The Box O' Truth #39 - Oil Vs. Primers

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The Box O' Truth #39 - Oil Vs. Primers - Page 1

We have all participated in debates about how harmful oils are to primers.

In fact, I, along with most folks, often said, "I bet WD-40 will quickly kill a primer. You had better keep it away from your ammo."

But, just how fast does this happen?

I had one respected firearms instructor tell me that in the post I did on Cleaning and Lubing a Semi Auto Pistol, I needed to warn folks not to get any oil in the firing pin channel.

He stated that any oil on the firing pin or spring or channel would drip down on any loaded round in the chamber and quickly kill the primer.

I told him that I had been cleaning pistols like that for almost 50 years and had never had a problem. But it got me worrying… what if this was true?

I recently saw an article where a guy tested this phenomenon of oil and primers and decided to do my own test.

First, let's settle the question: "Will penetrating oil "kill" primers?"

I placed a few Small Pistol Primers in a dish.

Then I sprayed them with WD-40 and let them soak for several hours.

I then seated them in a sized 9mm case...

... and loaded them, one at a time, in my Beretta 92FS.

I pulled the trigger on them and they all failed to "pop".

They were dead. Here's a picture of the dents in the primer made by the pistol.

Good, hard strikes, but no joy.

There is no question that penetrating oil will "kill" a primer, if sprayed into the open end of the primer.

But how would it affect loaded ammo?

Here's what I did.

I placed separated lots of 10 rounds of Winchester 9mm White Box ammo in a holder.

I choose 5 different oils to test.

I then placed a "puddle" of each oil on the primers of the rounds and let them sit, undisturbed.

I tested them with the following oils:

Birchwood Casey Synthetic Gun Oil, Break Free CLP, Kroil Penetrating Oil, Hoppe's #9 Bore Solvent and WD-40