Seriously, I would not use these measurements for a bore slug. BUT a bad primer squibbed a load. How do I know it was the primer? Though the brass ejected...onto the table and not into near earth orbit...there was a lot of unburned powder behind the squib. I will admit that I did not notice anything and got lucky as I was doing a double tap drill and had pulled the trigger for the second round before noticing a problem. Thankfully, that second round had not loaded. My Gaurdian Angel gets overtime pay. Alot.
Squib was approximately 2.5 inches down the bore.
Rock Island Armory 2011 TacII FS 10mm
CCI primer
9.6gr Longshot
Rainier Plated 180gr Hollowpoint
Widest Part of the Base Measured .3988 (actual not what is pictured)
(http://i27.photobucket.com/albums/c167/wyckedflesh/zombiepocolypse%20prep/020EFC4C-7AD4-4CA1-9126-9FE7E16DF878_zpsxonb9et4.jpg)
Widest Part of the Visible band above crimp grove at head measured .3986 (actual not what is pictured)
(http://i27.photobucket.com/albums/c167/wyckedflesh/zombiepocolypse%20prep/31EDB092-6953-4AE6-8FBB-CAD914B3D7DD_zps2hgd4nxf.jpg)
Using calipers for the crimp grove since I don't have a point attachment for my mic=.387
The primer must have moved the bullet before the powder could ignite...I have only had one squib, it was 38Spl revolver using H-110 with a light bullet, powder melted some, turned yellow but failed to ignite.
Interesting situation.
I have a question... I can't tell from the pics if that is cannelure or a hefty engraving/swaging from the crimp. If it is from the crimp, I have a theory about what might have happened.
If, and I want to stress "if" what photos appear to look like a heavy crimp... if it is, then that would be excessive to the point of swaging the bullet diameter down, and compromising neck tension. I have seen this scenario a few times. Once was at an IDPA match where a guy kept getting his bullet jammed into his barrel. What was happening was his bullet was slipping out off the case when the slide was slamming home. Upon unload and show clear, the case ejected, bullet stayed lodged into the grooves, powder everywhere. I loaned him my squib rod 3 times that match.
After the third time, we got to talking. He was heavily crimping his rounds. His neck tension was destroyed in the process.
Another sort of similar time was when I pulled down a few hundred reloads that I got from an estate sale. I bought them for the components. For some reason, about half of them were heavily crimped. Almost without exception, those slipped right out of the case with the kinetic hammer. In a way, the slide return is like a kinetic hammer. The other rounds crimped normally were much more difficult to pull because he had not ruined the neck tension at the crimping station.
So my theory is that if the photos do show signs of a heavy crimp, then I would suspect that your bullet popped out of the case and into the lands when the slide returned. That could certainly result in an ignition problem.
It is possible, I don't have the measurement right in front of me as my 10mm box is put away, but the external measurement is the intended measurement for the crimp/headspace.
Keep in mind, that is a plated bullet with a soft lead core. It takes little effort to deform that bullet. Certainly a lot less effort than a regular jacketed bullet.
If the crimp die is engraving the bullet with the case mouth at all, it is excessive crimp and will degrade the consistency of these bullets AND impaired neck tension. You're right. They're soft. Plating is thin. By the way, PowerBond has a much better bullet with thicker copper. Tjconevera has good prices usually.
Now back on track...
Much better accuracy and neck tension come by just barely closing up the case mouth without biting into the bullet at all. This really true for any straight wall auto loading cartridge. If the bullet is not engraved, and the round keplunks into the chamber, that's the sweet spot. Best neck tension. Best bullet integrity.
Good points Taterhead! As I am doing the pull-downs I started measuring the amount of indentations on the projectiles to show if the crimp was causing it!
I also had issues using the LEE FCD as a final crimp causing it to squeeze the case and bullet down too small making a loose fit!
I have a difficult time comprehending how a primer can cause enough pressure to push a bullet into the barrel, but not ignite the powder. It's not like Longshot is difficult to ignite like H110/296/ball powder (at least I haven't heard it is difficult to ignite, it doesn't need a magnum primer). I almost wonder if the powder charge was contaminated some how... I'm not doubting OP or anything, I just find it surprising and think contaminated powder or some other explanation is more likely than a bad primer (if the primer caused enough pressure to get the round into the barrel and eject the case...)
The contamination issue crossed my mind as well as the flash hole having a piece of media inside.
Another contamination I have seen was spider nest in range pickups!
Quote from: The_Shadow on March 12 2015 05:38:38 PM MDT
The primer must have moved the bullet before the powder could ignite...I have only had one squib, it was 38Spl revolver using H-110 with a light bullet, powder melted some, turned yellow but failed to ignite.
H-110 is famous for not igniting. I had a 454 Casull load not ignite.
Look on youtube or in any gun forum and about 50% of the time a powder fails to ignite it will be H-110.
.
Quote from: control_the_trigger on March 13 2015 09:19:50 PM MDT
I have a difficult time comprehending how a primer can cause enough pressure to push a bullet into the barrel, but not ignite the powder. It's not like Longshot is difficult to ignite like H110/296/ball powder (at least I haven't heard it is difficult to ignite, it doesn't need a magnum primer). I almost wonder if the powder charge was contaminated some how... I'm not doubting OP or anything, I just find it surprising and think contaminated powder or some other explanation is more likely than a bad primer (if the primer caused enough pressure to get the round into the barrel and eject the case...)
I agree with you that the primer is the unlikely culprit. That is why I floated the idea about the bullet slipping out of the case and jamming into the lands. With that much crimp, there would be limited bullet pull. Depending upon how much freebore, volume of the combustion space could be substantial, and relatively slow burning powders like LS need some tight quarters to properly ignite. A primer has enough juice to get a bullet stuck, and it might partially cycle the slide.
A primer can produce enough pressure without producing enough heat to ignite the powder. Somewhere around the net is a set of experiments that shows just how a primer ignites the powder, as well as how a primer can produce pressure but still be too weak to ignite all but the fastest of powders. I just don't have the link to it anymore and my quick looks failed to pull it back up. Since I deprime at the same time I full length size, it would be difficult for media to be stuck in the flash hole, which is why I do that step after having run it through the tumbler.
Some of the powder ignited, enough to smoke out the case, but not enough of the powder ignited to either cause the bullet to keep going or to cause an explosion instead. There was also primer residue still in the primer cup. The primer pocket was totally blackened.
Considering the comment about the crimp, a test of other randomly picked rounds from the same sitting, and my trusty Kinetic Puller, still took 5 or 6 solid blows to get any of the rounds to separate. Crimp measures a consistent .4186
I am not arguing, as I appreciate the differing views. I can't find the mistake I made if it truly isn't a bad primer, if no one points out what else could be the problem.
Interesting update about the kinetic puller. That's a good test, Since I've seen hundreds of rounds that fail that test. This might be one of those "we'll never know things," but contaminated powder might be next on the list of suspicions. Do you wet tumble by chance?
Nope, dry tumble.
Run brass through bulge buster, inspect cases
Dry tumble
Whipe off tumbler residue, lightly lube outside of case
Full length resize and deprime.
Whipe off cases and measure for length
Prime using hand primer
On press (Lee Classic Turret)
Flare case and drop in powder using lee powder measure
Seat bullet
Crimp Bullet (Lee FCD)
Eject and inspect (measure overall depth and crimp) (have not purchased gauge block, plunk test performed randomly using pulled barrel)
Every 10th bullet: weigh primed case, flare and add powder, re-weigh case to determine amount of powder dropped.
New thought in the "Squib" load department.
Loose primer pocket...I didn't notice the pics didn't come out to well so I don't have any to show. When I deprimed the case. There was a LOT of blackening around the primer itself as well as the pocket. It also popped out VERY easy. There was also a lot of soot around the breech face.
Flash hole plugged maybe?
Quote from: sqlbullet on March 25 2015 07:38:35 AM MDT
Flash hole plugged maybe?
Probably not. The primer had enough gusto to push the bulls a couple of inches down the barrel.
I am currently out of new primers at the moment as they are all loaded into brass waiting to be completed or I would drop in a primer to see how easy it is. A spent primer pops in and out super easy.
If these are being fired in a semi they should be taper crimped,not a FCD.