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Old January 16, 2011, 02:41 PM   #1
mellow_c
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Saber Defense AR-15

After shooting a buddies Saber Defense AR-15, we were disappointed to find it would frequently FTF. There would be a little dent on the primer, but would often not fire. We would try those rounds again, and sometimes they would go the second time, but usually not. Then we would put them in the Mini 14, and they would fire every time. We tried some different ammo out of the AR, and it worked fine with that. IT was happening probably 1 in every 8 shots or so.

The gun is not too old, The firing pin "looks" fine to me...
The ammo we were shooting was the 100 round boxes of Federal .223 from Walmart.

So here are my questions:
Does it need a new firing pin?
Does this particular ammo have hard primers? But still the mini shot it fine...
Does the gun need a stiffer hammer spring? if so, how easy is that to buy and change?
Any other solutions?

Also, the pin that goes through the lower receiver that holds the trigger in place seams to easily move, and it will sometimes wind up out of one of the ends of the receiver and be slightly tweaked inside the receiver. It requires that you open up the gun, push back on the hammer group stuff, while pushing the pin from the opposite end to get it to go back into the hole. Any suggestions to fix this? The pin doesnt seam to click into place, it's just pressed in and can sometimes walk it's self loose overtime.
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Old January 16, 2011, 04:36 PM   #2
Ridge_Runner_5
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Make sure the firing pin channel in the bolt is clear. I bought a new in package bolt recently, and it had a fair bit of gunk in it that made it hard for the firing pin to travel through it. Used some specialized q-tips to clean it out.

As for the pins, sounds like they are out of spec. Easiest fix is to buy some KNS anti-rotational pins. They will keep the pins solidly inside the upper receiver, and will keep them from rotating, which can wear out the holes in the receiver.

I'm surprised by your troubles, though...Sabres are generally very good guns...

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Old January 16, 2011, 05:55 PM   #3
mellow_c
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The pin we are having trouble with is the hammer pin, I believe the hammer pivots on it. It goes through the hammer and the hammer spring, in the lower receiver. That is the pin that is able to move easily, and does not lock in place...

As far as the gun being dirty... I'm not sure... I cleaned it since then, it was pretty bad. It hasnt been shot since. Maybe that could be part of the problem, if not the whole problem. Hmmm... I suppose I shoulda though of that

There was a good amount of carbon that I had to chip off inside the bolt carrier, and I dont remember exactly, but it may have kept the firing pin from going forward enough.. I think I'll go take a look at it and see how it works... That could be it.

Either way, I still need a solution for that hammer pin thing

Last edited by mellow_c; January 16, 2011 at 06:27 PM.
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Old January 16, 2011, 06:26 PM   #4
mellow_c
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After looking it over again. I'm not sure that It being dirty was the problem. The area inside the bolt carrier that I remember chipping carbon off was on the area that faces the Bolt, not the opposite area that faces the top T part of the firing pin. I was thinking maybe if I was chipping off carbon from the area that the T part of the firing pin comes into contact with, it may have been enough to stop the firing pin from protruding all the way through the hole in the bolt face. But I dont think that was it. And we did a quick clean before shooting it, and the firing pin channel was clear.

It is MUCH cleaner now... we could always try it again with the same ammo and see if it's better now. But I'd still appreciate some advice if anyone has some more ideas of what could be wrong. Thanks

Edit:
On second thought, the side that I chipped the carbon off would also have kept the bolt from coming far enough back, making it so there is a thick hard layer of carbon between the bolt and the bolt carrier, which I guess would increase the distance the firing pin had to travel to hit the primer fully... Having essentially the same effect as if it were on the other side of the bolt carrier like I had originally thought.

Cleaning may be the issue here. Will have to take it back out with the same ammo and see what happens now that it's clean!

Last edited by mellow_c; January 16, 2011 at 06:34 PM.
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Old January 16, 2011, 06:39 PM   #5
Ridge_Runner_5
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I mean inside the bolt itself, not the carrier. The hole that the firing pin travels through to hit the primer on the face of the bolt..
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Old January 16, 2011, 06:50 PM   #6
HiBC
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I would not jump to the conclusion it is a bad rifle.
First part of January it was pretty cold in Colorado,not far from zero F.That sort of weather caused problems in the fine M-1 Garand in Korea.Some lubricants will thicken and slow things down.
If the rifle was taken from cold to warm and back to cold,condensation may have added ice to the problem.
The walking hammer pin is an issue that will slow the hammer down,but it also may indicate the hammer spring is not installed just right.I have seen hammer pins with no grooves,but many have grooves for the legs of the hammer spring to rest in.Some trigger jobs include altering the legs of the hammer spring,if this has been done,it could compromise reliability.
If,for any reason,the bolt carrier was not fully forward at the moment of firing,it would absorb hammer energy.
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Old January 17, 2011, 01:49 AM   #7
mellow_c
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This was about a month or two ago.. and it was not so cold that ice or thick lubricant would have been a problem... Also, the firing pin channel was as clear and clean as I think it would need to be when the malfunctions were happening.

Thats good to know about the groves for the legs on the hammer spring pin. I'll look into it a bit more. Maybe I can just replace the pin with one with groves, maybe even a new stiffer hammer spring if that seams to be a problem. But so far I think the FTF could have been a cleaning issue. I will look into the hammer pin further. Thank you

Last edited by mellow_c; January 17, 2011 at 01:59 AM.
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Old January 17, 2011, 09:44 AM   #8
Quentin2
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Your buddy should contact Sabre and I bet they'd send a new hammer and spring. They make an excellent AR and should stand behind it.

It sound like the J-spring inside the hammer is bad as that's what would allow the hammer pin to walk out. The trigger pin is the one that's retained by the hammer spring.

Replacing the hammer isn't hard but look at pictures first to make sure you orient the spring properly. Don't push the outer notch of the hammer pin through the hammer, you just want the j-spring to contact the center notch so there's no reason to make the job harder.
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Old January 17, 2011, 10:51 AM   #9
tirod
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Check and see if the hammer pin has the channel for the spring leg to lock it in place. If the spring is jumping out, something is wrong. Milspec M16's rarely have the problem, but M4's seem to get it slightly more often. The carbine length gas may have a harmonic problem firing full auto.

In a semi gun, it's usually improper assembly or someone attempting a target trigger job on a field quality gun. A trigger set screw for adjustment will do more.

White box ammo ins't milspec ever. It's under loaded, and not top quality. The primer marks are 100% normal, not being able to shoot it indicates the hammer spring may have been weakened in an attempt to lighten the trigger pull. That's the main thing wrong with the target trigger job - the hammer spring controls the trigger pull weight.

With the pin walking and failure to ignite, it's time to fix it. If it is exactly the way Saber shipped it, send it back. If it was messed with, put a good spring back in. Light trigger pulls don't add any accuracy to a 2MOA barrel anyway, it can only shoot so well. Accurizing an AR starts with a guaranteed 1/2 MOA barrel first, then free float, then stock and grip, and then trigger pull travel adjustment (ALL target triggers have that,) then a light trigger.
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Old January 17, 2011, 04:06 PM   #10
mellow_c
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Sounds like we might have to have someone who knows what they are doing look at it. I have a general knowledge of AR's. But I wouldent be able to tell if it's a stock trigger set up or not. I can atleast try to see if there are any groves in the hammer pin.

So by the sounds of it. If it has a good strong hammer spring, and a hammer pin with groves. Then the pin wont walk, and the rounds should fire just fine. Sounds good to me. Will see what we can come up with.

Thanks for the help everyone

I'd like a Saber Defense. It's a nice shooting gun other than these little anoyances.
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Old January 17, 2011, 04:18 PM   #11
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The primers are hard, and I've had the same trouble after doing a trigger job. You need to increase the hammer tension. A new hammer spring should be less than $10. Sometimes the whole trigger group set sells for $15. Punching the pins out and replacing them all is a whole other deal. Call Sabre.

-7-
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Old January 17, 2011, 05:40 PM   #12
mellow_c
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I Fixed it!!!!!

HAH... Thanks everyone for the posts. Your little bits of info were very helpful. Previously I had no idea how an AR trigger works. But now I've got a basic idea.

So this is what was wrong. It was not the Hammer pin that was loose, it was the trigger pin (my mistake) And it was loose because the Hammer spring was in UPSIDE DOWN! Before the legs of the hammer spring were coming down OVER the grove in the trigger pin. But now that I put the hammer spring back in the RIGHT way (thanks to pictures on the internet), the legs lay straight in/over the grove in the trigger pin. And so It killed both birds with one stone. Since now the trigger spring is in the right way, it is stiffer and forces the hammer to fall harder!

GREAT!

Now we can really enjoy this nice Saber Defense AR-15! Pluse it's clean as a whilstle.

Last edited by mellow_c; January 18, 2011 at 12:36 AM.
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Old January 17, 2011, 06:10 PM   #13
Ridge_Runner_5
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Even better. Glad to hear you got it worked out. Look forward to the next range report
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Old January 17, 2011, 06:54 PM   #14
Quentin2
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Now I'm really curious, mellow. Please don't tell me that it came from Sabre Defence installed backward! Tell us more of this rifle's history...

Once I saw a castle nut installed backward on an AR. I always wondered if it came from the factory that way...
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Old January 18, 2011, 12:33 AM   #15
mellow_c
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I highly doubt it came from Saber that way. My friend got it from a friend who got it from the original buyer. The castle nut on this gun was loose, and I think they put some after market stuff on it. front grip, pistol grip, and shoulder stock. So I would be willing to guess someone messed around with it a bit.

I'm thinking that they may have had a little bit of an idea of what they were doing and removed and reinstalled the spring upside down to give it a lighter trigger. One of the things I though when I first shot this gun was how nice the trigger was. There is much less tension with it upside down. And realistically, for a fun range gun with no real serious use, the trigger pin doesnt need to be held in so well, and an occasional FTF is no big deal. But I'd prefer to have a gun which I knew would work, rather than sacrifice reliability for trigger feel, even for just a range toy.

With everything properly installed, the trigger is back to being a stiff combat style trigger. heh. but I'd bet it works perfectly now.
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Old January 18, 2011, 12:41 PM   #16
madcratebuilder
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Quote:
Once I saw a castle nut installed backward on an AR. I always wondered if it came from the factory that way...
How in the heck would they tighten that?
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Old January 18, 2011, 03:06 PM   #17
Quentin2
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Quote:
How in the heck would they tighten that?
Good question! Superglue? And how would you stake it? Well, yeah I guess you could stake the big notches.

I hope whoever ended up with it noticed it.
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