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Author Topic: Range Report  (Read 1854 times)
kfeltenberger
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« Reply #20 on: July 08, 2018, 09:03:31 PM »

Both FDE?

Yes, both were FDE.
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Kurt
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« Reply #21 on: July 09, 2018, 09:35:08 AM »

Lucky. Those FDE guns look good.
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Blackandwhiteknight
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« Reply #22 on: July 09, 2018, 09:25:28 PM »


This is how round 20 was found when the ejection chute was removed:



Dude, I have no idea how you got the bolt over the rim like that Cheesy  I sat in the garage for like 15 minutes today trying to replicate this malfunction.  You mark the magazine? Even with magazine partially inserted I was only able to catch the shoulder past the rim by dragging the bolt to just the right spot.  The only thing I can think of is there might be something catching in the mag that's doing something weird with the feed lips or the follower.
« Last Edit: July 09, 2018, 11:49:01 PM by Blackandwhiteknight » Logged
Zeiram3f
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« Reply #23 on: July 09, 2018, 11:23:07 PM »

Sounds like a similar experience on my end as well. The warranty department is either too busy, understaffed, or having difficulty tending emails. I had to email an entirely different department to get an RMA. 2 Voicemails and 3 emails werenít enough.  Undecided

That said, I also agree with the ejection chute issue. Iím eager to see a replacement paw and spring in near future.
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kfeltenberger
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« Reply #24 on: July 10, 2018, 12:13:57 AM »


This is how round 20 was found when the ejection chute was removed:



Dude, I have no idea how you got the bolt over the rim like that Cheesy  I sat in the garage for like 15 minutes today trying to replicate this malfunction.  You mark the magazine? Even with magazine partially inserted I was only able to catch the shoulder past the rim by dragging the bolt to just the right spot.  The only thing I can think of is there might be something catching in the mag that's doing something weird with the feed lips or the follower.

It's a gift.   Grin

After each round, the bolt locked back; there weren't any failures there of the 39 rounds fired.  The bolt was released by pressing the bolt release tab behind the magazine and allowing the bolt to move forward under spring tension.

After thinking about this for a few days, my thought is that the gremlin is the ejection chute.  When the rifle is fired, the bolt velocity rearward should be relatively constant, but any amount of drag or debris that cause more force to be expended to overcome it, will glitch the system.  Normally, this wouldn't be an issue, but the cycle then needs to provide enough lateral force to push the brass case into the chute and against a clip that is not contoured to facilitate this, so brute force is required. 

What happened to me is that I think the bolt wasn't moving fast enough rearward and the spent brass wasn't fully seated in the chute when the bolt was released to load a new round.  That's what happened to that rifle before it was sent back. 

The clip needs to have that edge removed and re-contoured to allow the spent brass to roll into the chute, rather than trying to force its way past a sharp edge.  Then the while thing needs to be polished and smoothed, with all edges radiused to remove drag points.  Your modification is probably the key to this.
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Kurt
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« Reply #25 on: July 10, 2018, 12:15:13 AM »


This is how round 20 was found when the ejection chute was removed:



Dude, I have no idea how you got the bolt over the rim like that Cheesy  I sat in the garage for like 15 minutes today trying to replicate this malfunction.  You mark the magazine? Even with magazine partially inserted I was only able to catch the shoulder past the rim by dragging the bolt to just the right spot.  The only thing I can think of is there might be something catching in the mag that's doing something weird with the feed lips or the follower.

I'm not sure how it happened either. The bolt had been locked back by the last round being fired from the previous magazine. The bolt was released using the release button just behind the mag well. Since the rifle wasn't sighted in yet, the range rules limited us to one round per magazine, so there weren't any other rounds in the magazine when this happened.

My hypothesis is that the front got hung up somehow, and low spring pressure from the magazine follower allowed the back of the round to drop back into the magazine. This round getting stuck would be the cause of the stoppage, not the empty case in the ejection chute. That case didn't show anything other than a minor nick which could not account for the stoppage.
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Blackandwhiteknight
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« Reply #26 on: July 10, 2018, 12:57:08 AM »


This is how round 20 was found when the ejection chute was removed:



Dude, I have no idea how you got the bolt over the rim like that Cheesy  I sat in the garage for like 15 minutes today trying to replicate this malfunction.  You mark the magazine? Even with magazine partially inserted I was only able to catch the shoulder past the rim by dragging the bolt to just the right spot.  The only thing I can think of is there might be something catching in the mag that's doing something weird with the feed lips or the follower.

It's a gift.   Grin

After each round, the bolt locked back; there weren't any failures there of the 39 rounds fired.  The bolt was released by pressing the bolt release tab behind the magazine and allowing the bolt to move forward under spring tension.

After thinking about this for a few days, my thought is that the gremlin is the ejection chute.  When the rifle is fired, the bolt velocity rearward should be relatively constant, but any amount of drag or debris that cause more force to be expended to overcome it, will glitch the system.  Normally, this wouldn't be an issue, but the cycle then needs to provide enough lateral force to push the brass case into the chute and against a clip that is not contoured to facilitate this, so brute force is required. 

What happened to me is that I think the bolt wasn't moving fast enough rearward and the spent brass wasn't fully seated in the chute when the bolt was released to load a new round.  That's what happened to that rifle before it was sent back. 

The clip needs to have that edge removed and re-contoured to allow the spent brass to roll into the chute, rather than trying to force its way past a sharp edge.  Then the while thing needs to be polished and smoothed, with all edges radiused to remove drag points.  Your modification is probably the key to this.

 Well removing drag from anywhere possible will help the system for sure.  Sounds like Nick liked the idea too so hopefully they do something with it.
  Your MDR 2 that's giving you trouble may have a rough spot or a bind somewhere.  I think you may want to remove the ejection chute, and see if it runs that way.  If it runs I would put a few magazines through it with the chute off, on adverse.  Just running some rounds through it may smooth it out.

  Then I would start swapping variables. Take both panels from MDR 2 and put them on MDR 1 and see if it changes the function.  Would tell you if its the panels or something else.

  I would certainly take a close look at the mag if you get another stoppage like that.  PMags should be good, but weird things happen.
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ney1
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« Reply #27 on: July 11, 2018, 03:29:30 AM »

Removing the firing pins from the bolt carriers will cause the cam pins to fall out during cycling and lead to improper bolt closure.  I'd suggest firing the rifles, or cycling dummy rounds, or grinding your firing pins down if you want to avoid this issue.  Also slow cycling of the charging handle is not recommended for reliable manual ejection.
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kfeltenberger
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« Reply #28 on: July 11, 2018, 12:46:39 PM »

Removing the firing pins from the bolt carriers will cause the cam pins to fall out during cycling and lead to improper bolt closure.  I'd suggest firing the rifles, or cycling dummy rounds, or grinding your firing pins down if you want to avoid this issue.  Also slow cycling of the charging handle is not recommended for reliable manual ejection.

I never slow cycled the charging handle; always draw it back and release.  As for the cam pins falling out, this was not an issue for the few times it was cycled.
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Kurt
JesseJames38
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« Reply #29 on: July 11, 2018, 01:00:23 PM »

quick question Ney, sense you mentioned to grinding down the firing pin.  How dose one obtain a new firing pin and how much dose a firing pin cost? Some times its nice to have spares
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newguy2k3
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« Reply #30 on: July 11, 2018, 02:33:02 PM »

Removing the firing pins from the bolt carriers will cause the cam pins to fall out during cycling and lead to improper bolt closure.  I'd suggest firing the rifles, or cycling dummy rounds, or grinding your firing pins down if you want to avoid this issue.  Also slow cycling of the charging handle is not recommended for reliable manual ejection.

I never slow cycled the charging handle; always draw it back and release.  As for the cam pins falling out, this was not an issue for the few times it was cycled.

He's emphasizing that not pulling the handle back vigorously leads to unreliable ejection, not necessarily feeding.
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kfeltenberger
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« Reply #31 on: July 11, 2018, 06:08:49 PM »

Removing the firing pins from the bolt carriers will cause the cam pins to fall out during cycling and lead to improper bolt closure.  I'd suggest firing the rifles, or cycling dummy rounds, or grinding your firing pins down if you want to avoid this issue.  Also slow cycling of the charging handle is not recommended for reliable manual ejection.

I never slow cycled the charging handle; always draw it back and release.  As for the cam pins falling out, this was not an issue for the few times it was cycled.

He's emphasizing that not pulling the handle back vigorously leads to unreliable ejection, not necessarily feeding.

Which is what I did.  Good grief...do I need to make a video next time?  I wasn't gentle with the damned thing and it didn't work.  I sent it back.  Now one works, at least 20 out of 20 times and one only works 19 out of 20 times.

I'm not upset with you, but I don't know how many times I need to explain what I did. 
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Kurt
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« Reply #32 on: July 11, 2018, 06:12:49 PM »

 Popcorn Popcorn Popcorn Popcorn
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newguy2k3
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« Reply #33 on: July 11, 2018, 09:41:06 PM »

Well you said draw back. When someone draws back a bow for example it's generally taken that they're pulling it back slowly.

With the mdr you have to rip the charging handle back to get it to eject properly if it even will at all even then without smoothing out the ejection chute.
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kfeltenberger
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« Reply #34 on: July 11, 2018, 11:17:29 PM »

Well you said draw back. When someone draws back a bow for example it's generally taken that they're pulling it back slowly.

With the mdr you have to rip the charging handle back to get it to eject properly if it even will at all even then without smoothing out the ejection chute.

I am well aware of this...I've been reading the same posts you have and am generally smart enough not to make the mistakes others made and posted about.  I guess I'm going to have to get super detailed for my next report on my MDRs' function...shall I get a Kestrel weather station, too?   Wink Cheesy Grin
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Kurt
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