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1/22/2020 12:12:56 PM
Posted: 10/6/2007 1:32:09 PM EST
i just finished another build and im preety happy with it, it is the lightest one ive built so far, I have one problem when i pull the bolt back and it latches if you bump the buttstock on the ground or bump it on your palm the bolt slams forward. any help?


Bushmaster 14.7 m4upper
RRA lower
Magpul P-Mag
Hogue grip
BUIS
Fiberlite 4 pos stock
Link Posted: 10/6/2007 2:30:24 PM EST
The bolt going home if the stock is bumped is a normal thing if there is no empty mag in the rifle. The bolt catch is only being held in place by the carrier being pushed against it by the buffer/spring. When you bump it the carrier goes to the rear and the return spring on the bolt catch drops it out of the way and allows the bolt/carrier to go forward again.

Congratulations, the bolt catch works as it should. I completed a build where it stuck, and I had to replace the bolt catch and pin.
Link Posted: 10/6/2007 2:48:22 PM EST
this is doing it with a loaded mag in the rifle
Link Posted: 10/6/2007 2:59:04 PM EST
Then you may have the same problem I had and the bolt stop is not moving up. can you push it in at the bottom? Is it real stiff? Will it drop back down on it's own?

If it is real stiff and the magazine floor plate cannot move it into position, then it needs to either be lubed real well, or the bolt catch needs to be relplaced because the pin hole is out of spec.

What brand Lower Parts Kit did you use? The one I used when I had the problem was a Model 1.
Link Posted: 10/6/2007 3:04:33 PM EST
Wait I reread your reply. You said it was doing this with a LOADED mag. Once again the floor plate of the Mag is no longer in contact with the bolt catch so just the Buffer/Spring tension is holding the bolt back.

If it goes forward with an unloaded mag in place then there are problems.

If it locks back after the last shot and goes forward after tension is removed then it is working well. It's just like pulling the charging handle back and releasing it.
Link Posted: 10/6/2007 3:08:30 PM EST
i will go check and see if it does it with a unloaded mag,
Link Posted: 10/6/2007 3:14:56 PM EST
[Last Edit: 10/6/2007 3:18:50 PM EST by flatop_a3]
negative it doesnt do it with a emty mag i hit the sum bitch hard on the ground and it stays in place, so you say the floorplate isnt touching the bottom of the catch could it be a faulty p-mag. i am half tempted to say f*** it and leave it like it is but its kind of not safe


edit--- i dont think my lower is out of spec its never givin me any problems tell i used this mag
Link Posted: 10/7/2007 6:01:45 AM EST
nice biuld, tell us how it shoots
Link Posted: 10/7/2007 7:25:25 AM EST
Nice rifle... Did you drive to the moon? That is wierd dirt.
Link Posted: 10/7/2007 8:09:18 AM EST
[Last Edit: 10/7/2007 8:10:46 AM EST by flatop_a3]

Originally Posted By TheRegulator:
Nice rifle... Did you drive to the moon? That is wierd dirt.


no, I shoot next to a canal, and they had just moved some livestock down the road so its pretty beat up

Edit-- i looked at the pic closer and you can see a hoof print in the upper part of the picture
Link Posted: 10/8/2007 8:50:11 PM EST

Originally Posted By flatop_a3:
negative it doesnt do it with a emty mag i hit the sum bitch hard on the ground and it stays in place, so you say the floorplate isnt touching the bottom of the catch could it be a faulty p-mag. i am half tempted to say f*** it and leave it like it is but its kind of not safe


edit--- i dont think my lower is out of spec its never givin me any problems tell i used this mag


Your good to go, the only time the follower (not floor plate) can hold the mag catch in position preventing the bump/jolt from releasing the bolt carrier is when the mag is empty. A loaded mag or no mag will allow the the bolt to release when bumped.
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