A Tale of Two 10/22s

by GunsmithUSA Contributor Dan Rogers

Recently I was commissioned to build two identical 10/22 rifles for a local gun shop. The two consisted of Brownells receivers, KIDD light weight threaded barrels, KIDD bolts, Ruger BX trigger, and MagPul hunter stock. I figured this would be a relatively easy task especially since the components of the rifles were identical. I soon came to realize that just because parts are sourced from the same manufacturer does not mean they will assemble in the same means with the same desired results. If you have a little time, let us delve into this little semi-automatic dilemma and see how it all panned out.

The first thing I always do in any build or assembly project is inventory and assess all parts, pieces, and components associated with the project. I verified I had the necessary parts to end up with two complete firearms once the project was complete, so without further ado I began assessing the components. During this process I like to take into consideration any tuning, modification, or critical measurements of parts that may need to be addressed so that the best results can be attained. I started with the bolts. I was pleasantly surprised in the quality of machining and dimensions of the KIDD bolts. I had never used any KIDD 10/22 parts, so this was my first experience with them. Both bolts measured exactly .043” headspace and had .033” firing pin protrusion. I was fairly impressed by that and moved on to firing pin tip profile. Upon removal of the firing pin I found the tip was a simple bevel cut with a thickness of a whopping .048”. Given the protrusion and headspace measurements I probably could have left the tip unmodified, but I went ahead and radius cut the tip and brought the thickness down to .032”. Happy now with the bolt and firing pin I verified the extractor angle and set the bolts aside I turned my attention to the remaining components.

I will refrain from expounding on all the inspections and checks I made in the interest of time and boredom of readership. So don’t blow me off thinking this article is just a constant string of numbers and figures. I was simply encouraged by the consistency of the bolts and certain my little project would run expeditiously along. Next, I turned my attention to test fitting the barrel and receiver of one of the rifles. The fit was EXTREMELY tight. I measured the shank of the barrel and the receiver opening and they were very close. In addition to them being very tight the barrel shank had about .002” taper. I decided use a method I like to call “thermal bedding”. I am not sure if this is the correct usage of the term, but I will explain my methodology. When I have 10/22s that have a tight fit, but I feel do not necessitate removal of barrel tennon or receiver material is necessary I use this technique. I simply take the barrel and place it in the deep freezer allowing it to reach -10 degrees Fahrenheit. In my experience overnight is sufficient time to allow the barrel to cold soak. I have never had to cold soak one over 24 hours. Before I decide to join the barrel and receiver I put the receiver in the oven at 180 degrees Fahrenheit. This heating process seems to take place much quicker than the cold soak in my experience. When my parts were properly heated and chilled I slipped them together and made sure to time the extractor grove. Once the barreled receiver’s temperature equalizes the components now have a nice tight fit. I refrain from installing the V-Block until the assembly’s temperature has equalized.

As my first barreled receiver’s temperature was equalizing I turned my attention to number two. I did not bother measuring the barrel tenon or receiver, assuming I would again test fit and thermal bed since the parts were from the same manufacturers. I moved immediately to test fitting the barrel to the receiver. To my surprise the barrel plopped right in. I was pretty darn amazed given how tight the first assembly was. I checked to see if there was any appreciable slack or droop. The barrel fit the saddle really well, but the tenon would contact a bit in the receiver opening. It was barely perceivable, but it sure did bother me. I generally measure my tolerance and shim at the saddle to remedy this, but I could not get anything between the saddle and barrel on this rifle. I then tried to wrap the tenon with shim stock since best I could determine I had just barely over .001” clearance to take up in the receiver. I had little luck in this process using shim stock, so I stopped and scratched my head a bit. I thought why not use some 620 Loctite! 620 Loctite is a press fit compound that is designed for friction and press fit components. It can fill a void of up to .008” if memory serves me correctly. It is specified for assembling some of the components on the diesel engines I have worked on. I applied the 620 to the barrel tenon and slipped the assembly together and wiped the excess.

Like I said I will not bore you with all the details of my little project, but I can assure you when all was said and done I had two functioning 10/22 rifles. The next question would be could I determine whether either assembly method was superior to the other. Without further delay here are some target photos.

When I was really concentrating and doing my part both rifles shot really well. Shots were from bags at 50 yards. The numbers scratched on the targets denote the receiver numbers. One was my thermal bedded receiver and the other my 620 bedded receiver. I started with the 620 bedded receiver. When I got set up and ready to shoot I noticed a dragonfly had landed on the top of my target frame. I honed my sights on him and plucked him right off of there with one round. I chuckled and took that as a good sign. In my best estimation I cannot find an appreciable difference in accuracy of the two rifles. They may very well be limited most by the nut behind the stock. The two and three shot sighters as well as six shot groups look nearly identical from either rifle. These pictures are representative of all of the groups fired from the rifles that day. I certainly believe 620 loctite was a viable method given the circumstances and maybe it can help someone in the future. Maybe I could have done something better, but considering the results I believe my methods were satisfactory.

Questions, comments, snide remarks, sound off in the comments. Thank you for your time and patronage. Until next time shoot safe, shoot straight, and do some ‘smithin’!