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Discussion Starter · #1 ·
Just recently shot my new 17 over the weekend. Awesome rifle. However upon collecting my brass I noticed a pattern in the spent casings.

WP_20150510_001.jpg WP_20150510_003.jpg

Every single fired casing has identical markings. It's about an 1/8" long beginning at the neck. It also slightly dents inward. I recently started reloading and I'm pretty sure these casings won't be suitable to reload.

Seems like it could be from the shell defector? Has anyone else come across this?
 

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Over gassed brother. You need to order a assortment of gas screws to dial her in. Hopefully a member with a lot of experience in gas screw will recommend the one. If not I'd order 3 or 4 small port screws and test them at the range. It's like goldilocks and the three bears, you don't want to under gas it(not reliable), you don't want to over gas it(damages cases and parts), you want to find the perfect one in the middle. Normally I say send the gun back to the manufacturer if under warranty....but I doubt FNUSA is going to fix the problem correctly, and it's cheaper/faster to fix it yourself.
SCAR 16S Gas Control Screw
 

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It's not the brass hitting the mag as it is loaded in is it? I just noticed after read this and looking things over I took and stripped a case from my 20 round mag and noticed that the case hit the front of the mag pretty good and I could see that mark being made by this action,just a thought as I looked mine over. Can't say anything about the dent I just see a scratch were it would hit the front of the mag.
 

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Just recently shot my new 17 over the weekend. Awesome rifle. However upon collecting my brass I noticed a pattern in the spent casings.

View attachment 37798 View attachment 37799

Every single fired casing has identical markings. It's about an 1/8" long beginning at the neck. It also slightly dents inward. I recently started reloading and I'm pretty sure these casings won't be suitable to reload.

Seems like it could be from the shell defector? Has anyone else come across this?
Normal. Pretty sure. Caused by shell deflector and or lug of barrel extension as its ripped out of the chamber. All my brass looks like this as well--including the small countersink-like-relief between the neck and shoulder of the case.
 
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Discussion Starter · #9 ·
10-4
Should have mentioned this is from factory ammo.

So it looks likes this is not something too far out of the ordinary.

Thanks for the input guys. There doesn't seem to be any consensus on what exactly is the cause of the damage however....

I think I will hold off on reloading my spent SCAR brass until I gather more info
 

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Just recently shot my new 17 over the weekend. Awesome rifle. However upon collecting my brass I noticed a pattern in the spent casings.

View attachment 37798 View attachment 37799

Every single fired casing has identical markings. It's about an 1/8" long beginning at the neck. It also slightly dents inward. I recently started reloading and I'm pretty sure these casings won't be suitable to reload.

Seems like it could be from the shell defector? Has anyone else come across this?
I've no idea if it's normal, but after my first trip to the range with my new 17S this last weekend (just had a hell of a great time with it!), I experienced the exact same issue with dents on the mouth. I was using '83 147 grain Hirtenberger surplus, which I hadn't had any prior experience with, so I initially considered that it my be an issue with that particular ammo. I've since settled on it being caused by the shell deflector, but I'm still curious if that is indeed the cause.
 

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10-4
Should have mentioned this is from factory ammo.

So it looks likes this is not something too far out of the ordinary.

Thanks for the input guys. There doesn't seem to be any consensus on what exactly is the cause of the damage however....

I think I will hold off on reloading my spent SCAR brass until I gather more info
https://m.youtube.com/watch?v=atntd0XlQxg

Fast forward to 1:35--obviously not my video--the gun is owned by a user on the forum, though.


Sent from my iPhone using Tapatalk
 

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I was wondering about this as my SCAR does the same thing only some of the casings are fairly well deformed at the top. Why would it be "over gassed" from the factory? I was using PPU 308 ammo.
 

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I'm new to this but i read that the gas regulator needs to be in the 12:00 position if that would make some difference if it was off a bit.
 

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I'm new to this but i read that the gas regulator needs to be in the 12:00 position if that would make some difference if it was off a bit.
Just in the ejection pattern and cycling of the weapon, really wouldn't effect the brass so much.

From the pics I would not have any hesitation on reloading the brass, I've run brass the has been beaten worst for many reloads with no problems. If you want to be really picky, sort out the brass you feel is in rough shape and use them for your plinking or range training ammo. This is what I do when I feel some of my brass is reaching it's end in life or if I get what I feel is not a good candidate for my "match" loads.
 

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Here, this will mess with you: "I occasionally get a few cases that look like that." That has been my experience, I don't reload YET, but I began saving my brass a few months ago. Could be over gassed, it only happens with one of my SCAR 17s.
 

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I'm new to this but i read that the gas regulator needs to be in the 12:00 position if that would make some difference if it was off a bit.
If it were off a bit it wouldn't work at all. There are only two holes in the regulator, I believe it has to be in one position or the other. However, he could try running in suppressed mode. It works for one of my SCAR 16s, but not for my 17s.
 

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I'm not a reloader, but that dent ain't nuthin'. I've seen brass ejected from HK91 (and clones) that had been safely reloaded...at least for about four or five times until the flutes in the chamber began to crack the case.
 

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These are examples of amongst the worst that came out of my rifle. Something I wanted to do when switching over to 308 was to learn to reload but these cases caused me to wonder. Some of them have that scratch on the side but it seems minor compared to the deformation.
 

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Could be wrong, but I don't think over-gassing is as much a concern on the SCAR. While I don't doubt it can be over or undergassed-you'd probably see malfunctions if it was measurably so. Since it's a piston gun, the gas is acting on the piston which in turn strikes the heavy bolt carrier. I believe over gassing would cause case-head-separation or double-feed since the timing would be off and the brass wouldn't have yet contracted enough to pull as it should from the chamber.
I think the scratch and dent on the neck of the case is tends to look more traumatic than it should because more damage is caused do to the brass still being soft as it's yanked out of the chamber and therefore more easily dented--whether it's by the chamber lugs and/or the deflector. Remember the brass is extremely hot as it is ejected and is cooling the entire process to the ground and quickly(you're probably more aware of the hot brass if you're a lefty, like me, and take hot one's to the arm or down the back of your shirt!)
 
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