Powder Ignition Failure

[CINDERS]

Strange EL17 that you reckon the hand primer was the issue I went the other way as a hand priming tool allows you to feel the crush as you seat the primer where as a press with its leverage you can actually crush the anvil to the point that you will get spurious ignition of the rounds. I have been using a hand priming tool for the last 8 years and have great result but before I was using a press with a bit of gusto caused me to have all sorts of click bang episodes I find your post #30 most interesting.....

One tedious thing I do first is remove from each one all inside case primer hole burrs also uniforming all the holes to the same depth that way you are getting consistent ignition results once it is done you do not have to worry about it

[Eaglelord17]

This was just a issue I had, mainly because I had a tough time figuring out where exactly my primer was by feel, it was either too deep or not deep enough. With the press (at least mine) it prevents me from crushing the primers, so that works for me even if it takes a little extra time.

[bombdoc]

Thanks for the input regarding primers..

not sure it is relevant in this case, but you never know. I use an RCBS bench priming tool which seems very consistent..

[Parashooter]

. . . My theory is that the weak neck tension and probable worn throat is causing a condition akin to a low density load in that the initial pressure pulse is blowing out the bullet into the bore and increasing the size of the apparent chamber. The rapid increase in volume is dropping the pressure to the point where, for some reason, the propellant is not igniting! I just think this is odd as the pressure in the chamber should not be affecting the primer performance - at least I have never seen this reported in the literature...!

The theory sounds good if we add the relatively large volume of the Lebel case and consequent low load density. With light loads of relatively slow powder, pressure and temperature simply never rise high enough to light up the charge and the powder flame extinguishes prematurely.

Experience with .323" bullets and IMR4895 in my 1886/93 rifle (modified for Balle N} demonstrated to me that the few published loads for the 8x50R are much too conservative for consistent ignition and burning. Significantly increasing charges eliminated these problems completely.

With N140 and the .323" 200-grain Sierra, QuickLOAD estimates it would take 47 grains to reach normal working pressure in this cartridge -

Cartridge : 8 mm Lebel M/93 (8x50R)
Bullet : .323, 200, Sierra HPBT MK 2415(2430)
Cartridge O.A.L. L6: 2.849 inch or 72.37 mm
Barrel Length : 30.0 inch or 762.0 mm
Powder : Vihtavuori N140

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.064% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill Chg. Vel. Energy Pmax Pmuz Burnt B_Time
..%...%..Grain fps. ft.lbs psi. psi. % .... ms

-10.6 82 42.00 2382 2519 36390 4814 100.0 1.709
-09.6 83 42.50 2404 2567 37504 4845 100.0 1.690
-08.5 84 43.00 2426 2615 38650 4876 100.0 1.667
-07.4 85 43.50 2449 2663 39828 4906 100.0 1.645
-06.4 86 44.00 2471 2711 41040 4936 100.0 1.624
-05.3 87 44.50 2492 2759 42287 4966 100.0 1.603
-04.3 88 45.00 2514 2807 43569 4995 100.0 1.582 ! Near Maximum !
-03.2 89 45.50 2536 2855 44887 5025 100.0 1.562 ! Near Maximum !
-02.1 90 46.00 2557 2904 46244 5054 100.0 1.543 ! Near Maximum !
-01.1 91 46.50 2578 2952 47639 5082 100.0 1.523 ! Near Maximum !
+00.0 92 47.00 2600 3001 49074 5111 100.0 1.504 ! Near Maximum !

[CINDERS]

There is no way known that you should be achieving 100% burn my quickload program states that in rather red letters under the chart with pressures p-max ect, with my reloads I try to get 98%+ burn in the barrel but never 100% as the last thing you really want is the burn to be completed before the projectile exits the barrel relying on the residual gas to push it out. JM5centsW

[Parashooter]

There is no way known that you should be achieving 100% burn my quickload program states that in rather red letters under the chart with pressures p-max ect, with my reloads I try to get 98%+ burn in the barrel but never 100% as the last thing you really want is the burn to be completed before the projectile exits the barrel relying on the residual gas to push it out. JM5centsW

I'm using QL version 3.2. Can you post a screenshot of that red-letter warning?

Many great loads, including most .22 Long Rifle factory rounds, burn all their powder before the bullet exits a reasonably long barrel. Seems to me that's often a good thing. Why waste powder by leaving some unburnt?

[Patrick Chadwick]

"Why waste powder by leaving some unburnt?"


- Because a bullet that remains in the barrel is going to cause big trouble when you fire the next round. The first (and last) time I used a nitro factory load 45-70 with my Pedersoli Sharps (nitro-proofed) there was a feeble sound as if a .22 had been fired, and a bullet driven into the bore just far enough that it would have been possible to chamber another round with disastrous consequences. The case was still full of nitro powder with the yellow look already described.


Sometimes trying for maximum efficiency can be counter productive. I would rather "waste" some powder than waste a rifle and my face.

[Parashooter]

Patrick, do you know little appropriate powder it takes to blow a normal-weight jacketed bullet out the barrel of the usual medium smokeless military rifle? I do - and it ain't much. 3 to 5 grains of Bullseye will normally do the trick. It's all a matter of matching powder burning rate to the desired result. Your .45-70 experience appears to be another example of somebody loading too little of a medium/slow powder in a large-capacity case. Not a good recipe for success.

[CINDERS]

Parashooter in reply and as requested to post #36 I did a spurious load up for my 6.5 x 284 though this one to excessive pressure limits but also indicates 100% burn, I know that with loads that are within SAAMI certain powders regardless of loaded grains will indicate a safe level of pressure whilst telling you of 100% burn achieved before base of bullet exits muzzle in black font.
I also understand and realize what your saying that 100% burn is not wasting powder and desirable but at what point is the 100% achieved and how far is that going to push the projectile down the barrel I just like to play it safe even if it means throwing a bit of gravel out the end of the muzzle like anything in what we do it is up to the individual and what they are comfortable with.
In my 6.5/284 having a little gravel going out the end is paled compared to the fire cracking and throat erosion this cartridge is famous for but for inherent accuracy I can put up with it originally I was going to go with a Shooting times Westerner till I read the barrels are normally toasted at 700 rounds + - dependent on how hard you drive them.
In the second pic I have included a load that whilst getting up in pressure shows the bullet exited the barrel and a 99.39% burn so .61% is not much out of 51 grains

[Parashooter]

OK, thanks Cinders. I see the same red lettering in 3.2 - if the load estimate exceeds maximum average pressure (PMAX). Has nothing to do with % burned, really. As you note, do the same exercise with a lower pressure load of sufficiently fast powder and we get the same burn statement without the red letters. In reality, physics dictates that once we get the bullet moving at a fair clip, momentum will carry it out the barrel long after all the powder has burned. (This is why the .22 LR, where burn is 100% at about 16" from breech, works fine in much longer barrels.) Stuck projectiles usually occur when we either use very light loads or something prevents an otherwise-adequate powder charge from burning normally.

Attachment 67485