ideal rate of twist (MLP firearms and shooting thread)

Discussion in 'The Backstage' started by Frogfur, Jul 4, 2017.

  1. Frogfur

    Frogfur Senior Member

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    Easiest way is to look down the barrel and pull the trigger..if you get a powder burn on your lips you didn't burn it all !
     
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  2. Frogfur

    Frogfur Senior Member

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    Lol..thats why i explained how to figure out load density. Once you know that, then you research the different powders that come as close as possible to filling your case with a propellent that will provide the velocities and pressures that are acceptable, and produce good accuracy.
     
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  3. BlankinLoud

    BlankinLoud Senior Member

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    :hmm: Like this??

    [​IMG]
     
  4. BlankinLoud

    BlankinLoud Senior Member

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    My understanding of what you just said is......similar line of thinking to black powder cartridge shooters using a filler such as starch or cream of wheat to make sure there's no void space in the load.

    Only with modern propellant, you don't use a filler, you use a propellant with a density that causes your desired charge to completely fill the case.
     
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  5. Frogfur

    Frogfur Senior Member

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    And as you know, true black powder can be set off by static electricty. That can out in the garage ? Been on the metal shelf the last 10 years ? Grab it and slide across that shelf and its better than sex! But the way powder canisters are produced, usually by the pound, 7000 grains ? I think, but they burst if ignighted which imeadiately qualifies you as legally blind most modetn defination.
    but propellents burn. They don't explode unless contained. Then you got a bomb. That is why they come in the packaging they do.

    In a sense, yes. But in reality compressed charges are seldom aquired but are possible, but most certainly blow allot out the barrel too.

    The main limiting factor of course is overall bullet length which Rob covered excellent earlier today.

    The longer the bullet the less case capasity due to overall cartridge length restrictions.
     
    Last edited: Jul 5, 2017
  6. Who

    Who are you? Who who who who.... Premium Member

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    I stopped following the thread. Sorry.

    But while reading the thread, I came across this. I want one. I think I might need to get one.

    Even though I don't even go shooting anymore.

    NY legal. AR mags. 5 lbs and 26 inches long.
    [​IMG]
     
  7. Malikon

    Malikon 仮面ライダー V.I.P. Member

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    that's...what? Where do you even grab onto? I don't see a handle or a place for your thumb to wrap around. It sort of looks like a toy?
     
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  8. S_G_D

    S_G_D Senior Member

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    This may be my favorite gun thread.

    History, explanations, smackdowns, physics.... and I don't know jack about guns.
     
  9. BlankinLoud

    BlankinLoud Senior Member

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    Booyeah! I found a digital copy of Dr. Franklin W. Mann's The Bullet’s Flight from Powder to Target.

    If anyone else is interested it's actually available for free from Google Play books.
     
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  10. BlankinLoud

    BlankinLoud Senior Member

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    Bottom eject, meaning ambidextrous!!!! Since I can shoot a rifle with either hand, this would be great.

    I bet a Leaper's Bug Buster scope would be perfect for this thing.
     
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  11. Frogfur

    Frogfur Senior Member

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    Check out Six Guns, by Elmer Kieth, and rifles for big game a wealth of knowledge.
     
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  12. Roberteaux

    Roberteaux Alien Hominid V.I.P. Member

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    No, I make a lot of observations.

    You made such a statement approximately one month ago. IIRC, you also added your now-traditional pew-pew-pew crap along with the rest of it, though I might have conflated your shoulder-roll statement with another, more recent post you did in which you gave us another dose of your hackneyed onomatopoeia.

    But: if you're not interested in gun threads, and get sick of seeing others posting them, what are you doing in one to begin with? Do you think you'll have some sort of influence over site content by acting as you do? Why go around bugging people when you can simply just not bother with such threads at all?

    Think about it.

    Well, you seem to be only casually interested in the subject-- and I notice that the scads of other known firearms owners on this site haven't exactly flooded the thread with comments. So perhaps there are more like you out there, who simply are not interested enough to jump in. You ever think of that?

    I've noticed that the golf, motor-building, and carpentry crowd can go pretty deep as well-- especially the luthiers. But why not? Is there something bad about knowing a lot about a given subject? And who is the one who is to set the limits of another person's areas of expertise to begin with?

    The reason that we go into extreme detail in reloading is because there are physical factors that affect not just cartridge performance, but also safety. Sometimes the differences between a normally functioning round and a catastrophically malfunctioning round is measured in tenths of a grain of gunpowder, or thousandths of an inch of case length and so forth. Attention to very slight details is fully called for in the reloading field.

    Irrelevant. You're not a shot caller when it comes to site content-- this site doesn't exist simply to please you. Doesn't matter if you like gun threads or not.

    If it comes to where admin or staff tells us to knock off the gun talk, then we'll knock it off. Until then you're just gonna have to suffer, I think.

    I don't care if you're pro or anti guns.

    And it's not "zeal" that allows some of us to comment with depth and meaning in a given subject. Instead, it's actual know-how and experience. Meanwhile, you're only an outsider because you choose to feel that way. And then you enforce that status by means of your comportment.

    But that's all on you.

    If you haven't got much to contribute, then you haven't got much to contribute.

    Nobody cares, or thinks any more or less of you, simply because of your limited acumen when it comes to some subject at hand.

    I have been reloading metallic cartridges for rifles and handguns since about 1976. This was a good, long time and I was able to learn quite a bit about the subject by means of study and practice. The fact that you don't have the same grip on the subject as me doesn't make me feel somehow inherently superior to you. All it means to me is that this is not an area of expertise in your personal case. No big deal either way, so try not to take things so personally.

    The subject at hand in the OP was something that called for a detailed response. Doesn't matter to me whether or not this was information you could use or were interested in to begin with.

    Wasn't talking to you anyway.

    And nobody cares if you show in a gun thread or not. If you want to show and be cool, then I'm sure that everyone else would be cool too. But if you want to show just to rag on people, then expect others to get raggedy right back.

    Very simple formula. Not sure why so many can't seem to understand it.

    --R
     
    Last edited: Jul 5, 2017
  13. LtDave32

    LtDave32 Sua Sponte Super Mod Premium Member

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    I'd say you "pew-pew-pew'ed" it rather accurately, Rob. Nail on the head, in fact.
     
  14. Roberteaux

    Roberteaux Alien Hominid V.I.P. Member

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    Whoa! :shock:

    Thanks for the compliment, Larry-- but you know, my firearms niche has always seemed to be in the generalized field of reloading. I'm a "close enough for government work" marksman, and of course, I spent a long time as an M60 gunner... but that's about it

    As was apparently the case with Lt. Dave, all I did with firearms in the military was to learn to strip and reassemble weapons for cleaning and inspection. Also like Dave, I did learn to do that with more systems than those outside my MOS were exposed to... but I sure as hell wasn't an armorer.

    And while I'm at it: an armorer sure as hell ain't no gunsmith!

    Just so you know: that day that you, Harmony, and I spoke together on the phone was really something. I had a list of questions in my head-- don't know if you noticed how many I asked or not, because the flow of the conversation was so smooth and enjoyable.

    But as I said to Harmony while dialing you up, I meant to run a hose through your ear and into your brain, and to then go to work on siphoning. :laugh2:

    After the call, she told me how much she enjoyed speaking with you, and then asked how it all went for me. I looked at her, feeling slightly shocked and more or less elated, and my answer to her were these very words:

    "Dude! I talked with that guy for just two hours, and learned more about firearms in that one conversation than I have picked up elsewhere over the last three years!"

    (And yes, I really do sometimes refer to Harmony as "dude"... but I always noticed that she seems faintly amused when I do so and has yet to correct me about that)

    :D

    She smiled, but looked a little surprised herself. After receiving instruction from me on the rifle range, I think she might have thought that I knew more than I actually do. But really, there are huge gaps in my understanding of the overall field.

    I explained that as a gunsmith, you actually knew a whole lot more about the fine details of firearms mechanisms than I ever did, and went on to tell her you were capable of work that I wouldn't even dare to try myself. In some cases, I wouldn't even know where to start to begin with. Finally, I told her that it's also kind of rare to find a gunsmith so open about discussing their trade. I really appreciated it that you didn't hesitate to answer any question I might have. It was quite a treat!

    You are to me what a luthier who plays guitar is to somebody who just plays guitar.

    So don't you forget that, bro. :)

    --R :thumb:
     
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  15. Roberteaux

    Roberteaux Alien Hominid V.I.P. Member

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    :laugh2::laugh2::laugh2:

    Oh, be quiet! :rofl:

    --R :applause:
     
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  16. Roberteaux

    Roberteaux Alien Hominid V.I.P. Member

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    Well... so long as this thread has gone to sprawling, guess I'll talk about a couple of subjects that came up along the way...

    First, when it comes to the powder currently used in military cartridges:

    WC844 is indeed the powder of choice for US military cartridges of the 5.56mm type. About 90% of the powder used comes from a single plant, located in Crawfordville, Florida. The company that manufactures the stuff is known as St. Marks Powder Inc. The company itself is owned by General Dynamics.

    During the occasional production pinch, other companies will produce smaller lots of powder for military cartridges. However, it is most often the case that the powder needed for both the 5.56mm and 7.62mm military ammo (which are two different powders) comes from St. Marks.

    Florida, baby. :laugh2:

    WC844 is what is known as a "pull down powder". What this means is that the stuff is produced, tons at a time, but that different lots of the product feature slightly different characteristics when used in a rifle cartridge. We're mainly talking about rate of burn in confinement, volumetric gas production, and so forth. These details will vary from one lot of WC844 to the next, and these differences must be accounted for before the stuff is actually loaded into a cartridge.

    Once the powder has been produced, factory ballisticians will sample different lots and determine how much of the stuff to set the machines to dispense according to lot. Sometimes they blend lots. Once it's typified and documented, it goes to the Lake City ammo assembly plant in Independence, Missouri. Once there, they run checks on the stuff themselves, dial in their powder dispensers, hit the button, and let 'er rip until another lot of powder calls for an adjustment.

    Hodgdon markets a powder sold to reloaders that is known as H335. I use the stuff an awful lot myself. However, H335-- which is actually made by General Dynamics/St. Marks and sold on the civilian market by Hodgdon under license-- is not a pull down powder. Instead, it is what's known as a canister powder.

    The difference is only this: canister powders are made in much smaller lots, and so control over the burning characteristics of a batch is easier to accomplish. The short story is that canister powders are easier to use than pull down powders because you don't have to experiment with the powder at all before you can start loading it in earnest.

    Canister powders are far more consistent and predictable. One batch of the stuff varies not at all from the next batch with canister powders.

    I sometimes run into pull down WC844 at gun shows and the like. Sometimes the plant has a bit of an overrun, and they will turn around and let others bid on the stuff. These others then go forth and sell it to whoever seems to want it. Sometimes you'll see the stuff being hawked on milsurp sites:


    [​IMG]

    Again: this stuff is NOT precisely analogous to H335. Instead, it's easier to say that H335 represents the mathematical average of WC844 if you compare a hot load of WC844 to a milder one.

    And again: H335 is far more consistent. You always know what you're gonna get with it. It never changes.

    Case in point: one of my friends bought some WC844 surplus at a gun show, and then came to me with the stuff. What we did with it was to apply the minimum charge weight of H335 for the mildest .223 Remington loadings with a 55 grain bullet-- which is 23.0 grains of powder. The deal there was that if the rifle failed to cycle correctly, we needed more powder. But in the meantime, WC844 is close enough to H335 that it wasn't gonna blow the rifle apart if the lot we got our hands on was a lil' hot...

    It cycled the rifle, and no signs of high pressure were in evidence. So back to the bench, and now we loaded a succession of rounds, averaging .3 grains apart in powder charge, all the way up to the max for H335 in .223 Remington, which is 25.3 grains.

    Fired 'em all up and found no signs of high pressure-- no flattened primers, pierced primers, failure to extract, split necks, cases smeared on ejection, or any of the rest. So we loaded up yet more cartridges-- this time going with 25.5 as a starter, and going up .1 grain in a series of cartridges beyond that baseline, until we loaded a few at 26.1 grains.

    This is well beyond the boundaries of .223 Remington safe loadings and pressures, and into distinct M193/M855 NATO country.

    Fired 'em up again and found that we were seeing flattened primers at 25.8 grains. We didn't even fire the ones with heavier charges because it simply wasn't gonna get better after that. Meanwhile, the chrono was reading about 3150 fps out of a 16" barrel with 25.6 grains of WC844. We knew that if we fired the same stuff out of a 20-incher, we'd be seeing the 3200+ fps that you get from good M193.

    And so we were happy with what we got. My pal went ahead and loaded all eight pounds of that WC844 up to M193 specs. He ended up with a little over 2,000 rounds like that. And the powder was cheap, too-- almost $40 bucks less than anything else for an 8-pound jug. Just, it's a pita to work with until you've got things dialed in.

    So that's how you deal with pull down powders.

    ***************​

    If you're going with H335 and a 55 grain bullet, 25.0 grains is almost universally acknowledged as being one in the same as an M193. You can use a magnum primer with it if you like 'em on the hotter side, but a regular small rifle primer will ignite 'em just fine if you're in the mood to save a dab of money.

    NOW THIS IS IMPORTANT: I NEITHER RECOMMEND THAT YOU USE THE LOAD I JUST SPECIFIED OR ENDORSE ITS ABSOLUTE INFALLIBILITY IN YOUR PERSONAL RIFLES. CONSIDER YOURSELF TO HAVE BEEN WARNED.

    (My attorney told me to stick that in there) :)

    Always best to work up to what you figure you're going to want. It's also the case that sometimes a rifle has a sweet spot that calls for a powder charge that is less than what any load approaching maximum calls for.

    In fact, that is often the case.

    I ain't done talking yet. I still mean to cover spherical powder types vs. extruded powders, powder types beyond WC844 and H335, types of materials I have used as cartridge case fillers and my results, and a few other things others might find to be interesting.

    But for now, I am pooped. Thus, I bid you all a good evening, but will be back pretty soon to talk about some of this other stuff that has come up in the thread-- unless somebody gets there first!

    --R :thumb:

     
    Last edited: Jul 5, 2017
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  17. bulletproof

    bulletproof aka tarddoggy Premium Member V.I.P. Member

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    Man,you guys rock.....now Im all fired up to get busy learning to reload. Now,Ive been looking at the Lee presses,however,Im gonna ask y'all what you started off with.
     
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  18. Frogfur

    Frogfur Senior Member

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    Man, that's what I'm talk'n about. A clear explanation on the subject. Very good Rob, as usual. l think you explained this so everyone can understand. Wonderful.
     
  19. Bobby Mahogany

    Bobby Mahogany Senior Member

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    And I thought my friends and I were crazy over discussing leaving
    tremolo springs in place or not after blocking the trem movement in a Strat.

    I say this in a good way:

    [​IMG]

    :thumb:
     
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  20. LtDave32

    LtDave32 Sua Sponte Super Mod Premium Member

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    Lee presses and related equipment are a great deal cheaper than the other brands, say RCBS or Dillon.

    But they are made cheaper, and to compare them to say, RCBS it is readily evident to see the difference. RCBS presses are much bigger and way more robust. The Lee presses are made out of what appears to be pot metal, with aluminum operating handles. RCBS stuff is way more robust and built to last for years, made out of what appears to be cast iron and steel workings.

    Nothing wrong with Lee gear. It works. It was my starter stuff, and I reckon the choice of beginners everywhere. But I would try to find a used RCBS rock chucker (or turret style, if you're into high production) before I would buy a new Lee. I still have that Lee, along with two RCBS rock chuckers. The difference in quality and robustness is huge.

    In fact, bought my two RCBS presses at a yard sale for $25 apiece. I reckon they are all over the 'bay or Craigslist used. I figure it's like workout equipment for some; people really get into it, then get tired of it and try to sell the workings to recoup their investment. I wouldn't buy used dies, but I see no drawback to purchasing a used RCBS press itself. The damn things are built like tanks.
     

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