I am reloading my 7mm-08 won’t 119gr Absolute Hammer bullets which do not follow traditional load data. They require a faster burning powder and there’s very little info out there. So I’m looking for opinions on whether I am near the end of a “safe” reload. Essentially what I’ve done is loaded up in 0.2gr increments and evaluated velocity and then watched for ejector swipes and flattened primers. The round on the left is a factory once fired round. The round on the right is what I’m in question on. I know the primer is a bit flatter, would you guys deem this as getting on the hot side and discontinue pushing it further? I didn’t have heavy bolt lift.
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New to diagnosing a “HOT” load
- Thread starter bmicek
- Start date
I respectfully disagree based on this picture alone. I don't know what the OPs goals with this round are but this casing could be pushed a bit harder. Caveat being if there are no other signs of pressure....... like a sticky bolt. I'd also like to see the powder burn.
I personally prefer a "medium" load but I do start out with a goal in velocity I would like to reach.
I am shooting suppressed too btw. Let me know if this isn’t exactly what you were wanting a pic of.
Looks like a light powder burn, if I see one at all, all the way back to the shoulder which is where I like to be near or just short of. What powder are you using? It looks to be burning extremely clean.
This is where my knowledge ends. There are many here that I'm sure can get deeper into the science of it than me.
This is where my knowledge ends. There are many here that I'm sure can get deeper into the science of it than me.
I’m using 8208XBR. Not positive on the case fill that I’m getting as far as percentage goes, but I definitely have room for more powder. Which I might have to drop down to TAC which would be a touch slower burning. It’s what’s recommended but I had 8208 on hand and it’s just barely a touch faster than TAC. But I probably should aim for a little more case fill and it may allow me to push it a bit more.
I guess as more info, I’m shooting an 18” Kimber Adirondack so I’m trying to wring the velocity out of it since I’m working with a shorter barrel but still knowing I’ll be limited a bit.
Yah that makes sense. Usually I tend to be really careful working up once I see signs. Blew myself up once and I’m determined not to do it again
If it were me, I would continue on with that load development. There are no markings on the case head, the primer is a little flatter than the factory round but nowhere near what I would call a flattened primer. You stated you did not have a heavy bolt lift, so my opinion is that you have room for more experimentation. Stick with your .2gr increment and continue to watch for primer flattening, ejector swipes on the case head and heavy bolt lift.
That picture doesn't show abnormal pressure. It would be far easier if you told us your load, measured velocity, and barrel length. You can back into your pressure using a 120gr Barnes solid for load data. I'd hazard that powders with a burn rate close to H4895, or slightly faster, will be ideal.
That's upper end for sure. You probably have some more room to go but not a lot. If it's grouping well and consistent you may want to stop there.
Maybe I can help you out. Different caliber but I bet you will have the same results. Below is a ladder I did on a 6.5 creedmoor with 123 Absolute Hunter Hammer's. You're correct they are a different beast to load and do not quite act normal. If you will note that for every 1 grain of increase you see about a 40 fps increase all the way through. This increase is directly proportionate to the powder. The AH bullets like faster burning powders. With slower powders you probably will never see pressure unless you have a very very long barrel. The pressure comes on these bullets when you hit the secondary explosion or ignition of powder as seen at 50.0 grains. Notice the dramatic increase. I never see any pressure exhibited characteristics until that point. You need to and have to recognize when loading these bullets the amount of FPS increase per grain of powder. Then you will be able to see and recognize the pressure. The bullet also seems less susceptible to seating depth, but more to accuracy comes on a particular powder charge. Also, giving a very very light crimp, like 1/8th turn, will increase the accuracy. Go figure. Anyways. I hope it helps. Also, most people shooting the 7mm-08 are shooting that bullet over 3,100 fps. Call Steve over at Hammer Bullets and he would be glad to help you I promise. Very nice guy. Just saw you had a 18" barrel. I'm betting you never see pressure unless you use an extremely fast powder.
Fan of Hammers, but not absolutes. I found myself in the same dick dance as load developing lead bullets. Hammer Hunter line has been my jam in multiple cartridges and load development has always been quick to settle on a recipe. With 708 - 120HH N135 40.5gr 18" AR10 2880fps 75 F.
Bolt gun - I had a 22" Kimber running 120HH @3080fps with 41.5gr IMR3031, bug hole load. Killed deer and hogs like lightning bolt.
Of note, let your ammo sit and match the ambient temp. Could have ammo cold from the house AC and ride to range AC and then shoot slower, lower pressure. Then you go spending hours in the field hunting in hot weather and you could experience an over pressure round. Just FYI.
Bolt gun - I had a 22" Kimber running 120HH @3080fps with 41.5gr IMR3031, bug hole load. Killed deer and hogs like lightning bolt.
Of note, let your ammo sit and match the ambient temp. Could have ammo cold from the house AC and ride to range AC and then shoot slower, lower pressure. Then you go spending hours in the field hunting in hot weather and you could experience an over pressure round. Just FYI.
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Powder burn marks are a new one for me. What’s the chances you all have photos of the differences we should be seeing?
I'll try to take a picture for you tomorrow. It's late now and I have to get up early with a pretty full day but hopefully tomorrow evening I can get it for you. If I don't have a picture up by tomorrow, remind me
All of my brass is currently tumbled and clean. I'm not finding a peice here on my bench to take a good picture of to show you the kind of powder burn I like to see on the neck of my spend casings. I apologize
Capt Obvious shit here:
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Crystal balls and bad advice on the internet will get your head blown off .
www.gunsandammo.com
Ammunition Pressure Testing - Guns and Ammo
Demystifying the methods and terminology of ammunition pressure testing.
www.gunsandammo.com
Wrong. There hasn't been one person who's had their head blown off report that it happened.Crystal balls and bad advice on the internet will get your head blown off .
Ammunition Pressure Testing - Guns and Ammo
Demystifying the methods and terminology of ammunition pressure testing.
OP, read this
Understanding Pressure :: Primal Rights, Inc
Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.
www.primalrights.com
OP,
When developing a load I find it useful to keep track of brass and the powder charges that were in them to see how the primer pockets are holding up. In many cases loads that appear OK based on bolt lift and case head appearance cause primer pockets to loosen up because of too much pressure for those particular cases. So then you have to make a decision: Do I want this level of performance with this degree of case life? Or do I want my cases to last longer? Sometimes the former is acceptable. Also, just because you don’t have pressure signs today doesn’t mean you won’t have pressure signs another day, i.e. hot vs cold days. So keep this in mind when evaluating pressure.
When developing a load I find it useful to keep track of brass and the powder charges that were in them to see how the primer pockets are holding up. In many cases loads that appear OK based on bolt lift and case head appearance cause primer pockets to loosen up because of too much pressure for those particular cases. So then you have to make a decision: Do I want this level of performance with this degree of case life? Or do I want my cases to last longer? Sometimes the former is acceptable. Also, just because you don’t have pressure signs today doesn’t mean you won’t have pressure signs another day, i.e. hot vs cold days. So keep this in mind when evaluating pressure.
X100
I find monitoring the primer pocket growth and inspection of primers (decapped) keeps me well away from pressures that screw up precision and/or ES/SD consistency. Let alone far & away from dangerous pressures territory. Brass being as expensive as it is anymore, I want it to last a little while. Lol
The brass life doesn’t bother me. It can be 1 shot brass life and it wouldn’t bother me. But I agree, that’s why I’ve been trying to do load development while it’s hot still.
As long as the bolt is opening fine. I am on the its OK to shoot side. Things I have seen that were over pressure signs. Some of the material from the primer has flowed and tried to get into the bolts firing pin hole. Basically the primer is no longer flat and there is a ridge around the firing pin dent. For me the bolt opens OK but I know I need to back off a little. Also on the base of the case if there is a mark from where the ejector is located on the bolt.
Some powders are temperature sensitive. If you work up your load in cold weather when it warms up what was safe now can become over pressure. Also if you leave the ammo in the sun it can heat up a lot and cause problems.
Also if it is not a full case capacity load. I learned this test is important. Chamber a round then point the gun up bring it down slowly so the powder is up against the flash hole. Then run it through the chronograph. Inspect the case. Then do the same thing except this time point it down and slowly bring it up so the powder is away from the flash hole. I have seen a safe load become unsafe when doing this test. Even if its a safe load you should notice a velocity difference.
NDR
Some powders are temperature sensitive. If you work up your load in cold weather when it warms up what was safe now can become over pressure. Also if you leave the ammo in the sun it can heat up a lot and cause problems.
Also if it is not a full case capacity load. I learned this test is important. Chamber a round then point the gun up bring it down slowly so the powder is up against the flash hole. Then run it through the chronograph. Inspect the case. Then do the same thing except this time point it down and slowly bring it up so the powder is away from the flash hole. I have seen a safe load become unsafe when doing this test. Even if its a safe load you should notice a velocity difference.
NDR
