FN 49 parts compatibility (barrel)

[Tom]

Does anyone know if the Egyptian 8mm barrel is compatible with the 7mm frame on an FN 49? Anyone made this barrel swap? Would like to replace my 7mm barrel but can't find anything other than the 8mm. I'm familiar with how the rifle headspaces don't know if the 8mm barrel is compatible with the frame. Apparently there are several variations of FN 49 parts. Thanks.

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[diopter]

Seems all the barrels were M27x1.5mm RH pitch.
Gas cylinder parts of the 7mm and 8mm are both of the Thin Lug(first design) and should be inter-changeable. You might need to enlarge the gas passage diameter of the gas plug from .085" on the 7mm to .130" for the 8mm. extraction might be a problem as the ejection slots are different lenghts 7mm= 3.15" 8mm = 3.24"
Larger concern is that the 8mm has a recoil lug cut and the 7mm did not need it.

Did you wear out the 7mm barrel? Why else change it?

[Tom]

I'm just being picky. The 7mm bore is less than "new dime" bright for 6"-8" before the muzzle and there are some rust pits on the exterior of the exposed portion of the barrel. The pits are no surprise coming from South America, a lot of thier guns seem to be that way. And last but not least the 8mm barrels are reasonably priced. An interesting aside is that the rifle has a 30-06 bolt (marked .30). If it looks like too big a hassle I'll probably just live with the 7mm. Thanks.

[diopter]

If the barrel near the muzzle is slightly dark, this might help.

Get some grease, just about any grease. Get a 7mm/.284 calibre nylon bristle brush tip for your cleaning rod. Dip the brush into the grease and apply it to the barrel as fast as you can after a fast string of shots, say 3-5 in quick succesion. Get the barrel HOT! Next day use a jag and patch to clean out the grease. You might be suprised how much gunk it takes off.

[Tom]

Sounds interesting Diopter. Haven't heard of that one. I'll give it a try. Thanks.

[maasz]

The swap works just fine, except for cartridge lenght since the 7mm. magazine is some .120" shorter.
In my Colombian 7mm, the gas cylinder opening was large enough and
the headspace improved by .002".
Rifles are marked for caliber on receiver floor, and changed that to 8mm.
To remove old barrel, I cutted a circumferential groove on barrel very close
to the receiver, as to relieve some of the pressure.
The groove was cut with a hacksaw to approx. 1/8" depth.
Wrapped emery cloth to old barrel used a pipe wrench and vise.
It came out easily. new barrel installation was very easy as theads were
time correctly!
I think that you will be happy with it.
The kick, muzzle flash and action gas realese goes up considerably!
good luck!
Maasz

[maasz]

Back to the barrel swap, please notice that the flash hider is undersized
for 8mm. I drilled mine to .437" (7/16), but later I cut it off at the end of the threads and used it as a thread protector.