M4 Barrel Extension Question

[nCarnage]

So I finished my first build earlier in the year. Haven't shot it yet. I know, im a horrible person. Just haven had the time this year. So I decided to lubricate my pistols and was like, "hey why not lube the rifle too." As I was lubing the upper, I noticed that my M4 feed ramps on the barrel extension are slightly canted. As in they are not aligned with the M4 ramps on the upper.

Like I said, I havent shot the thing yet. But decided to chamber a bunch of Magpul dummy rounds. I removed the firing pin from the BCG and decided to cycle some live rounds. Didnt seem to have a problem doing so.

Question: from your experiences on builds and handling the AR platform, will this cause issues? How can I fix it if it needs to be fixed?

Link to Flikr pic. I currently can not add attachments. https://flic.kr/p/p2K2sc

[GaSwamper]

How bad canted is it?

[nCarnage]

How bad canted is it?

If you look at the picture in the link, on the right feed ramp close to center, it's not lined up properly. Enough where I can feel it with my finger nail that it's not centered.


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[Gaspipeshooter]

Dremel tool with a small round tapered stone will fix that right up.

[GaSwamper]

Sorry I missed the link. Yep only fixin is polish out, short of a barrel swap. It could cycle fine plenty of times but there is the possibility of feeding problems and tip damage.

[nCarnage]

Thanks guys. Probably take it to the gunsmith get that job done. Plus I don't have a dremel. Lol


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[Stone]

Take it out and run some of your favorite ammo through it first. Why fix something that may not even be a problem until you find out its a problem...

[MoxyDave]

What kind of torque did you use on the barrel nut? I would check the extension pin to make sure it's not partially sheared off. That's not right.

[GaSwamper]

It could be the angle of the pic but it appears the offset isn't even between the two cuts. Is this the case or is it evenly off on both ramps?

[rob_s]

What brand is the barrel?

[UWone77]

Thanks guys. Probably take it to the gunsmith get that job done. Plus I don't have a dremel. Lol


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Don't buy a dremel. Then you'll be tempted to use it.

Call the manufacturer before you do anything and see if they will take a look at it and/or replace it.

[nCarnage]

Don't buy a dremel. Then you'll be tempted to use it.

Call the manufacturer before you do anything and see if they will take a look at it and/or replace it.

Thinking its out of spec? I laughed at the "don't buy a dremel" comment.


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[Eric]

Like I said, I havent shot the thing yet. But decided to chamber a bunch of Magpul dummy rounds. I removed the firing pin from the BCG and decided to cycle some live rounds.

STOP doing that! Without the FP in place there's a chance you can lock the thing up. If it's a complete factory upper get the manufacturer on the phone and inquire what they suggest. Otherwise, clean, lube, shoot, then report back.

[nCarnage]

STOP doing that! Without the FP in place there's a chance you can lock the thing up. If it's a complete factory upper get the manufacturer on the phone and inquire what they suggest. Otherwise, clean, lube, shoot, then report back.

Really? Never knew that. Glad I only did it this one time. Wonder how that can be? Google here i come.

Edit: found out cam-pin will rotate and lock it up. That is good to know. Thanks Eric. Thinking of going to the range within the next 2 weeks.

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[Gaspipeshooter]

Don't buy a dremel. Then you'll be tempted to use it.

Call the manufacturer before you do anything and see if they will take a look at it and/or replace it.

The first part made me laugh out loud. Made me think of "hold my beer, watch this". The second part is excellent advice as well if you feel that there may be a serious issue. Me, I'm pretty old school when it comes to "fixing my stuff". In my mind, I made the assumption that the OP had already checked that the dowel pin in the barrel is solid, indexed properly into the upper receiver, and the barrel nut is properly torqued. That leaves only the barrel extension was drilled slightly off for the dowel pin, or the feed ramps in the receiver were machined slightly off. I always sight down a new barrel to make sure the gas hole is lined up with the dowel pin. I also like to polish the feed ramps in a receiver and barrel extension so they match up perfectly and are smoooooooth. I was not advocating massive material removal to fix a badly out of spec or dangerous condition.