by Robert D. Beeman Ph.D.
Reproduced from American Airgunner, July/Sept 1995.

Several years ago some of us at Beeman Precision Airguns Inc. undertook an interesting experiment using Dermestid beetles of the variety commonly used in zoological museum preparation rooms to clean dried muscle and grease from animal skeletons. It has been known for centuries that the larvae of such beetles can clean skulls, and other skeletal parts, with far greater precision than any chemical, boiling, or mechanical means. Dermestid beetle larvae work so well that even the delicate, lace-like ethmoid bones of the nasal cavity septa and the auditory ossicles of mammalian skulls are left both perfectly clean and perfectly in place. It occurred to us that the grease eating properties of these organisms could be applied to cleaning out grease, particularly hard, caked grease from airgun mechanisms. We entered adult beetles into various airgun mechanisms and were delighted to note that the resulting larvae worked just as well in the nooks and crannies of airguns as they did in the tiny chambers of various skeletal parts. We found that it was not necessary to select beetles for caliber so long as the adults selected were of small enough size to be entered into the bore of the barrel. Pregnant females, or beetles of both sexes in breeding condition, were entered into the area to cleaned. It was necessary that these organisms be restrained to the area to be cleaned, but it was also important that such closure or capping not be airtight. These beetles, in all of their stages, need atmospheric air.

Cleaning airguns with Dermestids takes longer than conventional methods. It requires letting the beetles lay eggs and develop larvae. However, this biotechnical method produces superior results. Dermestid larvae should produce results that are superior to those obtained with genetically engineered, grease eating dung beetles (as reviewed by Robert Walls Jr. in 1992: RAC Airgun Magazine, vol. 3, no. 1). This because Dermestid larvae can clean into far smaller spaces and crevices than can adult beetles. In either case, it is important to uncap the gun and allow both of the feeding stages of the beetles to escape before their diameter exceeds the caliber of the gun being cleaned. We did this test only in .177” caliber airguns and found that escape must be allowed between nine and ten days after entry of the breeding beetles.

There is an undesirable side effect of such cleaning by Dermestids. Although the removal of excess grease and oil was meticulous, to say the least, the adult beetles would sometimes attack leather piston seals and destroy them, or crater into synthetic piston seals. Of course, the digestive tracts of the beetles were clogged by the indigestible material of the synthetic piston seals. This caused death of the beetles, but not before they had removed an average of 27.3% of the piston seal mass. This removal created a crater near the center or one edge of the seal. These craters, much like those which appeared in the seals of early model Beeman RX rifles that had been overcharged, caused such a drop in the compression ratio that a very significant power loss occurred. A similar, or even greater seal problem would be expected with the larger dung beetles.

I still maintain my research ties to Stanford University. It was in those laboratories, specifically at the Cornelius van Neil Memorial Microbiology Laboratory at Stanford's Hopkins Marine Station, that we discovered an alternative biotechnical method of cleaning airguns which was not only faster but did not present the above problems. We started with some of the newly discovered “oil eating bacteria” which became famous in the cleanup of the Alaskan oil spill. Through genetic recombination at their TK and RD gene loci we were able to produce bacteria that attacked the polymers of airgun lubricants, at least those polymers found in Beeman airgun lubricants.

One of the absolute beauties of this new system is that it is completely caliber independent. As noted above, we had to be careful in selecting small enough Dermestid beetles, and dung beetles reportedly were available only for guns between .177” and .22” calibers. There are no such size restrictions here. One need only pour a small amount of liquefied agar-agar media solution, containing an inoculation of not less than 1070K of bacteria that bear the modified genome, into the gun cavity to be cleaned. This cavity, generally the barrel bore/compression chamber unit, must be sealed with an inorganic sealant grease and the muzzle capped. These bacteria actually depend upon being in anaerobic conditions so there are none of the ticklish problems of providing sufficient atmospheric oxygen, as is the case with the beetle introductions.

After only 17 hours of being sealed in the gun, the rapidly growing bacterial population creates an absolute cleaning, even down into crevices into which only a microbe could reach! After that interval, the bacterial broth should be decanted into a Pasteur flask for autoclaving. The cleaned gun cavity should then be rinsed with a mild organic solvent, to remove remaining traces of the culture solution and sealant grease, and the involved surfaces sterilized by thermal means or ultraviolet radiation. The clean surfaces should be dry and lightly treated with a metalophilic polarizing oil. After cleaning several hundred airguns by this wonderfully easy method, we have found perfect cleaning with no damage whatsoever to seals or other gun parts.

After Mrs. Beeman and I sold Beeman Outdoor Sports (the Northern California section of the former Beeman Precision Arms Company) in October 1994, we turned our grease eating bacteria cultures over to the new owner, Laurie Brown. The new company operates under the name of Airguns International* at 3451G Airway Drive, Santa Rosa, California 95403. A sealed flask containing a starter population of these bacteria can be obtained from AGI for their actual cost of $34.60. While that may be high for individual shooters, a dealer or club can obtain a single inoculation and maintain it easily in a one or two liter glass culture container full of inexpensive growth media. Then, virtually without any additional cost, any number of shooters, even hundreds, can obtain their own starter cultures for cleaning their own guns. If an equal amount of sterile growth media is added each time a bacterial sample is removed and simple, proper growth conditions are maintained, it should be possible to maintain the culture for decades.

Written April 1, 1995.
*Airguns International closed in 1996.

Post Script by author Robert Beeman: The above article actually was published in American Airgunner magazine in the July-Sept 1995 issue. I was sure that the editors would understand the nature of this article. I certainly did not intend to deceive them, but to this day I am not sure if the editors originally understood that it is a "mad scientist's April Fool's joke" (Note the April 1 date!). They issued a note in the next issue warning readers not to take it seriously. The most amazing result of the article's publication came from a top officer (name withheld here to avoid embarrassing the innocent) of S/R Industries. He phoned me to indicate that giving the bacterial cultures to Airguns International was a violation of the non-compete provisions of the contract that transferred all national and international interests of Beeman Precision Arms Inc. to S/R Industries. He indicated that it was okay to sell these cultures in the Northern California area that we had reserved for ourselves (since S/R was not willing to buy our local business), but that sales outside of the Northern California area, as specified in the contract transferring ownership of the Beeman company, was a violation of that contract. I replied that we would transfer the entire international rights to our bacteria to the new Beeman Precision Airgun operation in Huntington Beach, California without cost. I don't know if he passed on the news of this generous offer to his management team and lawyers, but we never heard about the problem of the contract breaking bacteria again!

"RD and TK gene loci"? Well, our names are R.D. Beeman and T.K. Beeman.