Initial thoughts on the American Rifle Company “Nucleus” action.


I wanted to post up about the American Rifle Company “Nucleus” action. We have had one in our shop for about a month now and I wanted to share some detailed pictures and thoughts on it so far. Instead of repeating what is already available, I will post a link to American Rifle Company’s website with the information for the Nucleus and I will just give my thoughts on what I like and don’t like.

I want to say first off that I took full liberty to do whatever I wanted to with this Nucleus knowing that it will not be in the hands of the public. I did sweep back the bolt handle and American Rifle Company does not warranty the action if that service is done. Since this is not a customers rifle, just a prototype for testing, I modified it because I prefer a swept back bolt handle. I have lots of time behind Remington 700’s, Defiance Deviants and PTG bolts with swept back handles, so it is my preference.

American Rifle Company Nucleus Action

-Controlled round feed works great, have not had one failure to load, extract or eject
-The bolt lift is super smooth, dual cocking cams works great
-Heavier firing pin for more consistent ignition
-Bomb proof bolt stop
-Removable bolt heads for multi-caliber applications
-Salt Bath Nitride finish is very smooth and the bolt feels like it is on roller bearings
-Rifle has been super accurate, a testament to the ignition system and execution of threads, lugs and action face
-A lot of value for $1000

-Shipping date is still not determined
-A lot of moving parts in the bolt
-Like any mechanical eject action, the bolt needs to be run with a certain amount of velocity for proper ejection
-Another action wrench which is not even manufactured yet will be required for conventional barrel changes
-Bolt knob is still undetermined, current knob is not for everyone

I grabbed a Bartlein Heavy Palma, 1-7.5″ twist barrel and chambered up the rifle in 6×47 Lapua. This is my Go-to cartridge for competition and I was itching to get this rifle out and shoot a match.  With out any real practice I was able to shoot a local match and place 6th with some pretty competitive shooters.  I’m in no way saying it was because of the Nucleus, but I will say that it just felt so good working the bolt, it was smooth and crisp and I had 100% confidence in the action which helps! I typically like to run a good bedded stock like the Manners T6A or the Manners PRS2 with their Elite Tactical finish, but this rifle I wanted to try something different. I ordered up a Kinetic Research Group “Whiskey 3” Gen 6 chassis. I also wanted to run their new Enclosed Forend  because I typically run my support arm up front and grab the forend when shooting on barricades. KRG’s Whiskey 3 chassis has excellent grip geometry which helps promote consistent trigger pull and all the tool-less adjustments are nice. In addition, we have found all of KRG’s chassis are very accurate and the folding mechanism has one of the tightest lockups of any chassis we have used. To finish the rifle off, we installed a Trigger Tech Diamond (Pro Curved) set to 12 oz, an Area 419 Hellfire muzzle brake system up front and for optics, I prefer the Kahles 624i scopes. The MSR2, SKMR and SKMR3 are some of the best reticles and the glass is super clear. I have found the the eyebox is so forgiving and the sight picture can easily be acquired.

Overall, I have really enjoyed the action. The one in our shop is just a prototype. We had to relieve a little material on the back of the bolt for clearance with the action. I believe the ejection port needs to be lengthened to the rear to aid in getting the brass out of the ejection port and the bolt knob that was on it from SHOT show was horrible at best. I ended up taking an Area 419 bolt knob, bored out the 5/16 x 24 threads and drilled and tapped the knob to work with the Nucleus action. I also heated up and swept back the bolt handle. After doing this, the action felt better, and the biggest change that I felt made the bolt manipulation feel better was the Area 419 bolt knob. I have also run the American Precision Arms bolt knob and it felt great too.  Before I even played with the bolt handle the bolt could be run smoothly and your hand has lots of clearance with the optic.

So what are the big differences with the Mausingfield and the Nucleus and why is the Mausingfield $600 more than the Nucleus?

Answer: The Mausingfield has more complex geometry with the integral lug, there is more raw material required to build it. The extractor on the Mausingfield is larger and has more going on with it than the Nucleus. The DLC Coating is a lot more expensive than Salt Bath Nitriding. Salt Bath Nitriding is not currently available on the Mausingfield due to the current material and heat treat specifications.

So which is the better action?

Answer: It depends on which features are more important to you the shooter. Do you insist on an integral recoil lug? Do you insist on a conventional, large claw, Mauser style extractor? The Nucleus is going to be hard to beat due to the cost, features of the 3 lug/72 degree bolt lift, dual cocking cams, and Salt Bath Nitride finish. They are both great actions and I’m currently shooting 2 Mausingfields. One is a 6mm Creedmoor and the other is a 6.5 PRC / 223 Switch barrel and I really like them. I have swept back the handles on both of them and am running different bolt knobs.

Shopping cart

Shipping and discount codes are added at checkout.