I'm in a constant quest for knowledge. I'd like to know exactly the reason for the size and structure of shotgun primers. -- Why were they made different than standard metallic cartridge primers??
Excellent question , I'm just not certain as to the difference but will give You and educated guess .
I will tell You about #38 years ago ,with the introduction of plastic shotshell hulls ,a standardization for primer size was needed and Winchester 209 became that standard ,beating out CCi and others from their 157 size .
Shotshell primer dimensions and other common knowledge factors .
The Shotshell primer slurry is significantly different than Rifle or Pistol matrix . As the shotshell has it's load spread out more than a pistol or rifle cartridge and runs significantly LESS pressures ( generally flake wafer powders more air less actual powder in a confined space ) ,it would stand to reason it's Brisance is greater but pressure is significantly lessened as a result of ignition .
Hottest to mildest supposedly
1. Rem 209 STS,
2. CCI 209,
3. Winchester 209,
4. Noble Sport 209,
5. Cheddite 209,
6. Fiocchi 209,
7. CCI 209M,
8. Federal 209A
.240 = Rem.
.241 = CCI, Fed,
.242 = Nobel Sport, Win, Wolf,
.243 = Cheddite, Fiocchi,
.244 = Rio.
These dimensions are from an article by Tom Ceretto in Trapshooting USA, issue 4, page 50, Nov/Dec 2009
Borrowed this tidbit :
Remington STS - 209's
Length - 0.2930
Diameter - 0.2395 ... just below rim
Winchester - Western - 209's
Length - 0.3030
Diameter - 0.2435 ... just below rim
So, if your once fired hulls have loose primer pockets, use the Winchesters with the larger diameter
And if you have any Remington 57's ... They were used only for old Remington SP cases that were plastic with a fiber "base" wad. About 30+ years old
Length - 0.2940
Diameter - 0.2275 ... just below rim
Here are some Hodgdon numbers. The only thing changed in the two shot weight loads is the primer.
1-1/8 oz Test
Primer Velocity Pressure
Win.AATP 1176 fps 11,200 PSI
Fed.209A 1172 fps 11,100 PSI
Win.209 1173 fps 10,900 PSI
Fio.616 1171 fps 10,800 PSI
CCI209M 1171 fps 10,400 PSI
Rem.209P 1157 fps 8,500 PSI
CCI209 1162 fps 8,400 PSI
Now look at a
7/8 oz Test
Primer Velocity Pressure
Win.209 1214 fps 10,300 PSI
CCI209M 1217 fps 10,200 PSI
Fed.209A 1195 fps 9,100 PSI
Fio.616 1196 fps 9,000 PSI
Win.AATP 1191 fps 8,400 PSI
Rem.209P 1187 fps 8,200 PSI
CCI209 1180 fps 7,700 PSI
Note that as the payload weight changes, the effect of different primers changes. It is not consistent. WinAATP is the “hottest” primer with a 1-1/8 oz load, but only ranks 5th when the load is reduced to 7/8 oz.
Like so much else in shotgunning, it’s hard to be precise about some things. It’s particularly hard to isolate changes to the shell and barrel. So often one change depends on another.
- Small rifle primers – which are about .175 inches in diameter and .120 inches tall.
- Small pistol primers – which are about the same size as small rifle primers but designed specifically for handguns.
- Large rifle primers – which measure about .128 inches in height and .212 inches in width.
- Large pistol primers – which are an average of .120 inches tall and.212 inches wide.
https://www.outdoorlife.com/cartridge-primer-technology-developments/