Any ideas on strange happening?

[JDL]

I had a strange incident this afternoon. I had put my scope back on my B-78 .45-70 this morning after trying to shoot it with the iron sights. It sucks getting old!! Anyway, I was sighting it in to finish up our deer season, using a 310 grain paper-patched boolit pushed with 45 grains of IMR-4198 without a filler.
I wasn't chronographing but, previously these loads recorded 1845 fps. I checked the poi with the 3 rounds I had and found it shooting 3" left, so I went back inside and loaded 4 more in order to fine tune it. I hand weighed each charge and looked into the cases after charging them so I know all the charges were the same. After making an adjustment to the scope, the next shot went 4 inches right, but was normal. Next shot was 4" higher, next was back down, next.....I saw an orange flash and felt my cap being blown up!
My initial thought was a piereced primer but, that wasn't the problem and the case is fine although sooty. Somehow, gas must have passed the case and blew upward from the breechblock. The bottom of the scope and mount is sooty as well but, appears unharmed.
Of the last 4 cases involved, one (I believe this to be the first) was clean and bright. The last 3 were progressively dirtier, with the last showing a lot of soot to just below the cannalure. I would be most intrested and appreciative to anyone who could shed some light on this. -JDL

[Bass Ackward]

Somehow, gas must have passed the case and blew upward from the breechblock. The bottom of the scope and mount is sooty as well but, appears unharmed.
Of the last 4 cases involved, one (I believe this to be the first) was clean and bright. The last 3 were progressively dirtier, with the last showing a lot of soot to just below the cannalure. I would be most intrested and appreciative to anyone who could shed some light on this. -JDL


JDL,

What is on your case is in your chamber. As that soot builds up, it takes more pressure to seal it. So more pressure leaks out or bleeds off.

My guess is that you were getting progressively less seal and then maybe you had a mild primer that just pushed the bullet into the throat where it jammed and as the rest of the powder ignited, the gas took the path of least resistance. Back.

You have to keep chambers clean. And I am becoming more and more a believer in compression by filler as I read more and more of this kind of thing.

[45 2.1]

What is the boolit alloy and hardness? What size is the patched bullet?

[Bass Ackward]

JDL,

Sorry.

The most important conclusion is one that I failed to mention and that is thank God you are alright.

And what is strange is that playing around with a computer program that will go unnamed, it appears that you were in the 35k to 40k area. The seal may not have been perfect, but it shouldn't have been like that either.

[45 2.1]

Bass-

Sometimes you just got to know what is wrong, and thats something your computer program won't tell you.

[JDL]

45 2.1,
Alloy is close to pure lead at about 5.25 BHN. Core girth is .450" with patched diameter of .4562". As usual, I lubed the patch with a mixture of Parafin Jelly and Beeswax; CCI 200 primers were the ignighter in a W-W case. The only thing I did different was not clean the primer pockets from the privious fireing, but they were all seated slightly below flush with the case head.
Bass Ackward,
Thanks for the pressure info. I was guessing somewhere slightly below the 30k neighborhood.
I tell you fellers, this has me kinda concerned as I've been at this game for 40 years and I don't like something happening I can't explain. I have shot this load for a long time so it wasn't under development. It's also strange that the soot on the case is only back about 1/3 of the way back from the mouth with the rest clean. I was going to shoot some RCBS 45-300 out of w/w and 43 grains of IMR-4198, another established load in my rifle, but got cold feet. I hate sticking my nose right up into several thousand pounds of pressure when I don't know what's going on! Thanks much and keep thinking. -JDL

[Bass Ackward]

Bass-

Sometimes you just got to know what is wrong, and thats something your computer program won't tell you.


Bob,

Here is a case where you may never know what is wrong whether you use a computer, a reloading manual, or aslide rule. Typically, the first step to finding what went wrong is to understand what "right" was supposed to be. That's what the computer did for me.

Since I frequently operate in this same velocity / pressure range with a case design that is somewhat similar, I wanted to compare apples to apples to understand if I might be vulnerable to a similar occurance.

Normally, one would not consider a load occupying the percentage of the case that it does, running at the pressure that it was supposed to be, to be one susceptable to what happened.

[45 2.1]

Alloy is close to pure lead at about 5.25 BHN. Core girth is .450" with patched diameter of .4562". As usual, I lubed the patch with a mixture of Parafin Jelly and Beeswax; CCI 200 primers were the ignighter in a W-W case. The only thing I did different was not clean the primer pockets from the privious fireing, but they were all seated slightly below flush with the case head.JDL

I'm shooting about that weight bullet also. I would suggest you try the following. Size the bare bullet to 0.454", then patch with onionskin. Try SR 4759 (not 4756) starting at 24 gr. and working up to 30 gr. That should cure any problems you have. Your patched diameter was undersize for smokeless. It should have slugged up sooner, but from your post, it wasn't doing it with the 4198. Try to firmly touch patch to throat and see if you can crimp lightly into a lube groove where the patch shrinks into the boolit if one is there on your bullet. Lymans 457191 works very well for this. You didn't say if you crimped your load, but with that slower powder, it could well be most of the problem along with the undersize patched bullet.

[45 2.1]

Bob,

Here is a case where you may never know what is wrong whether you use a computer, a reloading manual, or aslide rule. Typically, the first step to finding what went wrong is to understand what "right" was supposed to be. That's what the computer did for me.

Since I frequently operate in this same velocity / pressure range with a case design that is somewhat similar, I wanted to compare apples to apples to understand if I might be vulnerable to a similar occurance.

Normally, one would not consider a load occupying the percentage of the case that it does, running at the pressure that it was supposed to be, to be one susceptable to what happened.

Bass-
I'm not going to argue the case. The only thing you have to do is let that GREAT PROGRAM tell us what was wrong if you want to prove it to everybody, otherwise I don't want to here it.

[Bass Ackward]

JD,

The thing that has always bothered me about paper patching is that if something went wrong with the paper patch, I have a pure lead slug without any viable lube sourse that is going to throw enourmous pressure.

I don't play with ultra fast powders that may cause ignition problems and SEE. I don't put wads directly on top of powder without compression even though thousands of rounds may be shot that way because someone ringed a chamber. And thus I don't paper patch. If I did, I would want a bullet with lube under it to prevent what I suspect happened to you.

[Bass Ackward]

Bass-
I'm not going to argue the case. The only thing you have to do is let that GREAT PROGRAM tell us what was wrong if you want to prove it to everybody, otherwise I don't want to here it.


Bob,

I think I undestand you 100%.

But nothing presented on this board is proved at all. Any computer program is simply an extension of this board. You get information here when you ask a question. You still have to screen it and see if it makes sence based upon your experiences or just plain common sence.

The computer program is no different when you ask it for information except that it has no opinion, adjenda, or biases. The result has to be screened just the same. Some programs are more effective than others, I think this is one is pretty good.

And whether you like it or not your choice to not hear it is 100% under your control. Use it, or get over it.

JD,

You are welcome. I am no better at guessing pressures than you are. The range was strictly aguess on normal seating depths I had with a lever. Obviuosly, if you have no throat and had to seat way deeper, then this could be another 7000 psi higher.

[45 2.1]

Bob,I think I undestand you 100%.

You don't and have no idea either.

But nothing presented on this board is proved at all. Any computer program is simply an extension of this board. You get information here when you ask a question. You still have to screen it and see if it makes sence based upon your experiences or just plain common sence.

You have to have enough knowledge too screen something, not conjecture.

And whether you like it or not your choice to not hear it is 100% under your control. Use it, or get over it.

I choose to ignore the half truths I hear, but will say something when I here BS.

[JDL]

I understand what your're saying about the pressure build-up, but shouldn't the case show signs of high pressure? I was discussing this with a firend last night and he asked if maybe some of the patch of a priviously fired round was left in the bore? I dunno, but the barrel isn't damaged nor do the cases show anything out of the ordinary.
The chamber demintions are as follows: Throat =.4605" X .148"; bore= .450" lands, .456" grooves

The boolit is made by a swageing process. The core is poured in an adjustable mold, then ran through my swaging die to profile a .4505" projectile of any chosen weight. I then use .0025" onionskin paper to patch and, when dry, it mics .4562". The OAL was established by using firm thumb pressure to seat, with the breechblock completing the seating process. When ejecting an unfired round, the lands and forcing cone imprints can be seen on the paper. I have been using this process since 1992 and this is my first faux pas with it. -JDL

[Trailblazer]

Is the brass work hardened from several firings and resizings and is not sealing because it is to hard? Maybe annealing is in order?

[45 2.1]

The chamber demintions are as follows: Throat =.4605" X .148"; bore= .450" lands, .456" grooves
The boolit is made by a swageing process. The core is poured in an adjustable mold, then ran through my swaging die to profile a .4505" projectile of any chosen weight. -JDL

You have a swaging setup that is neither right for black or smokeless. For smokeless, you will get the best accuracy patching to throat diameter. The unpatched boolit should be at bore diameter or more depending on your throat diameter. In your case I would use thicker patching paper, something about 0.0028" (try 11 to 16 pound paper to find what gives you that) thick to get a patched diameter of 0.460". I would also go to a powder that lights easier since you have no place to crimp to give increased resistance. Perhaps your only problem was a bad batch of powder.

[44man]

That sounds like a boolit way too small in diameter for the bore and the case never expanded to seal. I would say the pressure was so low it was like leaving the case out of the chamber. Sort of like shooting loads with no powder, just a primer where the primer backs out and the cases get real dirty, as in those rubber bullets I shoot in the basement. You just pushed everything out and pressure never developed.
My Browning's bore is .450X.4595 and I use boolits from .460 to .462. If I push a .458 or .459 boolit through the bore, there will be no marks on it from the bottoms of the grooves.
.4562 sounds way too small and I would make a casting of the throat and bore to measure it again. Browning says their bores are .450X.458 but most I see are larger.

[grumble]

I had a similar thing happen in my old Turk. I still don't know what caused the "woosh," but I assumed at the time (and still do) that it was something in the powder that caused it to burn extra slow, maybe a bit of grease or oil in the case? A clump of powder that didn't have enough surface area to burn as quickly as it should?

I dunno, but it never happened again, so I just go merrily on my way, enjoying my own ignorance. <G>

[Bass Ackward]

When ejecting an unfired round, the lands and forcing cone imprints can be seen on the paper. I have been using this process since 1992 and this is my first faux pas with it. -JDL


JDL,

I have been around when a 223 and a 257 WBY let go. The case ruptured on the 223 just ahead of the bolt and you saw nothing, but felt hot gas while the bullet exited. The 257 WBY blew instantly with the bullet still in the bore and did show orange as the powder burned in the air. Playing CSI, you said you saw an orange flash. Then the powder was burning out where it could be seen. This tends to indicate a slow moving or stopped projectile. IF the bullet had been going up the bore at that time, the weight of the powder should have carried up the bore to burn. Unless it was a dark day. Was it?

Did the slug hit paper?

[44man]

If the boolit stayed in the bore and high pressure was created, the case would have been destroyed and maybe the rifle also. He says the case was not damaged and was just dirty.

[w30wcf]

JDL,

No doubt, the case did not seal in the chamber, thus allowing some of the powder gases to get by with the result that you described. It sounds to me like the paper patch or a portion of it blew out allowing the partially unsupported case mouth to deflect slightly inward allowing some pressure escape between the case and chamber. As a result, the powder did not burn well, giving the bright flash.

Two things I would do is increase the bullet diameter and definitely anneal the case necks as was mentioned. The faster powder suggested would also be more suited to the bullet weight / velocity range that you are loading to.

Good luck,
w30wcf

[JDL]

The day was nice and bright sun and the boolit hit the target. I believe, after digesting all the discussion and possibilities, thay you are correct, in that somehow a little gas got back into the chamber before the case sealed, then when it obturated, it squirted back out of the breech. Perhaps the patch partially or wholly failed, but whatever, it was rather exciting, although I hope to never experience it again.

I worked up enough courage this afternoon to shoot some of the RCBS 45-300 FN I had loaded up with 43 grains of the same IMR 4198. Everything went without a hitch, accuracy is back, and the cases were cleaner without any unburned powder left in the barrel or cases. -JDL

[Frank46]

JDL, first off I would say that your bullet was too small. Paper patch bullets should be at least groove diameter. Maybe your cases do require annealing. I was shooting some 5744
in my ruger #1 with the gas checked lyman bullet. Very sooty cases even with their recommended loads. Accuracy was not what I would have expected to be. I once had some INDEP 7.5x55 swiss ammo. Every case was covered with soot from case neck to base of case including the extractor groove. Lousy ammo. The smell was like burnt rubber. Either the powder was not being properly ignited, or was not the right powder to begin with. This ammo was loaded w/j bullets. I believe the INDEP ammo was made in portugal. Frank

[Pilgrim]

Did you happen to notice any reduction in the recoil? If not, I wouldn't be too surprised as the gas puffing in your face would be a bit more than disconcerting {:o). I once had a .22 Hornet case show ridiculous pressure with a greatly expanded primer pocket, etc. Not sure what happened then either! All of the other cases were normal...the powder charge was weighed, and filled 80%+ of the case so a double charge was impossible...no other powder could have been used as I ALWAYS empty my powder measure and remove all powder from my bench when done with it, and I only allow one powder can on my bench when reloading any given load. Anyway...is it possible that somehow you wound up with a lighter charge than expected? If the pressure wasn't high enough to seal the case in the chamber, but was high enough to push the bullet out of the case, then it may be that the path of least resistance to the gases was around the case instead of out the barrel. FWIW.......Pilgrim

[JDL]

Did you happen to notice any reduction in the recoil?
Anyway...is it possible that somehow you wound up with a lighter charge than expected? If the pressure wasn't high enough to seal the case in the chamber, but was high enough to push the bullet out of the case, then it may be that the path of least resistance to the gases was around the case instead of out the barrel. FWIW.......Pilgrim

I didn't notice any reduction in the recoil department and the bullet hit at about the same poi as the others. I hand weighed each of the 4 charges and visually noted that all were consistant. I do believe there must have been a time delay of short duration to let some gas leak into the chamber before obturation of the case sealed the chamber. The "WHY" is what I'm concerned about, although I'll probably never really know. My speculation, along with some here, is the light weight of the boolit, along with the slower burning 4198 worked to create this condition and it scared the bejabbers out of me. Thankfully, no harm to my equiptment or to me. -JDL