FNM 8mm tested in K98K and G43

[KneverKnew]

Got to range to test the two batches of FNM 8mm ammo I got. One with headstamp 71–11 and the other 73-5.

These are berdan primed cases but my understanding is they are non-corrosive. I cleaned both rifles the next day with Hoppes No. 9. I did not use soapy water.
I pulled one each of the ‘71 and ‘73 headstamps. I found same FMJBT bullet of 197.3 and 197.5 grains respectively. But I was surprised to find the ‘71 has 45.1 grains of a small spherical powder but the ‘73 had 43.4 grains of a gray square flake powder.


In my dou44 K98K the ‘71 averaged about 2434 fps with a 19.8 standard deviation. The ‘73 averaged 2348 fps and 19.9 standard deviation from same gun. Sampling size of 10 shots. 100 fps difference in production dates.


In my ac44 G43 I only tried the 73-5 rounds, 10 shots. Average velocity was
2314 fps and 31.1 standard deviation. Cases ejected 8’-10’ using second smallest gas port installed.


Accuracy in the K98K was pretty good at 2-3/4” and 2-1/4” respectively at 100 yards.
I had troubles with my zf4 scope on the G34 so no measurements for it.

Please share opinions on the supposed no-corrosive nature of this ammo.

[Brian Dick]

I've been shooting Portuguese FNM 7.92 and .303 British for years. It's excellent ammo and as accurate as ball ammo gets. My second choice for 8x57 is Romanian but it has corrosive primers. It's also very accurate.

[Sapper740]

If there is any concern whatsoever that your ammunition could have corrosive primers you need to clean every nook and cranny of your G43 with an aqueous based cleaner or hot soapy water.

[KneverKnew]

Shot G43 with FNM again yesterday. Only at 25 yards to get my zf4 zeroed for it, as well as find the right gas port size for proper function. All went very well. Groups pretty tight with the FNM, but it is only 25 yards.

[KneverKnew]

Still need to tweak scope a bit.

[KneverKnew]

One thing I don’t understand is why the PRVI “match” ammo 200 FMJ at 2087 fps seems to kick harder and eject further than the FNM 198 FMJ at 2314 FPS.
I can only assume different powders causing different pressure curves, maybe?