Is pressure too high? .30-06, IMR 4350, 165 grain Accubonds

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The Nosler cases that failed were nearly 10% heavier than the ones I'm using now. They weighed 204 grains. My current cases are 185-186 grains. Also, I full length resized those cases. That gave them more room to stretch upon firing. I currently only partially resize my cases.

After a few firings, I noticed a ring around the case 0.35" from the base. Upon examination with a strong magnifying glass, I saw that the shiny ring was actually a groove. I used a piece of bent wire to feel inside the case and could also detect a groove on the inside. None of these cases ever leaked because once I saw the ring, I discarded the entire box. Not happy with only getting 3-4 shots out of Nosler cases, I weighed the cases trying to figure out what had happened. That's when I found out that this particular box was quite heavy compared to my other Nosler cases.

My bolt was replaced a few years ago after I had 3 or 4 primer perforations. The jet of hot gas coming out of the perforation made gouges in the bolt face. These were VERY old Federal primers that failed with moderate loads. All the failures were at the edge. I had to send the rifle back to Remington to get the bolt replaced because Remington told me they needed to fit the bolt to the rifle to get the proper head space.

I looked at the bolt face with a strong magnifying glass tonight. It does show very tiny specks of brass on much of the face. I didn't see any obvious brass that had been sheared off at the ejector pin. The explanation of the shiny spot being caused by brass extruding into the ejector pin then being sheared off when the bolt is opened certainly makes sense.

I looked at other cases (a variety of loads, some factory) to see if they show the circular machining marks seen on the ends. Some show no marks at all. Others show the beginnings of circular machining marks.

I also ran a patch into the chamber tonight. (I had not cleaned the chamber and bore on Sunday when I shot the five 60 grain shells.) It came out slightly blackened, but not oily. I would have been very surprised if it had come out oily.

I think this will have to remain a mystery. I certainly love the load's accuracy, but I have no desire to push the pressure to the limit. I've also learned a great deal from comments on this forum. But then, that's the whole point of this forum and web site anyway.

Thanks!
 
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One other thing to realize.When you do extrude brass back into the ejector hole,the case is held tight to the bolt face as the shoulder is fire formed to the chamber.
The hole for the ejector has sharp edges.You see a shiny spot because your bolt has sheared off the extrusion as you opened the bolt.
Don't put stock in the fact your fingernail does not catch on the extrusion.
I agree,extrusion is a serious sign,not to be ignored.

I do agree that IMR 4350 and a 165 or 168 gr Accubond is a great 30-06 combination.

But its great loaded to reasonable pressures.One way I watch for my rifles max,among other things,is diminishing velocity return for an increment of charge weight.
Like,maybe for four steps of 1/2 gr increase,I get 50 fps of gain.Then a step of 1/2 gr only gives 30 fps. That's hitting the wall.
And pressure increase is spiking because its outrunning the bullet.

Not all chronographs are precisely calibrated. Same with powder scales.
Either can mislead.

I have found if the sun is low,the shadows the chono reads are fickle,and results are not trustworthy.

After work,sundown at the range is not the best chrono time.
 
Zombie thread:

When a reloader starts worrying about pressure I always suggest the invent in a few gages. I have a Pratt & Whitney electronic gage that measures down to .000005", that is annoying, so I removed the electronics and then installed a precision dial indicator. And now I have one of the smoothest running height gages ever made and it does not hurt that is weight 35 pounds.

I would suggest a reloader learn to measure before and again after meaning the reloader needs to learn to measure the diameter of the case head before firing and again after. Starting out the reloader needs to understanding what it means to compare. Normal case head expansion, when compared with factory ammo is .00025". that measurement is taken from a new/factory loaded case. The second firing of the case if close to factory loading should not expand more than .00025".

If the reloader discovers the case head expansion is .001" on the first loading he should expect the case head shortened from the cup above the web to the case head, he should expect the primer pocket to expand, he should expect the flash hole to expand.

Reloaders skip the discipline of measuring before and again after when it comes to case head expansion, I am not surprised when they believe some cases have soft brass.

And then there are slow barrels and slow barrels, I have a very discipline reloaders that can add an additional 2 grains over maximum with no signs of pressure, hew could have a barrel that is larger in diameter than most barrels, he could have a chamber that is a few thousandths longer from the shoulder to the bolt face than a go-gage length chamber or he could be using old Winchester brass.

He had one rifle that shot one hole groups but he had to reduce the powder to cut down on case head expansion. I suggested he not mess with it so he sent the rifle back. He no longer has the problem with pressure signs and he no longer gets one hole groups.

F. Guffey
 
Is the OP even still alive? Boy this is old! One thing I noticed he said was that he partial sizes and leaves the case tight in the chamber an loading and unloading is a bit sticky because of it. Always been my though that one of the first sign's of pressure is a sticky bolt. He could have sized away to clue he needed. Lot of guy's like him around, they want the case fitting the chamber to well, they want to feel the neck rub. Well fine, there goes my best sign of pressure, a sticky bolt! My next sign it the ejector mark, he's seem's to have that. To presume a flat primer is a sign, it has to look like it was pored into the pocket. Some primer's that appear flat are not much more than soft cups. If the primer is a sign there should probably be some gas leakage around the edge of the primer. With the way he's sizing case's I could see how he'd easily miss a sticky bolt.
 
…And, note there is no longer a photo with OP, probably thanks to the Photobucket policy change, so it's impossible to see what he actually had to get the full context. IMHO, the thread should be dead for that cause anyway.

I'll point out that all published velocities where no gun is specified, like with commercial ammunition and Hodgdon's data, are fired in SAAM standard pressure and velocity test barrels. These have chambers that are minimum size to within half a thousandth of an inch, a barrel with a specific cross-sectional area, and they have a standard length, which, for rifle cartridges, is most often 24 inches (see the SAAMI standard to check the length for your cartridge). Additionally, the cartridges are manipulated to be sure the powder falls over the flash hole for firing, the position that produces the highest pressure and velocity just like the minimum chamber does. The tests are done within a specified temperature range. If your gun doesn't match theirs and the handling and conditions don't match theirs, you typically won't get the same velocity they did. It's just a reference point.

Meanwhile, given the missing images, I think I'll put this one to sleep.
 
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