Buffalo Arms (BACO’s) Moulds/Bullets: Changes & Decoder

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Buffalo Arms (BACO’s) Moulds/Bullets: Changes & Decoder

Post by TexasMac » Thu Mar 07, 2019 10:02 am

Some of you may be familiar with or use the so called Jim Kidwell or “Kidwell” bullet in your .40 caliber rifles as I do in my Shiloh Sharps 1874 Sporter. Until recently Buffalo Arms (BACO’s) designation for the mould was JIM409400M4, which was incorrect since the 1st three driving bands are reduced. While doing some research on BACO’s bullet moulds I found 6 moulds/bullets, including the “Kidwell” mould, which were either incorrectly identified or had errors and typos in the designation and/or description. Subsequently, around the end of January I notified BACO of the errors which have since been corrected. Therefore the JIM409400M4 is now correctly identified as JIM409400M5.

Refer to the following information if you are unfamiliar with BACOs designations. But keep in mind that there may be possible exceptions.

JIMDDDWWWXY (BACOs common mould format)
JIM: the guy that makes all the moulds.
DDD: the bullet diameter (0.000”) as cast with 20:1 (lead:tin) alloy
WWW: the bullet weight (grains) with 20:1 (lead:tin) alloy
X or sometimes XX: designates the bullet nose design and other characteristics as per the following list:
C – Creedmoor nose
E – Elliptical nose
FN – Flat nose
M – Money bullet nose
P – Postell nose
S – Spitzer nose
T – bullet is tapered over the full length (i.e. the band diameters get larger from nose to base).
HB – Hollow base
GC – Gas check base
Y: designates how many bands are reduced in diameter as indicated below:
1 - No bands reduced
2 - Tapered 1st band
3 - 1st band reduced
4 - 1st two bands reduced
5 - 1st three bands reduced
6 - 1st four bands reduced

Therefore the JIM409400M5 “Kidwell” mould as made by Jim will, when using 20:1 alloy, produces a 0.409” diameter bullet weighing 400grs, has a “money bullet” nose profile and the diameter of the 1st three driving bands are reduced (less than 0.409” for this example).

I hope this helps.

NRA Life (President's Council) Member, TSRA Life Member, NSSF Member
Click on http://www.texas-mac.com/index.html to my home page containing information on my Browning/Winchester BPCR book & associated articles.