November 29, 2007, 05:40 PM
Seeing how this was brought up (in the past) today I thought I would post video of it. What you're about to see is an M1 "blue tip" incendiary round burst in the air after being fired in an M82. When reports of this first started to appear on the net the consenus was it was from being demilled.
Demilled bullets are ripped apart and when you buy them they are either sized or not. What the final thought on this issue was is that the jacket had seperated enough from the core (when sized) to allow the hot gases from being fired to come into contact with the incendiary mixture. The result is an airburst right after leaving the barrel. Enjoy.
November 29, 2007, 05:47 PM
I'm getting a page cannot be displayed when I try to click the link directly, but I was able to right click and save as.
November 29, 2007, 06:36 PM
I've loaded a bunch of Blue-tips and believe the real problem is the base sealing being compromised by corrosion. Being as these projos are over 50yrs old (mostly) they can be getting deteriorated and loading one with the base getting rotten is likely to allow the hot gasses to get up into the live incindiary mix.
Not really buying the cannelures causing the bursts as they explode, rather than just flying apart as I'd expect from a case rupture. And, remember that military ammo of the day was allowed/expected to have a certain percentage of problems. Watched a film of a gun test on a F-86 (6 50's in the nose, 3 on each side) and there were several clear airbursts just clear of the muzzles...and this ammo was fresh!
I carefully inspect all bases before using them and haven't had any problems even with running them over 225grns of 5010. Won't shoot the corroded ones, though. And I doubt that the commercial reloaders were as fussy about the condition of the projos they loaded.
November 29, 2007, 10:32 PM
Wasn't there some conjecture that they were loading them too hot for the twist rate, and were causing them to fly apart? It's interesting that the problem only seems to occur outside the barrel, or right on the edge (like in the muzzlebreak someone posted a picture of a while back). That's suggesting to me instability rather than burn-through...although who knows for sure.
November 30, 2007, 05:56 AM
I'd like to see what type of groups he's shooting in that video. :)
November 30, 2007, 07:05 AM
It appears to just be a case of a poor base seal; the M1 Incendiary has a lead plug at the base to hold the internal components together, and if the gas pushing the bullet can find ANY way of getting inside the jacket, it'll cause muzzle bursts.
November 30, 2007, 12:31 PM
I dunno...that's a fairly sizeable mass of lead in the back..I'm guessing about 3/8" or so. That'd be an awful lot of lead to burn through to get at the incendiary mixture. Could the jacket be pulling away from the lead base, and allowing gases in through the edges?
November 30, 2007, 04:44 PM
That's what most were thinking was happening from when the bullets were resized. I would like to see the video that Rob was talking about.
November 30, 2007, 07:10 PM
The video was on a History Channel show a while back 'Wings' on the Sabre IIRC.
And, I include pics of some Bluetips from one of my cans. The end bullets are what I would call shootable, while in the middle are the decomposed ones that I believe are mostly responsible for the air bursts.
Yes, there IS a pretty sizeable chunk of lead plugging the base, but it also can get mighty corroded after 50 years. The commercial reloaders aren't/didn't spend so much time culling the rotten ones and I'd be surprised if many people have loaded ones that muzzle-burst. Unless they were rotten ones...then shame on them!