Nucleus and steel match ammo

[dgheriani]

I have an early serial number Nucleus (I got in on the original pre-sale) and it's run flawlessly with over 5700rds of .223 and 1000+ 6 Creed since April (all handloads). I just tried some Hornady 75gr Steel Match in it as I can get it for the same price it costs me to reload with 75gr BTHPs and it's plenty accurate (5rds 1/2moa @100y) albeit slow as balls (2688fps vs my handloads that are about 2920) but I keep getting light strikes. I got 17 light strikes out of a box of 50 (they all went off on the 2nd trigger pull). None of the primers seemed to be proud. I remember hearing about issues with light strikes with some Nucleus' early on, does this sound like something that could be solved by going to the heavier firing pin spring? I emailed ARC on Friday but have yet to hear back (not that I expected to over the weekend).

Edit to add I'm using a TT Special trigger

 

[m1match]

Read the Nucleus threads, the first ones shipped had a 16# striker spring, but they changed to I think a 25# spring because people were reporting light strikes. My Nucleus was shipped with a 16# spring and with a Huber trigger in 6.5 CM I have had no issues with light strikes shooting reloads with CCI BR2 primers, Hornady factory, and Prime factory ammo. From other peoples reports, the triggers used had a lot to do with whether you had light strike problems.

 

[Northernjets]

I have an early serial number Nucleus (I got in on the original pre-sale) and it's run flawlessly with over 5700rds of .223 and 1000+ 6 Creed since April (all handloads). I just tried some Hornady 75gr Steel Match in it as I can get it for the same price it costs me to reload with 75gr BTHPs and it's plenty accurate (5rds 1/2moa @100y) albeit slow as balls (2688fps vs my handloads that are about 2920) but I keep getting light strikes. I got 17 light strikes out of a box of 50 (they all went off on the 2nd trigger pull). None of the primers seemed to be proud. I remember hearing about issues with light strikes with some Nucleus' early on, does this sound like something that could be solved by going to the heavier firing pin spring? I emailed ARC on Friday but have yet to hear back (not that I expected to over the weekend).

Edit to add I'm using a TT Special trigger

Could be possible that Hornady runs a harder primer on the steel stuff like milsurp ammo? I've only ever run steel match through my semi. I haven't had any light strikes with my nuke yet but even my Tikka CTR has some issues lighting off Federal XM80 that I bought for my M14 type battle rifle.

 

[NWnewguy]

If you've got 6700+ rounds of reloads that all went bang and then switched to slow as crap AR ammo, I'm not sure I would say that the action is the problem. However a stiffer firing pin spring would probably set them off. The fact that the rounds went off the second time, to me says that the primers weren't all the way seated to begin with and the first one was seating the primer and that robbed a lot of KE. The second one, with the primer seated, had plenty of KE to set the primer off.

 

[Steel head]

Get a 19# or 25# spring.

 

[dgheriani]

ARC are sending me 19 and 25# springs. Hopefully the 19# does the trick. Looking forward to less time reloading, haha

 

[TheMammoth]

ARC are sending me 19 and 25# springs. Hopefully the 19# does the trick. Looking forward to less time reloading, haha

The 19 was the sweet spot for me. Good luck!

 

[Steel head]

The 19 was the sweet spot for me. Good luck!

I’m running the 19# as well.

 

[Kiba]

I never had any issues with the 16# spring other than one piece of brass that had the primer pocket cut so deep the firing pin barely even left a mark; I'm now running the 19# for a little extra margin. No failures in 1000+ firings with the 16# spring and another 3500+ ignitions with the 19# spring all with Remington 7.5 primers. I prefer the lighter bolt lift with the 19# spring compared to the 25# spring, but the 25# spring would be the absolute most reliable if that's what you're after.

 

[dgheriani]

I'm hoping the 19# does the trick as I don't really want increased bolt lift.

 

[MilSpecOkie]

I had issues at first until I took the bolt apart and cleaned all the grease out of it. No more light strikes for over a thousand rounds. I started getting a few light strikes again and I cleaned the bolt again and all was well. I’m still running the original 16 pound spring.

I think there is a great chance you would return to normal with a thorough bolt cleaning.

 

[Dooby]

You're using AR-15 ammo? No ignition make sense. AR platforms use a free floating firing pin. AR ammo use harder primers than match primers.

 

[Rob01]

Steel match is not AR ammo. It's just steel cased .223. I use it in my 700 and never had a light strike. All went bang. I would clean up the bolt like mentioned above and see what happens and then adjust the spring poundage after that.

 

[Steel head]

You're using AR-15 ammo? No ignition make sense. AR platforms use a free floating firing pin. AR ammo use harder primers than match primers.

Modern Bolt actions typically have more than enough energy to deal with any primers.

 

[Dooby]

Modern Bolt actions typically have more than enough energy to deal with any primers.

Agreed, but from what i've read the Nucleus had a weak firing pin spring. 16lbs and 60* throw, i believe most "modern" actions have a heavier FP springs. I think there was discussion on it on the Nucleus thread about light strikes.

 

[Steel head]

Agreed, but from what i've read the Nucleus had a weak firing pin spring. 16lbs and 60* throw, i believe most "modern" actions have a heavier FP springs. I think there was discussion on it on the Nucleus thread about light strikes.

72 degrees throw and many had no issues with the 16# including myself.

 

[Dooby]

72 degrees throw and many had no issues with the 16# including myself.

Right 72*, and sure, many didn't have problems, but many also did have light strikes. That's why ARC released the 19lb and the 25lb springs.

 

[MilSpecOkie]

And if most disassembled the bolt and thoroughly cleaned it, they wouldn't have needed a heavier spring. Many got them because they were free and thought they needed them.

 

[dgheriani]

Well swapped in the 19# spring and 100 rounds of Steel Match later and zero light strikes. I honestly can't really tell the difference with regards to bolt lift either. My barrel sure likes that Steel Match though!

 

[MilSpecOkie]

Well swapped in the 19# spring and 100 rounds of Steel Match later and zero light strikes. I honestly can't really tell the difference with regards to bolt lift either. My barrel sure likes that Steel Match though!

I think my 16 pound spring has lost tension, suddenly I’m having unexplained light strikes after a full season of shooting. I’ve ran it dry and still not lighting off rounds.

How long did it take to get get your replacement spring? Did you find any step by step procedures for changing it? Did you use the washer to disassemble it?

 

[2aBaC̶a̶]

Does lighter spring make for a lighter bolt lift?

If so how noticeable is it?

 

[Steel head]

Does lighter spring make for a lighter bolt lift?

If so how noticeable is it?

Yes.
16 to 19 is pretty mild difference

16 to 25 is noticeable.

I could live with the 25 but I’m 100% trouble free and happy with the #19

 

[2aBaC̶a̶]

Yes.
16 to 19 is pretty mild difference

16 to 25 is noticeable.

I could live with the 25 but I’m 100% trouble free and happy with the #19

Cool, I will order the 19 as my Nuc just came in and while molesting it I noticed it was unusually stiff to open.

 

[dgheriani]

I think my 16 pound spring has lost tension, suddenly I’m having unexplained light strikes after a full season of shooting. I’ve ran it dry and still not lighting off rounds.

How long did it take to get get your replacement spring? Did you find any step by step procedures for changing it? Did you use the washer to disassemble it?

After I called ARC they immediately sent me the 19 and 25# springs. Took maybe a week or so to show up (and I'm up in Canada so had to go through customs, etc plus it was over the holidays). I watched Ted's video on the Nucleus where he disassembles and reassembles the bolt. I downloaded the schematic they have with the bolt dimensions and the dimension from the top of the castle nut to the tip of the firing pin (to maintain proper pin protrusion). It took maybe maybe 5-10 minutes to do the swap including redoing it a second time to adjust pin protrusion. Super easy to do with the included washer.

 

[MilSpecOkie]

After I called ARC they immediately sent me the 19 and 25# springs. Took maybe a week or so to show up (and I'm up in Canada so had to go through customs, etc plus it was over the holidays). I watched Ted's video on the Nucleus where he disassembles and reassembles the bolt. I downloaded the schematic they have with the bolt dimensions and the dimension from the top of the castle nut to the tip of the firing pin (to maintain proper pin protrusion). It took maybe maybe 5-10 minutes to do the swap including redoing it a second time to adjust pin protrusion. Super easy to do with the included washer.

I pulled mine apart and got it back together with a little bit of effort. I need to develop a load for a new caliber and have a match in a couple weeks. I’m hoping I can get the spring and it dialed in that time.

 

[Steel head]

I pulled mine apart and got it back together with a little bit of effort. I need to develop a load for a new caliber and have a match in a couple weeks. I’m hoping I can get the spring and it dialed in that time.

If you know some with a lathe make something like this.
so much nicer to use than the washer.

 

[Kiba]

If you know some with a lathe make something like this.
so much nicer to use than the washer.

Indeed. For a few bucks, LRI makes a nice one.

Mausingfield Fire Control Compression Tool.

Tear a Mausingfield apart once and you'll soon discover just how impressive the spring rate is on the firing pin. LRI has an elegant/simple solution for this task. Our compression tool fits comfortably in your hand and effectively delivers the ability to compress the spring and unload the...

www.longriflesinc.com

The included washer works, but if you slip you can easily launch the castle nut and washer to the darkest corners of your garage where the missing AR takedown detent pins live.

The LRI tool or similar gives you a lot more control and makes the job a lot easier.

 

[Steel head]

Indeed. For a few bucks, LRI makes a nice one.

Mausingfield Fire Control Compression Tool.

Tear a Mausingfield apart once and you'll soon discover just how impressive the spring rate is on the firing pin. LRI has an elegant/simple solution for this task. Our compression tool fits comfortably in your hand and effectively delivers the ability to compress the spring and unload the...

www.longriflesinc.com

The included washer works, but if you slip you can easily launch the castle nut and washer to the darkest corners of your garage where the missing AR takedown detent pins live.

The LRI tool or similar gives you a lot more control and makes the job a lot easier.

I believe ARC makes one now as well.

 

[Kiba]

I believe ARC makes one now as well.

Yep, they do... Forgot to post a link to ARC's version.

Striker Spring Compression Tool

For use only with Nucleus and M7 Mausingfield

americanrifle.odoo.com

 

[Ledzep]

I'll echo what others have said here. 16lb spring had a failure rate of 4-5 percent. 25 was really stuff so I did some coil spring calculations and cut my 25lb spring to be a 20lb spring and all is good in the world now.

Steel cases stuff is probably tougher eastern European berdan primers.

 

[MilSpecOkie]

Got a 19 on the way.

 

[dgheriani]

I'll echo what others have said here. 16lb spring had a failure rate of 4-5 percent. 25 was really stuff so I did some coil spring calculations and cut my 25lb spring to be a 20lb spring and all is good in the world now.

Steel cases stuff is probably tougher eastern European berdan primers.

I don't think Hornady uses Eastern European berdan primers but I could be wrong

 

[2aBaC̶a̶]

Got a 19 on the way.

Meh, $7 shipping on a $10 spring.

 

[MilSpecOkie]

Meh, $7 shipping on a $10 spring.

Meh, they sent a 19 and 25 pounder for free, no shipping.

 

[MilSpecOkie]

Just an update. I’m 99% sure there was nothing wrong with my 16 pound firing pin spring. The culprit is my Alpha 25 Creedmoor SRP brass. The primer pockets are so freaking tight that it’s crushing the primers and disrupting the priming compound between cup and anvil. I’ve had to uniform all the pockets and my issues seem to have been corrected. Maybe someday I’ll put the 16 pound spring back in to test this theory. But it would explain why I suddenly started having problems after taking my 6BR barrel (Lapua brass) off.