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Safe or Not safe?
Mr. Gunz
Member Posts: 1,621 ✭✭✭
Now I know this is not a good practice, its just that the best of my curosity has got me.
If I loaded 10 grains of Unique in a 308 case with a 130 grain bullet on top of all that being lit by a CCI Primer, would it be safe...I know the velocitys would be nill and such but I just have a curosity. Trust me I won't try it, if I did I would use a rest and a 10 foot string.
If I loaded 10 grains of Unique in a 308 case with a 130 grain bullet on top of all that being lit by a CCI Primer, would it be safe...I know the velocitys would be nill and such but I just have a curosity. Trust me I won't try it, if I did I would use a rest and a 10 foot string.
Comments
A minimal amount of powder in a large case will not be dangerous. What you described is in fact how to get a bullet out of the middle of your barrel because you missed powdering a case and the primer sent it half way up the barrel. I have used normal rifle powder to do that. DO NOT fill a case half or 1/4 full of Unique. That would be way too much pressure too fast.
Somewhere between minimal amounts of powder that would not effect anything and starting loads is a point you will get to that the powder can 'reversely ignite' or detonate. This happens when the body of powder is below the primer hole enough that the primer can ignite the front of the charge as well as the back. What you have then is rather than the powder body burning forward and pushing the bullet out, powder burn to the middle and an explosion occurs. With enough powder this can take your action apart. With minimal amounts of powder there is not enough pressure working from back to front and front to back at the same time to cause the explosion. Never use more than 1/4 charge of powder to remove a stuck bullet from an action. The load you suggest is about the maximum you should use if you ever have to do this.
Sandwarrior: First, are you recommending that bullets stuck part way down a barrel can be removed by loading and firing a cartridge with a partial charge of powder and no projectile? If so please provide a more complete explanation. Second, can you provide more information or references for your explanation of "reverse ignite" or detonation of partial charges, please?
Thank you
Tim
The load you mention seems safe. The engraving pressures are a lot higher with jacketed bullets but that load is on the low side.
Lyman lists the #311334 187 grain cast bullet for the .308 at 9.5 to 14.5 grains of Unique. Max load is 1680 FPS at 38,600 CUP.
Sorry for not clarifying. Removing a bullet from the middle of your barrel of a rifle, you will NOT use another projectile. This does not work in a revolver or any blowback type semi auto as the pressure either blows out between the cylinder and barrel or pushes the slide back and releases the pressure.
The detonation theory goes back to my military days of demolitions training. C4 being the primary medium. The principle is that if opposite corners of a quantity of explosive substance are detonated(in our case contained gunpowder being ignited)the shock wave when the two meet will move directly outward from the point of meeting. This is how we were taught to cut trees, cement blocks, etc. Now as described in the previous post the gunpowder would be the explosive medium. It would not work in an external situation like C4 would but it being contained in the small chamber would work much the same way. The front of the powder charge is ignited as well as the entire top of the powder charge. As noted rather than burn from rear to front progressively it could(not always) burn from the front to the rear. Without the bullet moving as with normal progressive powder burn pressure builds excessively and the powder burns more rapidly. From the main point of ignition, a shockwave is sent in each direction of burn. The largest shockwave goes in the direction of the most substance to burn. The other possibility is that as the entire top of the powder body is ignited the shockwave goes laterally, that is to say across the chamber not out the end of it. I don't have the old FM number but the new manual is FM-5-250. It won't be published though for six months. Anyhow, that is the principal on which detonation or 'reverse ignition' works. We want it to happen in certain places, we don't want it to happen in our chamber. I hope that clarifies some.
A note here: If you do not feel comfortable doing this let your gunsmith handle it. Also, This won't work if you have peened the bullet into your barrel with a cleaning rod. I'm saying this because I did this with a rifle and I have it on VERY good authority that this is the way to clear a barrel.
Some experts can exlain things like that, and the novice should just take his word. The novice (not a put down) should not try and improvise or modify it based on a desription of the process that may not be physically correct.
A novice becomes an expert by following the path experts use to become experts. It isn't easy. I involves a great deal of drive, study, research and devotion.
A novice becomes something else if he tries to work as an expert while he is still a novice.
There is a legal phrase "Ignorance of the law does not excuse your breaking it" . The same is true of the laws of physics, except that the penalties can be, uh , really bad.
I don't want to start an argument but the information given is the way I was trained by the U.S. Army. That is what was taught to me and that is how I passed the class. If you feel that what I described is not how it works, do explain.
Now, I don't have a set of tranducers in there to see exactly where the shockwaves go. But when you have detonation what I explained is pretty much what happens. Again, your theory would be welcome. I do agree with you that in order to learn what is safe and not safe, one must spend some time in a lab environment to see the actual principles at work. Even when these principles are taken to the field there are factors that make it unsafe. Ones level of awareness of the factors can lead to saving your life or leading to disaster.
Also, if you will note I did say that if you are not comfortable with the information, then do not use it. Take the question to a gunsmith, I will add, or an expert of your choice. I've been there and done that and I hae my face still to prove that I have not blown up a firearm in my face. When faced with problem I do get facts and parameters in which I can work. I don't hold a PH.D in explosives...but I don't find many of them out blowing up bridges either. I find Sergeants, Sp4's, P.O 1st Class's doing it. Because they understand it pretty much the way I do because their training is probably very similar.
Temblor,
Thanks for the humor. (I hope you were making light of it) It's pretty much the same principle, big or small. I thought I had answered the original question, that 10 gr. of unique in a .308 case is okay. I did get off track though, and I'll look to stick to the question at hand...at least in the near future while I have my mind on a leash. Think about it though, 10 gr. of unique...bridge blown up...Macgyver would be proud.
Rustynail,
I mentioned it...thought it was a good point to bring out at the time....I say at the time as when going off track you think your right on?
For the record (FWIW) smokeless powder is a propellent -- not an explosive - And I've never heard of anyone blowing up bridges, etc. with 10 grains of Unique [:0][:D].
Strictly intended to be good natured ribbing, but you know I forgot to consider Macgyver [:0]. I could be wrong about that bridge [;)].