Nucleus owners/holders: mausingfield comparison and CRF issues

[wesc]

These questions are for those with experience with the ARC nucleus action. I understand it is new so there likely won’t be very many answers and I’m ok with that.

1. If you have experience with a mausingfield, how does this action compare. I’m not interested in hard facts like bolt throw and lug number, integrated lug vs not, I can read those in the specs of the action. Loading, cycling, feeding both, what are your thoughts about a direct comparison between these two actions as it pertains to reliability and functionality of the actions? Any thoughts on which one is more comfortable to shoot (yes I know bolt throw has a lot to do with that so it’s apples/ oranges/preference but I’m still interested in your thoughts). Are they largely equivalent or does one clearly stand out as superior?

2. This segues into my second question. How well is your nucleus consistently controlled round feeding and what mags and bottom metals are you using. I’d like to see if there is a consistent combination that is successful or a consistent combination that fails to CRF. My reading about mausingfields indicates they have no difficulty CRF but I’ve been seeing a lot in the nucleus threads about push feeding.

I’m beginning a build and want to use an ARC receiver. I have other components picked out and I’m looking at inherent reliability/functionality of the receiver component before making my decision between the two. unfortunately can’t find either action to sample where I live (eastern NC).

 

[lennyo3034]

Mine is being run in a Dasher. While it is not capturing the round as soon as it leaves the magazine, it is not push feeding either. The rim of the case is still sliding in under the extractor at the bottom of the bolt. The extractor is not snapping over the rim.

After several hundred rounds both fast and slow, I have not had any issues feeding. No jams or even tight areas.

 

[wesc]

Mine is being run in a Dasher. While it is not capturing the round as soon as it leaves the magazine, it is not push feeding either. The rim of the case is still sliding in under the extractor at the bottom of the bolt. The extractor is not snapping over the rim.

After several hundred rounds both fast and slow, I have not had any issues feeding. No jams or even tight areas.

Thanks for the reply. May I ask what chassis or stock/BM as well as magazines you are using?

 

[Loki_The_Trickster]

My Nucleus in a KRG Bravo is not controlled round feeding with either MagPul or Accurate Mags. I tried trimming the feed lips back on one of my MagPul mags. It gets the round to pop up sooner, but the extractor still doesn't grab the case rim until the bolt face is almost flush with the front edge of the ejection port. It's not exactly like the push feed Savage, Remington, or Rugers I've had, but it isn't truly a controlled round feed, either.
I've been fine with push feeds my whole life, so it's not that big a deal, but since it is sold as a controlled round feed action, the issue needs to be addressed in some way.

Here's a video showing how it feeds and ejects. I've sent a similar video to ARC hoping they'd have some advice. I know they're super busy, but I hope to hear back soon.

I managed to shatter the camera lens on my phone making this video.
Also, I said "ejector" when I meant "extractor" at least once.


Edit:
I realized the video I just made didn't show what happens when the round jumps forward during travel and isn't in exactly the right place when the bolt face passes the front of the ejection port - it doesn't grab the round at all and the bolt needs to be closed completely, just like all other push feeds. But the video I sent to ARC did. I meant that video to only be for them, but I think it's valuable information to share, so here it is.


I still love the action. Even if it isn't a true CRF, I haven't experienced a failure to feed, failure to extract, or failure to eject. Sometimes closing the bolt is a little stiff since the round jumped forward during travel, but it doesn't bind, is really smooth, ejection is the best I've ever experienced in a bolt gun, and the bolt handle is amazing.

For comparison, here is the CRF of a Bighorn TL3.

 

[whatsupdoc]

It kinda looks like a hybrid controlled round push feed action.

It looks to me if the extractor was made a little lower in front of the bolt lug It may work better as a CRF action.
I dont have mine yet so my statement may be completely wrong.


Is there any other 3 lug CRF action out there?

 

[NovaHunter]

Tagging.

I am running my Nucleus in a Mcree chassis. Shot 2 matches, a 2 day PRS match and a 1 day today. No issues. I am using ARC mags.

Haven't even checked if it is truley controlled round feeding or not, but I definitely will check and see if is functions similary to the video posted.

 

[character0]

My Nucleus <snip>

Same exact thing with a trimmed accurate mag.

 

[Loki_The_Trickster]

Same exact thing with a trimmed accurate mag.

Thanks, that's good to know. I won't be messing with them, then.

 

[lennyo3034]

Thanks for the reply. May I ask what chassis or stock/BM as well as magazines you are using?

MPA chassis. AICS mag with PVA mag kit.

 

[wesc]

Same exact thing with a trimmed accurate mag.

Is that also with a krg bravo?

 

[BLKWLFK9]

I've had mine in an XLR Evo and now it's in a KRG whiskey3. haven't had 1 single malfunction, whatsoever. it's smooth and fast and throws brass a country mile. I'm in love and that's a good thing bc I've got a JHR coming too. You want to talk about reliable? I find it hard pressed to find one more, other than maybe the AI and it's biggest advantage is the trigger assembly. much much better than any R700 style trigger assembly as far as reliability goes. Thats just my .02

 

[NovaHunter]

Whelp, ran some rounds through my Nucleus. Had a similar experience where the rounds didn't lock into the extractor until the bolt passed the end of ejection port. It looked like the pressure from the feed rams is what is locking the round into the extractor. It's an interesting little issue, but not one I am worried about as the action has run flawlessly in the two matches I've shot with it.

I will note, the last round in the mag seemed to snap in a little earlier, maybe an inch or so, then all other rounds. Not sure why this is, but thought it was worth noting.

I am running a Nucleus with Barloc, Mcree G10 Chassis and ARC mags.

 

[prcomte]

My mausingfield action does the exact same thing. Its in a KRG chassis with an extended mag catch so i could fine tune the magazine height in the action. I'm using ARC mags with LRI followers. Nothing has changed it. I'm running with it. I expected it to run right when I bought a $1600 action.. though you know what they say, "if you have no expectations, you have no disappointments."

 

[character0]

Is that also with a krg bravo?

MPA competition.

 

[prcomte]

Though if you watch the videos by arc on YouTube that might be how it’s supposed to be.

 

[308pirate]

It kinda looks like a hybrid controlled round push feed action

Winchester did the same thing in the late 90s /early 2000s with the M70 CRPF, except it was a two lug bolt with the extractor integral to the ejection side lug:

Sako did a few years back what ARC has done now when they introduced the 85:

ARC:

Sure the extractors are different, but conceptually they are the same exact thing and probably both work just about as well.

 

[Dooby]

I'm considering an ARC Nucleus barreled action from PVA, is this issue happening on some stocks and mags? I have a KRG Bravo ready to go for this action.

has anyone brought this up with ARC? any fixes?

 

[whatsupdoc]

Im not sure if it is "broken" just works a little different. I believe most have had no feeding or extraction issues.

 

[Loki_The_Trickster]

No failures at all. Just doesn't feed exactly as expected.
I've emailed ARC with the videos and an explanation of what's happening, haven't heard back yet.

 

[NovaHunter]

Im not sure if it is "broken" just works a little different. I believe most have had no feeding or extraction issues.

Yeah, That's how I am thinking of this. I was previously using a Stiller action for my PRS rifle and usually would have 1 to 2 failure to feeds or extracts in a match. In two matches, zero issues with the Nucleus and the extraction is amazing. Definitely think it is an upgrade and much more reliable even if it isn't technically a true CRF.

 

[308pirate]

Yeah, That's how I am thinking of this. I was previously using a Stiller action for my PRS rifle and usually would have 1 to 2 failure to feeds or extracts in a match. In two matches, zero issues with the Nucleus and the extraction is amazing. Definitely think it is an upgrade and much more reliable even if it isn't technically a true CRF.

And that's all that really matters

 

[Ledzep]

My mausingfield action does the exact same thing. Its in a KRG chassis with an extended mag catch so i could fine tune the magazine height in the action. I'm using ARC mags with LRI followers. Nothing has changed it. I'm running with it. I expected it to run right when I bought a $1600 action.. though you know what they say, "if you have no expectations, you have no disappointments."

Extractor tuning has been a "thing" since inception with the M5. Some light material removal in the right place(s) is all you need if you care to change it. Feel free to PM me if you'd like to know what to do, it's easy enough to do yourself with a rotary tool.

 

[NovaHunter]

And that's all that really matters

Yep!

 

[clyancey]

I will second Ledzep. I have the Mausingfield and it simply needed a little extractor tuning to get it to feed/CRF smoothly/early in the cycle. I can't say for sure with the Nucleus, but the Mausingfield is intended/WILL control the round as soon as its released from the magazine if the extractor is fitted/tuned and I suspect this may be the case with the Nucleus. Ted personally tuned my Mausingfield extractor in front of me and told me (at that time) they intentionally sent the extractors on the "tight" side so that they wont be loose but could be tuned to fit any manufacturer's brass.

If you have a Mausingfield (@prcomte) and it doesn't capture the round as soon as it snaps free of the mag your missing out on full design/function.

 

[Dooby]

I will second Ledzep. I have the Mausingfield and it simply needed a little extractor tuning to get it to feed/CRF smoothly/early in the cycle. I can't say for sure with the Nucleus, but the Mausingfield is intended/WILL control the round as soon as its released from the magazine if the extractor is fitted/tuned and I suspect this may be the case with the Nucleus. Ted personally tuned my Mausingfield extractor in front of me and told me (at that time) they intentionally sent the extractors on the "tight" side so that they wont be loose but could be tuned to fit any manufacturer's brass.

If you have a Mausingfield (@prcomte) and it doesn't capture the round as soon as it snaps free of the mag your missing out on full design/function.

Agreed. I think it's great that the action will work even if it doesn't CRF. However, it is built like so and advertised like so. That said, i just put in a barreled action order from PVA.

 

[308pirate]

Mauser-type extractor tuning is nothing new. It's been done by rifle makers since Paul Mauser put out the first one.

What IS new is that there is an action with that same exact extractor that is sold by itself, so it's maker has no ability to tune the extractor. It's the responsibility of whomever builds the rifle itself.

In the past, professional gunsmiths did that sort of thing 100%. But now, with bolt action rifles almost approaching AR-15 style DIY, more end users are having to do this sort of thing. Some know to expect it, I suspect many don't (or didn't)

 

[ThePretzel]

1) The bolt feels a lot smoother than the Mausingfield, at least to me. The Mausingfield (at least the newer versions, the original didn't have it) has a bit of a hitch to it when you're opening the bolt. The Nucleus doesn't have that, the bolt lift is smooth and consistent. That said, the bolt lift is heavier than if you bought a similar 3-lug action such as those offered by Curtis Customs.

As far as ejection goes, you're going to lose a lot of brass with either action. They both eject it in strange and unpredictable ways (often forwards).

2) Out of Accurate Mags or AICS mags with standard feed lips I would get push feeds if the bolt wasn't run at a brisk pace. If I run the bolt at a brisk pace it'll CRF with any magazine I stick in there. The best results I had, however, were using an ARC mag that already has shorter feed lips. I ran a full match with an ARC mag that had an extension and a spacer kit and never once noticed the rifle not CRF (you can feel it if it doesn't when you close the bolt).

That said, if you're concerned with making sure it's always going to CRF you should probably work on tuning the extractor a little. I don't plan to do much with mine, though I might check it out and see if it's worth polishing it up with some 600-2000 grit sandpaper to make things smooth in there if anything is rough.

 

[Loki_The_Trickster]

Has anyone asked ARC about this and gotten a response? I'm on day 12 of nothing but silence.

 

[sgtsmmiii]

Has anyone asked ARC about this and gotten a response? I'm on day 12 of nothing but silence.

I'd try again. They have been pretty quick to respond the couple of times I contacted them.

 

[Skunkworx]

@Jon_ARC do you guys have any feed back/tips for tuning the nuke CRF?

 

[Loki_The_Trickster]

Day Sixteen. Seven (now eight) attempts at contact. Not one word from ARC.

 

[Lonestar1027]

To be fair, I called yesterday and they picked up almost immediately.

 

[steve123]

I called yesterday and got Justin first try. There was a mix up with my order, turns out there's another guy that has my exact name, good thing I called, LOL.

 

[Tactical Taz]

I talked to Justin this week and last week both, the calls were initiated by me.

 

[Loki_The_Trickster]

Well, they must be ignoring their website and email contacts. I'll try calling.

 

[Loki_The_Trickster]

I tried calling last Friday with no answer, and just tried three times and finally left a message. I've tried eight emails through their website in the last sixteen days.
I just want a response from them. Anything. This is like pulling teeth.

 

[karagias]

In general, an action is considered to be controlled round feed (CRF) if its extractor is capable of engaging a cartridge on its way out of the magazine and then pulling that cartridge reward for delivery to the ejector without the need to rotate the bolt closed as one would need to do in a push-feed action such as a Rem 700.

Pushing the bolt forward as slowly as possible and expecting the same result as one would get had they pushed the bolt forward at normal speed is senseless because cartridge inertia matters.

The advantage offered CRF actions is a reduction, in the likelihood of double feeding the chamber which would otherwise cause a jam. This tends to happen during times of stress, such as during timed competitive events. Again, it CRF reduces the risk of double feeding. It does NOT eliminate it.

The degree to which the likelihood of double feeding is reduced depends on the magazine and its feed lip geometry, the diameter of the cartridge body, the diameter of the bolt, the shape of the extractor hook, and the position of the cartridge shoulder along the length of the cartridge, the speed with which the bolt is cycled, the width of the cartridge extraction groove, and more. Variations in any of these will affect CRF reliability.

While designing both the Nucleus and the Mausingfield, I never once assumed that CRF functionality would be necessary when running a bolt as slowly as possible in an attempt to capture the case being forced under the extractor when the forward motion of the bolt is purposely stopped an instant after the mag has released it. That said, we can create the conditions for that to happen, or not happen, but that would be a stupid waste of time. And that's true of any CRF action, Mauser 98 included. Just because I can cause a certain Mauser 98 to fail to engage the head of a certain cartridge by running it in a certain manner would not lead me to conclude that the M98 is not a CRF action. And that's saying something because Mauser rifle were built as cartridge specific rifles. Moreover, anyone who has every built custom rifles on M98s will tell you that mods are required to get reliable CRF functionality.

If you want to capture controlled round feed on video, record the bolt cycle at normal speeds (fast) and replay in slow motion. I'll leave that up to someone else.

Oh, and one last point. Never write anything in a public forum about a bolt action until after you have come to understand the Mauser 98. I can't stress that point enough.

Ted

 

[JLP.Payette]

In general, an action is considered to be controlled round feed (CRF) if its extractor is capable of engaging a cartridge on its way out of the magazine and then pulling that cartridge reward for delivery to the ejector without the need to rotate the bolt closed as one would need to do in a push-feed action such as a Rem 700.

Pushing the bolt forward as slowly as possible and expecting the same result as one would get had they pushed the bolt forward at normal speed is senseless because cartridge inertia matters.

The advantage offered CRF actions is a reduction, in the likelihood of double feeding the chamber which would otherwise cause a jam. This tends to happen during times of stress, such as during timed competitive events. Again, it CRF reduces the risk of double feeding. It does NOT eliminate it.

The degree to which the likelihood of double feeding is reduced depends on the magazine and its feed lip geometry, the diameter of the cartridge body, the diameter of the bolt, the shape of the extractor hook, and the position of the cartridge shoulder along the length of the cartridge, the speed with which the bolt is cycled, the width of the cartridge extraction groove, and more. Variations in any of these will affect CRF reliability.

While designing both the Nucleus and the Mausingfield, I never once assumed that CRF functionality would be necessary when running a bolt as slowly as possible in an attempt to capture the case being forced under the extractor when the forward motion of the bolt is purposely stopped an instant after the mag has released it. That said, we can create the conditions for that to happen, or not happen, but that would be a stupid waste of time. And that's true of any CRF action, Mauser 98 included. Just because I can cause a certain Mauser 98 to fail to engage the head of a certain cartridge by running it in a certain manner would not lead me to conclude that the M98 is not a CRF action. And that's saying something because Mauser rifle were built as cartridge specific rifles. Moreover, anyone who has every built custom rifles on M98s will tell you that mods are required to get reliable CRF functionality.

If you want to capture controlled round feed on video, record the bolt cycle at normal speeds (fast) and replay in slow motion. I'll leave that up to someone else.

Oh, and one last point. Never write anything in a public forum about a bolt action until after you have come to understand the Mauser 98. I can't stress that point enough.

Ted

Mic drop!

 

[Rexwagon]

Seems like a dick with the last paragraph. Condescending.

 

[Primus]

Seems like a dick with the last paragraph. Condescending.

He's just setting the mouth breathers strait. Tards bitch and moan about the dumbest of non issues and then force the owner ( who would be better off making/designing more products then responding to dribble) to defend it in a way that a novice may be able to understand. Ted is on a whole nother level intellectually when it comes to engineering so let's give the man the benefit of the doubt. If you want to pull the dragons tail don't bitch when you get crispy around the edges.

 

[Rexwagon]

Hahaha

 

[hereinaz]

He's just setting the mouth breathers strait. Tards bitch and moan about the dumbest of non issues and then force the owner ( who would be better off making/designing more products then responding to dribble) to defend it in a way that a novice may be able to understand. Ted is on a whole nother level intellectually when it comes to engineering so let's give the man the benefit of the doubt. If you want to pull the dragons tail don't bitch when you get crispy around the edges.

Hahahhaa, crispy!

 

[stereo.pete]

I loved this line @Primus "If you want to pull the dragons tail don't bitch when you get crispy around the edges."

 

[Jory45acp]

In general, an action is considered to be controlled round feed (CRF) if its extractor is capable of engaging a cartridge on its way out of the magazine and then pulling that cartridge reward for delivery to the ejector without the need to rotate the bolt closed as one would need to do in a push-feed action such as a Rem 700.

Pushing the bolt forward as slowly as possible and expecting the same result as one would get had they pushed the bolt forward at normal speed is senseless because cartridge inertia matters.

The advantage offered CRF actions is a reduction, in the likelihood of double feeding the chamber which would otherwise cause a jam. This tends to happen during times of stress, such as during timed competitive events. Again, it CRF reduces the risk of double feeding. It does NOT eliminate it.

The degree to which the likelihood of double feeding is reduced depends on the magazine and its feed lip geometry, the diameter of the cartridge body, the diameter of the bolt, the shape of the extractor hook, and the position of the cartridge shoulder along the length of the cartridge, the speed with which the bolt is cycled, the width of the cartridge extraction groove, and more. Variations in any of these will affect CRF reliability.

While designing both the Nucleus and the Mausingfield, I never once assumed that CRF functionality would be necessary when running a bolt as slowly as possible in an attempt to capture the case being forced under the extractor when the forward motion of the bolt is purposely stopped an instant after the mag has released it. That said, we can create the conditions for that to happen, or not happen, but that would be a stupid waste of time. And that's true of any CRF action, Mauser 98 included. Just because I can cause a certain Mauser 98 to fail to engage the head of a certain cartridge by running it in a certain manner would not lead me to conclude that the M98 is not a CRF action. And that's saying something because Mauser rifle were built as cartridge specific rifles. Moreover, anyone who has every built custom rifles on M98s will tell you that mods are required to get reliable CRF functionality.

If you want to capture controlled round feed on video, record the bolt cycle at normal speeds (fast) and replay in slow motion. I'll leave that up to someone else.

Oh, and one last point. Never write anything in a public forum about a bolt action until after you have come to understand the Mauser 98. I can't stress that point enough.

Ted

If you are going to go online and make accusations about a product don't be surprised if someone smarter and more knowledgeable comes along and corrects you. No one is going to argue with Ted about Mauser style actions and win. The guy forgets more knowledge than most can hope to understand. Kudos to him for coming online and clearing all the speculation on this topic. I agree as stated above we all can wonder about this or that and make our ideas known, just be prepared to be corrected which may be in a way you don't like. Ted's a great guy who designs amazing products. No one orders his actions because they think he's "friendly", they throw money at him because his designs work....period!

 

[Ledzep]

Does anyone have BOTH a Nucleus and a Mausingfield?

I'm curious to know how,
a) The ejection port location
b) the bolt handle location

compare between the two.

 

[ThePretzel]

Does anyone have BOTH a Nucleus and a Mausingfield?

I'm curious to know how,
a) The ejection port location
b) the bolt handle location

compare between the two.

This weekend at a match I know one of the MD's has 2 Mausingfields. If he brings one I'll see if I can take some pictures of the two side by side for comparison.

 

[leftyk82]

I do, the nuke isn't in chassis, however. I can get some pictures tomorrow.

 

[Ledzep]

Much appreciated guys. Im going to be building a 300PRC this coming spring and ordered the manners inletted for a MF, but I handled a Nucleus a few days ago and Im liable to go either direction on the action. I think they will be very similar, just want to make sure it's not a certain no-go/headache.

 

[craigos]

Just because I am here (and we are talking Nucleus) , dont buy a geissele trigger for you Nucleus ... doesnt work - got mine today (Geissele). Firing pin wont fall. Havent tried a Mausingfield ... informed Geissele (and sent Ted a note in case folks call). Oh the joys of rem 700 trigger mfgs. Whats interesting is all my other triggers (huber, BnA (2 different ones) and calvin elite worked fine on the nucleus , no issues . No problem, i love the nucleus enough i will just use my BnA or Calvin Elite with it. The giessele worked on a rem 700 action (GA Precision Gladius).

 

[leftyk82]

@Ledzep , let me know if these suit your needs. The ejection port is certainly wider on the Nucleus.