Constantan is a variation of
cupronickel with 55% copper and 45% nickel and a resistivity of 19.63495 [micro] [ohm] -inch.
Using harder tube materials such as
cupronickel and titanium can allow higher velocities to be used without much erosion.
Indeed, the government's intention was not to replace silver dimes and quarters with
cupronickel dimes and quarters, but only to reduce global demand for silver by removing the United States Mint from the ranks of the buyers.
Concerning the roughness of the technical surfaces the following values (average values) could be achieved with Slow-Tool-Servo (STS) and the same technological machining parameters: Material roughness [R.sub.q] [nm]
CuproNickel 5.4 Aluminium RSA-905 5.2 Aluminium AlMgSi1 7.4 Plastics Zeonex E48R 14.1 PMMA gs 7.7
The
cupronickel and silver coins, which are both larger than a 50p coin, will sell for pounds 9.95 and pounds 39.95 respectively and are both worth 25p.
The demand for the new 10, 20 and 50 cent coins has been much higher than for the earlier
cupronickel coins.
In 1919 DuPont reduced
cupronickel fouling in rifles by incorporating tin in granules of early Improved Military Rifle (IMR) powders, denoted by adding "1/2" to the powder number.
If you have been firing such junk ammo, though, use "Shooter's Choice" bore cleaner to remove the corrosive primer fouling, the powder residue and the
cupronickel fouling.
Allowing for the construction of the
cupronickel jacketed lead-core bullet, as the long heavy 244-grain 0.323-inch roundnose bullet was squeezed down in diameter to 0.311-inch undoubtedly a small portion of the lead core would have bulged out through the open end of the jacket at the base of the bullet.
The Soviet 7.62x25mm bullet contained a lead core with a
cupronickel jacket.