10 April 2010

Secrets of the Zephyr

As a result of our Underhammer Action Roundup, there has been some discussion about the various ways in which barrels are, or can be, attached to an underhammer action. The resulting exchange of ideas lead to the question of how it is that the Zephyr and the newer Faeton barrels are attached to the receiver as neither of those rifles display any apparent tapered pins or screws.

The breeching system that I chose for the Zephyr is very simple, secure, and aesthetically pleasing because of its covert manner of wedding barrel and receiver in tight union. But that's not the only advantage of this system as study of the accompanying graphics will clearly display.

Breeching begins by reaming and tapping the front of the Zephyr/Faeton receiver to accept a ¾” X 16 TPI (threads per inch) breechplug. The breechplug is an unheard-of 2 inches in length and it is cut from all-thread steel rod. While most muzzleloading rifles feature a breechplug with about ½” of threaded journal which is screwed into the barrel, the Zephyr’s breechplug is seated 1 ½ inches into the barrel. Such an arrangement provides advantages that are most unique to the Zephyr and help contribute to its fine accuracy.

First and foremost, the barrel and receiver are torqued together like the head bolts on a diesel engine. That quality of tightness of barrel and receiver provides a stiffness that any serious target shooter will tell you is paramount to consistent accuracy. All things being equal, the stiffer the rifle, the more accurately it will deliver the goods to the target.

Unlike most other muzzleloaders, where the nipple is screwed directly into the barrel, in Zephyr and Faeton rifles the nipple screws into the breechplug. That's right - directly into the breechplug. While it's okay to screw the nipple directly into the barrel, the result is that the cap flash is sprayed into the body of the powder charge thereby allowing the powder ignition impulse to follow any random burning pattern which can result in shot-to-shot inconsistency and deterioration of accuracy.

By screwing the nipple through the barrel wall and into the breechplug, not only do we create a stronger breech, we also have the basis to utilize a coned-breech. With the coned-breech, the ignition impulse always begins in exactly the same spot, the point of the cone, and burns straight forward through the powder column. In addition, the coned breech also provides the advantages of the shaped charge principle, which some of you military men may recall.

Simply stated, the shaped charge principle will amplify the ignition impulse to get the full charge up and burning much quicker and more efficiently. Another reason why the 20-bore Zephyr or Faeton can completely burn 200 grains of blackpowder in only 30 inches of barrel.

Clicking on any of the images will enlarge them for detailed viewing. Clicking the Back button on the top left of your screen will return you to the text.

Additionally, screwing the nipple directly into the breechplug will result in the creation of a nipple pocket in the barrel wall as seen in the drawing of the Faeton breech. One must first counterbore through the barrel wall in order to reach the body of the breechplug.

Provided the hammer is properly designed and fitted to the barrel and the nipple, the result is a nipple and cap that are virtually enclosed at the moment of ignition. Cap spitting is the number one complaint that most shooters have about underhammers. Utilizing an enclosed nipple pocket – and using musket caps - will solve that problem.

So, in summary, the stiffer the rifle, the more accurate it is likely to be. BTW, a tapered barrel will generally deliver better accuracy than will a straight barrel. But we need more than just fine accuracy from Zephyr and Faeton rifles. While accuracy is absolutely important, we build hunting rifles. They not only must be accurate, they must also be tough as nails to stand up to the rigors of prolonged and rough outdoor hunting.

As an additional point on the stiffness and ruggedness of the Zephyr and Faeton rifles, the photo below will illustrate the back half of the stiffness/ruggedness/accuracy equation that we believe is essential in a big game hunting rifle. Such over-engineering, as some call it, eliminates any flexing or bending of the rifle at that critical joint of buttstock and receiver.

If you would like more information about the Zephyr, you may contact Pacific Rifle Company at their new e-mail address:  pacificriflecompany@gmail.com.
If you would like more information regarding the Faeton, please contact me at: underhammers@safe-mail.net.

Hope that’s been helpful.




Anonymous said...

Mr. Renner,

I really like your Faeton rifle, but I am wondering if you can make it with a regular pistol grip instead of the metal one. I think a full wood pistol grip would make a beautiful rifle.

What are your thoughts on that?

Billings, MT

Roger Renner said...

Hello Mr. Hackman. Thank you for your comment and inquiry.

Several years ago I had a customer who asked the very same question. I gave him his wooden pistol grip and a few other custom features as well. He loved the rifle.

I'll see if I can find the pics of it and post them on the blog as an example of what can be done when you start to think out of the box.



Donna said...

Mr. Renner,

I taught high school math for years, and we had a phrase in math .... "the elegant solution." Your breech plug installation is definately an elegant solution! It also gives a tyro like me a "duh" moment. :-)

Don Lohr in the mountains of West Virginia

Roger Renner said...

Thanks Don, for your kind words. Glad you liked the elegant solution.



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About Me

Roger Renner

Hi. I've been a student, admirer, and designer/builder of underhammer guns for over 30 years. In that span I've built over 200 semi-custom underhammers exploring the possibilities from the ordinary to the exotic. In 1996 I founded Pacific Rifle Company to explore the market's interest in a high-quality underhammer rifle. Thankfully, that interest was, and still is, there. I sold PRC in 2006 but continue to craft high-end underhammers as I am truly afflicted with underhammeritis - which can be contagious!