ARC Nucleus action reviews

[dminn1]

If you have owned or shot one of these actions I would like to hear your experiences, likes, dislikes etc. This action has a lot of interesting features and now that it has been out for awhile I would be interested in reading how it has performed from an accuracy, as well as an operational smoothness standpoint. Particularly interested in bolt opening feel, ignition performance, and does it have any cock on close issues with various triggers that have been used.
Thanks
Darin

 

[Dusty Stevens]

I have built quite a few of them now. Everything is top notch i assure you. As far as trigger timing that is a function of the builder- they can make them good or bad on the same action. They are slick as glass unless you think you need it coated for that tactical look. I dont own one myself but i talk about them to the owners i built them for and they still love them. I have a pair of mausingfields so im not a nucleus guy but any action from arc is alright i assure you. They are hard as glass and i think thats why they stay slick. Nothing can embed in the metal like some of the more popular followings and get rougher over time. My take on it, after owning or building pretty much every mainstream action most have heard about, is that if you need a repeater and you cant have a mausingfield a nucleus is the next best choice

 

[Dusty Stevens]

Oh and as far as bolt opening feel, its the same or better than any 3 lug action. Not near as good as a 2 lug if thats what youre wondering- its no exception. A tikka is probably the smoothest 3 lug

 

[squint-n-squeeze]

Oh and as far as bolt opening feel, its the same or better than any 3 lug action. Not near as good as a 2 lug if thats what youre wondering- its no exception. A tikka is probably the smoothest 3 lug

Tikka makes a 3 lug?

 

[Dusty Stevens]

Tikka makes a 3 lug?

Meant to say sako- sorry bout that

 

[PatMiles]

I have two rifles with Nucleus actions and will echo Dusty's comments.

 

[PatMiles]

Patriot Valley Arms puts offers a John Hancock rifle using the Nucleus action with a Timney 519 trigger. There were numerous complaints regarding light strikes on the primer causing a failure to fire situation. The reported weight of the firing pin spring was 15#, in an effort to cure this problem ARC offered 19# springs free. Both of my rifles, 6 Dasher & 6 Creedmoor, came with the 15# springs. I installed BixN'Andy benchrest triggers in both and have not had any ignition problems whatsoever. The problem seems to revolve around the Timney 510 trigger that comes with the rifle.
Trying to find initial CBTO and shoulder setback measurements is somewhat of a PIA with the Nucleus action. The bolt strips easily, about a minute, but requires the firing pin and thus the complete assembly to be in the bolt to retain the bolt head. Obviously with the firing pin assembly in place the cocking piece interacts with the trigger and causes problems with "feel" doing both measurements.
I made an insert to replace the firing pin assembly. The threads inside the bolt are .500"x20tpi so I took a .500"x20 bolt, cut the head off, drilled a .125" hole in the threaded end so I could Loctite in a 5" long piece of .125" diameter drill rod. The drill rod was pointed on one end so it would just enter the firing pin tunnel in the bolt face and keep everything centered when in place.
I put the insert into the bolt, through the cross pin. Screwing it into the bolt until it finds the firing pin tunnel and then finger tighten it.

 

[Dusty Stevens]

^ very good work. When i cant or dont feel like removing the firing pin assy i just polish the bullet with some steel wool and use a jewelers loupe to see the marks on the bullet

 

[D.Stone]

I ordered two short actions from the first batch. One for myself, and one for my gunsmith.

My biggest issue with the action is that it doesn't work with a lot of triggers because the sear on the bolt that engages the trigger is not the same as a Remington.

Of the triggers I have, it will not work with either a CG Xtreme Model 21 (the OG), or the Geiselle Super 700 2 Stage. It will work with a Trigger Tech or a Bix N Andy.

(And I have the Geiselle Super 700 that is supposed to work with the ARC before anyone asks.)

Ignition problems are also likely because of the cocking piece dragging on the trigger sear as it falls. I haven't had any light primer strikes with the Trigger Tech yet, but would have definitely had some with the CG if we had decided to use it.

There is also a redesigned bolt head to reduce the bolt lift slightly, and it has been challenging to get ahold of ARC to get mine replaced or upgraded.

Overall, I like the design of the action, but I hate the execution. It's the small details that means I will probably only ever have the one.

 

[Dusty Stevens]

I ordered two short actions from the first batch. One for myself, and one for my gunsmith.

My biggest issue with the action is that it doesn't work with a lot of triggers because the sear on the bolt that engages the trigger is not the same as a Remington.

Of the triggers I have, it will not work with either a CG Xtreme Model 21 (the OG), or the Geiselle Super 700 2 Stage. It will work with a Trigger Tech or a Bix N Andy.

(And I have the Geiselle Super 700 that is supposed to work with the ARC before anyone asks.)

Ignition problems are also likely because of the cocking piece dragging on the trigger sear as it falls. I haven't had any light primer strikes with the Trigger Tech yet, but would have definitely had some with the CG if we had decided to use it.

There is also a redesigned bolt head to reduce the bolt lift slightly, and it has been challenging to get ahold of ARC to get mine replaced or upgraded.

Overall, I like the design of the action, but I hate the execution. It's the small details that means I will probably only ever have the one.

If you use one of the mainstream triggers there will be no issues. Even a tuned factory remington works well as does the bix, jewell, triggertech even a timney

 

[D.Stone]

If you use one of the mainstream triggers there will be no issues. Even a tuned factory remington works well as does the bix, jewell, triggertech even a timney

The CG has worked on every action I have put it on besides the ARC, from one of the very first 40X actions produced, to my Surgeon, to a Panda action. It might be going on a Defiance action next.

Geiselle has had to re-engineer their trigger to work with the Nucleus...I think it's a new sear if I recall, but don't quote me on that.

That's what rubs me the wrong way. Making sure that you have the correct relationship between the cocking piece and trigger should be action engineering 101...but if you compare a cocking piece from the Nucleus with a Remington 700...you will see that they are not the same. The Nucleus is cut at a straight 90 degree angle while the standard Remington is sloped.

I don't know if there is an engineering reason for this...or if it's just because it saves a machining operation to meet a price point.

The reports of light strikes, changing the firing pin spring, and not working with certain triggers is not very confidence inspiring. I'm very glad mine works well so far, but I am kind of leery that it might let me down in the future.

 

[Nature Boy]

My Mausingfield has been such a good action (love the ARC rings too BTW) that next time I start another build it will likely be with a Nucleus action.

But I guess it doesn’t work with a lot of triggers.......except it does work with Jewell, Bix n Andy, Trigger Tech and Timney. Oh well

 

[SierraCJ5]

I grabbed one of the first Nucleus when the pre-buy was offered. Have used it with two barrels; a 6.5 creedmoor and 223. I've had zero FTF issues using a trigger tech trigger and the OEM striker spring (I haven't updated to heavier than the 15# it came with). The bolt close is a bit notchy if you work it very slow, but if you manipulate the bolt in one single fluid motion it is very smooth on closing and almost like an assist as the primary extraction ramp initiates bolt rotation. Opening is smooth and fluid. I like the action.

 

[Pinetreebbs]

I have one of the Patriot Valley Arms John Hancock rifles. I've only shot about 100 rounds, but so far I couldn't be happier. It is a very smooth action.

The action does have an odd bolt retention device that took a little getting used to, not bad, just different.

 

[PatMiles]

I have one of the Patriot Valley Arms John Hancock rifles. I've only shot about 100 rounds, but so far I couldn't be happier. It is a very smooth action.

The action does have an odd bolt retention device that took a little getting used to, not bad, just different.

Yeppers, and you best remember to turn it into the locking position after inserting the bolt or when you go to take the rifle out of the case with the bolt open and muzzle point skyward said bolt is going to zip right out of the action into the dirt.
Don't ask me how I know this!

 

[Medic505]

(love the ARC rings too BTW)

me too

 

[D.Stone]

Here is a comparison between the cocking piece on a Surgeon and the cocking piece on a Nucleus. That's the difference I was talking about in the earlier post.

 

[Dusty Stevens]

Heres one of my personal mausingfields. Put every good trigger in it and its flawless no matter how fast you run it. I suspect the sharper angle is to lessen contact area thus friction

 

[6ShotsOr5?]

I have a Nucleus barreled action in 6 Creed ‘smithed by Patriot Valley Arms. It is my first custom action. I put it on a Magpul Pro 700 stock with a TT Diamond trigger. I knew it was a shooter when my first two shots from this rifle went through the same 0.243” hole at 100 yds. I had to shoot a few more to convince myself that was what happened, because I never had a rifle shoot like that before. The rifle has shot several 5-round 100 yard groups in the 2s, and one group in the 1s. I use a Redding FL TypeS die to size my brass and a Redding competition seater. I don’t do any brass or bullet sorting. I have not had any light strikes after 350 rounds. I’m not crazy about the bolt retention device but I’m used to it now, and it’s a lot better than some of the ones that I have on factory rifles where it can be a small struggle to get the bolt out. I appreciate the warning from @Pinetreebbs about remembering to turn the retention knob shut after re-installing. The best thing I can say about the accuracy is after I saw how it was shooting with 150 rounds through it, I called PVA and ordered another barrel hopefully as close as possible to the first one. I didn’t know anything about the firing pin and bolt assembly / disassembly, so I was glad to see some of those details.

 

[D.Stone]

View attachment 1121974

Heres one of my personal mausingfields. Put every good trigger in it and its flawless no matter how fast you run it. I suspect the sharper angle is to lessen contact area thus friction

Tried a Bix N Andy TacSport Pro Two Stage...and we get this. (Keep in mind the other Bix Trigger I have works in it.)

I suspect that the sharper angle is because it's easier to manufacture...or a galaxy brain decision that I'll never understand.

So we are 3 for 5 triggers that do not work.