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Pressure Difference : 45acp Jacketed vs. Plated ?

geo57geo57 Member Posts: 13 ✭✭
edited December 2007 in Ask the Experts
I've read this debate go both ways & I'm hoping someone truely " in the know " can settle this. If you have 2 cartridges , in this case, a .45 acp with a 230 gr. Win. FMJ bullet and a .45acp with a 230 gr. Berry's plated round nose bullet, both atop the same 6 gr. Unique charge, which will create more chamber pressure ( & likely more felt recoil ) given ALL other factors for the 2 loads are exactly the same besides the projectiles, and both fired in the same pistol ? Thanks

Comments

  • bpostbpost Member Posts: 32,669 ✭✭✭✭
    edited November -1
    It depends on the gun. A chronograph will show the MV of each. since the weight of the bullet and charge is the same the round with the higest MV will have the higest recoil. The engraving forces are less on the plated bullet but the drag of the coating may actually increase its resistance to movement in the bore. Your gun may have some difference in the chamber throat area that allow easy engagement of the FMJ keeping pressures low. Only testing can tell.
  • haroldchrismeyerharoldchrismeyer Member Posts: 2,213
    edited November -1
    Check the loading data, and be sure to use the data for cast bullets when loading plated bullets.
  • heavyironheavyiron Member Posts: 1,421 ✭✭✭
    edited November -1
    Hi,

    Both ways of the argument as stated above are both wrong.

    In response to your hypothetical question, the answer is there will be no difference whatsoever in the recoil between the two loads because chamber pressure is not a factor relating to recoil.

    According to Newtonian physics the variables that determine the recoil of a gun are as follows:

    Free Recoil Energy = 0.5*(Wg/32.2)*((Wb*Vb+Vg*Wc)/(7000*Wg))^2

    Where:
    Wg=Weight of gun, pounds
    Wb=Weight of projectile, grains
    Vb=Velocity of projectile, feet/second
    Vg=Velocity of gas, feet/second
    Wc=Weight of powder charge, grains

    Therefore, if you wish to reduce recoil as outlined in the above case it will require that either a heavier pistol is used, the bullet weight is reduced, or the velocity of the bullet is reduced.

    Unless you want to change pistols your best bet is to reduce the weight of the bullet and the powder charge. Yes, there are always trade-offs.

    Because of variations in individual barrels and bullet diameters, etc. it would be basically impossible to predict which load would produce a higher chamber pressure.

    Regards,

    Heavyiron
  • perry shooterperry shooter Member Posts: 17,105 ✭✭✭
    edited November -1
    + 1 on Heavy Iron most 230 grain FULL METAL JACKET is less then .452AND MOST PLATED IS .452+ I have seen some military ball as small as .449 Most times plated or lead bullets will not shoot with out some leading if pushed to the very highest velocity but jacketed bullets will run out of a safety factor in pressure before they start to foul the bore.
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