Loading density to avoid detonation?

[FOTIS]

We are all aware that using slow powder in certain cases can cause double detonation. What is the minimum loading density required to avoid this. I am thinking at least 80 percent. Would you guys agree???

 

[jmad_81]

I have never even heard of this :shock: Somebody please explain.

 

[ScreaminEagle]

I have never even heard of this :shock: Somebody please explain.

It's when you have to little power in the case. Detonation occurs when the primer ignites the powder at the rear of the case, the spark jumps to the front of the charge, and you no longer have a bullet. You have a grenade!

 

[bullet]

At least 80% to remove all doubt. When I use slow powders I am basically dealing with compressed charges and us mag primers. :mrgreen:

 

[JD338]

Fotis,

I would agree, 80% load density.
I always try for 90%+ when I develop a load.

JD338

 

[DrMike]

Also known as secondary explosion effect; some ballisticians question whether it is real. What is apparent is that charges lower than a threshold amount can cause dangerous pressure spikes. The mechanics are not at all understood. In general, it is wise not to try to load light charges of slow powders. I honestly don't know the threshold, but I would think 80% would qualify as a minimum. Personally, I aim for 85% of case capacity as my minimum with slow powders.

 

[onesonek]

Double Base powders are worse for this phenomena as well, specially in cold temps

 

[Win_94]

Hang-fire. I get that with a light charge of H414 in my 30-06 in cold temperatures. I cured it with a stouter charge, some fix it with a magnum primer.

Supposedly H110 in a 45 colt cartridge will cause a very dangerous condition with a light charge. I have never experienced a hang-fire using H110 in my 357.

 

[FOTIS]

I thought about 80% would do it!

 

[Guest]

I've always used the term "hang fire" to mean a slow ignition, where you pull the trigger, the pin strikes the primer, and it takes a second or two for the round to go off. The detonation issue is different. I've seen it with small charges in a 44Mag. Made the case sort of resemble a golf ball in texture, to some degree.

The theory I subscribe to is that the pressure spikes are caused by multiple flame fronts crashing into one another in the case when a powder charge is insufficient to fill the case up above the flash hole.

In most magnums, you won't get detonation at 80% charge weight with slower powders, in my experience. What you will get is inconsistent ignition and huge variations in velocity, and something akin to minute of barn door accuracy.

 

[SJB358]

and something akin to minute of barn door accuracy.

Isn't that Remington's guarantee from the factory? :twisted:

Sorry, couldn't help myself!!!!!!

 

[Bruce Mc]

Many years ago there was print in the rags about IMR-3031 and its use in medium cased rounds like 308 win 243win, with marginal loadings causing this problem.

 

[Mountain Goat]

and something akin to minute of barn door accuracy.

Isn't that Remington's guarantee from the factory? :twisted:

Sorry, couldn't help myself!!!!!!

That sounds like me shooting a 30-30 lever gun. Between a 30-30 and muzzle loader, I'll choose my bow! :wink:

 

[Oldtrader3]

It has been theorized that during the initial phase of firing slow burning powder in large capacty cases can create a transition conditon during the time which the powder is inignited and starts to burn it does so with the powder granules in gas suspension so that they are burning induvidually and separately. This would create instantationus conflagration and could spike prussures to the point of blowing up the gun. It has never been duplicated in the ballistic laboratory. It has been show as being statistically possible by mathmaticians and there have been some unexplained rifle wreakings under these conditions but never in a lab. So it remains conjectual.