A serious question

Gene LGene L Senior MemberPosts: 10,152 Senior Member
When we were talking about bolts and locking lugs on a previous thread, I posted what I thought was a serious question, namely: if the bolt doesn't serve any purpose except moving the bolt head [and holding the firing pin], why not replace the bolt with for example one of aluminum or polymer? This was met with scorn from the Usual Suspects, those who didn't have an answser and resort to sarcasm, so I'm putting it up for general and serious discussion.

Why not some lightweight substitue?
Not too many problems you can't fix
With a 1911 and a 30-06
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Replies

  • JayhawkerJayhawker Moderator Posts: 14,962 Senior Member
    I suspect it has something to do with supporting the firing pin, cocking mechanism and bolt handle....I would imagine that something like aluminum or polymer would wear out/strip out fairly quickly...
    Sharps Model 1874 - "The rifle that made the west safe for Winchester"
  • Gene LGene L Senior Member Posts: 10,152 Senior Member
    Well, I'd sleeve the firing pin in steel. And the bolt head would screw into a steel insert. Should lose 2-3 oz. And it would be cheaper to make.
    Not too many problems you can't fix
    With a 1911 and a 30-06
  • tennmiketennmike Senior Member Posts: 25,957 Senior Member
    A titanium or scandium bolt body with a steel bolt head would be fairly light. A hard chrome plating could be applied for added wear resistance.
    Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.


  • TeachTeach Senior Member Posts: 18,340 Senior Member
    Glock manages to make a large part of their guns out of Tupperware, buit the stressed parts are steel. I think the relatively minor weight saving of a plastic bolt would be offset by the likelihood of the handle breaking off, or distorting and bending or binding at the worst possible time. Tempered aluminum might be an option, but modern casting and machining methods can produce very lightweight steel parts that would rival aluminum for weight, and be considerably stronger. If I'm facing something several times my size with big teeth, I'll gladly lug a few more ounces of weight around to be sure I get more than one shot off.
    Jerry
    Hide and wail in terror, Eloi- - - -We Morlocks are on the hunt!
    ASK-HOLE Someone who asks for advice and always does something opposite
  • snake284snake284 Senior Member Posts: 21,832 Senior Member
    I think what you're saying Gene is that the head and lugs would be made of hard steel as like now, but the bolt body would be aluminum for lightness. I know they make some very durable aluminum. Of course not for the bolt head or lugs, but for holding the firing pin and spring. Of course they make plenty of different lighter metals, like tennmike said, titanium. But it would increase the cost of the bolt somewhat. I like the idea of a steal bolt that's been fluted.
    Daddy, what's an enabler?
    Son that's somebody with nothing to do with his time but keep me in trouble with mom.
  • DoctorWhoDoctorWho Senior Member Posts: 9,496 Senior Member
    Benelli has made a composite bolt carrier for the Nova shotgun that is in part aluminum.

    The M-16 variants bolt carrier has always been made of steel, even though the upper and lower receivers are indeed aluminum, the other high stress parts are all steel.
    "There is some evil in all of us, Doctor, even you, the Valeyard is an amalgamation of the darker sides of your nature, somewhere between your twelfth and final incarnation, and I may say, you do not improve with age. Founding member of the G&A forum since 1996
  • TugarTugar Senior Member Posts: 1,841 Senior Member
    Teach, you might be onto something. For an analogy, look to aluminum engines. At least, I thought, they had steel sleeves for the pistons. I really don't see any reason the bolt body itself couldn't be aluminum. Makes perfect sense to me. In a lightweight rifle that is being packed around, every ounce counts.
    Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.
    Winston Churchill
  • jbohiojbohio Senior Member Posts: 5,507 Senior Member
    Gene L wrote: »
    Well, I'd sleeve the firing pin in steel. And the bolt head would screw into a steel insert. Should lose 2-3 oz. And it would be cheaper to make.

    That's probably the answer. The machining and such to machine the aluminum bolt, then machine the inserts, put it all together, make it safe, would be cost prohibitive. Especially for a very small gain. You'd probably double or triple the CNC time. Add the costs of steel vs. aluminum, you'd probably add hundreds of dollars to the price of the bolt, to save a couple ounces.
  • BigslugBigslug Senior Member Posts: 7,002 Senior Member
    You need only to look at the gas and piston versions of the AR-15 for your answer.

    The standard AR-15 directs gas into the center of the bolt carrier, and the carrier gets pushed to the rear along its centerline. This is why you can get away with a steel carrier running at 900 RPM inside an aluminum receiver.

    With the piston AR's there have been reported incidents of accelerated wear from "carrier tilt" caused by the piston shoving the carrier back from a point above its centerline.

    In the case of a bolt action rifle, the operator's hand can be torquing and twisting the bolt in all kinds of funny directions - much akin to carrier tilt in a piston AR. Beer can would not be the ideal material for this task.
    WWJMBD?

    "Nothing is safe from stupid." - Zee
  • breamfisherbreamfisher Senior Member Posts: 13,081 Senior Member
    Gene L wrote: »
    Well, I'd sleeve the firing pin in steel. And the bolt head would screw into a steel insert. Should lose 2-3 oz. And it would be cheaper to make.

    I think that's what you'd have to do. The bolt body has to contain both the force of the firing pin spring, but also the torsional force of unlocking the bolt, especially with a tight case. It's probably more a matter of it being easier and cheaper to do it all in steel rather than using some kind of alloy outer housing. Polymer might be a possibility, depending on how much wear it would get during cycling. You'd probably need strengthening ribs made into the steel sleeve to prevent twisting.
    Overkill is underrated.
  • JayhawkerJayhawker Moderator Posts: 14,962 Senior Member
    I think that's what you'd have to do. The bolt body has to contain both the force of the firing pin spring, but also the torsional force of unlocking the bolt, especially with a tight case. It's probably more a matter of it being easier and cheaper to do it all in steel rather than using some kind of alloy outer housing. Polymer might be a possibility, depending on how much wear it would get during cycling. You'd probably need strengthening ribs made into the steel sleeve to prevent twisting.

    On the other hand, in order to clean it, you could just toss it in the dishwasher...
    Sharps Model 1874 - "The rifle that made the west safe for Winchester"
  • knitepoetknitepoet Senior Member Posts: 18,738 Senior Member
    Another consideration, in some actions the bolt handle acts as an additional, last ditch, locking lug. Its only real purpose, as I understand it, is to prevent the bolt from becoming imbedded in your head in the event of a catastrophic bolt failure.

    With modern metallurgy, the odds of needing it are SLIM but in today's litigious society, you're not going to see the lawyers allow the removal of ANY perceived safety feature
    Seven Habits of Highly Effective Pirates, Rule #37: There is no “overkill”. There is only “open fire” and “I need to reload”.


  • TugarTugar Senior Member Posts: 1,841 Senior Member
    jbohio wrote: »
    That's probably the answer. The machining and such to machine the aluminum bolt, then machine the inserts, put it all together, make it safe, would be cost prohibitive. Especially for a very small gain. You'd probably double or triple the CNC time. Add the costs of steel vs. aluminum, you'd probably add hundreds of dollars to the price of the bolt, to save a couple ounces.

    True....IF you were to normally machine it. However, if you get Ruger or a company like it to use investment casting, the machining would be minimal.
    Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.
    Winston Churchill
  • bullsi1911bullsi1911 Moderator Posts: 9,684 Senior Member
    knitepoet wrote: »
    Another consideration, in some actions the bolt handle acts as an additional, last ditch, locking lug. Its only real purpose, as I understand it, is to prevent the bolt from becoming imbedded in your head in the event of a catastrophic bolt failure.

    That is my thought as well. While I like the idea, and think it has merit, that last little bit of safety is worth the few ounces.
    To make something simple is a thousand times more difficult than to make something complex.
    -Mikhail Kalashnikov
  • sarg1csarg1c Senior Member Posts: 1,705 Senior Member
    Case hardining is only so many thousands of a inch, as this wears the parts would get weaker. Take an lawn mower engine all alum. including cylinder, but never hone an alum. engine the piston then would be running in soft alum. NOT GOOD... don't let these gun co's read your question....They have cheapened some guns enought...SHHHH!
  • DanChamberlainDanChamberlain Senior Member Posts: 3,365 Senior Member
    Of course, a round that requires the bolt be nearly pounded up to remove as in a case head separation or overload would probably break it off.

    A composite receiver might make more sense for weight shaving since the bolt is locked into the breech.

    Dan
    It's a source of great pride for me, that when my name is googled, one finds book titles and not mug shots. Daniel C. Chamberlain
  • mkk41mkk41 Banned Posts: 1,932 Senior Member
    Gene L wrote: »
    Well, I'd sleeve the firing pin in steel. And the bolt head would screw into a steel insert. Should lose 2-3 oz. And it would be cheaper to make.

    Besides wear issues , manufacturing costs would be higher than any weight (an ounce or two max) savings would be worth. There are already several bolt actions that use a fabricated steel bolt.

    The Savage 110 uses 5-6 piece bolt. Even it ya made the bolt's tube/body which connects the bolt head to the handle , out of a steel liner with an hard-coat aluminum outer , you would add greatly to manufacturing cost at a minimal weight savings.
    "There are no victims , only volunteers!"
  • beartrackerbeartracker Senior Member Posts: 3,116 Senior Member
    If they ever come out with a bolt action rifle that the bolt is not steel, whoever wants to can buy it go right ahead, but I will only have a rifle that has a steel bolt for all kinds of safety issue due to bolt thrust that is a reaction force described quantitatively by Newton's second and third laws. When the round is fired, expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on the bolt. I want steel controlling the bolt thrust, not some alloy or plastic.
  • TugarTugar Senior Member Posts: 1,841 Senior Member
    If they ever come out with a bolt action rifle that the bolt is not steel, whoever wants to can buy it go right ahead, but I will only have a rifle that has a steel bolt for all kinds of safety issue due to bolt thrust that is a reaction force described quantitatively by Newton's second and third laws. When the round is fired, expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on the bolt. I want steel controlling the bolt thrust, not some alloy or plastic.

    Now wait.....isn't this the light versus heavy argument? You'd rather have a heavy sledgehammer projectile that a lighter faster one?

    The machining these days isn't that big of an issue, esp if it were investment cast.
    Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.
    Winston Churchill
  • beartrackerbeartracker Senior Member Posts: 3,116 Senior Member
    Tugar wrote: »
    Now wait.....isn't this the light versus heavy argument? You'd rather have a heavy sledgehammer projectile that a lighter faster one?

    The machining these days isn't that big of an issue, esp if it were investment cast.

    investment cast as long as it is steel I am fine with. I stated my preference and will only buy a bolt action rifle that has a bolt of steel or titanium. My 7mm-08 with scope, bases and rings only 7.7 pounds and I can carry it all day long in these mountains. Weight with steel bolts is not really an issue with me. I want steel not aluminum or plastic or even a mix of aluminum and plastic or steel and plastic. As I said, just my preference and how I want it. Also, in a magnum rifle like a lot of them I own, a little fast bullet can still produce a lot of bolt thrust.
  • TeachTeach Senior Member Posts: 18,340 Senior Member
    Does anybody remember the Chevy Vega? GM took a tried and true design, an aluminum piston running in a cast iron cylinder, and decided to tinker with it. Wrong move! They cast a high-silicone aluminum block without cast-in iron sleeves, finish-bored and honed the cylinders, then acid-etched them to expose microscopic buttons of silicon for the piston to ride on. Then they plated the aluminum pistons with a thin layer of iron. The entire goat rope was designed to save a few pounds of weight by eliminating the cast iron sleeves, and a little bit of cost in the casting process. There was no way to replace a piston in field service, because of the sophisticated honing and acid-etching process. The experiment was a colossal flop. Thousands of those engines got retro-fitted with flanged cast iron sleeves and conventional pistons by machinists like me, and we made a lot of money from some GM engineer's stupidity! A piston failure didn't imbed it in somebody's forehead, however!
    Jerry
    Hide and wail in terror, Eloi- - - -We Morlocks are on the hunt!
    ASK-HOLE Someone who asks for advice and always does something opposite
  • Make_My_DayMake_My_Day Senior Member Posts: 7,110 Senior Member
    When I was on the P.D., I had a 5 shot S&W revolver I took to the range for optional practice with it. The hammer on it had a small piece of the cocking lever broken off from dropping it on a hard floor once. I asked the range officer if this would cause any problems with the firing of it. He said that the loss of weight to the hammer could cause misfires because of light impact with the primer. I ground down the rough edge of the lever and it never caused any misfiring issues. Maybe this is why they don't make the bolt out of lighter material because of the same issue.
    JOE MCCARTHY WAS RIGHT:
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  • coolgunguycoolgunguy Senior Member Posts: 6,413 Senior Member
    A lightweight substitute seems like a good idea as long as it functions as well as whatever it replaces. Like Dan C., I think a lightweight reciever might be a better idea as the actual action of said rifle could be molded into a ploymer or even just bolted in. I don't know that I'd be comfortable with the same material as the main ingredient for a bolt, at least not for a high-pressure application. Might just be the old lady in me, but I'm spooky that way...

    Same goes for aluminum. I see LOTS of auto parts made from it and they all suck. Screw threads stripping out, flanges breaking off, and on and on.
    "Bipartisan" usually means that a bigger than normal deception is happening.
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  • mkk41mkk41 Banned Posts: 1,932 Senior Member
    Teach wrote: »
    Does anybody remember the Chevy Vega? GM took a tried and true design, an aluminum piston running in a cast iron cylinder, and decided to tinker with it. Wrong move! They cast a high-silicone aluminum block without cast-in iron sleeves, finish-bored and honed the cylinders, then acid-etched them to expose microscopic buttons of silicon for the piston to ride on. Then they plated the aluminum pistons with a thin layer of iron. The entire goat rope was designed to save a few pounds of weight by eliminating the cast iron sleeves, and a little bit of cost in the casting process. There was no way to replace a piston in field service, because of the sophisticated honing and acid-etching process. The experiment was a colossal flop. Thousands of those engines got retro-fitted with flanged cast iron sleeves and conventional pistons by machinists like me, and we made a lot of money from some GM engineer's stupidity! A piston failure didn't imbed it in somebody's forehead, however!
    Jerry

    The Cosworth Vega. And the no-liner engines were originally another brilliant :uhm: British idea.
    "There are no victims , only volunteers!"
  • TugarTugar Senior Member Posts: 1,841 Senior Member
    I think some are getting confused. I was talking about the bolt body being aluminum, NOT the bolt head. I wouldn't trust a bolt head made out of aluminum.
    Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.
    Winston Churchill
  • irondukeironduke Member Posts: 143 Member
    Several years ago, the Remington 710 had a steel bolt head with lugs, but a polymer bolt. The head pinned onto the bolt body. I am confident that there is a material that would serve as a good bolt material, but I think for sheer strength and reliability, steel is the way to go. I have had some hot loads from time to time that gave me sticky extraction requiring I beat the bolt handel up to open the bolt. I am not confident that Plastic would allow that to be done.

    I have heard of Remington Bolt handels coming off from the brazing letting go. Similarly, I have heard of Winchester bolt handels spinning on the bolt since it is press fit onto the bolt body. I have never had either of those things happen to me, but I still prefer the one-piece bolt/handel of the Rugers and Mausers.
  • TeachTeach Senior Member Posts: 18,340 Senior Member
    mkk41 wrote: »
    The Cosworth Vega

    The Cosworth cylinder head was a high performance twin cam option. It actually allowed the basic Vega engine to develop its full power potential- - - -to the point that the aluminum block started distorting and galling pistons when it was pushed to the limits of the design. The original Vega engine had a single overhead cam design that sucked like a Hoover upright! Later, GM went to a cast iron block with the Cosworth head, and those engines made some pretty respectable HP numbers.
    Jerry
    Hide and wail in terror, Eloi- - - -We Morlocks are on the hunt!
    ASK-HOLE Someone who asks for advice and always does something opposite
  • mkk41mkk41 Banned Posts: 1,932 Senior Member
    Look at any bolt action that's seen even moderate use and ya see longitudinal wear marks along the hardened steel body. Imagine how aluminum would have (not) held up?


    The Savage 10/110 , British SMLE , Russian M-N all use a bolt with a seperate head. The handle & body stll see a lot of stress & damage.

    Still say the added pounds of manufacturing complications and durability drawbacks are not worth the ounce(?) of weight saved.
    "There are no victims , only volunteers!"
  • Gene LGene L Senior Member Posts: 10,152 Senior Member
    I agree, but then the original post was in favor of saving weight by fluting the bolt.
    Not too many problems you can't fix
    With a 1911 and a 30-06
  • wizard78wizard78 Senior Member Posts: 1,004 Senior Member
    Gene L wrote: »
    .......I posted what I thought was a serious question, ........why not replace the bolt with for example one of aluminum or polymer? This was met with scorn from the Usual Suspects, those who didn't have an answser and resort to sarcasm, so I'm putting it up for general and serious discussion.

    Why not some lightweight substitue?

    Many answers were given but I believe the bottom line is, cost. The process of attaching the bolt to the steel bolt head and ensuring the handle doesn't come off, would be expensive, vs a steel unit that weighs only a couple of ounces more. Remington came out with a lightened Titanium rifle and discontinued it because of cost and lack of sales.

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