AR issue

[sgreen10]

Ok question for the AR guys in here.... just picked up my barrel to complete my first AR build (havent torqued it down yet) but hand tightened everything dropped the bolt in to see how everything was fitting and the bolt is jammed forward, i have to "mortar" the charging gun to get the bolt to even creep back inch by inch. and have no idea what it could be hanging up on. it went in smooth then wont charge back

[ar15jules]

[QUOTE=sgreen10;2939458]Ok question for the AR guys in here.... just picked up my barrel to complete my first AR build (havent torqued it down yet) but hand tightened everything dropped the bolt in to see how everything was fitting and the bolt is jammed forward, i have to "mortar" the charging gun to get the bolt to even creep back inch by inch. and have no idea what it could be hanging up on. it went in smooth then wont charge back[/QUO gun right?

Hmmm...Your bolt lugs are designed to lock into the chamber lugs when fully forward. The cam on the bolt carrier group needs to hit a "bump" on the inside of the upper to "unlock" the lugs. I am suspecting that because the barrel isn't torqued into position, the "timing" of these things happening is off and you are partially locked. Did you eventually get it out?
Jules

[pennlineman]

Firing pin retaining pin in backwards?

[sgreen10]

Hmmm...Your bolt lugs are designed to lock into the chamber lugs when fully forward. The cam on the bolt carrier group needs to hit a "bump" on the inside of the upper to "unlock" the lugs. I am suspecting that because the barrel isn't torqued into position, the "timing" of these things happening is off and you are partially locked. Did you eventually get it out?
Jules

i did eventually get it out, but took it to a shop today and their smith just left for the weekend, and even one of the shop flies who has done a few builds took a look at it, put some lube on it and put the bolt in and stuck.

the weird part is every inch that i get it to move back takes a whole lot of force and it will move about an inch, stop, move half an inch, stop so on and so forth. even after getting past both the locking lugs and the "bump"

[sgreen10]

Firing pin retaining pin in backwards?

im hoping thats not this issue, i purchased a complete BCG brand new

[dkf]

Remove the bolt from the BCG and see how it fits in the barrel extension lugs.

[pennlineman]

im hoping thats not this issue, i purchased a complete BCG brand new

Installs left to right with the gas key up and bolt facing away from you. Real easy fix if that's the problem.

[sgreen10]

Remove the bolt from the BCG and see how it fits in the barrel extension lugs.

thanks, ill try that in the morning when i get out of work

[USMC3531]

make sure the fdorward assist isnt dragging on the bolt you should see some rub marks on either the bolt or upper to lead you to the cause.

[ghost183]

unless you left the barrel completely loose and not seated against the upper, it should lock and unlock against the barrel extension, regardless if hand tight.. my assumption would be youre letting it slide forward and gently against the lugs and its jamming, and/or its turning the bolt cam pin partially against the journal inside the carrier,

if you have the carrier out? check the bolt cam head, clean or scuff marks? check the carrier same location

then.. make sure your bolt moves in and out of the carrier with about 1/2 pound resistance, make sure it moves all the way back and all the way forward

give it a generous coat of thin oil and slam IT and the charging handle forward into the barrel extension as if you just pulled the trigger and the gun is cycling round, quick forward push from the back of the carrier, the bolt needs a nice tap against the BE and locking lug after it makes the twist during forward movement towards the BE, otherwise, im assuming, it floating into position and jamming against the locking lugs which in turn is jamming the bolt cam against the carrier housing


and dont worry, its only till the first shot is fired