There's been discussion here before regarding the effects of dampness and oil contamination on primers. Most often heard is the opinion that oil will "kill" primers and dampness can also render them ineffective.

I decided to do a little test and find out for myself. 10 small pistol primers were submerged in water for 4 hours and 10 in Kroil, also 4 hours. After soaking they were drained and allowed to dry for 96 hours in a warm/dry area.

The primers were loaded in cases (38Spl) and popped off in a 2" barreled revolver.

Water soaked, all fired. Kroil soaked, 7 fired, 3 duds. Judging from the noise level, the water soaked primers were as good as new, the Kroil soaked primers, however, seemed to have lost some of their brisance.

It would seem, oil over time may or may not "kill" a primer, water doesn't.

I think the next test will be the same as above, but without the drying time.

I tried similar with water & WD-40. As you noted with the water once dried they all went off. With the WD-40 I found the longer the drying time the more would go off though it never was 100%. With thge WD-40 they did seem to loose a bit of there umph.

I haven't checked lately but years ago Saeed did such a test and it was published in the information section of this site. It was quite thorough. You might check it out as it was very informative and very thorough.

Hey Bob338, Didn't Mr. Foster also do a very controlled Test of this a few years ago?

Yes he did. Bob Foster was one of the most knowledgeable posters around. He's now retired and hangs out at another site I frequent.

Bottom line is it takes a helluva lot to kill a primer.

[QUOTE]Originally posted by Bob338:
Yes he did. Bob Foster was one of the most knowledgeable posters around. He's now retired and hangs out at another site I frequent.

Bottom line is it takes a helluva lot to kill a primer.[/QUOTE

When I started loading,(1963), I was told empahaticly that just the oil on my fingers would kill primers. Have primers gotten better,(better sealers), or were the primers of that era that fragile?

Kroil and wd-40 are both penetrating oils. They probably dissolve the sealant to render the primers inert. I would think a simple petroleum based oil would have less effect on primers.

Originally posted by grizz:

quote:

When I started loading,(1963), I was told empahaticly that just the oil on my fingers would kill primers. Have primers gotten better,(better sealers), or were the primers of that era that fragile?

I was told the same thing. I'd try the same test on with some 40 or 50 year old primers but I don't have any that old. I do have some 50yr old Turk 8mm, maybe I'll pull some down and see what Kroil does to the primers used in it.