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7/23/2014 11:27:11 AM EDT
I'm finishing up my first build. I have no prior experience with ARs. I ran some cartridges through from a magazine. All fed and ejected. The cartridges ejected with what seems to me to be a lot of force. The ejected cartridges have shallow scratches on the bullets and some have scratches on the shell casings. Hopefully, you can seem them in the photo.

Is this normal? If not, any idea what the problem is?

http://i40.photobucket.com/albums/e227/jebbranham/P1020626_zps114e6ec7.jpg
7/23/2014 11:39:42 AM EDT
[#1]
Quoted:
Is this normal? If not, any idea what the problem is?
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It's completely normal, and caused by sharp edges at the front of the feedramp cuts in the barrel extension.

You can (carefully) smooth those out just a bit and lessen the scratches.

Post-SH it seems that most barrel extensions have been skipping the deburring step, not that it was unknown before.
7/23/2014 11:50:11 AM EDT
[#2]
Do you think the scratching will affect accuracy? It seems to me like it could. The build is a varmint/target build, so little things can mean a lot.
7/23/2014 11:56:03 AM EDT
[#3]
unless you are shooting bench rest for extreme accuracy there should be no issue with these scratches. I would be more worried about repeated chamberings causing the bullet to push down into the neck.
7/23/2014 4:53:46 PM EDT
[#4]
Quote History
Quoted:
Do you think the scratching will affect accuracy? It seems to me like it could. The build is a varmint/target build, so little things can mean a lot.
View Quote


Have you ever seen a fired bullet? The rifling will make much deeper grooves that a little bit of scratching. I wouldn't be concerned about accuracy being affected at all.
7/23/2014 11:40:07 PM EDT
[#5]
Quote History
Quoted:


Have you ever seen a fired bullet? The rifling will make much deeper grooves that a little bit of scratching. I wouldn't be concerned about accuracy being affected at all.
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Quoted:
Quoted:
Do you think the scratching will affect accuracy? It seems to me like it could. The build is a varmint/target build, so little things can mean a lot.


Have you ever seen a fired bullet? The rifling will make much deeper grooves that a little bit of scratching. I wouldn't be concerned about accuracy being affected at all.


I agree. I used to be paranoid about it, but i've never noticed a difference in my groupings due to it. And some of my rounds have/had some gnarly scratches
7/24/2014 12:01:07 AM EDT
[#6]
I noticed in my barrel prior to assembly the feed ramps kinda sharp and being OCD as I am massaged the sharp edges a bit on ramps and lugs. Don't have a comparison, but it operates very smooth and no scratches of the sort. With this being said, you shouldn't have any problems and will smooth out after a couple hundred rounds.
7/24/2014 12:05:00 AM EDT
[#7]
Quote History
Quoted:
Do you think the scratching will affect accuracy? It seems to me like it could. The build is a varmint/target build, so little things can mean a lot.
View Quote


LOL no.

Shooting @ 200 yards one day, something happened and one of my 77gr rounds didn't feed correctly and the round got smashed... Well I loaded it up anyway, still hit the 1" ping pong ball @ 200 yards
7/24/2014 7:40:46 AM EDT
[#8]
All that sort of makes you question the value of all the other super-persnickety things that precision shooters pay a lot of attention to like making sure nothing even barely touches the barrel, minute differences in loads, shooting with the rifle even slightly canted, and so on.
7/24/2014 8:51:52 AM EDT
[#9]
Please don't function test with live ammunition. Use Snap Caps or Magpul dummy rounds. -W
7/24/2014 11:09:19 AM EDT
[#10]
Quote History
Quoted:
All that sort of makes you question the value of all the other super-persnickety things that precision shooters pay a lot of attention to like making sure nothing even barely touches the barrel, minute differences in loads, shooting with the rifle even slightly canted, and so on.
View Quote


Well think of it this way.... The rifling being smaller then the projectile does much worse to it then a light scratch.
7/24/2014 12:05:01 PM EDT
[#11]
Quoted:
I'm finishing up my first build. I have no prior experience with ARs. I ran some cartridges through from a magazine. All fed and ejected. The cartridges ejected with what seems to me to be a lot of force. The ejected cartridges have shallow scratches on the bullets and some have scratches on the shell casings. Hopefully, you can seem them in the photo.

Is this normal? If not, any idea what the problem is?

http://i40.photobucket.com/albums/e227/jebbranham/P1020626_zps114e6ec7.jpg
View Quote


Normal
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