FAL in 7.62x39

[edp]

Has eny experimented with building a FAL in 7.62x39?

after comparing a 7.62 cartridge and AK mag
to a metric fal, the mag is probably 0.040"
too wide and needs some kind of adapter to
handle the rear latch. maybe an inch receiver
would work out better.

bolt face looks OK. possibly use locktite
black max to glue in a chamber adapter?

any experince or thoughts?
cost is a consideration or I'd just go
have a barrel made.


Why 7.62x39?
something a little different.
ammo 2/3 the price of 308.
I have a stack of 7.62x39 ammo I need to use up and an AK doesn't thrill me.

[EMDII]

Way different operating pressures and curves. The recoiling mass is also very different on the 7.62x51 systems. Is this enough difference? I don't know. The original MOD spec was for a .280 (7mm) class cartridge, IIRC. But the 7.62x39 is way different.

It can be done. But it is $$$ intense. Get a Bulgarian or East German AK,and spend your money on ammunition.

Chamber adapters have consistently been rejected by major powers' armed forces. The heat transfer, fitment, and bore alignment are just too critical, and too finicky.

.02

PS- the 7.62x39 case head measures 1.104 cm. The 7.62x51 case head measures 1.2 cm.

------------------
1*.....Train Like You Fight: Second Place is NOT an Option.

E.M. (Ted) Dannemiller II

[This message has been edited by EMDII (edited November 25, 2000).]

[kev]

Biggest problem with the chamber adapter idea(other than the fact that they don't work well even in .30-06 to .308 conversions)is that the 7.62x39 case is smaller at the base than the .308. You can't shrink a .308 chamber to 7.62x39. You'd need an entirely new barrel. Everything else is do-able.

[Eclipse]

The original FAL was chambered in 7.92 Kurtz, a WW2 era German assault rifle round. Ballistics are similar to the 7.62x39.

[rob1]

I remember seeing an adapter advertised in an ad in an old Shotgun News (probably about 3 or 4 years old). It was listed for about $20 from what I can remember. I still have the old issue, but it's at the office. If I can remember, I'll look it up and see who the distributor was, maybe someone can contact them (if they're still in business and didn't go under because of lawsuits where the things blew up in someones face!). Maybe we can find out who made em and the specifics.
Sounds like it was just a chamber adapter, don't know what they did about the other differences.

[FALPhil]

One of the problems you will run into is bore compatibility. 7.62x51 bullets are .308 inches in diameter. 7.62x39 bullets are .311 inches in diameter. Shooting .311 bullets in a .308 barrel may cause unpredictable results. http://www.fnfal.com/forums/tongue.gif

Originally posted by rob1:
I remember seeing an adapter advertised in an ad in an old Shotgun News (probably about 3 or 4 years old). It was listed for about $20 from what I can remember. I still have the old issue, but it's at the office. If I can remember, I'll look it up and see who the distributor was, maybe someone can contact them (if they're still in business and didn't go under because of lawsuits where the things blew up in someones face!). Maybe we can find out who made em and the specifics.
Sounds like it was just a chamber adapter, don't know what they did about the other differences.



------------------
..Phil
Download free targets at
http://harringt.home.mindspring.com/targets.htm

[Eclipse]

This place sells a 7.62x39 chamber adapter for the 308.

http://www.mcace.com/adapters.htm

Simply coat the the outside of the adapter with non permanent Locktite™, place a fired 7.62x39 case inside the chamber and close the bolt. After 10-12 hours, eject the 7.62x39 case and you are ready to start shooting. Inexpensive Russian ammo costs 25-50% less than any regular 308 or 30-06. A broken shell extractor will remove the adapter and return the gun to it's original caliber.

[This message has been edited by Eclipse (edited November 26, 2000).]

[kev]

And what tool do you use to remove the blown case, which is .027" undersize in the base? This is an UNSAFE mod and anyone selling such a thing deserves to serve time.

[edp]

first off, for those who shout "impossible!",
the Imbel MD3/MD2 is a slightly modified
metric FAL converted to 223, so something
similar was done before, and mass produced.

the mini-30 has a 308 bore so I'm sure the
FAL could take it.

a machined chamber adapter would support the
case all the way back to the extractor
groove. I checked out the adapter from www.mcace.com (http://www.mcace.com) and it looks very good.
spontaneous ejection of the adapter would
be my only concern, but this could be
handled.

FYI black max is a locktite brand adhesive
which can take a temp up to several thousand
degrees. it's frequently used to "glue"
scope mounts on, and it's very permanent.

and if the adapter was ejected and a
7.62x39 round went into the bare 7.62 NATO
chamber, it drops in at least a 0.25" below
the breachface, and I don't think the FP
could reach it.

the gas port may need to be opened up a bit,
and the recoil spring may need to be replaced
with a weaker one (or just remove one
spring).

so no one has tried this?

anyone have the width of the mag well
opening on an inch cut Imbel?

inch cut receivers have wider mag wells,
correct?

[rob1]

I found the old ad I was thinking of, it was just a chamber adapter.

[kev]

Hey edp, I don't think it can't be done. I don't even think it 'shouldn't' be done. I like it, but I don't like the chamber adapter. I was under the impression it was like the .30-06/.308 adapter and just addressed the length problem. Even if that's not the case and it fits the chamber full length, I can see problems. The skirt of the adapter is going to measure somewhere around .012" which seems awful fragile in the slam-bam of an autoloader.

You're right about the bore; a non-issue. A couple thou there matters not. I think you could re-work the gas system easily enough. The gas is adjustable in the FAL, you know;^P

Haven't measured the receivers, but the inch and metric FAL mags are exactly the same width at the rear. Both are 1.00"+/-. The AK mag is only .015-.020" wider.

Another option might be to take a scrap $10 barrel and cut 1/2" off the chamber end. Turn back the shoulder and just rely on the few remaining threads. Shouldn't take much to keep the barrel in the receiver. You could recut the threads if you're set up to do that. You'd also need to shorten the gas cylinder and piston a like amount to keep everything together. The chamber would still be slightly over diameter without an insert, but the cases can take that. You may need to re-work the extractor for the smaller rim.

[frank1ray]

Sounds like an interesting project, but AKs and SKSs are pretty cheap if you want to shoot 7.62x39

I love that cartridge (mostly cause it's cheap!) But I don't really see any advantage to firing it from a FAL vs. an AK or SKS.

[edp]

why this project vs. AK or SKS?

partially for fun and "because it's there".

plus, the
AK and SKS are typically inaccurate.
(here comes everyone with their
sub-MOA AK's ;-)

their triggers stink. their sights are poor.
stocks are cut for shorter people.

if this project works out the way I
think/hope it will, you will be able to
convert between 7.62 russian and 7.62 NATO
by inserting/replacing a locktited chamber
adapter, an AK mag adapter block, and the
gas setting (possibly the recoil spring too).

I hope to avoid enlarging the gas port,
or if I must, I hope to drill it out to a
size workable for both calibers.

from examining a 7.62 russian cartridge and
a std FAL bolt/extractor I think the std
FAL bolt/extractor should work without mods.
at worst case cutting a few thousandsths
off of an internal extractor surface should
do it, but I think I can do without that.


again, if someone would please measure and
email me the width of an inch cut Imbel
mag well hole I would sincerely appreciate
it. I am under the impression that an Inch
cut Imbel's mag well is cut a bit wider than
a metric Imbel, and I need some clearance
to insert a stock AK mag.

[kev]

OK, just measured a bunch of each; inch and metric Imbels. No measurable difference in the magwell width. Both are too narrow by .015-.020" for the AK mag I had to check. So much for the drop-in conversion. If you don't mind altering the receiver, you still can open it up the required amount without affecting the original FAL mag fit. Since the AK mag is shorter and will need to feed from the front of the well to work, you can leave the very rear portion of the well the original width. That should be enough to stabilize the FAL mag. HTH

[edp]

Kev,
thanks for the quick reply.

Hmm, I'll have to check out a DSA and
Entreprise mag well widths, otherwise it
looks like a couple AK mags have a date
with a belt sander ;-)

I think you're right, Kev, the chamber insert
may be the weak link. I was thinking that,
even if the skirt was thin, it has the real
chamber to back it up and prevent it from
displacing/expanding.

[kev]

AK mags have plenty of metal, as I'm sure you know. They can stand a bunch of sanding. The thickness of the skirt of the adapter isn't a problem of strength. You're right, the chamber provides all that. I think it will be more a problem of durability. That razor thin edge worries me, but I might be wrong. I think of .010" steel as being almost foil, but it's not that bad, especially in an unbroken cylinder. Then again, there's an awful lot of drag between the expanded case and a steel liner no thicker than the case itself.



[This message has been edited by kev (edited December 01, 2000).]

[Templar]

Well, it's not exactly a FAL in 7.62x39mm, but it is an AK with a FAL front end....

http://albums.photopoint.com/j/View?u=848514&a=6168649&p=33233552&Sequence=0&res=high

Here's the rest of the info.
http://www.ak47forums.com/Forum50/HTML/000021.html

[edp]

That's what happens when you leave
a slut AK and a horny FAL in the safe without
the AR-15 as a chaperone!

I wonder if that's just a mock up or if it
actually runs?

personally I think it's an abomination! ;-)

[W.E.G.]

Did anybody happen to save that FAL/AK pic in Templar's dead Photopoint album?

If its the pic I think it is, it is the one which stimulated tool's apocryphal observation as to its source (i.e. the freshman class of the Wile E. Coyote School of Gunsmithin')

[Dirtfarmer]

Saw one at Knob Creek.
Guy said it was a pain-in-the-axx .
Class 3 item, and he said (...believably)that it ran great. Gas pressure stuff was the pain.
Don't remember/didnt ask 'bout the bore, though I am/was aware of the .311 projectile.
It CAN be done(...of course.)
Goodwill,
-Dirtfarmer

[Radio]

Was this the actual, fatal picture that gave Tool such inspiration? I have been scratching my head over this; fuzzy memory seemed to point towards the old wwwboard for the first time I spied this photo, but the dates above would seem to conflict. And that sure was an odd-looking puppy, too!

--Radio

(No I didn't save that picture, I have respect for small dogs and children!)

[Willard]

I just found an old DSA catalog from 1993 or 1994 that shows their experiemnetal 7.62x39 and .223 FALs. So they have been made. Whether or not it was/is worth it to a manufacturer is another matter entirely. But I'd love a .223 FAL.
When I get moved in to my new house I'll scan it and post a pic (if DSA doesn't mind!)

Willard