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Re: AR15/M4 question

Posted: Sun Jan 15, 2017 2:11 pm
by Daryll
No, wasn't yours then... mine was black, as nature intended... :D

Bought from Suffolk Rifle at Phoenix 2012.

Re: AR15/M4 question

Posted: Sun Jan 15, 2017 5:07 pm
by toffe wrapper
Does it affect accuracy,
Shoot 1 5 round group feeding by hand & 1 from mag. If no difference and if feeds and extracts fine crack on.
If it is affecting group and or function, contact one of the AR plumbers for advice & rectifying.

Re: AR15/M4 question

Posted: Sun Jan 15, 2017 5:47 pm
by harrier
Accuracy is fine, after smoothing the cutout a little more it cycles better and only leaves minor scores which I think is unavoidable on a metal to metal contact.

Re: AR15/M4 question

Posted: Mon Jan 16, 2017 4:18 am
by rufrdr
Trust me, what you are experiencing isn't acceptable. The bullet guides may have been cut incorrectly.

Re: AR15/M4 question

Posted: Mon Jan 16, 2017 9:42 am
by channel12
You are only seeing scoring marks because you are extracting an unfired round. The scoring isn't happening to the bullet on loading but there's no way of seeing this.
When you extract the round the extractor grabs the cartridge and the spring loaded ejector in the bolt face is forcing the bullet against the barrel locking lugs which scratch the bullet.

I don't think you have a real problem.

Re: AR15/M4 question

Posted: Mon Jan 16, 2017 11:56 am
by Maggot
channel12 wrote:You are only seeing scoring marks because you are extracting an unfired round. The scoring isn't happening to the bullet on loading but there's no way of seeing this.
When you extract the round the extractor grabs the cartridge and the spring loaded ejector in the bolt face is forcing the bullet against the barrel locking lugs which scratch the bullet.

I don't think you have a real problem.
This. The front faces of the locking lugs are not designed to deal with bullets getting pulled through them backwards after being rammed over by a half decent ejector, and are quite sharp, so you will get scores on them.

The anodised alloy snap caps are much harder than the soft copper bullets and usually a different shape so feed ok but dont catch as well on extraction.

Old type drill rounds used in the L85/98 end up pretty well mullered.

To the OP

Are you full length re-sizing the standard length? I changed dies and found quite a difference in length that was leading to seperated cases after a few firings. I got hold of a Dillon gague and I was quite a way off the standard length so I backed the die out and did some tests.

I found the bolt action datum to be fine, and the rounds still feed nicely.

Also, never ride the bolt on any of these rifles, the inertia of the carrier is required to ensure the round is chambered correctly. Ride the bolt and you will as likely get miss feeds.

Treat them rough as the gas system would and you should be OK, slow things down and they may well feel rough.

Re: AR15/M4 question

Posted: Mon Jan 16, 2017 3:40 pm
by harrier
Thanks guys for your help, I think I'm a little wiser now.