rifle detonation again

[Don McDowell]

30% over saami would barely get you into the so called "marlin" loads listed in most load manuals.
But yes no amount of proof testing is going to keep some ardent ballistics expert from loading with a powder in a manner in which the loading manuals tell you not to do..

[Martini2]

As mentioned the incident is regrettable and thanks to the photos provided some sense for possible cause(s) are coming to light. I'd refer interest to book "Down Range Data" by William T. Falin , Jr. Not that you have to agree with this gentleman's entire ideas but here are some facts. Mr Falin was the Chief ballistician at Accurate Arms. He was "solely responsible for XMR-5744 becoming a standard in that line". pg. 23 "Thus , I had the the opportunity to establish strict performance criteria during product development." " My goal was to produce a smokeless propellant that was as position insensitive as is feasible". The above quotes are from Mr. Falin's text and everyone is recommended to read same. He went on in other chapters to advocate loads WITHOUT wads and particularly "Dacron fiberfill" for one. The amount of 5744 necessary to replicate Black Powder velocity
is 25 grains or less. So indeed a double load could fit in 45-70 case.
It would be very interesting in ruptured barrel's case if bore has one or two slugs in residence. I.E. did shootest have misfire followed by second round? Lastly, this rifles manufacturer as well as other Italian imports have a very specific printed disclaimer packed with their rifles. Essentially NO HAND LOADS are allowed and use of same voids warrantee. However print does point to factory ammunition. Therefore their product should be proofed for those pressure specs.

[Kevin Alexander]

In my 15 years of shooting these rifles I've only fired them with black powder. I have no interest in shooting smokeless in them. I'm just guessing, but I bet there's a good reason the NRA matches don't allow duplex loads anymore. Of course the attendance to their matches have been declining since that decision was made. To me there would be nothing more exiting than pulling up to the match and seeing 600 plus shooting, visiting, selling, trading and just living life.

There are a lot of guys reloading that don't know what they are doing. They just hear parts of reloading conversations or read a part of the reloading manual, or get into a rush reloading at the last minute to get to the next shoot.

I wish at these big long range matches it was black powder only, but sadly that would result in the attendance going from 600 to probably 100 and no body wants that, especially the people who are selling items and making money at these events. Safety needs to be the main concern at all matches. If repeated accidents happen then it needs to be looked into and fixed somehow. I agree we can't fix stupid, but we can maybe chip away at it.

My 2 cents.

[Lumpy Grits]

30% over saami would barely get you into the so called "marlin" loads listed in most load manuals.
But yes no amount of proof testing is going to keep some ardent ballistics expert from loading with a powder in a manner in which the loading manuals tell you not to do..

Agree, and not know'n what level of SAAMI loads they refer to either, doesn't help much.
I sure don't fault the gun here.
Gary

[Don McDowell]

The amount of 5744 necessary to replicate Black Powder velocity
is 25 grains or less. So indeed a double load could fit in 45-70 case.
.

I'm not particularly interested in defending smokeless powder used in a blackpowder designed case/firearm. I am interested in actual fact, and not to wild about somewhat bogus info being posted.
So with that said, even a "ruger" only charge drawn from one of several loading manuals with a 500 gr bullet runs at or around 38 grs of 5744, that charge amount fills a 45-70 case to within 1/4 inch or less of the base of most any 480-540 gr grease groove bullet. So it becomes quite apparent that when someone is using the often recommended 25 gr charge in a 45-70 a "double" charge isn't going to fit without even the least observant of reloader discovering the over charge when seating the bullet.
This incident was most likely caused by the use of a wad to hold the powder down over the primer. Something that all the loading manuals, and the powder manufacturer says not to do. The pressure spike caused by that, just so happens to take place at the thinnest portion of that particular rifles barrel.

[Martini2]

Don, I'm also not interested in touting "bogus info" The 25 gr mentioned may potentially be 50%+ case fill granted. But it is within range of typical 45-70 loads of up to 28 grs. listed in some data which is what was on this old geezer's mind. That aside please is there any factual info yet on the actual load used in mishap. Just a break down of another cartridge from the unfortunate person's loading box, at proper time of course ?
I do not load 5744 in 45-70s myself but sought Falin's info for the ballistic tables which have helped predict useful velocity VS sight correction data. I have employed other smokeless loads for decades in complete safely however. I agree there is null rewards in trying to hotrod rifles in these large for caliber BP cases. Recoil alone is a self limiter for me so the same velocity in 45-70 as black powder with accuracy is the goal here. An underlying fact here is reloading cartridges requires common sense, knowledge and good safe practices.

[Tom Herman]

Thanks for all of the pictures, and the discussion.
Does anyone know how pressure and rise/fall time of 5744 compare to that of FF black powder?

[Premod70]

Sorry for the late reply but after reading this thread I would like to add a little of my experiences with the 5744 powder. First I shoot smokeless powders in my Browning BPCR in 40/65 with the original chamber and lead. At the time I bought the rifle I used SR 4759 loaded with a wad made from target paper placed on top of the powder; I got better accuracy with the wad than without. When SR 4759 played out I switched to 5744 and tried various ways of wad placements; fore, act, in between and without. Again I got more consistent accuracy with the wad bearing on the powder. The one thing I noticed was the rifle sounded different when the bullet was seated off the rifling compared to when it was pressed into them. Having previously read of 5744 being used as the powder in a rifle that exploded and the discussion that followed I have for my own satisfaction began to reload my rounds with a wad on the powder with the bullet seated out into the lands. My thinking is the jump on a deep seated bullet moves to the rifling and momentarily stops when the rifle is first fired and the powder burn is changed by the bullet stopping however slightly. With the bullet in the rifling the powder does not meet an "obstruction" and go haywire in it's burn rate. Just my humble opinion but I think the problem is not on the wad in itself rather the wad and the bullet off the riflings together jointly contribute to the problem. Please feel free to add your thoughts as I am here to learn.

[Lumpy Grits]

Sorry for the late reply but after reading this thread I would like to add a little of my experiences with the 5744 powder. First I shoot smokeless powders in my Browning BPCR in 40/65 with the original chamber and lead. At the time I bought the rifle I used SR 4759 loaded with a wad made from target paper placed on top of the powder; I got better accuracy with the wad than without. When SR 4759 played out I switched to 5744 and tried various ways of wad placements; fore, act, in between and without. Again I got more consistent accuracy with the wad bearing on the powder. The one thing I noticed was the rifle sounded different when the bullet was seated off the rifling compared to when it was pressed into them. Having previously read of 5744 being used as the powder in a rifle that exploded and the discussion that followed I have for my own satisfaction began to reload my rounds with a wad on the powder with the bullet seated out into the lands. My thinking is the jump on a deep seated bullet moves to the rifling and momentarily stops when the rifle is first fired and the powder burn is changed by the bullet stopping however slightly. With the bullet in the rifling the powder does not meet an "obstruction" and go haywire in it's burn rate. Just my humble opinion but I think the problem is not on the wad in itself rather the wad and the bullet off the riflings together jointly contribute to the problem. Please feel free to add your thoughts as I am here to learn.

WELCOME
Don't agree, in the last issue at the Q. IIRC-It was a cast rec'r built for BP only and the shooter was load'n smokeless. I also seem to recall that rec'r was not built for the caliber that was be'n fired.
IMHO-It was a 'overcharge' that lead to the explosion.
With a lead bullet-That 'jump' doesn't really spike the psi much.
Gary

[Don McDowell]

The blowup in the situation was an imported sharps with a rung chamber. My guess is the blowup probably had more to do with what ever condition rung the chamber in the first place.
Altho there is a ton of nonsense out there about loading smokeless powders, and playing safe and staying within saami spec for the cartridge the rifle is chambered in is always the correct way to go.
Following manufacturers recommendations is always proper.
And never loose sight of the fact that if you are the one with a gun malfunction and someone else gets hurt, the trial lawyers will uncover anything and everything they can about your previous loading experiences and any internet load recommendations that are beyond manufacturer/saami spec, could cost you everything you ever had and anything you could ever hope to have in the future.. Not to mention the mental anguish of knowing it was at your hand that someone else got hurt, disfigured or killed.