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  1. #1
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    Default very interesting find on bi metal bullets.

    i use them all the time, i load these things in all my 30 cal rifles. i never have accuracy issues and i never have experienced increased barrel degregation due to the use of mild steel under thick copper jacket.

    supposably a bi metal jacket is as follows

    lead core
    thin steel jacket
    copper washed in a chem bath up to .008 inch

    .308 caliber barrels anyone? this means the lead core and the steel jacket ring in at about .300 or so + - .001. the rifling will dig down through the copper protection and maybe, maybe not barely kiss the mild steel. very unlikely to get that far.

    the jacket applied is .008 or so

    after the bullets are ran through what ever sizing die or press you have a .300 bullet with .008 inch worth of protection for your rifling.

    actual hardness scale in brinnel scale

    Pure Aluminum

    15

    Pure Copper

    35

    Mild Steel

    120

    304 Stainless Steel

    250

    Hardened Tool Steel

    650/700

    comparitivly a rifle barrel is infact tool steel (common chrome moly bottom of the line barrel material is infact the same steel they use in your transmission gears and such things in your motor;TOOL STEEL) is 675 respectivly on the scale. copper jacket which your barrel is infact in contact with most is 35, we can do this all day. mild steel? 120. compared to 675 we will never be in any kind of trouble concidering how much of our rifling would contact it if at all with a properly broken in/seen a few rounds barrel.

    fankfort arsnal did a test with taxpayer money with the miliary. they wanted to find out the difference in barrel wear with copper jacket bullets or bi metal jacket bullets (bullets with copper jacket .008 thick with mild steel jacket underneath). propelled with air (not gun powder) and the results. NONE AT ALL.

    verdict.........powder blast and heat errosion of powder fires degrades your barrel, not bullets.

    till next time

  2. #2
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    Interesting!!

    Thanks!

    I know most all my 6.5x55 ammo is steel cased lead and my K-31's are tack drivers.
    The Republic of Texas Not just a state but an attitude!

    For monthly shooting events in DFW TX visit me at:
    www.meetup.com/TexasGunOwner-DFW/


  3. #3
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    QUOTE:verdict.........powder blast and heat errosion of powder fires degrades your barrel, not bullets.

    Big +1 and dont forget over or improper cleaning techniques
    If you find yourself in a fair fight, your tactics suck!

    LETS GO PENS !!!!!!!!!!!!!

  4. #4
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    What you guys said. A bullet doesn't wear out a barrel because of friction. It's the white hot gasses at 50,000 psi that do it.

    Most bullets with steel in the jackets are what is called GMCS. That is Gilding Metal Clad Steel. Three layers. Inside and outside are Gilding metal and center is soft steel. At least here in the US, they are not plated or washed, they are clad.

    The US has experimented with solid steel bullets, copper plated, but they always return to the proven standby, GMCS.

    Ray

  5. #5
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    Big +1 and dont forget over or improper cleaning techniques

    i heard this one alot!!! id have to say that would be a +1+1. tell me, if one had a cleaning rod that was coated in du pont plastic ( not a lick of steel, aluminum ect) and used that with nothing but patches and solvent cleaning from the breach to the muzzle, would this also destroy barrels if no bore guide was used?

    Most bullets with steel in the jackets are what is called GMCS. That is Gilding Metal Clad Steel. Three layers. Inside and outside are Gilding metal and center is soft steel. At least here in the US, they are not plated or washed, they are clad.

    The US has experimented with solid steel bullets, copper plated, but they always return to the proven standby, GMCS.

    thankyou for your knowlege on the exact construction of the bullets, any kind of industry construction of these bullets helps further my know and others. i heard about steel dipped in aqueous soulutions of copper and doing the "cathode/sacrificial anode" method of applying the jacket, but my bullets that i usually buy from my secret vendor, looking at these i see that its a super bright jacket, not like those usually found from wolf cheap as$ ammo company. these would appear just as you called it, steel jacket with a copper jacket over it.

    have you guys ever seen the construction of a bullet? i saw it on the history channel. the lead core is really a roll of special dia lead wire, the lead is cut into small pieces and goes into a hopper. the jacket is what apears to be a roll of copper water pipe but not. it to is cut into pieces. a machine takes the two pieces slides the lead into the copper and a press machine presses the two together, making what looked like a fmj. i take it if you have a gmcs theres just one more process; a cutting of a steel jacket and applying into the assembly.

  6. #6
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    [QUOTE=odfairfaxsub;1691887] ""tell me, if one had a cleaning rod that was coated in dupont plastic ( not a lick of steel, aluminum ect) and used that with nothing but patches and solvent cleaning from the breach to the muzzle, would this also destroy barrels if no bore guide was used?""

    Have you ever wondered why high quality cleaning rods were made of hard steel? Soft metal rods and the plastic coated ones like you mentioned can and do "pick up" very tiny particles of material. This material when embedded in the rods surface acks just like a rubber polishing stick with abrasives in it. So yes your plastic coated rod can be destructive to you bore.
    Motor

  7. #7
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    Virtually all competition shooters use coated cleaning rods. If they thought they would damge their $500 barrels they would not use them. The secret is to keep the rod clean. And the use of a bore guide is almost mandatory.

    All cleaning rods flex while being used. A hard steel, uncoated rod is guaranteed to hammer against the rifleing. The coating acts as a cushion and prevents barrel wear. If you'll look at the surface of a coated rod after it's been used a lot you can see the marks left by the rifleing.

    JMHO

    Ray

  8. #8
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    Quote Originally Posted by odfairfaxsub View Post
    . . .the jacket is what apears to be a roll of copper water pipe but not. it to is cut into pieces. a machine takes the two pieces slides the lead into the copper and a press machine presses the two together . . .
    A bullet jacket starts out as a "blank". A thin, round, piece of gilding metal that looks like a coin. It is swadged into a cup. The core is inserted into the cup and the two are swadged into the final shape.

    To make GMCS jackets, the three layers of GM/steel/GM are rolled together under high pressure and the jacket blanks are then punched from that sheet.

    Ray

  9. #9
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    not what i saw on the hist channel. it was quite a show. i saw how they make shell casings, that looked like a penny coin that got swadged into a cup just like your talkingabout

  10. #10
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    hey ray, i appologize. i looked it up on google.......

    A coin-shaped piece of jacket metal is punched out of a strip or a sheet. The punch is usually a round metal cylinder that is pushed through the jacket material into a depression in a table. Some punches are rounded so that the piece of metal is shaped like a cup. Sometimes, tubing is used instead of a coin or a cup of metal.

    Read more: How bullet is made - material, manufacture, making, history, used, parts, steps, industry, machine, History, Raw Materials, Design, The Manufacturing Process of bullet, Quality Control http://www.madehow.com/Volume-7/Bull...#ixzz1HeWAruka

    what you said ray makes more sense from a non-exposed bottom type bullet of higher quality like noslers or certaint hornady types, ect

  11. #11
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    I no longer use rods to clean weapons. I use Otis pull thru cables.

    I no longer use brushes, I use Wipe Out Foam or I use the liquid version called Patch Out: I let chemicals do the work on the bore
    and clean it.

    I do not have bore damage by rods rubbing down bores, I have clean weapons, I have an easier time cleaning bores and I have very accurate rifles maintained this
    way.

  12. #12
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    Quote Originally Posted by odfairfaxsub View Post
    hey ray, i appologize. i looked it up on google.......

    A coin-shaped piece of jacket metal is punched out of a strip or a sheet. The punch is usually a round metal cylinder that is pushed through the jacket material into a depression in a table. Some punches are rounded so that the piece of metal is shaped like a cup. Sometimes, tubing is used instead of a coin or a cup of metal.

    Read more: How bullet is made - material, manufacture, making, history, used, parts, steps, industry, machine, History, Raw Materials, Design, The Manufacturing Process of bullet, Quality Control http://www.madehow.com/Volume-7/Bull...#ixzz1HeWAruka

    what you said ray makes more sense from a non-exposed bottom type bullet of higher quality like noslers or certaint hornady types, ect
    This reminds me of an old issue of Firepower I had from the 80's where the author of an article used 1/2 copper pipe to make jackets for .50 cal. I wonder if 1/4 could be adapted to .30 cal?

  13. #13
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    once saw were barrels were less effected by flat based bullets and accuracy was better in a wore barrel than boat tail bullets? maybe gas here too?

  14. #14
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    Quote Originally Posted by CW View Post
    This reminds me of an old issue of Firepower I had from the 80's where the author of an article used 1/2 copper pipe to make jackets for .50 cal. I wonder if 1/4 could be adapted to .30 cal?
    The old Barnes bullets were made using copper tubing for jackets. He had dies that would close the base leaving only a very tiny opening. The front of the bullet was then swadged in the conventional way.

    Right before and after WW II, materials to make jacketed bullets were hard to come by. During the war, of course, they were impossible to come by. Shooters in those days used anything they could get their hands on to make bullets. Fired RF cases, cut down pistol cases, copper tubing, etc. That's how some of the big names like Sisk, RCBS, Speer, Hornady, got their start.

    Ray

  15. #15
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    once saw were barrels were less effected by flat based bullets and accuracy was better in a wore barrel than boat tail bullets.

    had a m39 that shot flat base bullets better than bow tail type.

  16. #16
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  17. #17
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    The flat base vs boattail theory is that in a worn barrel, the flat base bullet has a longer bearing surface than a boattail. Visualize a wadcutter shape compared to a football shape, the football is more likely to tip and come out crooked. My only experience is from a sewer pipe barrel that wasn't real bad with flat base M2 ball, but wouldn't shoot boattail match ammo for squat.

  18. #18
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    husquvarnas not worn, new seem to shoot better at 200 +yards flat based speer in 300 mag... but 168 boat tails are as accurate...cost was less not any difference for hunting at that short distance...now longer i dont know?

  19. #19
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    i love those sierra 180 gr soft point flat based bullets, i found where to get factory seconds. i get em 4 dollar off 100. they do really well in my russian/finn mosins. i think they do great maybe due to the thickness of the jacket. other than that they don't win a contest on b/c

  20. #20
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    Boattail bullets have a very definite ballistic advantage at the longer distances. But, other than that, there is no evidence to support the many theories that they are more accurate or wear a barrel faster than a flat base design.

    Ray

  21. #21
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    you know now that you bring it up, i always thought this, not to suport it with facts or anything scientific.

    i bought a ton of .308 180 gr flat base bullets for a .311-.3115 size bore. i bought the sierras b/c the jacket is thinner than most i found. i figured the flat base would alow the concetration of gasses to hit the bottom of the bullet and make a cup seal that would fill most of the lands and grooves when the rush and pound of the powder gasses hit it. i did this load instead of a bow tail design b/c i thought to myself, bowtail design will not get the same type of barrel seal like the flat base. a undersized bullet would prob seal better in this case if it was flat based, not bowtailed.

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