Ron,

The little bit I have read of them is that you might still be dealing with relative readings rather than absolute due to variations in the strength of the chamber metal.

There is a poster on HA who goes by the name of OK Shooter and he is right into the thing so you address a post to him on HA. He has written some book about reloading.

This is my general method. Firstly I take the load up to the point of the first sigh of the ejector mark or ejector slot mark. That tells me what the absolute tops is and thus how far any of my using loads are below that point.

On calibres with small case capacities for the bore diameter such as 30/06, 375, 404 etc I think if the primer pocket is loose after 3 shots, that is, the primer goes in with no resistance, that is tops for me and will allow for pressure spikes due to bore fouling conditions or whatever. On big case capacity for the bore, 264 Win, 7mm Rem, 300 Ultra etc I want 5 shots unless it is a freebored Wby.

However, in reality, a very accurate rifle in calibres with small case capacity for bores size such as 375 or 404 type stuff, accuracy seems to fall off at lower pressure and it will be unlikely that the peak accuracy load will have the primer pocket loose after 3 shots.

Alf and some others seem to have a fixation on pressure and action set back. Perhaps with bigger diameter cases and very old rifles they perhaps have a point.

But I would be prepared to bet that average Rem 700 300 RUM that has been thrashed for 1000 shots will have one lug partly bearing and in lots of cases the second lug will not have been bearing.

Mike

Mike,
None of my Varget loads have shown the least bit of ejector slot marks. I stay two or three grains below Saeed's max loads for comparable weight bullets.

90 grains of Varget with the 340 grain North Fork is trouble free, and I have chosen to be 2 grains below that for elbow room: 88 grains!

That means that Saeed would probably use 92 to 93 grains of Varget and a compressed load.

Thanks for the pointers.
I feel quite safe, and will monitor the brass closely as you say.

The rules for the .404 Jeffery are being rewritten.

Ron,
The strain gauges are very reliable. You can epoxy the gauge on the underside of the barrel and tuck the wire out of the way into a little pocket in the stock when you aren't using it.

My present contract with a bullet company will keep me busy for the next few months, but the first rifle pressure barrel that I will be buying is for a 404.

I can get you all the data in the world then. At 110 degrees F even.

lawndart

PS I stop testing at 60,000 psi, period.

PPS I need a 404 reamer to borrow or rent. Anyone who lends me one or splits the cost gets all the data they can eat for free.

quote:

Originally posted by lawndart:
PS I stop testing at 60,000 psi, period.

lawndart,
I was hoping you would do that.
I predict my 88 grain Varget load with the 340 grain North Fork is less than 60,000 psi and hope you will try to prove me right.

I do not think that the 10" versus 14" twist rate will make any significant difference.

In fact, I do not think that the Lothar Walther and McGowen barrel differences (whatever they are) will cause any significant pressure variables.

Get a 14" LW and CIP chambered tight!!! I want one too.

As Elvis woud say in RSA: "Buy a donkey."

Rip,
Nice conversation your having with yourself, How long has this been going on in your life..BTW your lieing to yourself, you will find in the 404 that IMR will easily outperform 4350, were that not so I would be shooting 4350!!

That be IMR-4831 btw...misplaced brain fart it appears. but never the less you will arrive at the same conclusion that I have, if your honest with me and yourself...or can read a chronograph...whichever comes first

Ray,
If you would try the latest lots of powder you would find things have changed.

The old H4350 was comparable to IMR-4831 in burn rate.

The new H4350 Extreme is faster than IMR-4350.

Granted, that current IMR-4831 is faster than H4831 and H4831SC, but none of us have access to your magic keg of IMR-4831.

Yours is an enchanted world where one can get 96 grains of IMR-4831 into the case with a 400 grainer and have the velocity start hopping up by 222 fps for the 94-96 grain last step of powder stuffed in.

I have seen your data and printed off a hard copy of it. I still think you mixed data from two different rifles to get that.

No matter.

Remember that +2700 fps with a 340 grainer in a 24" barrel is the target. How much IMR4831 would it take to do that? 100 to 101 grains?

If the .416 Remington can do 2400 fps with 400 grainers at safe pressures, then there is no way in hades that the .404 Jeffery won't do these safe loads with Varget:

400 gr Woodleigh RNSP/FMJ: +2400 fps : 81 grains
380 gr North Fork SP/FP/CP: +2500 fps : 83 grains
340 gr North Fork SP: +2700 fps : 88 grains

The .404 Jeffery has 10 grains greater capacity than the .416 Remington case.

My velocities might all be done at lower pressures with H4350,
but I bet you won't be able to accomplish the 340 grain load at all with the slower yet IMR-4831.