Smilodon, I am a serious scholar of civil war Militaria, and therefore, a seeker of the actual Facts. So, I'm man enough to publicly say my previous reply about your find might be either correct, partially-incorrect, or entirely incorrect. (I am not sure at the present time.)
You asked if your find is a friction-primer, and you said you found it "at a site that had a few Enfield bullets" -- which indicates a civil war era Military site. I replied that although I've been in the field of civil war era artillery study for several decades, I did not recognize the object you found as a civil war era friction-primer. At the time I wrote my reply, I was unaware of the old T-Net post about a similar "T-head" object found in the Pacific Northwest. Nor about the 1911 Encyclopedia diagram. They got me curious, because I have seen an incredibly rare version of Confederate civil war friction-primer that somewhat resembles the Pacific Northwest one. (There is only one known site that the CS-made version has been excavated from -- and it is not a battle-site.) There was no civil war combat in the Pacific Northwest, so the one from there presumably isn't Confederate-made. The digger who found it said the site was occupied from 1850 to 1880... so it cannot definitively be said to be from the civil war era. (Also, note that the Encyclopedia Brittanica diagram is from 1911.)
I'm continuing to do research on the non-Confederate Pacific Northwest "T-head" primer and the extraordinarily-rare Confederate "T-head" version. To succeed at solving the mysteries, I'll need some additional information from you. (For example, you did not give any size-measurements of your find.) I realize you may not want to publicly post any information about the dig-site where you found your piece of a friction-primer, so I'll send my info-request to you in a Private Message.