Ken Waters' pressure testing method.

[lotech]

Regardless of method or methods, determining as accurately as possible where that "ragged edge" lies is certainly worth knowing. Heavy bolt lift is probably a decent indicator of high pressure if you're very familiar with your rifle. As for primer appearance, this was considered an almost infallible method of roughly determining high/dangerous pressure when I began handloading in 1965. It's considered pretty much a meaningless indicator nowadays and deservedly so, except
in some instances. I've noticed with several rifles I've had for years, fired primers of the same make and batch may generally show rounded edges or slight flattening with loads I'm quite sure are safe. However if I up the charge weight, the flattening increases. Now, if this isn't a sign of higher (though not necessarily dangerous) pressure, I'm not sure what it would be.

Some rifles, however, showed flattened primers regardless of the intensity of the load. Tells you nothing.

[44MAG#1]

Bottom line is everyone is in favor of THEIR way of determining pressure. None is totally reliable. Even the labs with load data is only for THAT lot of particular components. Change components and the data changes. No one way is the know all end all of pressure determination.
Let each one use what floats their boat.
Each one on here that has posted can give reasons as to why their way is the best whether it is or not. So there is really no pat answer and I think we all know that.
Using common sense and being cautious, but not to the point of paranoia, is what we need.

[Catshooter]

Thanks for all the good answers gentlemen.

Outpost,

That's interesting. I'll tell you, this one time . . . I failed to notice that a corner of the rag that I used to cover my scale was touching the pan underneath.

When I fired the first of the rounds loaded with the pan like that, (Glock 19) the chrono read 1,703 fps with a 115 grainer. Mmm, thought I. Did see to kick a bit, but 1,703? That must be a mistake of the chrono.

So I fired one more. The empty landed next to my foot and sat there spinning, caught my eye. I looked down (chrono said 1,728) and noticed a primer laying next to the spinning brass. Picked up the brass, sure enough, no primer. Opps. Pulled the rest of 'em.

Tough pistol, Glock 19!


Cat

[Tedly]

Would you say your tolerance of load development is any better? Bolt lift, primer appearance, etc., come on now.

No , not at all and that is my exact point...for my applications its fine. You forgot to re mention that I stated chronograph as well.

[44MAG#1]

I used ETC. also in what l said.

[ulav8r]

Probably any accepted method can work well most of the time and fail at other times.

Any load that can be loaded into one case 30 times and still have a tight primer pocket should be considered safe, but it can take a while to work up to max if each workup starts at book recommended starting point. If there is a 10 grain spread between starting and max, and you increase 1/2 grain at a time, it could take 600 rounds fired through 20 new cases to determine if the max load is acceptable. So use other indicators to come up with a load and then try reloading a new case 30 times.

[kingrj]

Without the use of direct or calibrated straingauge pressure measuring equipment...Most of us can buy a chronograph and as long as our load does not greatly exceed published loading manual loads in velocity with a given bullet AND bolt lift is not "sticky" AND the primer pockets remain fairly tight for several loadings AND there is NO ejector cut in the head of the case with a plunger type ejector bolt gun...then I am satisfied that the load is safe in MY gun...No matter what the actual CUP or PSI is...