Curtis Axiom Dasher Feeding Issue

[AIKNOWU]

Hi all,

I'm having issues with the feeding of Dasher through my Axiom action. I know a lot of people use this action/chambering combo, so it's got to be something on my end. Specs for everything I can think of below.

The rounds are tipping over the lug abutments and driving into the face of the breech instead of feeding into the chamber. This is occurring because the rounds are released from the magazine before the tip of the bullet is in the chamber.
The only magazines I've tried that don't do this are the AI-brand magazines. I use a Primal Rights kit to negate magazine-specific issues with the Dasher. I've tried Magpul, Accurate, and MDT mags- none work.
It seems to be that the AI-brand mags have ever so slightly longer feed lips, and release the round *just* late enough. The AI-brand mags are nearly 100% reliable, even at slow speed. I know I could just buy plenty of these mags, but I'd really like to be able to use something else. Not to mention I don't like being right on the ragged edge of barely working. That got me in trouble in a very important match last year.
The other mags sometimes work if I work the bolt very quickly, but almost never work at slow speed. All of these magazines work just fine in my Remington 700 action. No problem.

Anyway, what issues or workaround are others finding?

My barrel tenon is cut to the specs on the Curtis site: a .680" tenon. Chambered so go gauge has ~.155" exposed (can't recall offhand exactly how much, 'cause I headspace to suit the gauge, but it's damn close to the .155" recommended).
I'm using Lapua brass that's bumped back ~.003", and 105 Hybrid bullets at 2.358" COAL, which is about .020" off the lands. The chamber is a PT&G with .104" freebore.

Thanks for the help.

 

[DisplacedTexan]

Have you tried ARC mags?

@Birddog6424 what does your buddy use in his Axiom?

 

[Birddog6424]

Have you tried ARC mags?

@Birddog6424 what does your buddy use in his Axiom?

I have an Axiom Bry, as well as Brady. But we both have our actions cut for AW mags, and we modify the angle of the feed ramp.

I also have a Tempest with an AW cut and did the same thing with it.

 

[AIKNOWU]

Haven't tried ARC mags. Seems like they have so many issues reported, it wouldn't be worth the expense to try.
Really, I'm wondering if the root of the issue is something besides the mags.

 

[Potsy]

You said you had tried MDT mags, but I wasn't sure if you meant the MDT's with the Primal Rights Kits, or the MDT BR/Dasher specific mags.

I have the BR specific mag for my .22 BR and it feeds like it has eyes cycling slow, but I've not even tried to run it fast (only about 75 rounds in on this rifle).

FWIW, I'm running an Origin and it'll run a 5 round Mag Pull just fine, as long as the mag doesn't get pushed up, then the bolt hits the feed lip. The MDT doesn't do that.

 

[MDT_Josh]

The tricky thing about the 3-lug design (and why we typically warn users about using it with our 6BR magazine) is that they typically require some tweaking of the feedlips or spring/follower combo to get them to feed 100%. Guys like Jon Pynch (6 Dasher in a Curtis Vector) have had good luck with barely modified mags (AI), but I have no idea how!

What I have found is that by adjusting the feedlip spacing (+/- 0.010" front and/or back) you can make a large impact on the feeding. Additionally, on our design (as well as a lot of others) you are able to slide the spring location relative to the follower and either add or decrease pressure to the front or back of the round.

Let me know if you need any help

Josh

 

[Lowlight]

I think they hang on the plunger for the ejector

see if your plunger is long and catching the round, the ones I had in class modified this to get them to feed.

 

[AIKNOWU]

Thanks to both. Lowlight- I don't believe the rounds are catching on the ejector. I watched carefully this afternoon, and the rounds seem to be being pushed by the bottom rim of the bolt nose without hindrance of the plunger.
Then they sometimes just don't make it over the lug abutment without tipping a bit and touching the breech face. Sometimes it seems like they're "popping" up out of the mag and starting their forward travel with a slight downward tilt, aimed at the breech face.

@MDT_Josh - I didn't mean to bash your magazines. I'm aware that on your site you claim they're not good with the Curtis. I just used your mags as a data point.
I understand the basic concept of what you're describing, but can't visualize how I should adjust the lips to assist in the issue I'm having. If you have a possible solution, I'm game for trying!

 

[MDT_Josh]

@AIKNOWU I wasn't taking it as a bash to our mags, I was just offering some insight from our experiences From you're description, the rounds are diving down into the bottom of the breech face AFTER exiting the mags? If so, does this only happen when you run your bolt slow, or is it all the time? Occasionally, slow cycling short rounds gives them time to have issues, but fast cycling will help. If I am misunderstanding the issue, let me know.

Josh

 

[AIKNOWU]

@MDT_Josh
Yes, that's correct. It's primarily when I run the bolt slowly. If I go quickly/like normal, it is probably 80-90% fine, but the odd round gets jammed up.

 

[MDT_Josh]

@MDT_Josh
Yes, that's correct. It's primarily when I run the bolt slowly. If I go quickly/like normal, it is probably 80-90% fine, but the odd round gets jammed up.

Any way you could post a video of what you're seeing? It may be possible to bump open the front of the feedlips a little, angle the round up a bit more and ensure more even feeding?

Josh

 

[midwestoffroad]

I run Dasher in my vector with AI and PVA and MDT BR mags no problem magpul drag on the bolt. Only issue I ever had was my MPA chassis needed the mag block for the vector.

My axiom run a a 6br in a MPA moa and just took a slight tweek to run .

I agree a video.would help

 

[midwestoffroad]

Video of My Curtis vector and unmodified MDT BR mag Bank it stage

 

[AIKNOWU]

@MDT_Josh @midwestoffroad
Here's the video of my feeding issues. You can see I went slow at first, then fast (I'll wait for the jokes).
Yes, they're live rounds. Yes, I removed my firing pin assembly for the video.

AxiomFeeding.mov

• AIKNOWU
• Jan 14, 2020

And here's a comparison of the feed lip length between the AI mag (front) and MDT mag (rear). It's a .308 MDT mag, but the same issue occurs in the BR mags. I've had one (returned it for this problem) and also recently tried with my friend's.

 

[LawnMM]

Stick with the kitted AI, know a Dasher shooter that uses that combo no issues.

In the end, use what works, not what you'd prefer to work.

 

[midwestoffroad]

I just tested using an AI mag with the PVA kit and that works fine the MDT 10 round 308 mag no kit and that works fine by MDT six br mag that works fine and I used a accurate mag that jammed.


I noticed how your rounds pop out of the feed lips as you just are pushing them forward . Where mine feed all the way up

 

[MDT_Josh]

@MDT_Josh @midwestoffroad
Here's the video of my feeding issues. You can see I went slow at first, then fast (I'll wait for the jokes).
Yes, they're live rounds. Yes, I removed my firing pin assembly for the video.

AxiomFeeding.mov

• AIKNOWU
• Jan 14, 2020

And here's a comparison of the feed lip length between the AI mag (front) and MDT mag (rear). It's a .308 MDT mag, but the same issue occurs in the BR mags. I've had one (returned it for this problem) and also recently tried with my friend's.

View attachment 7225149

Thanks for the pictures and videos! That is very informative and unfortunately there is little that can be done on our end to solve that issue It looks like the AI's with the kit feed and function okay, and it may be worth giving the AI AW's a shot with the HRD gear kit too? I know that a lot of people have had good luck with that combination in 3-lug actions (if your action is cut for it that is).

Josh

 

[AIKNOWU]

@MDT_Josh and the rest, thanks very much for all the help.