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Hk416 ejector install

1175 Views 7 Replies 5 Participants Last post by  Steppone
So I bought a "complete upper" about a year ago and put it in the safe. I just took it to the range and the student casings wouldn't extract. Didn't take long to figure out there was no ejector pin or spring in the bolt. So I ordered the pin from hkp and the spring from HK haus. Well the spring is longer and seems to have more tension than the one I compared from a different bolt. Jess from HK haus says it came straight from HK and should work but I can't get it in. On top of that, I can't even get the shorter one back in so I'm looking for opinions/tips.


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almost looks like a detent spring to me.
Its slightly wider and much stiffer than a detent spring
Looks like the old one is fatigured and the new one is not. Both appear to have the same coil count (21 or 22?)

Personally, I have never been able to change the ejector in an AR15 bolt without a service tool. I have a Sinclair AR15 bolt vise. It's $25 worth spending.

Sinclair bolt vise at Brownells
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You're going to need an ejector tool. Never seen someone change an ejector without one. Spring looks fine.
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The ejector spring on a MR556/HK416 is a lot stiffer than your typical AR-15 ejector spring. The only way I could get it installed was to use a spent casing to push and hold the spring and ejector in and slide in a slave pin in the hole for the ejector pin. I used the hole in an armorers puck to hold the spent casing steady while doing this. Then I put the bolt into the Sinclair Bolt Vise and installed the ejector pin.
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Thanks guys. I have ordered a bolt vise, hopefully I can make it work without launching these little pieces all over the place. I did notice the other spring was much stiffer than a typical AR spring I'm just still not sure about the length of the new one
Finally got it installed. After I was able to get it in and compress it one time the length was similar to the other one. Was a major pain in the ass and I hope I don't have to do that again!
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