
Low Case Fill Woes
I recently acquired my first revolver, a Taurus Judge Public Defender Polymer in 45 Colt/.410. At the same time I purchased some Hornady FTX Leverevolution cartridges so I could go to the range to play with my new toy.
A new caliber is a sickness, I quickly got around to buying dies and finding some 250gr plated round nose projectiles and large pistol primers at the local gun shop. Looking around hodgdonreloading.com I saw a recipe using Winchester AutoComp which I already had on-hand. The same 8.0gr recipe was also found in Propellant Profiles.
I loaded up 20. As I was loading them I was concerned about the relatively low case fill and put a shout out on The Reloaders Network Headspace. There were a number of friendly comments as to what powders others were using with 45 Colt. But trusting my recipe I went to the range with chronograph in tow.
The first shot was 321 fps, the second 249, the third was a poof and spray of powder of a misfire, the bullet about 3/4″ into the barrel.
On the way home I stopped by the LGS looking for a pound of TrailBoss, or Unique, or Universal, or 231; he hasn’t received powder in two months. When pressed for a bulkier powder, he had some Alliant Clay Dot and a recipe in an older Alliant Catalog for 5.2gr. I purchased the Clay Dot, went home and pulled out Propellant Profiles again. Sure enough R.H. Vandenburg Jr had a ‘favorite’ recipe of 5.0gr of Clay Dot as well.
I weighed out 5.2gr of Clay Dot and 8.0gr of AutoComp. In the case they look similar. In the pan there is a considerable visual appearance.
(My Frankford Arsenal digital scale reads 0.1gr higher than my Ohaus 5-0-5 at 8.0gr, I defer to the Ohaus.)
I’ve heard of poor ignition with low case fill before, but I’ve never had a case as large (relatively speaking) as the 45 Colt, so I’m in uncharted, for me, territory.
In the name of science I found some 1/2″ O.D. acrylic tubing on Amazon, along with a 1/2″ serrated edge paper punch and set about an experiment.
I made some ‘transparent’ cartridges of 8.0gr of AutoComp without and with a cover card. I also made a 5.2gr of Clay Dot without and with a cover card. The Clay Dot is a bit more static prone and clinging to the acrylic tubing, but it looks bulkier and as a flake powder, it should be more ignitable than the AutoComp ball powder.
So the test is:
8.0gr of AutoComp with a cover card.
5.2gr of Clay Dot without a cover card to see it it ignites better than the AutoComp. My theory is it will.
5.2gr of Clay Dot with a cover card to see if there is a change of velocity and extreme spread.
And finally 6.2g of Titegroup, my go to 9mm match powder, without cover cards.
Now off to the range!

I owned a Marlin 60 since 1987, but never really got ‘into’ guns until 2011 when I bought my first 9mm pistol. That was soon followed by a .380 and a 12 guage pump, and I was all in. I had done some 20 guage reloading growing up, and threw myself into 9mm and .223 reloading in 2017, .380 in 2019, 7.62×39 in 2020 and my first revolver in 45 Colt in 2022. It is so satisfying to go to the range and string together ever improving groups with ammo I loaded myself; it doesn’t hurt that I’m a little OCD about technical things, the tangible/visible rewards are really gratifying.
I have a nagging but as yet unattained ‘want’ for a .358 Yeti unloader, it just looks like a really cool caliber. My next learning curve, space permitting, is casting and coating.