Terminator .22 Rimfire Action is alive!
Just over a year ago I started playing around with .22 rimfire benchrest shooting. I soon found out that this was quite addicting and it would have been cheaper to be addicted to crack. None the less it is a ton of fun and a great precision shooting training tool. I started off with a CZ 452 Varmint, then a CZ 457 Varmint (a fine factory rifle) and acquired a vintage Remington 40x Rimfire in excellent condition. The 40x really changed my thinking on precision rimfires, the other rifles were great and even excellent rifles for factory rifles but the 40x was defiantly a step above. It was at this point I decided to build a Remington 700 footprint Rimfire action of my own. Being a firearms manufacturer of mostly long range rifles this was not too much of a stretch to make happen. I roughed out a left handed 700 short action foot printed action using only a manual mill, indexing head and lathe. I admittedly made some mistakes and one small design flaw on this action but with the Hart barrel I fitted to it, it shot really well.
I quickly learned about 25 spot BR score shooting as well as the standard 5 and 10 shot IBS style competitions. The 25 spot targets might require some new range equipment. I purchase a NEO front rest. Coming from a machinist background this thing is a work of art and it upped my BR score game a substantial amount. Next was a taller and high quality rear bag. Finally I built a competition loading block and timer setup, this did not up my score but made life on the bench much more comfortable.
After putting a wheelbarrow full of Tennex through the rifle and playing with tuner settings / designs I decided to go “all in” and build a new competition rifle. This rifle would be a custom barrel blocked unlimited chassis with a target weight of 25-30 lbs. The barrel would again be a Hart 16 twist with a slightly heavier profile much like the 40 X profile. The optic would be a Nightforce 8-32x Benchrest scope. The trigger would be a Jewell 2 oz. competition trigger. I also discovered that I did care for shooting the left handed action I had made for the “Big Red” rifle on the bench. I much preferred a right handed action, even though I am left handed, so I could easily look into the loading port while single loading the tight “match” chambers. So again I spent hours drawing plates of action parts, redesigning pieces and laying out the new right handed action. So after a week of designing and drafting plates I was ready to start carving out a new action.
The new action started out life as a solid block of 416 stainless round bar stock. After quite a number of hours on the mill cutting, running the indexing head and time on the lathe the action body was done. The action lockup is handled by an internal lug and not accomplished by the bolt handle like most actions. The trigger cutout was standard Remington 700 style and shape even allowing the safety cut for later sporting applications. It was apparent at this point I was going to produce this action. With the action done there only 10 or 11 more pieces left to complete the action, no problem right? The next piece to make was the shell / ejector plate. I designed this action as a single shot only, so the shell plate has an angled groove for the shell to rest in with tapered sides forcing a live round to roll to the center loading position automatically. You can simply toss a round in the loading port and it will self-center to be fed into the chamber. From this point I built my way out of the action. I build the main bolt body, handle & knob followed by the floating bolt. Then the striker, extractors, firing pin, extractor spring, cocking piece and bolt shroud. The bolt release is unique in that it is a flush pocketed style that doesn’t protrude from the outside of the action. With the action completed as far as building I tore it down and sent the cocking piece, bolt release & floating bolt off the be titanium nitride finished.
While waiting for the nitride parts to come back I started on the barrel block chassis. The barrel block design allows the action to “float” as well as most of the barrel. The optic is mounted directly to the top barrel block cap. With these ideas in mind I designed the front bag riding surface to be a 3” wide tapered side design and the rear to be a square profile with half round tops. These tubes I wanted to make from carbonfiber for stiffness and to hold additional lead weight. It turns out that building the carbonfiber tubes from scratch was a little more complicated than I expected. However I managed to get the tubes built like I wanted, this required that I make forms, turning mandrels and learn a little bit about the different weaves of carbonfiber.
With this completed I sent the barrel block pieces and the barrel tuners piece off to be anodized blue. While waiting for the anodizing to be done I got the action pieces back from nitride and assembled the action. I next installed a Hart barrel 22” long with a 16 twist and an EPS chamber cut with .040” rim thickness. I crowned the barrel and also cut a short step on the outside of the barrel to accommodate one of our Terminator barrel tuners.
I patiently waited and finally received the barrel block parts back from anodize. The finish was awesome. I spent the rest of the day mounting the tubes together so the chassis assembly could come alive. With the tubes, end caps and other chassis pieces mounted I was excited to get the chassis , barreled action, tuner and Nightforce optic all together. Once I had these items assembled I added one of our anti cant levels and installed a Jewell trigger that was then tuned to 2.0 oz.
With every thing together and ready to roll I took several pictures and finished documenting all of the specs.
Rounds Down Range, I set up some standard IBS 100 yard rifle benchrest targets at 50 yards on a day with variable windy conditions. I got a rough zero on the rifle (hard to establish a solid zero in the wind with a Rimfire) and then shot some winds shots to get the barrel coated with bullet lube. After an initial warm up and work in I got serious about shooting groups. One of the first groups I shot was a .166” 5 shot group. I was quite pleased with this as I was still getting used to the new barrel block platform. I got snaked by the wind on the next group and moved on. I fired the first 4 of the third group into a hole that measured .039”. Of course you know the rest of the story, shot number 5 opened that baby right up to .225”. Now not quite as happy with the .166” group fired earlier I settled in to shoot another 5 shot group and kept it together for a .094” group. I was quite pleased with this performance out of the new rifle. No ammo testing, no tuner testing just shoots good right out of the gate. I sat down for my final test, I had anticipated a much longer testing secession to get even part of this performance. So with time and ammo left I fired a 50 shot group with an entire box of Eley Tennex in to .558” and same old story 1 shot cost me big, defiantly cost me a sub ½ moa group. The only testing left to do is to get a serious round count through the action and inspect it. Assuming that no issues rear their ugly head the Terminator Rimfire action is ready to rock!