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Discussion Starter #1
Hello all,

First, let me say this is a great forum. Been lurking here since the first of September when I bought my fnp-40. It's so nice to see straight answers to questions without name calling and bickering. :D

Now, on to my problem:

I bought a FNP-40 SAO. The Serial # is 61CMT06XXX, and the test cartridge was collected on 2/08/07, so it goes without saying that my weapon had been sitting on the shelf for awhile.

Here is my rifling, I first noticed it after my first range session yesterday:



I've had 4 sigs, 3 S&Ws, and a walther P99 before this, and have never seen this before.

These look like chatter marks from a button cutter, but that shouldn't be since these are supposedly hammer-forged and not button rifled.

I sent an email with the pics to FNH service, but heard nothing. So I left Bob a voicemail this evening.

What do you think?
 

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Wierd! It almost looks like copper fouling on the rifling, but the fact that the marks are exactly proportioned and spaced is quite odd.
 

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What type of round were you using? It may just be copper fouling from the rotation of the bullet as it leaves the rifling. The extreme consistency in the length of those segments is curious.
 

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Discussion Starter #4
Ammo is Winchester RA40155.

It isn't copper fouling, though the copper residue makes it more appearant. In fact, when the barrel is clean it's hard to see and that's why it probably wasn't caught earlier.

They are definite voids in the steel. A dental pick will catch them, and they are concentric.

Bob returned my call this AM to tell me that a return tag was issued and overnighted, so good communication with FN so far.

I'm not worried anymore since it seems FN will take care of it.

Edited to add: I've been doing some research on pistol barrel making and I've just had an epiphany. These are hammer forged barrels. Meaning the barrel blank is broached and then pulled over a mandrel with the negative of the rifling on it. Hammers then pound or "forge" the tube into the final shape whilst it takes on the shape of the rifling present on the mandrel.

So, I'm pretty positive that this happened because the broaching tool (basically a large drill bit) had a burr, or got a chip stuck on it's cutting surface causing the pattern inside the tube. When it was forged, then, the groves pressed out the bad marks, but the lands retained them since they aren't pressed as severly.

Sorry for such a long post, just thinking outloud. I certainly don't mean to scare anyone away from these pistols. Just putting the info out there hoping that it helps FN make a better product in the future.
 
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