Hot Load?

[robdaniels]

Would you continue to shoot this load? It is a max load. Note the small red arrow. The picture doesn't show it well, but there is a shiny extractor spot. It is not a bump, it is smooth. I am unsure if this is too much pressure because it shoots really well. The blot lifts easy and no other signs of high pressure. I measured the case above the case head and it is fine, no ring mark, etc. The target image is 3 shots at 100 yds.

 

[Broz]

Starting to flatten primer face, cratered primer strike, and starting to transfer brass into the ejector pin. Looks a little hot to me. That load depending on what powder could be trouble in warmer temps. I say you need to back off 1 to 2 gr.

Jeff

 

[danj]

Primer looks cratered . I would back down a bit.

 

[7stw]

Would you continue to shoot this load? It is a max load. Note the small red arrow. The picture doesn't show it well, but there is a shiny extractor spot. It is not a bump, it is smooth. I am unsure if this is too much pressure because it shoots really well. The blot lifts easy and no other signs of high pressure. I measured the case above the case head and it is fine, no ring mark, etc. The target image is 3 shots at 100 yds.

It does appear to be on the warm side. The dimpled primer is another indicator as well. When you get shiny brass on the base, that is clearly brass flow, and is warning you to not go further, or faster. I would back it down a bit, to be on the safe side.

 

[robdaniels]

Thanks guys. That is why I asked. Well back to the reloading bench.

 

[Lefty7mmstw]

Yep, she's warm; back her off a bit to be safe. 70 Kpsi will lift easy on a 7mmstw and has no brass flow. If I see any brass flow I back off until it stops or switch to a slower powder to get the speed without quite the peak pressure.

 

[Reloader222]

I do not see the so-called flat-hat-top on the primer and even the flow of the primer in the firing pin hole, is not all conclusive. My .222 Rem give me the primer flow even at minimum loads because of an over-size firing pin hole. Each rifle is not identical, but I agree with other forum members if you are at max load and you get one of the signs and there is no other explaination for it, then back off the load with at least 0.5gr or even 1.0 grain. One thing is that it is a very accurate load, but try making it safe. A rise in temperature can cause a blow-up. Do you keep records of your temperatures when you test your loads? If it was tested in cold temperature, downloading is a must!

 

[MudRunner2005]

My 5R .308 will crater the primer on every load, factory or handload. I think it has a really strong firing pin spring, since it's a relatively new gun, and had less than 200 rounds through it. Every handload does it, and so does every factory loaded Hornady bullet I've put through it... So, any input on why a factory gun with factory ammo would be cratering primers, other than my theory?

 

[Joe King]

My 5R .308 will crater the primer on every load, factory or handload. I think it has a really strong firing pin spring, since it's a relatively new gun, and had less than 200 rounds through it. Every handload does it, and so does every factory loaded Hornady bullet I've put through it... So, any input on why a factory gun with factory ammo would be cratering primers, other than my theory?

Some do some don't. My 7mag does the same as your 308, and I'm likely 1/2 through my 2nd barrel on it, the 22-250 does it as well but to a lesser degree, my 270 and 243 do not do that how ever.

 

[MudRunner2005]

Some do some don't. My 7mag does the same as your 308, and I'm likely 1/2 through my 2nd barrel on it, the 22-250 does it as well but to a lesser degree, my 270 and 243 do not do that how ever.

So, nothing to worry about then, just a strong spring....That's good to know.

Thanks Joe. I've been curious about that for a while.

 

[Broz]

Yes, some will crater primers due to an over sized pin bore. That is a given. But the OP's primer is flat all the way across and showing the beginning signs of a muffin topped primer as well. You can even see some tell tale signs of imprinting of the bolt face to the primer. That coupled with the shadow of the ejector pin bore and transferring of brass to it is where I came up with my conclusion. The pin strike cratering is only one indicator and not one I trust by it self.

Jeff

 

[bgouin]

I have had excellent accuracy with hand loads that were most likely also hand grenades. I am talking really too hot. I also noticed on these loads that as I increased the powder charge the velocity change began to flatten or go negative. For example I would observe a 40-50 fps change for every one additional grain of powder in the normal range followed by a 5-15 fps change per grain of powder, followed by a drop in velocity with the next grain of powder. This happened twice. The first time was with a 340 weatherby and the second with a 7 mm Ultra. in both cases the accruacy was outstanding with the hottest load. As powder charge is increased, accuracy nodes are often observed. I had to back off on my powder charge to the last accuracy node.

Also my primers look like yours even from factory ammo. Brass flow is a good indicator of high pressure as is primer condition, bolt lift, and others. Stop when you see any high pressure indicator and back off. You did the right thing.

 

[robdaniels]

Well I went back to the bench this morning and loaded some more rounds and then went to the range. Found a good shooter at 4 grains less than the one I reported as hot. By the way the hot one was at the powder maker's MAX.
Now I feel comfortable and safe. lightbulb
Thanks guys for all your input.

 

[Reloader222]

I am happy you could sort this out. Rather safe than not safe. The reason why we reload is to shoot buck, not to blow up ourselves. AND your rifle, cases etc would last much longer!