History of OpenTop

We asked the Inventor of the OpenTop, Sebastian Unger, to tell a brief history of the design and how it came to be…

The story of the OpenTop design began in autumn 2017 in the garage of my uncle near Vienna, where we met from time to time to talk about firearms, toolmaking and drink a few beers. He is a toolmaker and a firearms enthusiast and some day he decided to build a 10/22 from scratch, which is legal in Austria, as long as the rifle is registered by a gunsmith. He never completed the project, but thank god he started with the receiver.

A few weeks later I came to his garage for obvious reasons and he showed me his unfinished receiver. He had a friend who could cut EDM wire, so he decided to screw on the top of the receiver, and let his friend cut the inside with the EDM wire cutting machine to save some time. Removing the inside of the receiver on a manual mill is a lot of work, which is something I figured out a few weeks later milling the complete receiver from scratch on my Deckel Fp1 milling machine from the 1960s.

In a split second of time I realized that the complete rifle could be disassembled from the top in a much simpler way, if there would be no screws. In the very first moment I had the feeling that this is a once in a lifetime idea, a idea where people will say “why I didn’t have this idea”, which is what Mr. Darrel from Recoil wrote in his report, after he had tested one of the latest prototypes in 2021.

A few months earlier I had sold my first Ruger 10/22, because the disassembly and assembly procedure was annoying for me, so having the idea with the receivers after seeing the crude receiver with the screwed-on cover was basically fortune.

So for the next few weeks I couldn’t sleep well, because I couldn’t stop thinking about making a version of this that could be disassembled without any tools. As soon as I had the final idea I made a 2d drawing and started to mill the receiver from complete scratch.

As soon as the prototype was finished I went to the patent attorney in Vienna, asking if it could make any sense trying to get a patent for it. He told me that he sees a lot of useless things, but this is something very useful. He might say so to every inventor, but we made a pre-patent application to protect it, so I could show the receiver to the world without too much risk.

As soon as you show something in public, it is not new anymore and you can’t get a patent for it, so before you even take a photo of something, it is essential to apply for a patent.

A gunsmith registered the rifle for me, then I milled the bolt and the barrel and completed the rifle with Ruger parts. To my surprise – it was the first rifle I have ever built from scratch – the rifle performed flawlessly outright.

In January 2018 I contacted Ruger to show them my design, and for my surprise they sent me a NDA. Because of the NDA I can’t say anything about the correspondence, but Ruger didn’t buy the design.

So I started to show the design around and to my surprise Pete from Thefirearmblog supported the project and wrote a report about it. 

Pete supported this project from the very first day and without his help this complete project maybe would have failed completely.

The comments regarding the design were great, people loved it, but the few critics showed me that I had to improve things. It was people who understood the disadvantages of the design.
Having the picatinny rail on the cover would have resulted in decreased accuracy, because in mass production things have to have some play, which is something my prototype didn’t had.

So I started to design and build a technically improved version without technical advantages and viable for mass production.

Pete helped me again with a report for The Firearm Blog and people love the V2 as they have loved the V1, but the few critics helped me to understand that the receiver had to be 100% Ruger compatible.

https://www.thefirearmblog.com/blog/2018/09/20/austrian-topside-takedown/

I got many messages from manufacturers but nobody really offered anything. I even got invited to the IWA without having any success in licensing the design. Speaking with all those people was priceless anyway.

So after reading the critics in the TFB report I designed a V3, that was now 100% Ruger compatible. I learned how to create STP files for CNC machining and also figured the right tolerances out by testing. Every area of the receiver was improved several times and a lot of testing was done with each and every receiver of the various prototyping runs, till the V3 had a satisfying level. The accuracy was top notch, the reliability was exceptional. As a perfectionist I always found many small things to improve but overall the design worked very well.

In 2020, without having a manufacturer willing to produce the design, I did the first production run for Europe with the company who made the prototypes for me, which was completely useless commercially, because of the small sale numbers in Europe for those types of firearms, but at least I had real customers being happy with the design. Not a single customer had a complaint about the receiver, I didn’t sell too much but it gave me a lot of confidence that many years of hard work paid off.

After 3 years of hard work I really had something in my hands, I could not have even dreamed of in 2017.

At the end of 2020 I got contacted by Mr. Paul Fletcher, who was interested in the design. I have sent him the 3d files and the critical tolerances and he promised to produce some prototypes for testing.

I had absolutely no expectations anymore, because so many people made promises without doing something, so my optimism was at its all time low.

For my surprise he produced the prototypes quite fast and we agreed on the conditions.

So after nearly 4 years, this will finally be available in the United States, and I still believe this will become a huge success.