Nucleus Light Primer Strikes

Anderson_A

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I just read something Joel Russo wrote in regards to trigger compatibility with his curtis actions that I thought may have some value here I don’t know what trigger ted used when he designed the nucleus but I would think it is true of all actions depending where the pins are in relation to the cocking piece

“Our actions are timed with Trigger Tech, and Jewel triggers. Thus, you will have little cock on close, and .235” and .245” of pin fall respectively. We do not recommend Timney triggers as you lose a significant amount of pin fall, which will contribute to light strikes”
 

Steel head

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I just read something Joel Russo wrote in regards to trigger compatibility with his curtis actions that I thought may have some value here I don’t know what trigger ted used when he designed the nucleus but I would think it is true of all actions depending where the pins are in relation to the cocking piece

“Our actions are timed with Trigger Tech, and Jewel triggers. Thus, you will have little cock on close, and .235” and .245” of pin fall respectively. We do not recommend Timney triggers as you lose a significant amount of pin fall, which will contribute to light strikes”
I saw that.

My huber has just a touch of striker drag and cock on close but has been 100% now for about 500 rounds and is fantastic to shoot.

Seems like TT, CG, BnA and Huber all seem to be compatible with the Nucleus action.
 

schmi015

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CG extreme and TT diamond both were super heavy cock on close for me, installed a timney and it opens and closes pretty easy, sent ARC a note, waiting to hear back. Moved the TT to my Mausingfield and works great.

Edit: Heard back from ARC, they suggest swapping out the bolt head, will do that and see how it goes.
 
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tomcatfan

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CG extreme and TT diamond both were super heavy cock on close for me, installed a timney and it opens and closes pretty easy, sent ARC a note, waiting to hear back. Moved the TT to my Mausingfield and works great.

Edit: Heard back from ARC, they suggest swapping out the bolt head, will do that and see how it goes.
Thats interesting. I had a Timney Calvin Elite to start with and had light primer strikes. I switched over to the TT Diamond and haven't had an issue since.
 

Anderson_A

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If I understand correctly the fact that you get cock on close with a certain trigger indicates you are getting more firing pin travel
 

schmi015

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More than anything i was shocked how hard it was to push the bolt down with the Trigger tech. The timney goes right down, no effort required.
 

MarkLeupold

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Got home and put my Nucleus together today. Installed the 25 pound spring right away. I'm not even going to mess with the 16 pounder. Everything today has gone bang (about 30 rounds so far) with CCI 450's. The bolt lift is not bad at all, especially with the egg bolt knob I put on (which I now prefer to the standard knob).
 
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Darkhorse1

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Got home and put my Nucleus together today. Installed the 25 pound spring right away. I'm not even going to mess with the 16 pounder. Everything today has gone bang (about 30 rounds so far) with CCI 450's. The bolt lift is not bad at all, especially with the egg bolt knob I put on (which I now prefer to the standard knob).
I had my first light strike since I’ve had the nucleus, and was using the 25# spring. I ran it flawlessly last weekend at a local match, but it was a little dusty so wondering if something got into the bolt shroud. A little disappointed since I thought going with the heavy spring would alleviate that stuff. Ran the one round through again and it went bang. I really hope I don’t have to break down the fire control group every time I take it out. This rig is definitely deserving of its name resting bitch face....I still really like the smoothness of the action, just seems to be a finicky lil’ fucker.
 
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Txhillbilly

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I went shooting today,and still haven't had any issues with my Nucleus having any light primer strikes with the 16 lb spring. I'm running a TT diamond trigger,and it has gone bang every time I pull the trigger on CCI 450 primed brass.
 

whatsupdoc

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@Darkhorse1 was the misfire with hand loads, what primers?

Did you disassemble the fire control assy to see if there was enough dirt/dust to cause the issue.
Bad news if it has issues with the 25 lb spring.
 

Triple D

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so you didnt have any issues with light strikes when sighting in the rifle or practicing with it before the matches? or did the problems begin the day of the match out of the blue?
Sorry for the delayed response. Yes, I had a few minor issues during load workup, but had cleaned it and the issue seemed to be mitigated. If I recall correctly, I had 2 FTF when confirming the load and getting velocity data the day I was leaving for the first match. I cleaned it following the range trip since I already had the ammo loaded, but once I hit the cold temps, it was dead in the water.

I haven’t touched the Nucleus since the last match. Cleaned it and just put it in the safe.

I installed the 25lb spring earlier this morning on one of my Nucleus actions. It’s a very noticeable increase in force to cock the action. It’ll be interesting to see how it works off of a barricade, but it’s likely going to cause a shift off of target unless you’re running a heavy build or really locking the rifle down. I may try to get a 19 or 22# spring to try.
 

ldunnmobile

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I had my first light strike since I’ve had the nucleus, and was using the 25# spring. I ran it flawlessly last weekend at a local match, but it was a little dusty so wondering if something got into the bolt shroud. A little disappointed since I thought going with the heavy spring would alleviate that stuff. Ran the one round through again and it went bang. I really hope I don’t have to break down the fire control group every time I take it out. This rig is definitely deserving of its name resting bitch face....I still really like the smoothness of the action, just seems to be a finicky lil’ fucker.

You guys getting light strikes with a 25lb spring... what trigger are you running?
 
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m1match

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I don't know if my Nucleus which from the serial number appears to be #164 was blessed by the rifle fairy, but I now have over 600 rounds through it with no issues at all. I've shot 2 local matches with the best finishes I've ever done, and a 3 day Scott Satterlee class and my Nucleus has performed great. Here's the rifle and a group shot while taking sighting shots before yesterdays match:

Nucleus action with shouldered Barloc
PVA Rock Creek button rifled shouldered barrel 6.5 Creedmoor
Huber 2 stage, 2.5 lb. trigger
Manners T2AGAP stock w/Gen 2 mini-chassis, Americana finish

Primers fired were Hornady cases and CCI BR2 primers

Here's pictures in post #209
 
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Steel head

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Sorry for the delayed response. Yes, I had a few minor issues during load workup, but had cleaned it and the issue seemed to be mitigated. If I recall correctly, I had 2 FTF when confirming the load and getting velocity data the day I was leaving for the first match. I cleaned it following the range trip since I already had the ammo loaded, but once I hit the cold temps, it was dead in the water.

I haven’t touched the Nucleus since the last match. Cleaned it and just put it in the safe.

I installed the 25lb spring earlier this morning on one of my Nucleus actions. It’s a very noticeable increase in force to cock the action. It’ll be interesting to see how it works off of a barricade, but it’s likely going to cause a shift off of target unless you’re running a heavy build or really locking the rifle down. I may try to get a 19 or 22# spring to try.
The 19# spring was noticeably nicer in the bolt opening effort department.
 

Darkhorse1

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@Darkhorse1 was the misfire with hand loads, what primers?

Did you disassemble the fire control assy to see if there was enough dirt/dust to cause the issue.
Bad news if it has issues with the 25 lb spring.
It is with hand loads. Lapua sp, CCI450, H4350, TT Diamond. I broke it down today and didn’t see anything that would make me think is was dirt.
 

EchoDeltaSierra

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Also, after working through some initial issues, I’m having 100% reliable ignition using the #19 spring with a Huber Concepts trigger.
Range report: Took the rifle out today for a 100y drill/load validation (action screw came loose...sigh...needed to re-zero/test). Decided to install the 16# spring. All 26 rounds ignited nicely with my practice Nosler brass + BR-2s. Tuesday I’ll be at long range practice and text it with my match ammo; Lapua brass + BR-4s.

First practice match is next weekend and I‘m going into the season with a very high level of confidence in this build.
 

EchoDeltaSierra

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Decided to install the 16# spring. All 26 rounds ignited nicely with my practice Nosler brass + BR-2s. Tuesday I’ll be at long range practice and text it with my match ammo; Lapua brass + BR-4s.
I shot last night at 600y and again today at 100y. No light strike problems with the 16# spring and Huber tiger on either BR-2 or BR-4 primers.

Now I’m really curious what the issue was and my theory is one or more of the following:

1. Just needed to mechanically “break in”.
2. Bitchy in the cold (and I cannot test that again until October/November).
3. I effed something up messing with the springs when I did the initial cleaning (humans are stupid, myself included).

I’ll be starting competition season this Saturday with 100% confidence in the action and rifle build upon it.
 

Darkhorse1

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I shot last night at 600y and again today at 100y. No light strike problems with the 16# spring and Huber tiger on either BR-2 or BR-4 primers.

Now I’m really curious what the issue was and my theory is one or more of the following:

1. Just needed to mechanically “break in”.
2. Bitchy in the cold (and I cannot test that again until October/November).
3. I effed something up messing with the springs when I did the initial cleaning (humans are stupid, myself included).

I’ll be starting competition season this Saturday with 100% confidence in the action and rifle build upon it.
I hope it works moving forward for you. I’m putting my 16# back in and going to try some Federal 205m. Figure I have some time over the next few weeks to do more testing.
 

PatMiles

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I'm sure the info I want is somewhere in this thread but not wanting to read 11 pages I'll ask here.
Does anybody have the wire diameter for the 16, 19 and 25 pound Nucleus springs?
 

lennyo3034

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Just got my second Nucleus in SN 5xx. Imo it is much worse than my first one SN16.

It came with a heavier spring, I want to say 19 lbs. Very noticeable difference in bolt lift force between it and 16lb.

My bolt also hangs up when trying to close very frequently. This does not happen with the old action. I put the old bolt into the old action and it ran just fine so I think it’s the bolt head.

ETA: it may be the 25 lb spring based on what the ARC website says.
 

Northernjets

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Just got my second Nucleus in SN 5xx. Imo it is much worse than my first one SN16.

It came with a heavier spring, I want to say 19 lbs. Very noticeable difference in bolt lift force between it and 16lb.

My bolt also hangs up when trying to close very frequently. This does not happen with the old action. I put the old bolt into the old action and it ran just fine so I think it’s the bolt head.

ETA: it may be the 25 lb spring based on what the ARC website says.
It's probably the 25. Mine is a 6xx and it came with one that was coated in a red colour. I swapped it with a 19 and it's a very notable difference. Feels more inline, if not lighter, than my well worn in Tikka t3 now. Hoping to zero and test the rifle next week.
 

lennyo3034

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It's probably the 25. Mine is a 6xx and it came with one that was coated in a red colour. I swapped it with a 19 and it's a very notable difference. Feels more inline, if not lighter, than my well worn in Tikka t3 now. Hoping to zero and test the rifle next week.
Mines only going on a .223 without BR4s or 205s. I think I’ll put a 16 in it. I may have to replace the bolt head though due to it hanging up.
 

Darkhorse1

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So I discovered something that is interesting to me anyway lol. When I went to change the spring back to 16#, I noticed a little movement in the firing pin and the part it threads into. The pin wasn't loctited like it is supposed to be (referenced in the original ARC Nuke video that's approx 40 min) and I could turn it by hand. I'm wondering if that little bit of play is taking up some of the energy of the spring. I cleaned up the threads and put on some blue loctite so hopefully this will be some sort of improvement.
 

wvlapua

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Is this a SRP issue or have there been issues with LRP also? I only have 100 trouble free rounds through mine so far..all LRP 19# spring.

I seat all primers with an rcbs bench priming tool, to the bottom of the pocket.
 

lennyo3034

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Does anyone have a spare 16# spring lying around? Mine is for a .223 using federal primers, don’t need the heavier springs.
 

chadrp

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I have about 600rds on my Nuke and had my first light strike in a match today shooting factory Hornady and 16lb spring. Was pretty disappointed to have it happen with factory ammo. I did find out a little bit later that my anti rotation pin and screw fell out somewhere so don't know if that may have had something to do with it or what.
 

epeet

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Apr 30, 2018
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I probably have about 500 rounds of CC2 200 and FGMM through mine, no issues.

I then tried running some M118LR through it. Two fired first time, two fired second time, about five rounds wouldn't fire at all, no matter how many times the striker the firing pin. This is with the standard spring weight and a TT trigger.
 

cageli

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Did some testing this morning. Small sample size of 10 rounds each with CCI 41, CCI 450, Federal 205m, and Factory Hornady 140 ELD M. Had one FTF from CCI 41 and couldn’t get it to ignite. 16# spring.
Switch to heavier spring. The action is on the edge, when it’s cold or wet the situation gets much worse.
 

whatsupdoc

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Did some testing this morning. Small sample size of 10 rounds each with CCI 41, CCI 450, Federal 205m, and Factory Hornady 140 ELD M. Had one FTF from CCI 41 and couldn’t get it to ignite. 16# spring.
If that is the FTF round, im surprised as that looks like a pretty healthy strike.
 
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Kevin Brittingham

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While you may certainly have some other issue with the Timney putting excessive upward pressure on the sear or even the firing pin spring being too light, headspacing off a piece of brass isn't a good way to roll unless running false shoulders.

I've done exactly as you and have seen exactly what you are seeing here.

Run false shoulders and see if your issues disapear.

I'd bet money they do.
It's not the recoil spring weight. Take an engineering class.
 
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Winny94

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Stupid question, but i need to find out for sure. I know the Arc actions use a savage small shank for prefits, but if im ordering a carbon blank, is 1.2" correct?
 

MarkLeupold

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Stupid question, but i need to find out for sure. I know the Arc actions use a savage small shank for prefits, but if im ordering a carbon blank, is 1.2" correct?
If it will be shouldered, yes. 1.2" will work.
 

Darkhorse1

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Recoil spring weight?
I put back in the 25# recoil spring (jokes on nomenclature) and going to work up 100 rounds with Federal 205m. Hopefully put this to bed in my action, and not get booted off the line. I guess I should hone up my ro skills just in case 🥴
 

Northernjets

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Finally got my Nuke out to shoot today for the first time. Fired 40 rounds of factory Hornady 140 gr Match 6.5CM and didn't have any issues. Temperature was around 40F with some scattered hail and heavy crosswind. It's a SN 6xx with a 19lb spring that I replaced the 25 with and I believe .032" firing pin portrusion if memory serves me right. Hosed the firing pin and firing pin hole with brake cleaner when I first got the action.

7071696
 

Jmoesdad

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Feb 13, 2017
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I can’t seem to compress the firing pin spring using the washer enough to release the notched nut.
I have the rear washer and Allen bolt barely engaged, any suggestions.
 
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Steel head

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I can’t seem to compress the firing pin spring using the washer enough no release the notched nut.
I have the rear washer and Allen bolt barely engaged, any suggestions.
Put the washer on two wood blocks of with enough room to get fingers on nut and push down on back of bolt assembly.

Or buy (from ARC)or make a tool like this one I made as it makes it a lot easier.

7079019