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Posted: 5/17/2005 6:11:10 PM EDT
Hello All,

I am building my first lower and it seems pretty straight forward but I have a few questions. First, when I attempt to put the spring pivot pin in, I try and put the spring in and it goes all the way back to the little hole towards the center of the mag well. They say that there is supposed to be a little pressure so the pin can push the detent, but the spring gives no resistance. It just goes all the way in the hole. Im sure im using the correct spring. I just dont know what to do.

Second, I installed most of the other parts, and cocked the hammer, and it doesnt recoil when I pull the trigger. Is this normal. One would think that the hammer would fire back when the trigger is pulled.

THird,
I am installing a collapsable stock and I am not sure where the spring and Bolt type object go and how they stay in without recoiling out.

Thanks for the help guys

Brian
Link Posted: 5/17/2005 6:34:42 PM EDT
Check the Assemble your own lower... sticky at the top of this page. It's great info and pics help so much.
Link Posted: 5/17/2005 6:36:47 PM EDT
that is exactly where i went to put this together. It helped immensely.

I figured out the problem with the hammer returning...Lets just say the spring was in incorrectly.

I still need to know why the pivot pin spring goes all the way back into the hole and also how to assembly a collapsable stock.

thanks guys
Link Posted: 5/17/2005 7:42:33 PM EDT
Either your spring is too short or you have the wrong spring, wrong spring is the most likely cause. The spring should stick out of the hole a little bit when it's bottomed in its recess, and then the detent pin goes on top of that.
Link Posted: 5/17/2005 7:47:15 PM EDT
Well, either the spring is too short or the hole is too deep. Usually there is more than just a little pressure on this detent. It's usually the one that goes shooting across the room. Double check to make sure it is the correct spring. Check with your parts supplier as well. Sometimes lower parts kits are missing parts or have the wrong springs.

As far as the stock...

The buffer tube is what holds in the spring and buffer stop. If you look at the buffer tube's threaded end you will see that there is a slight lip that protrudes along the bottom edge. This is what keeps the buffer stop from shooting out of the receiver. Pictures do it better justice than I am able to explain here. Check out th "assemble your own lower" section at the top of this page for better details.
Link Posted: 5/17/2005 11:20:55 PM EDT
is the buffer tube that part that looks like a bolt that slides in and out of the stock? im not sure there is a threaded end on it.
Link Posted: 5/18/2005 3:30:10 AM EDT
The buffer tube is the large "cigar container" in which the buffer and recoil spring go into, and the buttstock slides on. Not all buffer tubes have the timing lip on them as refered to by RKangel above, some are just cut squarely across the tube. Should not present a problem but the buffer must be screwed into the receiver so that the stock is timed correctly (hence the timing lip) and far enough to retain the buffer retaining pin. The tube retains the pin by just covering the hole for the pin enough that the pin will not rise out of the hole. Screw the buffer tube into the receiver far enough that you can just get the retaining pin into the hole (don't forget the spring that goes in first), put in the spring and pin, press it down and screw the buffer tube in so that the timing is correct. That should be as far as it needs to go. (there are a couple of parts that go around the buffer tube such as the collar and retaining plate, make sure they are installed on the tube before starting.)

The pivot pin spring is probably missing or you just have the wrong one. There should be two and they are identical as I remember. I recommend that you print out the lower parts diagram found at the top of the discussion group (stickies) and compare parts to the diagram until you are sure you know which are which. There are several pins and springs that need to go into the correct hole, a mistake is not fatal but can be frustrating.

Before assemblying anything, test fit so you know what is what and where it goes and in what order. This will save you hours of hair pulling and cursing. Some parts might need minor fitting or cleaning before assembly, all instructions suggest cleaning everything throughly before assembly. So do I.

If all else fails, post a message in this forum again. Best of luck, take your time and be proud of your accomplishment.
Link Posted: 5/18/2005 3:53:07 AM EDT
[Last Edit: 5/18/2005 3:54:27 AM EDT by Mr45auto]

Originally Posted By ZCHF:
Hello All,
Second, I installed most of the other parts, and cocked the hammer, and it doesnt recoil when I pull the trigger. Is this normal. One would think that the hammer would fire back when the trigger is pulled.


Thanks for the help guys

Brian



Not quite sure what you're saying here. First off, without the upper and BCG installed do NOT dry fire it without riding the hammer forward slowly. You will damage the lower/hammer by letting it slam forward. If you mean it does not recock, it is not supposed to. A basic function check would be to cock the hammer, pull the trigger and ride the hammer forward while holding the trigger back. When the hammer is fully forward, release the trigger. You should hear a click and see the hammer move a bit. If you have the hammer spring in backwards the hammer will still work but will not have much oomph in going forward.

On the front pivot pin detent there is a small pin that goes in on top of the spring, if it's not there you are missing a part.
Link Posted: 5/18/2005 4:11:22 AM EDT
Your lower parts kit should have come with two identical springs. Both take down pins use the same exact spring. Their VERY easy to bend. Another close in size spring is the selector detent spring and should be a little stiffer than the two takedown detent springs. If your receiver is drilled to far what you could do is use two detents putting one in the lower put the spring on top of it and then another on the spring that would contact the take down/pivot pin normally.

I don't have another detent but let me know if you need a spring or two I'll send you a couple free.
Link Posted: 5/18/2005 6:08:51 AM EDT
[Last Edit: 5/18/2005 6:09:19 AM EDT by mongo001]

Originally Posted By Mr45auto:

Originally Posted By ZCHF:
Hello All,
Second, I installed most of the other parts, and cocked the hammer, and it doesnt recoil when I pull the trigger. Is this normal. One would think that the hammer would fire back when the trigger is pulled.


Thanks for the help guys

Brian



Not quite sure what you're saying here. First off, without the upper and BCG installed do NOT dry fire it without riding the hammer forward slowly. You will damage the lower/hammer by letting it slam forward. If you mean it does not recock, it is not supposed to. A basic function check would be to cock the hammer, pull the trigger and ride the hammer forward while holding the trigger back. When the hammer is fully forward, release the trigger. You should hear a click and see the hammer move a bit. If you have the hammer spring in backwards the hammer will still work but will not have much oomph in going forward.



Yep. WTF are you doing? Why would you expect the hammer to cock itself? The action of a completely assembled and functioning rifle does that. Dry firing a lower receiver by itself is hard on the bolt catch and hammer and shouldn't be done to often, if at all.
Link Posted: 5/18/2005 6:44:17 AM EDT
THanks everyone for your help. I really appreciate it.

First of all, I fixed the problem with the hammer not firing. I never meant to say that it wasnt recocking, but just when it was cocked and I pulled the trigger, the hammer wouldnt move. Well what I did wrong was I put the hammer spring on the "back" side of the hammer, thus causing it to not operate as a spring. I had to take it out, and put the "U" portion in front of the hammer with the legs going over the trigger assembly and all was well after that.

As for the springs, before I even started, I made sure I had all the parts lined up properly according to the parts picture in the thread atop this forum.

I am sure the spring is the proper one, but has anyone ever heard of a lower getting drilled to far?
I mean i thought these where mil spec and shouldnt have problems like that. Anyway, someone said that I should just get another detent, so I think that is what I will try.

As for the stock. Please refer to this thread www.ar15.com/forums/topic.html?b=8&f=11&t=200738 and that is the picture of my stock and lower. It has been built already and looks different, but is the buffer tube on this one a seperate part of the stock, or is it the stock itself? Also in what order do the buffer spring and buffer go in? Thanks

BRian
Link Posted: 5/18/2005 7:03:00 AM EDT
The threaded piece is the buffer tube. On the pic you have the end plate behind the locking ring. You need to change that, pull the locking ring off. It should wind up with the locking ring on the backside of the plate. It's only like that to keep it together for transport/shipping. If you pull down on the plastic elbow that releases the stock to go in and out you can pull the whole thing off the buffer tube. You screw the lock ring way back then screw in the tube until it just holds in the buffer retainer. Then tighten the lock ring pushing the end plate up against the detent spring which will secure the rear takedown pin.

As far as your front pivot pin spring and detent. You drop the spring in place then put the detent pin on the end of the spring that faces outward. You push it in then install the pivot pin.

If you're having difficulty I'd suggest trying to ask for help from a local arfcommer who could likely come over and explain the parts and help assemble it for you. We're a friendly bunch by and large, occasionally a bit egotistical but we share BRD and will help spread it.
Link Posted: 5/18/2005 9:51:13 AM EDT
Just noticed that this poster is in CA, the forbidden state of confusion. This must be a FAB10 lower, all bets are off. Never seen one, hope never to see one. Do they actually allow collaspable buttstocks on the FAB10?

No dissrespect but if you live on the left coast the only advice I can offer is get out of there as fast as you can.
Link Posted: 5/18/2005 5:35:55 PM EDT
[Last Edit: 5/18/2005 5:36:19 PM EDT by ZCHF]
well thankfully it isnt the fab10. I would like to get out of here, but there are other obstacles prohibiting that.

Link Posted: 5/20/2005 6:07:13 AM EDT
Is this a Vulcan lower, as mentioned in the other post you referenced?
Link Posted: 5/20/2005 6:40:06 AM EDT
yes it is a vulcan lower.

I have fixed the trigger and assembled the stock, but I still dont know what is going on with the pivot pin. Like I said before, the spring goes all the way in the hole. When someone said that I could just put a detent in, then the spring and then another detent, well that worked, but now I have to get another detent.

Do manufactures mess up the machining often??
Link Posted: 5/20/2005 6:44:18 AM EDT

Originally Posted By ZCHF:
yes it is a vulcan lower.


Do manufactures mess up the machining often??



As a gunsmith friend of mine said, Hesse ( vulcan ) cannot even make consistent garbage. I'd bet they just built it out of spec as is most of their abominations. If you move a few miles north you can have a real AR ( for now anyhow )
Link Posted: 5/20/2005 9:00:43 AM EDT
Well that sucks and that is good. It sucks because I got a shitty receiver, but its good because it looks like where they fucked up, wont be that big of a problem for me. I will have to put a few rounds through it before I make anymore statements though
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