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Ammunition by Bill Roberts |
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Bullets |
Percussion Caps Military, full-stock style rifles generally use musket caps. The musket cap produces more than adequate ignition for the rifle. Other rifles fitted with nipples that use number-11 caps may obtain better ignition with magnum caps rather than the standard-strength cap. Magnum RWS caps are designated number 55, in contrast to the standard number 75 cap. CCI now provides a magnum number-11 cap that is readily available from most dealers. Nipples Original British target rifles were furnished with platinum-lined nipples. The high pressure generated by the large powder load and heavy bullet rapidly erodes solid steel, stainless steel, Ampco alloy, and other materials normally used in round-ball-rifle nipples. Ceramic lined nipples were produced in Germany, and some shooters have used them with good results. When the hole in the nipple enlarges, accuracy is lost and excessive gas is blown into the hammer recess. Locks with weak mainsprings may have the hammer blown back to full cock and/or even suffer lock damage. Thus, nipple hole size and the strength of the percussion cap are very important variables affecting accuracy. If the ignition of the powder is not consistent, the velocity of the bullet will vary and shots consequently will string up and down. The author made platinum-lined nipples with a .032 inch diameter hole into the platinum. For most rifles this hole size is adequate. The fit of the base of the nipple in the snail or drum is not hypercritical. To minimize the potential of corrosion in the threads through the leakage of combustion products, however, the base of the nipple can be filed or lap fitted much the same as if one were seating a valve. Finally, it should be noted that ignition also is affected by the design and shape of the drilled passages in the breech plug. |
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© 2004 WA Roberts |
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