caution, no exceptions for safety. I shoot in a very hot climate so it is always a challenge to work up a hunting load for normal weather in other parts of the country.

 

[IDHUNTER]

Thanks for all the replies. A lot of excellent points made.

 

[Pharmseller]

And remember, extra fps is negligible.

Look at the difference 50-75 fps makes at 400 yards.

It ain’t much.





P

 

[sdupontjr]

I had a similar question not long ago about my 7mag and H1000. There was published difference in the same bullet and same powder. 68 - 70 grain difference. In doing my pressure checks, I actually went all the way up to 71 and still didn't find pressure. In the attached pics in the thread, some thought that the shiny mark on the brass was an indicator, but it was just a glare from the pic. So actually at 71g H1000, I was 3 grains over book max and 1 grain over powder max and still didn't have heavy bolt lift, brass markings or anything to speak off. Buddy is 3 grains over max in his 300 WM and same results. Could be gun differences, who knows. But i stopped at 71g. Here is my topic on similar issue.

https://rokslide.com/forums/threads/hornady-162-book-max-vs-hodgdon-max.317301/

 

[Harvey_NW]

I started reloading with this exact combo, so I'll throw what I learned into the mix. Don't put any merit into unfired brass, factory 7RM have sloppy chambers and you can get .012" growth on first firing. Make sure you're measuring and bumping .002" or you'll learn about case head separation. After you have fireformed brass, do your testing. I agree with the statements that pushing it much further isn't worth it in terms of ballistics, you'll lose more in brass life than you'll gain in actual trajectory. But I don't agree with some of the other advice, pressure signs are unique in each rifle, primers, ejector marks, swipe, etc. are all a part, but not one is an absolute indicator. There are plenty of threads on here about bolts leaving ejector swipe on unfired cases just by chambering. Bolt lift is the absolute indicator. If you get resistance opening the bolt, you're getting into unsafe territory. Last but not least, if you get resistance on chambering resized brass, bust out the wallet because you'll need the Larry Wilson collet die to resize the portion above the belt that the die won't reach when you're bumping shoulders.

 

[wind gypsy]

I've had Berger book MIN charges be too hot (300 NM) but have shot thousands of rounds considerably above their book max in other cartridges.

Learn what factors impact pressure and how that applies to your given scenario. Books are far from the full truth in many situations.