Re: Reloading Questions regarding Max loads
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Roger after posting a picture like that more of an explanation may be necessary.
I didn't see any blood or brains impregnated in the metal or wood so I'd guess whoever shot that lived and has a new found respect for handloading? [img]/ubbthreads/images/graemlins/confused.gif[/img]
Man, that thing is Junk now!!
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Okay, here it is. I put my long years of criminal investigation to work after the rifle blew and figured out what went wrong. There were some easy scapegoats that I could have blamed. The powder measure. The powder. The rifle. The first objective was to be totally honest with myself. In a situation like this, itís easy to lie to oneself. The second, was to fix blame where blame belonged, even if I was at fault. If I didnít, I wouldnít learn a thing.
If you are familiar with my past posts on this site, or on other sites, you know that I am conservative when it comes to hand loading. I donít push the envelope on velocity. I have a set of procedures that I developed over a period of 40 years + of hand loading. They have served me well, and safely.
First, and most important, I check, double check, and triple check my loads at every step of the process. A few years ago I had a Lady Bug experience that proved that if anything can go wrong, it will go wrong. Long story made short, a Lady Bug crawled up on the back side of my RCBS 1010 balance beam while I was out shooting the last 3 rounds I loaded. The next charge I had to trickle a lot of powder in the pan, so much more that when I dumped the powder in the case, it filled it to the top, and then some. I went looking for a problem and found the Lady Bug. Lesson learned.
Another rule I follow is to never reload when Iím distracted.
A third rule, is to be more careful than normal when I try new components.
Another rule is to weigh every charge and visually check every charge in the case before seating the bullet to make sure the levels are all the same.
Common sense stuff.
Sunday, August 9, I spent a good portion of the afternoon rearranging my loading bench. I built the bench to my specifications. Itís higher than normal so I can stand while loading without having to stoop with the neck and back pain that brings on. A few days ago I assembled a store bought workbench next to my home made job. The rearranging consisted of sorting things and moving them to the new bench. Over the years my custom built bench evolved into a all purpose bench, something I didnít want it to be. The new bench is for everything that isnít for hand loading, like my mini lath, which squatted on my loading bench when I bought it a few months ago.
I finished early and decided to get in a little shooting. I have a new Winchester Model 270 Winchester Stainless Featherweight that I was lucky enough to pick up a few weeks ago, one of the last on the market. I needed to develop a load for this rifle. I decided to dial the scope to shoot center on paper at 25 yards using a reduced load of IMR SR 4759. The Speer manual lists 20 grains as the starting load, at around 1700 fps. I use a Hornady powder measure to throw the initial charge, then finish the charge on a RCBS 1010 scale trickling the charge to the weight I want.
Since I was only going to load 6 rounds, I decided to dispense with weighing each individual charge. I decided to dial in the powder measure and charge each case from the powder measure. In something like 40 years of hand loading, I have never done this with a bottle neck case. I had the drop tube for larger calibers in place, and have had it in place since I purchased the powder measure 20, maybe as long as 30 years or more years ago. The large caliber drop tube worked fine for weighing and adjusting the powder measure to throw a charge of 20 grains, but it didnít work very well for charging the 270 casings. Powder spilled the first case I charged. I found the bottle neck drop tube in my loading box, new and unused, screwed it in, charged the 6 cases, and seated the bullets. A visual check of the powder in the case proved useless; 20 grains doesnít show up very well at the bottom of a 270 case. You can see it if you get the light right, but you canít judge how deep it is.
I fired the first round. No problem.
The second round demolished the rifle. I mean the sucker is toast for time and eternity. No salvage value whatsoever.
The force of the explosion split the stock from just in front of the trigger guard on the right side to the middle of the forearm. There is a second split from the front action screw that measures 3 inches down the centerline. The left side of the stock has an irregular break from in front of the action running forward and down into the checkering. In other words, the force of the blast broke the stock into 3 pieces.
The rear of the stock split backward from each side of the trigger guard past the pistol grip. These breaks extend upward through the stock. The bottom breaks extend back 4 inches toward the recoil pad. These break are gaping breaks. The top breaks extend back 4.5 inches and are also gaping, but less so than the bottom breaks.
The claw extractor bowed away from the bolt in a circular pattern with a full Ĺ inch radius. The ring holding the extractor to the bolt peeled back and up. The bolt wonít budge even a fraction of an inch even when hammered.
The one piece bottom metal bows out with a radius of .75 inches. The Bottom metal severed on both sides with jagged breaks and also bows down and out. The unloading plate bows down and out with a radius of 3/8 of an inch.
The magazine bows on both sides with a ľ inch radius on both sides adding a total of Ĺ inch to the width of the magazine.
The magazine follower and spring blew out of the rifle. I found them on the ground. The follower had a significant downward bow with an estimated 4/16 radius.
Me, I have a black eye, literally and figuratively, and a cut forehead, preventable with safely glasses, which I didnít take the time to find and wear. A bit of bleeding. I was wearing hearing protection. I have a welt across the inside of my right arm where the stock slapped me when it split. Same with my thumb. Iím right handed, but shoot left handed off the bench or with support. I was shooting standing up resting the rifle against the door jamb that lead to my back yard from my garage.
So what went wrong?
The Rifle Autopsy:
I checked all of my settings. The scale checked out slightly heavy. I adjusting my powder measure for 20 grains. When I threw a charge and weighed it, the charge balanced slightly over the balance line. It was no more than Ĺ grain over 20 grains. On a start charge I would rather be slightly over, than slightly under. I was slightly over, but not enough to do the damage inflicted.
I had 4 unfired shells left. After I cleaned up the blood, I pulled the bullets and weighed the charges,.
The first casing I loaded had a 10.2 grain charge.
The second, 9.4 grains.
The third, 11.6 grains.
The fourth, 15.1 grains.
Thatís a total of 46.3 grains.
The total accumulated charges for these 4 rounds should have added up to something like 80 to 82 grains.
At 20.5 grains per charge for 6 rounds, I dispensed a bit more than 23.0 grains.
I was missing 76.7 grains of powder. No matter how I divided the possible powder charges for the 2 rounds I fired, it came out to a scary number.
When I loaded the six rounds, I put them in a specific order in my loading block; back to front in a straight line so the charge for the first casing above was the first charge thrown, and the second charge for the second casing. The same with 3 and 4. I kept them in order as I pulled the bullets and weighed the individual charges.
When I was ready to shoot the two fated rounds, I took the number 6 load because it was the first up in the loading block, put it in the magazine, and carried the number 5 load to the door where I put it on my new bench to wait itís turn. The number 5 round is the one that blew.
When I initially set up the powder measure, I threw pan after pan of powder to check the weight of the charge my powder measure was throwing. I threw at least 2 dozen charges. While there was a slight variation, the variation wasnít enough to turn my rifle into a grenade.
After the blowup, I took 6 casings and charged them directly from the powder measure duplicating what I did with the 6 deadly rounds.
The powder charges would fall through the drop tube and into my scale pan, but would stick in the drop tube when I used a case. I didnít weigh each charge that came out of the case that I charged during this experiment. I dropped each charge on the a sheet of white paper and compared the piles. Very little powder cleared the drop tube for charge 1, 2, 3, and 4. The drop tube overloaded on charge 5 and dropped all of the accumulated powder into the case. I repeated the experiment a dozen times. Sometimes the powder dropped and properly charged the cases 6 times in a row. But most of the time, it didnít, and then it over charged either case #4 or #5, with 5 being the favorite. I did bang the charging hammer down several times to shake the powder loose, just like I pound it in the up position so I get the full volume.
The drop tube worked fine when I was holding the powder pan under it, but something about the case neck up in the tube made it hang up. I pulled the drop tube and rigged up a way that I could drop powder down the drop tube to see what would happen. I couldnít see why the powder would hang up with a case inserted, but it did.
It happened. A new rifle ruined on the on the second shot. Time to place the blame.
ME. I did it. Nobody to blame but me.
First, I an unrelated problem distracted me, a problem I was trying to solve, a decision I had to make. My full mind wasnít on what I was doing.
Second, I changed my standard practice which made other standard practices I developed and used over the years useless, namely, a visual inspection of the powder charge in each case before seating a bullet. If I couldnít do a visual inspection, had I not been distracted, I might have, and more than likely would have, weigh each charge, as has been my standard practice. I know what 58 grains of RL 22 looks like in a 270 Winchester case. I know what 73.5 grains of RL 22 looks like in a 300 Winchester Magnum case. I donít know, and canít know, what 20 grains of IMR SR 4759 looks like in a case. Itís too deep and too dark down that casing to get an accurate estimate. And I had never used this powder, so there was nothing to compare it with, even if I could see down in the case.
Third, I used a new piece of equipment, namely the drop tube, without a good and accurate trial run before I pulled the trigger. The end result shows every time I look in the mirror.
My mistakes in short:
No eye protection.
A new powder I wasnít familiar with.
Equipment I had never used, namely the bottleneck drop tube.
Deviating from standard practice so I would catch mistakes.
Not just poor quality control, but no quality control.
I was stupid and careless and I paid the price with a good rifle, and almost with my eyes, not to mention the humiliation.
A few days after the blow up, I did some experiments with the drop tube and the same powder. A simple solution: air in the case has to go somewhere. When I sealed the drop tube with the neck of the case, an easy thing to do, the powder bridged almost every time.