FN FAL metric help

[darkmark]

I have a rebuilt metric IMBEL
I have 10 mags ranging from used (8x)
to new (2x) all metric, the used in g-vg condition
from GPG.

My friend and I completely polished the feed ramp,
the mags, and where the round would seat itself
after being stripped from the mag, and for all ten mags
there is random FTF.
This is what is happening to live and dummy rounds alike:
http://www.geocities.com/hrabinowitcz/DSC00082.JPG
http://www.geocities.com/hrabinowitcz/DSC00083.JPG
(sorry for the fuzz)

I am wondering if the part of the bolt that strips
the round from the mag to chamber is worn enough
to scrape along the top of the rounds without actually chambering
them, sometimes.

We fired off about 220 rounds in one session,
fussed at the range for 3 hrs, field stripped and
cleaned it two times while there and couldn't really
determine what was happening.
We had about 15-20 FTF.
No FTE after we adjusted the gas properly.
(first time firing after built)

This was a home-rebuilt metric FAL from Entreprise arms
and it does use the old bolt, carrier, barrel, but almost new
everything else.

yes, we built them correctly.
many times, in fact.
I just want to see if I can reach a consensus of sorts,
as I've been given about 4 different answers.
AND minimize the amount of "exploratory money"
I spend on this trying to diagnose its problem.


thanks, mark
edit: spelling

 

[nicholst55]

rcmodel and WEG should be along soon, and they can doubtless answer your questions. I doubt seriously if your bolt is worn too much to strip ammo from the mags; you're talking about a hardened steel part that strips brass cartridge cases out of the magazine - do you see where I'm going with this?

 

[rfurtkamp]

Sounds like the gas is still low to me.

Failing that, magazine height issue.

Bet it's gas though.

 

[powermad]

Not the greatest pics or description but it sounds like a bolt over base issue.

Most likely caused by the feed lips on the receiver.
If the round doesn't want to pop out easy the bolt will ride over the round if it is worn a lil bit.

Polish the feed ramp all ya want to. On mine the tip of the bullet doesn't need the ramp to feed properly.

I haven't seen a new FAL yet that didn't need the feed lips filed back and smoothed out some.

I use cartridge rolls for porting heads and a die grinder but a small file works as well.

 

[Bwana John]

Sounds like a Failure-to-feed due to Bolt-over-base.

Classic Entreprise receiver problem.

A. Radius lower feed rails on receiver with 220/400 wet/dri sandpaper.
B. Install new bolt with sharp lower edges
C. Weld on extra material to tip of mag release to make mag release taller, making the mag sit higher.
D. Open receiver feed rails.

I doubt seriously if your bolt is worn too much to strip ammo from the mags;

You are wrong, Ive had a couple of bolts with worn out bolt faces. not a big deal with a in-spec receiver, but this is a Entreprise.

 

[darkmark]

Sounds like the gas is still low to me.

Should have stated that it happens when I cycle the action myself, also.

Classic Entreprise receiver problem.

Sucks, because we heard Entreprise wasn't too bad.
You wouldn't know from the price.

And thanks.

 

[Seven High]

Does the magazine fit loosely in the magazine well front to back? If it does, this will cause the described malfunction. You might try a small dab of j.b. weld on the catch on the magazine itself to take up the slack. You might have to file it to fit. It worked for me.

 

[W.E.G.]

Actually I HAVE seen a number of FAL bolts that showed considerable wear at six-o'clock on the face where the bolt picks up the round from the magazine.

Polishing the feed ramp is generally a waste of time on a FAL.
If a FAL has feed issues, it won't be the RAMP that is the cause.

I'd work on smoothing the sharp radius off the underside edge of the receiver rails as a matter of first priority.

If the back end of the mag has slop in it between the lug on the mag and the tip of the mag latch, that mag latch is a candidate for lengthening.

If the mag has a lot of fore-and-aft slop, you are kind of screwed, as it is a MAJOR undertaking to re-locate the ejector block to tighten a fore-and-aft issue.

It is highly unlikely that you have 10 bad FAL mags.

 

[darkmark]

FIRST OFF, thanks again for all the help!

I would also like to note I won't be able to test fire this until next summer, so I am in no hurry, but I do want to diagnose it correctly.
I hope cycling the action with dummies works ok?

Does the magazine fit loosely in the magazine well front to back?

There is some "wiggle" but there is less than 1mm of fore to aft movement.
I would call it more of a rocking than a reciprocal motion.

I'd work on smoothing the sharp radius off the underside edge of the receiver rails as a matter of first priority.

Since I am not a gunsmith, I would like to clarify by the picture here.

This is an underside shot of the mag well (all color coded).
How would you go about smoothing those rails?

As a last resort should I consider buying a new bolt?
Though having a new bolt would be great anyways,
I'd hate to still have the same problem post-purchase.


**sorry for image quality, it's an old camera**

 

[W.E.G.]

Man.

I just looked that pic.

Cell-phone camera?

Anyhow, you smooth the sharp edges on the rails I use 220 grit sandpaper, or a fine file. Hit the edges anywhere the edges might be able to dig-into your cartridges as they feed from the mag into the chamber.

Also, try supporting the magazine during firing so it is "sagging" as little as possible.
See if that has any effect on reliability.

You have to wait until NEXT SUMMER before you can shoot it again?
You mean like 2009?

Tantric anxiety.

 

[darkmark]

Sadly, it's Illinois.
Not many ranges and they do close down in winter, which is fast approaching.
Plus, I have a money concern.

Thank you for your help.
I will attempt.