45 ACP Shotshells (Handloaded)

Making 45 ACP Shotshells

45 ACP Shotshells are really a fun round. Essentially a mini shotgun shell for your 45 ACP Semi-Auto handgun. 45 ACP Shotshells can be formed from various source cartridges but, 308 Winchester is a good choice. 30-06 would work but should be avoided due to the potential for extractor breakage on the thin groove.

These rounds can be produced at home using either a special die set from RCBS or regular reloading dies.


The RCBS Die set consists of 4 dies and an extended shellholder.  The first die is a “trim die” and extended shell holder which are sold as a kit.  This is a very short die that does the initial forming of the source cartridge into your 45 ACP Shotshell.  It forms the neck and the cartridge protrudes out the top of the die where you can cut off the excess and file it flat, hence the name trim die.  Because the trim die is so short it must be used with the extended shellholder.   You can adjust the position of the neck to obtain proper headspacing by backing the die out.  You will need your 45 ACP barrel handy to test headspace while adjusting.  The trim die is needed for initial case forming, not for reloading already fired shotshells.

The remaining 3 dies are sold as a separate kit and follow the routine of traditional handloading die sets.  You have a full length sizing die which also decaps, an expanding die, and a crimp die.

  1. Start with clean brass, lubricate well
  2. Form and trim the case (skip this step if you are reloading already formed shotshell brass)
  3. Full length size and deprime
  4. Prime brass with a PISTOL PRIMER even though this is rifle brass. (the pistol primer will sit recessed, that’s ok)
  5. Expand the case mouth to facilitate loading (if needed)
  7. WAD (.410 wads cut down to 0.75 inches or use a cardboard disc punched out with a sharpened case).
  8. Tamp down the wad with a dowel, be careful your surface is clean as not to detonate primer.
  9. LEAD SHOT (choose the shot size desired and leave enough room to put a cover on top.
  10. OVERSHOT COVER can be an upside down gas check (0.375 works well) or a disc punched out of cardboard or plastic.  Primer box cardboard works well.
  11. CRIMP as desired with the crimping die.


The regular dies used are 45 ACP to size the body of the case then 41 magnum to form and size the neck.  Lubrication is required to ensure smooth forming and avoid damage to the dies and the brass.

  1. Trim your source brass (.308 brass works well) to 1.18-1.20 inches and debur.  (1.18 can increase compatibility if you are having issues).
  2. Lubricate the brass and send it through your 45 ACP full length sizing die which will also decap it.
  3. Send it up through your 41 Magnum SEATING die first to form the neck just short of where you want it.  The seating die has a tapered opening which will do the initial forming straight.  Going straight to the sizing die generally produces a crooked neck.
  4. Send it up through your 41 Magnum SIZING die to bump the neck to it’s final position.
  5. Prime the brass
  7. WAD (Cardboard disc punched out with a sharpened brass case)
  8. SHOT
  9. OVER SHOT COVER (cardboard disc or upside down gas check)
  10. CRIMP – I found the curved seating plug that came with my Lee 45 ACP seating die worked well for forming the crimp.  I was sure to lube the case mouth well first.  Also I got better results after sanding the lip off of the edge of the seating plug where the cases were getting snagged.  (The concave part of the plug didn’t extend to the very edges of the plug, so I sanded it until it did, which shouldn’t affect normal 45 ACP seating operations).


45 ACP Shotshell Specifications


VIDEO: 45 ACP Shotshell troubleshooting and home-made dies.