Almost KABOOM with AA-5 in 41magnum load...??

[william iorg]

I dontsee how this could be a double charge. Lets say the bullet was seated .360" deep. This would give you room for 21.4 grains of AA No 5. If his charge was 8.0 grains or more (his charge was 10.7 grains) he would see a double charge which would fill the case nearly to the mouth.

Believe me, relatively fast powders and soft alloys will raise presure, quickly.

[GLynn41]

it sounds like powder-- -- air gap --with powder bridged up front -- I am grasping here--
some way position in relation to primer it detnates? -- temperaure -- does it get too warm this time of year- I have some loads that can only be fired in 50 or below -- 60-70 + temps will stick the hull 100% of the time
alloy can be apart if you are over size- very over size-- a barrel contstriction at the threads area and it is size sensitive--
chambers are they smooth-- no tool marks etc- I had a Redhawk in . 41/44 and the max loads went down the more i shot it -- so on my other Rehawk some 0000 steel wool made a great difference-
seating depth?
let us know when you know

[odfairfaxsub]

that would be bullet size not alloy necessarly.

[felix]

Again, the obvious is being overlooked because it does not happen enough? ... felix

[bearcove]

Pull them and measure each. All you need is pliers. Run case up without die grab bullet with pliers pull. Measure each charge. If it doesn't vary, must be a double. He said only one powder and nothing fast but unique that wasn 't opened.

[41mag]

Well here is the deal on the powder charge.

I got the three remaining loads from my bud, and brought them home. I zeroed my scale to be sure it was on, then checked it with my standard just to be certain. It was right on the money.

I set it to 10.7grs, and pulled the first boolit and carefully scraped the powder off the bottom, then poured the remainder into the pan. When it settled it was right on the line. So I went ahead and pulled the other two, and other than the second one being maybe a tenth lighter, they were all right on the line.

So at least these three were all set and dumped to 10.7grs. As for as the type, well it sure isn't Unique for sure. I am going to get out my "Big Eye" and see if it compares to my can of #5 or #7. He did say he had shot some #7 the prior trip up but had emptied out the hopper when done. He said he only ran about 10 rounds of it so there wasn't much to be emptied. Even if it WAS #7 with this load it would have been exactly the opposite I would think. With the powder coming up to right at the half mark on the case I doubt it would have boosted the pressure.

For now I am lost on this one. I am going to punch the primers to compare to some 300's I have, just to see if they appear to be the same critter. Even if they were 350's I still doubt they would have had the type reaction he got with this particular load.

My other thought was position, but I have shot so many pounds of this, and other AA powders, in all sorts of loads, and NEVER had this type issue that it seems a bit stretching. Plus with the density there is in the case, I just can't see that happening.

Next step is to contact Accurate I guess, everything I have seen before me is just like I would think it should be, and how I expected it to be. Like I said this fellow is pretty particular about things, but we all mess up once in a while. I simply cannot put my finger on where he might have.

[41mag]

Again, the obvious is being overlooked because it does not happen enough? ... felix

I'm all ears if you have a handle on something I am overlooking.

Please share, we would like to make sure this doesn't happen again.

[william iorg]

With the confirmation of the powder weight on the remaining three loads you can be reasonably certain it was not a double charge. A double charge would have filled the case to the point of 100% load density or more probably, light compression. The double charge would have been obvious to even a causal glance at the charged cases. There would have been a difference in feel when seating the bullet on a lightly compressed powder charge.
With a 50% or better case full of powder and the bullet seated a good .300” deep in the case you know powder position was not an issue.
This leaves very little to cause a problem. It is unlikely there is a problem with the can of powder due to the other loads shooting as expected. No secondary indication such as strange smell or color of powder.
What did your friend do to soften his alloy?
If you do not have a lead hardness tester, scratch the base of the bullet with your finger nail and put your “big eyes” on the scratch.
Take a look at the forcing cone of your friends revolver and look for leading, cracks etc.

[geargnasher]

41Mag, I believe Felix is referring to secondary explosion effect.

Gear

[41mag]

This leaves very little to cause a problem. It is unlikely there is a problem with the can of powder due to the other loads shooting as expected. No secondary indication such as strange smell or color of powder.
What did your friend do to soften his alloy?
If you do not have a lead hardness tester, scratch the base of the bullet with your finger nail and put your “big eyes” on the scratch.
Take a look at the forcing cone of your friends revolver and look for leading, cracks etc.

I checked the hardness on two of them using my Cabine Tree and got an 80 on one and 82 on the other. They were both tested on the side since they were HP's and it's recommended not to check them on the bottoms. This would put them both right in the ball park of aged WW on the chart or a 14bhn.

As for hardening or softening of his ally, he is pouring with 4 different alloys. One is Isotope Ingot alloy, one is Iso Core alloy, one is 1-20, and the other is Lyman #2 both from Rotometals. He is air cooling and water quenching about 25 boolits each, from each alloy, simply to see if one excels over another in accuracy from his revolver. He also has a Cabine Tree Tester, and said that around 22bhn has been the hardest he has shot so far.

He had cleaned his revolver really well prior to heading up for the weekend. When done he swabbed the bore with a patch smeared with Alox simply to precondition it prior to shooting.

41Mag, I believe Felix is referring to secondary explosion effect.

Gear

I have had that in the back of my mind, and in fact mentioned it to my friend when he called the first time. My thought was that possibly the primer punched the boolit hard enough to start it into the funnel of the cylinders chamber, where it stopped, before the powder completely lit off causing just that. This said I personally would think this would at least cause somewhat of a weird report or somewhat of a hang fire.

The only time I have experienced anything close was using a compressed charge of 296 and a magnum primer. Not even sure that's what happened then but I DO know that it popped, then went BOOM with plenty more authority than some others I had previously shot. There was a millisecond in between the time I heard and felt the primer pop and the main charge go off. Totally different type of situation I realize but the only other situation I can compare to.

Back to the pulled cartridge, I measured down from the mouth of the case to the top of the powder using my calipers, where I got right at .5". Then I dumped the powder out and measured from the case mouth to the bottom where I got 1.085". Then I measured from the bottom of the boolit to the crimp groove and I got .335", which when subtracted from one another would leave a .250" area between the powder and boolit base. Personally I would think this would need to be considerably more to cause the SEE, especially in a straight walled case. Of course I might be way off base as well.

One other thought was that possibly the powder charge had been positioned so that the primer flame went across the majority of it while it was laying flat in the case, which caused more of it to light off at once thereby causing a more rapid build up of pressure. But after seeing how much of the case was actually filed by the powder when I pulled the boolit, I simply cannot bring myself to this conclusion.

[btroj]

SEE can easily be caused by a lack of bullet pull with some powders. A crimp alone doesn't work, you need a snug fit between bullet and case wall.

I would not expect any difference in the sound of a round with or without SEE, except the ones with would be far more noticeable in muzzle blast. I wouldn't expect any hang fire or delay. It doesn't take that long for the bullet to move, stop, and get going again.

[bearcove]

With the confirmation of the powder weight on the remaining three loads you can be reasonably certain it was not a double charge. A double charge would have filled the case to the point of 100% load density or more probably, light compression. The double charge would have been obvious to even a causal glance at the charged cases. There would have been a difference in feel when seating the bullet on a lightly compressed powder charge.
With a 50% or better case full of powder and the bullet seated a good .300” deep in the case you know powder position was not an issue.
This leaves very little to cause a problem. It is unlikely there is a problem with the can of powder due to the other loads shooting as expected. No secondary indication such as strange smell or color of powder.
What did your friend do to soften his alloy?
If you do not have a lead hardness tester, scratch the base of the bullet with your finger nail and put your “big eyes” on the scratch.
Take a look at the forcing cone of your friends revolver and look for leading, cracks etc.

The idea that you did not find a double charged case, eliminates the possibility of that being the cause is absurd! The assumtion that casual QC would prevent is the same. It didn't feel different is very casual.

The concept of a double charge is that it happens ocasionally! NOT EVERY TIME!

Very ocasionally! I've been reloading for 35 years and have not done it yet. Much less twice in 6 rounds!

SEE is not likely with these powders.

[mstarling]

Oh my!

I have an original H&G 256 6 gang mold and have shot a **** load of bullets cast with it. Have used a bunch of #5 and assorted other powders. But never #5 with the 256. Almost always Unique, #9, 2400 or H110.

You won't get consistent double charges. Powder bridging won't be consistent. Something systematically wrong here. Weigh the charges and then check the balance ... did you really weigh 10.7 grains?

[william iorg]

Bearcove, I bow to you expertise.
I was not speaking (writing) in absolutes - the individual we are discussing appears to be a reasonably well experienced reloader, even a moderately experienced reloader will look at his cases after charging them and before seating a bullet. It is reasonable too assume - yes an assumption - that he would see a 21.4 grain charge in a 41 Magnum case and recognize the powder charge in this case does not look like the others.
The odds of his having the two double charge loads next to each other in the cylinder are not astronomical -but they are high. If his powder measure was bridging there would be a low charge in one of the cases and this does not apper to have happened. It does seem logical that a double charge can be taken out of or at least, relegated to the bottom of the list of possibilities.
His alloy is hard enough that he is not sluging the throat so that possibility may also be eliminated.
Low bullet pull and rough throats have caused pressure spikes in rifles. Low bullet pull could cause a bullet to move forward and cause slow ignition and it is worth invstigation. The question could be asked, were the bullets difficult to pull?

[Dark Helmet]

Is it possible that the ammo was allowed to get hot before loading and firing?

[bearcove]

I also think that powder bridging is a myth. I use powder measures from various companies and then trickle my powder in the pan on the scale to finish the charge. For all my reloads. I do everything in a single stage press. Everything from flake to stick powder is fairly consistant. Granted some meter better than others I have never encountered a bridging in a powder measure. Maybe only 4 or 500,000 reloads but a short charge followed by a heavy charge would have been noticable.

Operator error is much more likely.

[Hoghound]

First of all I would like to thank everyone for their responses and putting heads together to try and figure this out. I was told that AA#5 was not temp sensitive from single digits to triple digits. Down here in east Texas the weather can change up and down rapidly certain times of the year not to mention the elevations, humidity, and baro pressures associated with that's what turned me on to this powder.

Its just like Mikie told it...I was trying to develope a consistent (sd) load from 1150 to 1200 fps. Im not into wrist twisters and fire belching big boomers anymore. I was shooting a conservitive 10.7 grs. of AA#5, cci-300's, Iso ingots air cooled 216gr. hollow points lubed with 45,45,10 lube. Starline cases trimmed to 1.280 and very little crimp loaded off my Dillon 550 press. Velocities were 1160,1160,1162,1162,1165,1167. I put 4 through the same hole and the other 2 were cutting the edge of the other group at 50 yards off a rest a month ago. Last weekend loading the same load but different alloy a/c Iso core things went south.

Im thinking this powder is temp sensitive. A month ago we were getting temps at night in the mid 60s and during the day in the high 70's. This past weekend the temps at night were in the mid to high 70's and during the day high 90's. I had the powder in my machine shop inside the barn. It's a metal barn with no shade, so it would be safe to say temps inside the shop exceeded 100*f.

A few years ago Mike and I were into long range shooting. I loaded my 300 rum with 185 vld bullets at 3400fps with RL-25 temps in the low 60's. During the middle of the day (high 80's) he spotted some hogs and took the rifle to pick one off. After he squeezed off the round he came back and said what did you load in that thing. I told him this is what I did with it this morning and showed him a 1 hole group fired at 300 yards with logged chronoed velocities 3400 and no pressure signs what so ever. So I sat down behind it and squeezed a round off. She was running 3700 and could not get the bolt open till the case cooled off. Changed powders and never had another issue. Bottom line RL-25 is temp sensitive in that 300 rum in my location. This AA#5 Is like dayjavoo again. I understand the week link is human error, but in this case I assure you that it was not. One thing I ain't gonna do is squeeze off another round of that lot to proove a point. Thanks again for any responses or imput. I'm going to contact AA tomorrow.

[geargnasher]

I have had that in the back of my mind, and in fact mentioned it to my friend when he called the first time. My thought was that possibly the primer punched the boolit hard enough to start it into the funnel of the cylinders chamber, where it stopped, before the powder completely lit off causing just that. This said I personally would think this would at least cause somewhat of a weird report or somewhat of a hang fire. I've never experienced the SEE, but I would expect the same thing, some stutter or delay. A person can detect a surpisingly small gap in time between events such as lock time or hangfire.

The only time I have experienced anything close was using a compressed charge of 296 and a magnum primer. Not even sure that's what happened then but I DO know that it popped, then went BOOM with plenty more authority than some others I had previously shot. There was a millisecond in between the time I heard and felt the primer pop and the main charge go off. Totally different type of situation I realize but the only other situation I can compare to.

Back to the pulled cartridge, I measured down from the mouth of the case to the top of the powder using my calipers, where I got right at .5". Then I dumped the powder out and measured from the case mouth to the bottom where I got 1.085". Then I measured from the bottom of the boolit to the crimp groove and I got .335", which when subtracted from one another would leave a .250" area between the powder and boolit base. Personally I would think this would need to be considerably more to cause the SEE, especially in a straight walled case. Of course I might be way off base as well. I don't know for sure. I was only trying to clarify what I thought Felix meant, and I could be wrong about that, too. I don't really think it would be SEE with the components used.

One other thought was that possibly the powder charge had been positioned so that the primer flame went across the majority of it while it was laying flat in the case, which caused more of it to light off at once thereby causing a more rapid build up of pressure. But after seeing how much of the case was actually filed by the powder when I pulled the boolit, I simply cannot bring myself to this conclusion.

A case more than half full of that kind of powder ought to light off just fine. This is still a mystery to me, but the only explanation I can offer is bad powder at this point.

As far as powder bridging goes, I've never had it happen either, but I take special precautions against it at all times.

Gear

[runfiverun]

heat and a magnum primer will jack up pressures with some of accurates powders.
[double based ball powders]
why do you think winchester dropped 680?
i had the same thing happen with aa-2230 in my 30-30.
i got a bunch of win mag primers for 10 bucks a k and was shooting them up in my savage 340a
the weather warmed up and i thought i was shooting a 30-06.
not only did i drop the mag primers i also lowered the load 2 grains permanently.

[william iorg]

“I do everything in a single stage press.”

We are of like minds on presses. I too use a single stage press or a hand press for all of my loading. I seat bullets as I charge cases.
I shoot quite a bit of low velocity ammunition – often loaded with fast powders in large cases – a double charge would spell disaster. I have never had a problem but I take a cautious approach with reduced loads,