Rimx with ModX conversion likes Vudoo mags better than RimX Mags

[DrA1]

The title says it all.

I just picked up a Rachel Precision Brux on a RimX action with the ModX bolt.
The guns shoot beautifully- tight groups at both 50 and 100 yards.

But here is the issue — I have 2 RimX mags with extensions and they are well built, but no matter how I adjust them, they do not feed consistently, so I decided to try a polymer Vudoo mag, as I had some with me and BINGO—- flawless feeding—— has anyone else experienced this.

When watching the rounds feed, it appears that the round hits the chamber a little low and shaves some lead and the cartridge hangs on the lower (6 o clock) aspect of the chamber. Probably about 1 in every 20 rounds does it. SO…… I adjusted the mag to sit as high as possible however that did not fix the problem— I believe the issue is the angle on the front edge of the rimx mag.

The Vudoo mag on the other hand feeds flawlessly over hundreds of rounds.

Thoughts??

 

[Hgrubbs22]

Buy more Vudoo mags and sell the RimX mags. . No more thoughts today.

 

[DrA1]

Buy more Vudoo mags and sell the RimX mags. . No more thoughts today.

That’s exactly what is about to happen — just looking for some feed back or ideas on getting the rimx mags to be more consistent.

 

[Csafisher]

Does it only happen on full mags?

 

[DrA1]

Does it only happen on full mags?

Reply — it can happen at anytime, first round, last round or anywhere in between and it doesn’t matter how many rounds are in the magazine.

I’m going to video some slow motion feeding to see if I can identify exactly wvhat is happening

 

[DownhillFromHere]

Try taking the extensions off, assuming you have the original floor plates. I only experience feeding problems with my RimX with the Zermatt 5-round extension in place on one magazine, and it can happen anywhere in the cartridge stack. The round pops off the stack in front of the extractor and gets shoved into the chamber, requiring steel fingernails or a tool to pull it out.

 

[pronelife]

does the chassis have an adjustable magwell such that chassis adjustments would raise the mag?

 

[DrA1]

Try taking the extensions off, assuming you have the original floor plates. I only experience feeding problems with my RimX with the Zermatt 5-round extension in place on one magazine, and it can happen anywhere in the cartridge stack. The round pops off the stack in front of the extractor and gets shoved into the chamber, requiring steel fingernails or a tool to pull it out.

Do you have the modX conversion or the factory original bolt face?

does the chassis have an adjustable magwell such that chassis adjustments would raise the mag?

it does not.

 

[DownhillFromHere]

Do you have the modX conversion or the factory original bolt face?

It's the original bolt face... although my point stands. I suspect that the original spring isn't quite strong enough for the height/weight of the additional cartridges.

 

[DrA1]

It's the original bolt face... although my point stands. I suspect that the original spring isn't quite strong enough for the height/weight of the additional cartridges.

I wasn’t implying that the bolt face was my issue, just wasn’t sure how many of the ModX rifles have made it into the wild.

I believe you are correct, based on speaking with several other shooters that have had similar issues with extension and feeding difficulties.

I’m going to remove the extension and shoot it today (but I also ordered the tandemkross green springs as the hopeful solution with the extension)

Thank you for the help

 

[DownhillFromHere]

I wasn’t implying that the bolt face was my issue, just wasn’t sure how many of the ModX rifles have made it into the wild.

I believe you are correct, based on speaking with several other shooters that have had similar issues with extension and feeding difficulties.

I’m going to remove the extension and shoot it today (but I also ordered the tandemkross green springs as the hopeful solution with the extension)

Thank you for the help

Please post back with your results - I'm interested for sure.

My feed failures with the extended magazine are frequent enough that I wouldn't even think about running the rifle in a match with "normal" par times. I did use it in a little monthly match series in 2023 which had long par times... and I usually had one or two failures every match, always with the extended magazine.

 

[Csafisher]

I guess I’m lucky. My 15rd rimx mag has been great. I’m using it in a XLR envy chassis. It has an adjustable mag catch. Have it set with very little vertical play.

 

[DrA1]

Please post back with your results - I'm interested for sure.

My feed failures with the extended magazine are frequent enough that I wouldn't even think about running the rifle in a match with "normal" par times. I did use it in a little monthly match series in 2023 which had long par times... and I usually had one or two failures every match, always with the extended magazine.

I wouldn’t consider using those mags in match, but hopefully will get it sorted out.

At least I have other mags that do run well.

I’ll let you know the results.

 

[KnowNothing256]

I run a ModX in an ACC Elite with a RimX mag fitted with the +4 extension from Zermatt, and see no shaving.

My only reliability issue is the bolt moves so freely that shoving it firmly into a bag on a solid prop can send a round halfway forward, and if I back the bolt up from there I get a jam. Would love to have a detent bolt retention mod done to it, probably have a smith look into that for me sometime this year.

 

[DrA1]

Update — so I was impatient while waiting for new stronger springs — so I modified a Vudoo follower (by cutting off the side tab) and it fits perfectly in the RimX mag, it allowed me to use a much heavier square spring and it changed the feeding angle enough to make it feed perfectly.

I spoke with Johnathan Elrod and he agreed the issue was spring pressure or feed angle in my particular chassis and the way the RimX mags sat in the mag well despite a nice snug fit with zero slop.

 

[DrA1]

 

[Csafisher]

View attachment 8732083

Where’d you get the new spring?

 

[DrA1]

Where’d you get the new spring?

I can’t even remember — had 2 of them in my “spare” parts bin along with several different followers from Vudoo and MKM.

I’ve got a set of green springs coming from tandemkross — when I get those, I may try to modify the rimX followers and give them a shot with the new springs.

I recorded my mis feeds in slow motion and could see that my round presentation was too nose up and wouldn’t seat all the way into the bolt face, so I went to work trying different things to make the rounds feed “less nose up” and changing followers allowed the rounds to feed at the perfect angle —- I’ve cycled a couple hundred rounds through it now without a misfeed, but I wasn’t shooting because I was at my home. I’ll get back to the range latter this week and confirm it is just as consistent when firing.

 

[Dan.Engellant]

We are using one of the new ace of spades from Alta arms in a RimX it has been flawless.

 

[RAVAGE88]

I can’t even remember — had 2 of them in my “spare” parts bin along with several different followers from Vudoo and MKM.

I’ve got a set of green springs coming from tandemkross — when I get those, I may try to modify the rimX followers and give them a shot with the new springs.

I recorded my mis feeds in slow motion and could see that my round presentation was too nose up and wouldn’t seat all the way into the bolt face, so I went to work trying different things to make the rounds feed “less nose up” and changing followers allowed the rounds to feed at the perfect angle —- I’ve cycled a couple hundred rounds through it now without a misfeed, but I wasn’t shooting because I was at my home. I’ll get back to the range latter this week and confirm it is just as consistent when firing.

I’ve been following along and was attracted to jump in when you said, “too nose up.” Forgive me if I missed somewhere above, but what stock/chassis are you using? Is there an adjustable release in addition to the adjustable catch on the RimX magazine?

“Too nose up” isn’t always (more rare than one might imagine) because of the magazine.

MB

 

[DrA1]

I’ve been following along and was attracted to jump in when you said, “too nose up.” Forgive me if I missed somewhere above, but what stock/chassis are you using? Is there an adjustable release in addition to the adjustable catch on the RimX magazine?

“Too nose up” isn’t always (more rare than one might imagine) because of the magazine.

MB

The mag release isn’t adjustable.

The chassis is an MDT that was a special build for Faxon at some point and it is no longer produced. It is a blend of the LSS and the Elite as far as features are concerned. I had previously used it with a B14R custom.

I also follow your post concerning DDG and your future products, as I also shoot a 360.

I believe the true issue is the mag well geometry, but I love the balance and feel of the chassis, so I made the mods to the follower and spring to get consistent feeding.

So here is my synopsis of everything to this point — the mag catch height on the rimX mag is set to be snug when the bolt is in the closed position. There is almost no lateral play in the mag. When I see the “problem” feeds the bullet orientation is slightly nose up as it enter the chamber and the rim is not fully seated into the bolt face. This can happen at any point throughout the magazine. Which makes me think it is not a spring pressure issue, but a timing problem based on the bullet presentation.

The bolt nose / face is ModX. I checked it’s function and geometry outside of the action to see that rounds will easily and fully seat in the face and sit appropriately between the face and extractors.

When I put a 10 round poly Vudoo mag in this chassis, I can see that the “lie angle” is about 10-15 degrees less nose up as compared to the RimX mag. So I tried to replicate the Vudoo mag presentation in the RimX mag — fully knowing this is likely a chassis issue, based on all the data acquired to this point.

I’m going to try the barreled action in another chassis this afternoon with all original RimX mags and see how it works in that chassis and report back.

 

[RAVAGE88]

The mag release isn’t adjustable.

The chassis is an MDT that was a special build for Faxon at some point and it is no longer produced. It is a blend of the LSS and the Elite as far as features are concerned. I had previously used it with a B14R custom.

I also follow your post concerning DDG and your future products, as I also shoot a 360.

I believe the true issue is the mag well geometry, but I love the balance and feel of the chassis, so I made the mods to the follower and spring to get consistent feeding.

So here is my synopsis of everything to this point — the mag catch height on the rimX mag is set to be snug when the bolt is in the closed position. There is almost no lateral play in the mag. When I see the “problem” feeds the bullet orientation is slightly nose up as it enter the chamber and the rim is not fully seated into the bolt face. This can happen at any point throughout the magazine. Which makes me think it is not a spring pressure issue, but a timing problem based on the bullet presentation.

The bolt nose / face is ModX. I checked it’s function and geometry outside of the action to see that rounds will easily and fully seat in the face and sit appropriately between the face and extractors.

When I put a 10 round poly Vudoo mag in this chassis, I can see that the “lie angle” is about 10-15 degrees less nose up as compared to the RimX mag. So I tried to replicate the Vudoo mag presentation in the RimX mag — fully knowing this is likely a chassis issue, based on all the data acquired to this point.

I’m going to try the barreled action in another chassis this afternoon with all original RimX mags and see how it works in that chassis and report back.

Thank you for the details, it helps ring all this out.

It's definitely a timing issue and definitely not a spring issue. I doubt it is follower angle. It'll be interesting to see if the interface pad on my magazine is providing a rearward load into the release (it has to be touching the forward face of the mag well in the receiver), as the RimX mag doesn't have that feature. That will help validate the mag well dims/constraints. Without the interface pad, the mag release pushes the magazine forward in a sloppy mag well, which throws off feed timing and can/will cause a nose up presentation.

Changing mag height on the RimX mag could help with the nose up condition, but it depends on how sloppy the mag well is; however, I know little to nothing about the ModX conversion.

MB