Small & Large primers Small primer VS large primer
Recently some companies started making cases with small pistol primers for the 45 ACP. Why? Who knows? Anyway it is something we have to deal with so I am doing testing on small VS larger through the chronograph. I have found that Federal and Fiocchi are using small primers in their ammo. It’s conclusive that large primers give more velocity with all powders tested especially the slower ones such as Herco. That is because the large primer has a stronger ignition on the powder charge. Felt recoil was different with some of the loads that read 100 FPS difference or so. You can also see that there is a difference between a 3” and 5” barrel and different guns with the same barrel length. It goes to show you that any change in components will change the end results. If you are using a max load and change any component you should drop down about 5% or so to evaluate the new load. Otherwise you could go over the top with the new load.
Rock Island 5” barrel
6 X Herco 230 grain Ranier (small) 816.8 high es
6 X Herco 230 grain Ranier (large) 931.2 nice
6.5 X Unique 230 grain Ranier (small) 935.6 consistent bit fast
6.5 X Unique 230 grain Ranier (large) 1012 consistent & fast
5 X Red Dot 230 grain Ranier (small) 714 3”
5 X Red Dot 230 grain Ranier (small) 739 5”
5 X Red Dot 230 grain Ranier (large) 726 3”
5 X Red Dot 230 grain Ranier (large) 770 5”
6.5 X 231 185 grain Ranier (small) 692 3”
6.5 X 231 185 grain Ranier (small) 728 5”
6.5 X 231 185 grain FMJ WC (small) 753 3”
6.5 X 231 185 grain FMJ WC (small) 782 5”
6.5 X 231 185 grain FMJ WC (large) 822 3”
6.5 X 231 185 grain FMJ WC (large) 825 5’
5” Iver Johnson
6.5 X Tite Group 185 grain Ranier (small) 1019 consistent
6.5 X Tite Group 185 grain Ranier (large) 1055 consistent
6 X Herco 230 grain Ranier (small) 823.9 high es
6 X Herco 230 grain Ranier (large) 867.9 consistent
4.5 X Tite Group 230 grain Ranier (small) 869.8 ok
4.5 X Tite Group 230 grain Ranier (large) 884.2 consistent
Sig 5”
6 X Herco 230 grain Ranier (small) 695.8 ok
6 X Herco 230 grain Ranier (large) 848.4 consistent
Many years ago the 38 and 357 mag cases had large primers but someone realized that a small would work just fine. You will probably never encounter these cases but if you do make sure you reduce your load especially if it is a hot one. If powder is over ignited that could cause a dangerous pressure spike. That is why the flash holes are the size that they are. Starline makes 45 Colts cases especially for blanks and the heads are marked as such. Under no circumstances use them for smokeless powder ammo as that will almost certainly result in disaster. I have also seen 400 Cor Bon ammo with both size primers. Such situations are a pain in the keister. But the prudent reloader should be aware of this situation. At one time they made small primers for the 30-30 but they evidently didn’t work out well due to under ignition of the powder and were discontinued.
Iver Johnson 45 ACP
