I screwed up and had an Oops.....

[jpjulian]

I got to find out just how strong the Defiance action is in my GA Precision 6MM Creedmoor. Sunday I was at my local range for one more session before heading to Florida for the winter. I had already shot my R700 .223 and determined an ignition issue from the prior week was corrected with a new firing pin spring. After switching to my GAP 6CM on about the 7th round fired I got a snoot full of gas. The bolt took some serious effort to open, (no tools required). A primer fell onto the bench along with the fired round. The primer pocket was noticeably enlarged and there was an extreme ejector mark on the case head. The case was very sooty. The primer was not pierced nor looked overly flattened. No doubt that round was way over pressure. The Lapua case was on its' 4th firing and had been full-length sized and trimmed as well as annealed prior to sizing. CCI 450 primers were used. The VV N555 charge was dispensed by an Autotrickler V4. Berger 108's were seated to 2.170 BTO. In other words, everything about that loaded round was as it should have been. But it wasn't. I screwed up somewhere. That single round somehow got overcharged. I don't know how but it happened. That was a first for me loading rifle ammo. Measurement of the case at home revealed the primer pocket enlarged by .015" and the case head had expanded by .011" just ahead of the extractor groove. I cannot imagine how high the pressure was for that round. No injury and the rifle is non the worse for wear, thankfully...... I screwed up somehow and need to exercise more caution in the future.

 

[jeffreybehr]

I'm glad NO ONE was injured.. Happened to me once, too.

 

[Capt. Oblivious]

What were you loading in the V4 before you started loading for the 6CM?

 

[Homerange]

Hmmm, you would do well to read this thread....ALL OF IT !

Best Ideas to Make Reloading Safer and Simpler?

Being my first time on here and mid 70's of age I'd like to pass on a thing or two I've learned over the years. I kept loading in the winters and camping, hiking, fishing, etc. in the summer. Then when I got more and more into reloading over 52 years. I had one Lyman hand help primer seater for...

forum.accurateshooter.com

 

[dgeesaman]

Glad you’re ok. Are there remaining rounds that will be disassembled to try and locate the root cause?

 

[rijndael]

What's your fill ratio with that powder? How much more powder could you get in before you start getting a compressed load, which I'd assume you'd notice on seating?

 

[Capt. Oblivious]

What's your fill ratio with that powder? How much more powder could you get in before you start getting a compressed load, which I'd assume you'd notice on seating?

I cant imagine that case being allot emptier than 90% with one fill

 

[6BRA]

The V4 is pretty hard to hold old powder. Simplicity 2 round tubes. Tilt the unit back and they have cleared themselves. Changing tilt angle or level of scale without rezeroing will change things.

 

[dantiff2]

I got to find out just how strong the Defiance action is in my GA Precision 6MM Creedmoor. Sunday I was at my local range for one more session before heading to Florida for the winter. I had already shot my R700 .223 and determined an ignition issue from the prior week was corrected with a new firing pin spring. After switching to my GAP 6CM on about the 7th round fired I got a snoot full of gas. The bolt took some serious effort to open, (no tools required). A primer fell onto the bench along with the fired round. The primer pocket was noticeably enlarged and there was an extreme ejector mark on the case head. The case was very sooty. The primer was not pierced nor looked overly flattened. No doubt that round was way over pressure. The Lapua case was on its' 4th firing and had been full-length sized and trimmed as well as annealed prior to sizing. CCI 450 primers were used. The VV N555 charge was dispensed by an Autotrickler V4. Berger 108's were seated to 2.170 BTO. In other words, everything about that loaded round was as it should have been. But it wasn't. I screwed up somewhere. That single round somehow got overcharged. I don't know how but it happened. That was a first for me loading rifle ammo. Measurement of the case at home revealed the primer pocket enlarged by .015" and the case head had expanded by .011" just ahead of the extractor groove. I cannot imagine how high the pressure was for that round. No injury and the rifle is non the worse for wear, thankfully...... I screwed up somehow and need to exercise more caution in the future.

Glad you were okay. Hope you may find out what happened and report back to us! Always wear glasses when shooting!!!

 

[Rocketvapor]

"Measurement of the case at home revealed the primer pocket enlarged by .015" and the case head had expanded by .011" just ahead of the extractor groove."
Got a picture. That has to be ugly.

 

[Bill K]

Makes me wonder if you and maybe others that have had a issue like this, miss the one step in reloading of checking/looking into the case to see powder and level, prior to seating a bullet ?
It is a very simple step in the stages of reloading and can sure show if a case is lower or higher than any of the others.

 

[JEFFPPC]

How long was the case. I trim every reloading. It's as fast to run them in the trimmer as it is to measure them. One or the other should be done every reloading. A long case can skyrocket pressure.

 

[Charlie-NY]

On rare occasions I've seen a small amount of powder bridge in the funnel neck. That left one case light and the next overcharged. The first time this happened, the case filled the neck so it was immediately noticed. Subsequent events were hard to notice without constant inspection.

Occasionally, I'll see a velocity that doesn't make sense and I'll wonder if I missed a bridging event.

 

[ruthless11]

I got to find out just how strong the Defiance action is in my GA Precision 6MM Creedmoor. Sunday I was at my local range for one more session before heading to Florida for the winter. I had already shot my R700 .223 and determined an ignition issue from the prior week was corrected with a new firing pin spring. After switching to my GAP 6CM on about the 7th round fired I got a snoot full of gas. The bolt took some serious effort to open, (no tools required). A primer fell onto the bench along with the fired round. The primer pocket was noticeably enlarged and there was an extreme ejector mark on the case head. The case was very sooty. The primer was not pierced nor looked overly flattened. No doubt that round was way over pressure. The Lapua case was on its' 4th firing and had been full-length sized and trimmed as well as annealed prior to sizing. CCI 450 primers were used. The VV N555 charge was dispensed by an Autotrickler V4. Berger 108's were seated to 2.170 BTO. In other words, everything about that loaded round was as it should have been. But it wasn't. I screwed up somewhere. That single round somehow got overcharged. I don't know how but it happened. That was a first for me loading rifle ammo. Measurement of the case at home revealed the primer pocket enlarged by .015" and the case head had expanded by .011" just ahead of the extractor groove. I cannot imagine how high the pressure was for that round. No injury and the rifle is non the worse for wear, thankfully...... I screwed up somehow and need to exercise more caution in the future.

sounds like a smaller case was loaded..011 is a lot of expansion

 

[clowdis]

A reasonable load of VV555 should be close to a compressed load with a 108. Hard to get enough into the case to blow it up I'd think. Maybe some residue or faster powder in the loader from a previous run?

 

[TaperPin]

I got to find out just how strong the Defiance action is in my GA Precision 6MM Creedmoor. Sunday I was at my local range for one more session before heading to Florida for the winter. I had already shot my R700 .223 and determined an ignition issue from the prior week was corrected with a new firing pin spring. After switching to my GAP 6CM on about the 7th round fired I got a snoot full of gas. The bolt took some serious effort to open, (no tools required). A primer fell onto the bench along with the fired round. The primer pocket was noticeably enlarged and there was an extreme ejector mark on the case head. The case was very sooty. The primer was not pierced nor looked overly flattened. No doubt that round was way over pressure. The Lapua case was on its' 4th firing and had been full-length sized and trimmed as well as annealed prior to sizing. CCI 450 primers were used. The VV N555 charge was dispensed by an Autotrickler V4. Berger 108's were seated to 2.170 BTO. In other words, everything about that loaded round was as it should have been. But it wasn't. I screwed up somewhere. That single round somehow got overcharged. I don't know how but it happened. That was a first for me loading rifle ammo. Measurement of the case at home revealed the primer pocket enlarged by .015" and the case head had expanded by .011" just ahead of the extractor groove. I cannot imagine how high the pressure was for that round. No injury and the rifle is non the worse for wear, thankfully...... I screwed up somehow and need to exercise more caution in the future.

Do you also load for a 25 caliber? Maybe wrong bullet?

 

[ebb]

Many times an unexplained pressure issue is a case too long that gets pinched in the chamber and results in the overpressure. You mentioned trimmed, could just one have slipped through your process?

 

[6Creed73]

Makes me wonder if you and maybe others that have had a issue like this, miss the one step in reloading of checking/looking into the case to see powder and level, prior to seating a bullet ?
It is a very simple step in the stages of reloading and can sure show if a case is lower or higher than any of the others.

This has saved me before. I had 50 cases in a loading block, charge case, move funnel, repeat. When I started seating, I inspected each one and noticed one had a double charge. Glad I looked.

Now, after I charge a case I immediately drop a bullet into the funnel. So when I move the funnel to the next case, the previous ones have a bullet sitting on the neck. This way, I can't accidentally double charge.

 

[nakneker]

I got to find out just how strong the Defiance action is in my GA Precision 6MM Creedmoor. Sunday I was at my local range for one more session before heading to Florida for the winter. I had already shot my R700 .223 and determined an ignition issue from the prior week was corrected with a new firing pin spring. After switching to my GAP 6CM on about the 7th round fired I got a snoot full of gas. The bolt took some serious effort to open, (no tools required). A primer fell onto the bench along with the fired round. The primer pocket was noticeably enlarged and there was an extreme ejector mark on the case head. The case was very sooty. The primer was not pierced nor looked overly flattened. No doubt that round was way over pressure. The Lapua case was on its' 4th firing and had been full-length sized and trimmed as well as annealed prior to sizing. CCI 450 primers were used. The VV N555 charge was dispensed by an Autotrickler V4. Berger 108's were seated to 2.170 BTO. In other words, everything about that loaded round was as it should have been. But it wasn't. I screwed up somewhere. That single round somehow got overcharged. I don't know how but it happened. That was a first for me loading rifle ammo. Measurement of the case at home revealed the primer pocket enlarged by .015" and the case head had expanded by .011" just ahead of the extractor groove. I cannot imagine how high the pressure was for that round. No injury and the rifle is non the worse for wear, thankfully...... I screwed up somehow and need to exercise more caution in the future.

Glad you’re ok, your rifle too. As mentioned above I always check the case length, it can be a little monotonous but it’s a good practice.

Any chance you pulled bullets and powder from those cases before loading them? I was doing that on some 6.5 PRC cases I was changing loads on just last week, after dumping the old powder I would do a quick check visually and if more was in there I’d bang against the garbage can and get the rest out. Once I pulled the rounds I thought I better take a flashlight and double check. I found four cases that still had a dozen kernels of 570 stuck in the case. Took and long Q tip and went back and rechecked every case. I’ve done some silly stuff reloading, more when I was starting out but I have learned to double or even triple check as I go through the steps of a loaded round. The link in reply #4 is worth a read for anyone, seasoned or beginner. Just reminders and Ideas on how to tune up the process to ensure the odds on in your favor.

 

[Doug Casner]

You said a mouthful when you said double check and triple check. Doug