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Post by bcelliott on Feb 23, 2022 0:55:53 GMT -5
I recently bought some 325 grain .50 caliber A-frames for use in my BFR 500 JRH and John Ross S&W 500. The BFR cylinder throats are right at .501", and the Smith's are .5005" so the .499" bullets fall right through the cylinder. Is two thousandths under size too small for jacketed?
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Post by bradshaw on Feb 23, 2022 10:08:19 GMT -5
I recently bought some 325 grain .50 caliber A-frames for use in my BFR 500 JRH and John Ross S&W 500. The BFR cylinder throats are right at .501", and the Smith's are .5005" so the .499" bullets fall right through the cylinder. Is two thousandths under size too small for jacketed? ***** Jacketed bullets are more forgiving of small variations in CHAMBER EXIT HOLE diameter. No handgun bullet I have tried enjoys a lousy forcing cone. The number of silhouette matches won with throats a couple-thousandths over bullet diameter counts high indeed, including state, regional, and world championships. The smaller the bore, the greater influence .002-inch has. As well as its tolerance of a slightly loose exit hole, a jacketed bullet is more tolerant than lead to passage through a tight exit hole. Lesson taught by steel targets @ 200 meters. Information from the Firing Line. Yet another reason why I call the TARGET is the FINAL ARBITER of ACCURACY. While a jacketed bullet tends to be less sensitive to thread diameter than a cast, neither jacketed nor lead achieve supremacy from a loose groove diameter. The Colt Python bears a history of generous exit holes coupling to tight groover diameter. For example, .358 throats----sometimes .359”----with .355 or .356 groove diameter. Especially as a .359 exit pours a bullet into a .355 groove, expanding gas works extra hard to side blast the cylinder gap. While this may show little or no detriment to accuracy, it lowers velocity. Exits of .501” on your BFR, and .5005” on your S&W are plenty firm to support the heal of a .499” bullet as its shoulder seats rifling (or freebore, if present). David Bradshaw |
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Post by 45MAN on Feb 23, 2022 11:34:00 GMT -5
DAVID: "THE SMALLER THE BORE, THE GREATER INFLUENCE .002 HAS.", SHUD THAT BE "THE SMALLER THE DIAMETER OF THE BULLET"?
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Post by taffin on Feb 23, 2022 11:38:29 GMT -5
I recently bought some 325 grain .50 caliber A-frames for use in my BFR 500 JRH and John Ross S&W 500. The BFR cylinder throats are right at .501", and the Smith's are .5005" so the .499" bullets fall right through the cylinder. Is two thousandths under size too small for jacketed? TRY 'EM AND SEE |
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Post by bradshaw on Feb 23, 2022 12:06:46 GMT -5
DAVID: "THE SMALLER THE BORE, THE GREATER INFLUENCE .002 HAS.", SHOULD THAT BE "THE SMALLER THE DIAMETER OF THE BULLET"? ***** Meant to say, .002-inch affects a .22 more than a .44, etc. Thus, a small diameter bullet is less tolerant of a set amount of: * chamber-to-bore runout. * bullet diameter vs throat (chamber exit hole) diameter. * bullet diameter vs groove diameter. * bullet diameter vs rough, or off-axis forcing cone, or a forcing cut cut at too-steep or too-deep. David Bradshaw |
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Post by bcelliott on Feb 23, 2022 12:18:33 GMT -5
Thank you for the info, Mr. Bradshaw. Mr Taffin, I will try them out!
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