Winchester Protected Primer


Does anyone have general information on two piece primers? Were they cheaper to manufacture, reliable or just different. There must have been some great idea behind it.




[quote=“Jones”]Does anyone have general information on two piece primers? Were they cheaper to manufacture, reliable or just different. There must have been some great idea behind it.


Jones, this primer was called the protected primer. Its purpose was to protect the primer(copper part) from the nose of the bullet behind it in a tubular magazine weapon. Upon firing, the cartridges are subject to being rammed into the bullet in the rear,(inertial energy) and could set off the cartridges in the magazine. M. Rea


While I agree with Mora’s explanation, I’ve always regarded the protected primer as marketing hype and the answer to a question which was not asked. These are only seen on cartridge types which used blunt nose bullets in the first place. Winchester was producing rounds in these designs before they added the protected primer to their product line, no one else pursued this sort of configuration (which, if it was truly a safety issue, would have been nearly universal) and there was no flurry of exploding ammo tubes when this type was discontinued.

They do look pretty neat, though! Not that anyone in the firearms / ammo business has ever embraced purely cosmetic designs to boost sales . . . .

My $0.01 (half as good as $0.02!).



I appreciate the input and the food for thought!

Thanks guys!


Post Script:

Is the “primer cover” an extra part of the primer or part of the case? And/or in using it, was the primer actually smaller than normal? Or was the primer pocket made larger to accommodate the “cover” with a standard size primer?

I don’t mean to ask silly questions, but I really am curious! (Lop sided grin!)


I think this is a great titbit of information I can’t wait for the next dinner party, when the conversation slows I’ll be able to say "well did you know…"


Speaking solely for myself, I don’t regard this as at all “silly” . . . I don’t know, had never considered it and think the answer would be interesting.

Somewhere in the FAQs and / or introduction material, we made a point to state quite clearly there is no such bloody thing as a silly or “stupid” question . . . other than those not asked!!! And if there were ever one which fell into this category, here it is. It is a simple matter, but one which I’ve never seen addressed in reference material and, again, “the answer would be interesting.” Sometimes folks don’t see the forest for the trees and in this instance, I plead guilty, Your Honor.

Thank you for your “silly” question and PLEASE keep them coming - we ALL benefit.



Teak, although I agree with you 100% concerning IAA Forum questions, as a high school teacher I must disagree and protest loud and long concerning questions asked in my little world. If I got a dime for every really stupid question asked in my classes, I’d be one of those rich teachers I hear so much about!


My 1/10 cent addition. According to Watros the protected primer was developed for some of the early smokless “high pressure” rounds (33 WCF and others) because of some problems with blown primers with the copper cups. Don’t have one to measure in my primer collection but they were slightly larger than a standard large primer. The copper cup was swaged inside the brass one and contained the anvil and priming compound. Am not sure but think they were available for reloading. The cups were made in both flat and oval shape.



Thanks all. It appears there’s more to this story than first sight!



it is possible to say in which period winchester these primers used?



Sorry was away at the Southwest cartridge show. Protected primer 5W was introduced in 1895 and used a 1 1/2 W primer (copper) inside a brass protective ring and was .210" in diameter. It was used in tubular magazine small and medium smokeless calibers. The 5 1/2 W primer was introduced in 1904 and used a 2 1/2 W primer (copper) inside a brass protective ring and was .237" in diameter. It was used in tubular magazine medium and large smokeless calibers. My 1916-1918 catalog lists them as seperate items for reloading. Lists the 5W adapted to .25-35 and .30-30 and 5 1/2W adapted to .32 Winchester Special, .33 Winchester and Winchester High velocity cartridges .38-55, .45-70, 45-90 and 50-110. By the way the price was $3.80 per M! According to one source the 5 W was discontinued in 1920 and the 5 1/2 W in 1927.




Very informative… were the “protective” rings stay in the cartridge when reloading? Or were they available to purchase along with new primers. it’s not clear to me from your post.




Jim, The protected primer was made by swaging a copper cup inside a brass ring. Actually a brass cup that had an opening in the center for the firing pin to strike. They were made in effect as a one piece unit and were inserted in the primer pocket and removed as such. The Winchester standard pratice was to stamp the copper primers used for smokless powder with a W (like a cartridge headstamp). On some of the protected primers you will see a W on the copper cup through the opening in the brass and some not. In the smaller ones (5) the copper cup would have to have been made smaller than normal primers as the brass cup was the same outside diameter as a normal large primer. In the 5 1/2 the cups were probably normal size as the brass cup had a larger O.D. Take a look at posted picture of the original question and you can see what they look like. They were really just a solution to a problem at the time. Some of the early brass primers had ignition problems with the older hammer fired guns and some of the early smokless powders used with normal copper primers would “blow” a primer. After they figured out how to get reliable ignition with later priming mixtures in brass cups the protected primers were no longer needed. Besides they took an extra step to make even though they were sold at the same price as regular primers.



Here is a scan of 2 shotshells, they seem to match this topic, also adds a bit of zest to the after-dinner discussion of protected primers.


In the book “the Black Shells” a history of USCCo shotshells it says these protected primers marked “WRACo New #4” were corrosive & C1928-9 Winchester introduced a new "new #4"which was non-corrosive & to differentiate them they were not stamped.By 1934 “the # 209 primer had completely replaced the New #4 primer”.