I am new to the ARs so any help is appreciated. Back in Jan. I purchased a Fab10 (yes I life in CA) and a LMT upper. I finally had a chance to take it to the range last month and broke in the barrel by cleaning after each shot. After completing 20 rounds I was going to load three shots at a time. This is when I ran into a problem:
Any more than one round in the mag and the bolt won't "catch" the round to be loaded. From what I can tell, when you pull the charging handle back, the bolt pushes down on the top round, the round is then not being pushed back up by the mag spring. The bolt then literaly drags over the top of the round and hangs up. No problem with just one round but big problem with 2 or more.
I don't know where to start..Is it normal for the bolt to push the rounds down a bit as you pull the charging handle back, if so, are the springs in the mag faulty? Or do I have an issue with the clearance between the mag and bolt??
Sorry if I seem to ramble, trying to give as much info as possible... I would appreciate any input.
I'm not familiar at all with the FAB-10, but jeah that could be a weak spring problem.
Also, there is NO need to follow the cleaning procedure you are following to break in the barrel.
I would do THIS instead:
Yes, I contacted Fab 10. They said they have produced a number of these with no issues. They also said they use brand new, top of the line components for the springs and follower. If I attempt to replace the mag spring it voids the little warranty. They offered I ship the weapon to them for them to trouble shoot.
Is it normal for the bolt to push done on the rounds when the charging handle is pulled?
I would prefer not to ship if it is something I can solve on my own.
I would love to have a "real" AR but living in CA has other advantages so moving isn't a practicle solution to this problem...thanks again for any uselfull feadback.
I am completely familiar with your issue as I have it with my FAB-10 as well.
Yes, it is normal for the bolt/bolt carrier to push the rear of the rounds down on it's way back, how else would it strip the rounds off the magazine on it's way forward?
The problem is that in order to fit 10 rounds (no more/no less) they cut the anti-tilt legs off the green follower. Obviously those anti-tilt legs were there for a reason and this is exactly why. Look carefully when using 2-5 rounds in the magazine, pull back the charging handle; the rear of the top round (and all below it) are pushed down, the 2nd round from the top lifts up and rolls outward where the neck "sits" on the indentation in the magazine and doesn't come back down.
When firing 10 rounds often times the vibration & recoil is enough to make it operate without jamming when you get to rounds 5-2. Sometimes it's not.
I've experimented with magazine springs of different length, strength, etc. I've messed with different followers, cutting off certain amounts of leg, etc. Nothing works 100% AND gives me full 10-round capacity.
Currently I have a full-sized green follower in my FAB-10. It limits me to 6 rounds, but operation is 100%. I can jam a 7th in there but you need to leave space for the rounds to be pushed down when you pull the charging handle back. I also have a modified Magpul follower which should allow me to fit 8 rounds and still retain 100% operation.
I have talked with the people who make the FAB-10 and they always deny having problems. Funny that he said the same thing to you even when I talked to him AT LENGTH (hours) about this issue. Even if I could send it back and get it "fixed" I don't think I'd ever trust it. Without the anti-tilt legs the potential for this FTF is CERTAINLY there regardless of if you've ever experienced the problems with your FAB-10 or not.
Good luck and feel free to contact me publicly or privately with further questions.
Just a few other beefs about the FAB-10: Grip area is wider than spec, causes problems fitting grips and not having them interfere with the safety. Buffer retainer hole is just slightly rearward of where it is supposed to be. The finish on the receiver is crap... I've heard they've changed this.
You can get into it by drilling out the rivet. Just make sure you have a pop-rivet tool and the proper rivets on hand to replace it when you are done.
Sounds like everything is just "too new". I had major problems with my first Fab-10 Build too, but I did recognize after the first test firing, that the magazine needs some major break-in.
I took just the lower receiver and while watching TV, just shoved 10 bullets into the magazine, then proceeded to quickly strip off each round, one by one with a plastic pen (simulating the direction the bolt would usually travel), then shove 10 more into the magazine (with the stripper clip and their loading tool). I did this countless times over a course of about 2 weeks and the next time I had range time, the magazine operated perfectly (with 10 rounds), and I was an expert in loading it with the tool and stripper clips. Also, when the lower was stored overnight or in between my excercising it, it was stored with 10 rounds in the magazine.
Of course, after that, I had other issues, like the buffer getting dented up by the retainer (due to the hole being a little too rearward), but after a few hundred shots and a new buffer retainer, that stopped too.
Then there was the issue of everthing being too tight and the take down pin with ring was so tight that the ring got all bent out of shape from me pulling it. That was replaced with key ring and eventually, everything broke-in the way it's supposed to.
Also, what kind of ammo are you using? I found that mixing ammo and using really cheap ammo (AKA Wolf) to break in a gun that might have issues is not a good idea. It's better to minimize potential problems in breaking-in a new gun, and then start worrying about ammo after you know everything works the way it should.