Help please, case neck sticking on chamber edge when closing bolt. Poorly drawn pic.

[doodedge]

Hey guys, I've found that when the bolt pushes the round to the point the magazine lips release it, the back side springs up to the top of the bolt above the grove the head should sit in, and the case neck catches while going into the chamber. If I close the bolt slowly it doesnt do this but when cycling it at a moderate speed they catch pretty much every time.

I just have to release pressure off the bolt to let the case head fall back into place then it closes fine.

I have CDI* bottom metal in a boyds stock.

EDIT:
So I found that the bullet head is catching on the ejection pin. The pin doesn't actually protrude from the recess in the bold face but when the bullet is at the angle in the picture its just enough for the bottom of the head to catch on the ejection pin.

So the bullet head catches the pin and the shoulder catches on the chamber. I've never taken the pin out, it compresses just fine and ejects fine. Any one know whats up?

EDIT/SOLUTION: Fixed. Took my dremel grinding wheel to my ejector pin. Filed it to just about even, or maybe a touch under the lower beveled edge of the bolt face then rounded it off. Feeds smooth as butter now.

Thanks every one for the input.


Any thoughts or ideas on how to fix this from any one would be appreciated.

[DrThunder88]

Interesting. What chambering? Does this happen with evey round in the magazine or, for example, just the first or last?

[doodedge]

.308 with a MDT magazine in CDI bottom metal

Happens with most rounds, a random one here and there will chamber smoothly but most do not.

[adammiddagh]

I have a pair of 110 actions that I made into 308win and 22-250. The 270 blind mags(both started as 270) would feed the 308 perfect, but the 22-250 would do as you have drawn. I came to the conclusion that the bullet tip needs to be in the chamber mouth before the case head comes out of the magazine lips. I am not sure of the solution for yours, but I ended up buying a short action magazine and making an adapter bracket to mount it into my long action.

Hope that helps,
Adam.

Edit.
What was happening on mine, and I believe yours, is that the bullet tip is not in the barrel, but against the rear of the barrel.

[doodedge]

Hey adam, thanks for the input.

I think the tip of the bullet is actually in the chamber when it releases, but when the head of the round pops out of the mag lips it springs up with a lot of force and its the neck of the case that catches on the edge of the chamber.

I tried some minor file work on the mag to get it to release the bullet a little smoother with no luck. I'm thinking maybe some polishing on the corners of the chamber where the neck is grabbing and also on the bolt face... and if that doesn't work I might try filing a groove into bottom plate of the magazine to try to take the spring pressure off the head of the bullet right before it gets released to stop it from popping up at that angle.

[adammiddagh]

Is the case popping up out of the lips, or is it sliding forward to get out?

[doodedge]

It is sliding forward. It releases where it supposed to at the end of the lips however it springs upward pretty hard as soon as it's released because of the mag plate pushing up on the bullet head.

I double checked and the bullet is definitely reaching the chamber before it is released from the mag lips.

I can recreate this with my finger just by sliding a bullet in with the head up slightly above horizontal, as soon as the angle on the neck gets to the chamber it catches.

[doodedge]

So I found that the bullet head is catching on the ejection pin. The pin doesn't actually protrude from the recess in the bold face but when the bullet is at the angle in the picture its just enough for the bottom of the head to catch on the ejection pin.

So the bullet head catches the pin and the shoulder catches on the chamber. I've never taken the pin out, it compresses just fine and ejects fine. Any one know whats up?

[doodedge]

Fixed. Took my dremel grinding wheel to my ejector pin. Filled it even to just about even maybe a touch under the lower beveled edge of the bolt face then rounded it off. Feeds smooth as butter now.

Thanks every one for the input.

[foxx]

^^^^ I don't get it. Can you draw another picture of what you did?

[adammiddagh]

Good to hear it worked out. I was going to suggest removing the ejector to test it, but if a little trim and polish fixed things up, great.

Foxx. I think he means that the case would jump up when leaving the feed lips. Then with the case head high on the bolt face, it would catch on the ejector pin and not slide down into the recess.

[foxx]

So how well does it eject now?

[doodedge]

Ejects fine still. I didn't remove much material from the pin. Adam explained right.

[DrThunder88]

Wow, I don't think I'd have thought of that as the cause. Good work diagnosing the problem and coming up with a solution! Thanks also for following up in this thread.

[devildogandboy]

similar to what alot of AR folks do to their ejectors, round off the square edge and maybe clip a coil or so off the ejector spring. i had to do this on my 6.5 Grendel.

Bruce

[mech1369dlw]

I have an 11VT that is doing exactly what yours was doing. I had others watch it as I cycled the bolt and then I watched it while they did it. I came to the same conclusion you did but was hesitant to grind on the pin. Guess that is going to be on my "to do" list in the near future.

[adammiddagh]

If you remove the ejector, you could test that this is the cause of your problem, before you grind on it. If it feeds smooth, then the ejector is already out and easy to work on.

[doodedge]

On the bright side, if it doesn't work out and ruins your ejection, it's only a 7$ replacement from midway.

http://www.midwayusa.com/product/117...g-all-calibers