aa

[Coyote Shadow Tracker]

broceinboise you are over thinking it. I see that you are very adverse in taking pictures and looking for over pressure signs so you must be knowledgeable about reloading. You need to chronograph along with checking what the suggested loads should be. I see all too often where a reloader is trying to get the highest velocity and pushing the limits. You didn't mention what the velocity is for your pictures of primers. My suggestion is go with a published load and work it for accuracy. You will be much better off for first an accurate load and most likely better barrel life.

 

[MagnumManiac]

First thing to look for is how easily a new primer seats. If it is loose, you have gone past the elastic limit of the brass, regardless of the velocity or other signs.
I find certain brands of brass will exhibit ejector marks straight off the bat, the brass is soft.
My comp Norma brass is only good for 5 firings, then primer pockets open up. It will also show early signs of ejector marks even though it has heaps more capacity than other brands.
If you use the same brand of primer and track appearance across several cartridges, you can get a good take on when you have surpassed normal pressures, but you must understand that just like brass cases, the hardness between lots can vary significantly.

Cheers.

 

[Deleted member 120585]

broceinboise you are over thinking it. I see that you are very adverse in taking pictures and looking for over pressure signs so you must be knowledgeable about reloading. You need to chronograph along with checking what the suggested loads should be. I see all too often where a reloader is trying to get the highest velocity and pushing the limits. You didn't mention what the velocity is for your pictures of primers. My suggestion is go with a published load and work it for accuracy. You will be much better off for first an accurate load and most likely better barrel life.

there is no "published load" for a 143 hammer or 145 lrx ...and chrono is enroute

 

[TRexF16]

there is no "published load" for a 143 hammer or 145 lrx ...and chrono is enroute

Have you found ANY published, pressure-tested load data for IMR 4166 in the 280 AI with any weight bullet? I only did a quick internet search but couldn't find any.
Please post the link if you've got some as that will help a lot with the discussion.

If the answer is no that could be a clue...
My gut says it's too fast-burning for optimum velocities with those bullets in the 280 AI but I could be wrong. That doesn't mean you won't get a good accurate load at a lower velocity, which will kill just fine. But I bet that's not what is being sought.

Cheers,
Rex

 

[TRexF16]

Hey Bruce,
In trying to run down some 280AI data for IMR 4166, I ran into your similar thread over on Rokslide.
It looks like you are doing a good job of your due diligence.
That chronograph is going to help out a lot - look forward to hearing what it shows you. Keep in mind that fast powder is going to hit its highest safe velocity at a slower speed than some of the slower burning powders might.
Also, as you probably know, folks who have tested what we tend to treat as traditional "pressure signs" against actual modern strain-gauge pressure equipment, have found our traditional "signs" don't often begin to manifest until north of 70K PSI, particularly in nice modern tight tolerance rifles. Can we get away with loading multiple times at these pressures in such rifles? Probably, maybe most of the time? Who knows?

Good luck with it - I think you're doing a good job of being careful.
Rex

 

[Bob Wright]

I think Reloder23 and a mag primer would be the correct combo. Quite a few of us have moved to it on the 280AI and it's just been worked up in my 7RM with a 180 Berger. Easy load workup and speed comes way easier than the Hodgdon powder I was using.