New member New Gun build got questions.

[Notonduty]

Over the past year I have gathered together a set of parts to build a custom AR10 styled rifle. Those parts are.

JD Machine 308 Upper and Lower Receivers.
Armalite National Match Barrel 20" 308/7.62x51 nato
PRI Brake for 308
DPMS Chrome BCG
DPMS A2 buffer tube and set up
Magpul PRS Stock
Armalite National Match 2 stage trigger
bullet button
BCM charging handle
Troy free float battle rail 13"

So here are my questions and findings. And these are simply to educate myself before the Rifle goes back to my builder for troubleshooting. He and I have already spoken and he said bring it to him but I just want to get some second opinions. After the rifle was first assembled it was not fired. I took it home cleaned it and liberally applied CLP to every working part and worked the action 50 or so times took it apart and cleaned it. I then place new rounds from PMC 147gr in my mags and loaded 1 round. I did not fire the round I just wanted to check it. When I tried to eject the round it was VERY hard to eject and it did it on several different rounds. I have since ordered new factory Remington rounds to be delivered. I also noticed slight to moderate dimples on the primers but I have read numerous posts here stating that is normal for 308. So that's not to concerning but what is concerning is I noticed the rounds were touching the rifling on the barrel. I know its the rifling because its on all side of the bullet.

So could the hard to eject be because of match grade parts the action needs to be worked more and broken in. Or the cases were not fully re-sized?

As for the bullets touching the rifling how can that be adjusted.
thanks.

[ar15barrels]

Shoot the gun.
It was not designed for easy hand manipulation.
A couple hundred firings will loosen up the fit of the bolt carrier.

[mod1217]

I said it before and I say It again. "308 AR's chambers are tight the first time around". I have build 3 308 AR's already and help build 2 more with friends and not one was able to chamber a "GO" gauge on initial try, but would fire and function perfectly specially after like 100 rounds go through them.

As long as you are able to chamber a round by just dropping the buffer spring and was able to extract the round just go to the range and shoot it. I promise you you are going to be delighted on how tight the grouping on your build, specially when dealing with a match barrel.

[Notonduty]

Neither of you two would be worried the bullets are touching the rifling already? If not it happy shooting time for me

[ar15barrels]

Neither of you two would be worried the bullets are touching the rifling already?

On a factory barrel?
Hahaha...

[Notonduty]

Received some new ammo today from Remington. First thing I noticed is that the PMC ammo was slightly longer this would explain why it was touching the rifling in the barrel already. I have lubed the upper and worked the action probably about 150 times now. cleaned it, loaded a magazine pulled the firing pin and the new remington rounds cycle effortlessly. That being said I think I got a bad batch from PMC. Now for the new problem bolt catch is not holding the bolt open with or with out a magazine in it. but I have already read the problems on that so today its going back to the builder. cheers

[Notonduty]

So just an update. Just got back from the builder. They bolt not catching. yeah that was user error. MY error. I had a Magpul SPR buttstock put on and had adjusted the cheek piece thereby preventing me from pulling the charging handle all the way back. As for the barrel. Mind you this is a Match Grade stainless barrel. I was defective from the manufacturer. Builder had to run a finish reamer through it to get the Go. No-go checks to work. go figure.