Follow Along for my First AR Build

[Nathan]

I was distracted by the muzzle device.

Yea me too. I was wondering if that was some new all foam suppressor!

[Brian Pfleuger]

Originally Posted by Nathan

Yea me too. I was wondering if that was some new all foam suppressor!

That's my special sound-deadening foam. Redneck suppressor. Cheap, single use (well, maybe twice if you can find it after the first shot). They'll never hear you coming.

[Brian Pfleuger]

Well, I've still got another 3 1/2 weeks on the projected barrel delivery date but I'm already making upgrades on a gun I can't even shoot yet.

I put an Armaspec Stealth recoil spring in it. Got it for ~$59 from Little Creek Trading.

Obviously I don't know exactly the difference under actual firing conditions but both the sound and feel of manually cycling the action are drastically different.

I'm trying to convince myself to buy (and convince myself not to buy) a Magpul PRS Gen3 as well...

[Nathan]

The Magpul PRS Stock on an accurate AR is a great fit...come over and shoot mine! LOP is pretty long though....might consider that.

[Brian Pfleuger]

Originally Posted by Nathan

LOP is pretty long though....might consider that.

That's actually one of the reasons I am considering it. I'm not super tall (just about 6') but apparently have monkey arms (or wide shoulders?), as almost all rifle LOPs feel really short to me. It seems the de facto standard is ~13.5-13.75 and I'd really like it longer.

It's kind of an odd measurement. I've seen several different "magic formulas" for calculating it....

The gun as configured with the Hogue stock measures 13 7/8" LOP, if I hold it up with my finger on the trigger and my forearm/upper arm at 90* angle, it lacks about 1 3/4" of touching my bicep... based on one method, this indicates I would want 15 5/8".

I also read you should have your wrist and forearm straight to one another and 90* to upper arm, simulate firing position and measure from index finger pad to shoulder.... that comes out to 17 1/8".

[jetinteriorguy]

Have you checked out the Luth-ar stocks? Might be something there that could work for a lot less money. They make a good quality product, I have a couple and really like them.

[Brian Pfleuger]

I appreciate the suggestion Jet, but I have a carbine tube and Armaspec carbine buffer. I’d have to replace both, which would make the Luther (~$150) more expensive than the Magpul (available at ~$195 if you look hard enough).

[jetinteriorguy]

They make a carbine/adjustable version as well as a full stock. That’s what I have on both my AR10 and AR15. The nice thing is how you adjust them so they don’t rattle. It’s such a simple setup I’m surprised more companies don’t do this. It’s the MBA-3 model.

[Metal god]

Well, I've still got another 3 1/2 weeks on the projected barrel delivery date but I'm already making upgrades on a gun I can't even shoot yet.

lol keep going , you'll have enough extra parts by the time it's completed . It will only make sense to build another

[Scorch]

I'm trying to convince myself to buy (and convince myself not to buy) a Magpul PRS Gen3 as well...

That was my suggestion a coupe of pages back. My main complaint with the PRS is weight, it is heavy. But it is also adjustable for LOP and comb height, so it helps fit it all together, and it feels super solid when shooting.

Shopping for parts for an AR build is like letting a kid wander around in a toy store right before Christmas. OOooooooohh!! Shiny! OOoooohh!

[Brian Pfleuger]

Originally Posted by Scorch

That was my suggestion a coupe of pages back.

I knew there was some reason I didn't like you.
You certainly seem to have no trouble at all spending my money.

I don't much care about the weight, this is meant to be a "bench" gun anyway.

Jet's suggestion is also a good one, but judging from various reviews, comments and suggestions I've seen here and elsewhere I think I'd rather spend an extra $50 on the Magpul.

Three weeks from yesterday is the indicated delivery date on the barrel...

[stagpanther]

It's be a tail-heavy boat anchor that PRS on a bitty AR 15 IMO. Now if you were going with a 24"+ hbar match--different story.

[Scorch]

I knew there was some reason I didn't like you.

You never needed a reason before.

You certainly seem to have no trouble at all spending my money.

I do my best spending with other people's money!

Just wait until I get you fired up about a Lilja barrel!

[Brian Pfleuger]

Little bit of an update....

still waiting on McGowen, which is annoying. When I ordered, the website said 10 weeks. Shortly thereafter they changed it to 12-16 weeks. Today is 15 weeks to the day. I emailed them last week (and plainly stated that it said 10 weeks when I ordered) and just got a reply today:

Your order placed on 3/31/21 with an estimated turnaround of approximately 12-16 weeks went to our gunsmithing department last week

So... from "gunsmithing" is it 1 week, 5 weeks, 10 weeks? I understand busyness, but I'm thinking my next barrel might be a Lilja, just so Scorch can spend my money.

Anyhow, also broke down and put a Magpul PRS Gen3 on it.... I was hoping to have pics of the completed gun by now.... by about a month ago really.

[stagpanther]

If it makes you feel any better--others are doing the same. I ordered a barrel from a "top tier" manufacturer in the beginning of February, and I was told then 10 to 12 weeks. Did the "timeline creep dance" for months until I was eventually told they couldn't even configure it the way I originally ordered. But I was told I could get an alternative configured barrel faster if I changed the order.

Tick tock, tick tock, still waiting.

[Scorch]

I'm thinking my next barrel might be a Lilja, just so Scorch can spend my money.

And you KNOW I like doing that! But you won't be disappointed if you do.

In the FWIW category, I don't deal with McGowen any longer. They used to be one of my go-to barrel makers.

[Geezerbiker]

Any opinions on Kreiger barrels. I'm not sure I spelt that right...

Tony

[Metal god]

Anyhow, also broke down and put a Magpul PRS Gen3 on it..

LOL , See how AR's are . You're already changing things and it's not even together yet , welcome to the dark side haha . FWIW how you want to use the firearm , I think that's a perfect stock for you .

[Scorch]

Any opinions on Kreiger barrels.

Krieger barrels are very good. It's hard to fault a barrel maker who racks up that many trophy wins. They are a cut rifled barrel, not button rifled, for what that's worth.

[Brian Pfleuger]

Well, passed 18 weeks yesterday with no communication from McGowen in over 3 weeks. They ignored a messages I sent them almost 3 weeks ago.

I sent them a message today telling them that if I didn't have a FIRM delivery date by Monday I would cancel the order and seek a refund in small claims for breach of contract if I had to.

Miraculously, they responded in less than 5 minutes that the barrel is ready and claimed they sent me a message 3 days ago saying so.

I guess they don't expect people to run their own mail servers, who can see every message that hits it whether it's delivered or not. So, that claim is either an outright lie or they somehow "magically" sent me a message that never made it to my server.

Sort of "odd" that I would not get that singular message, even though I got every previous one and both the response today and the invoice he emailed immediately after... but you, know, strange things happen, right? We need a "B.S." emoji.

In the meanwhile, I got bored and added this to my stable. Don't talk about it though, it's off topic for this forum.

[Brian Pfleuger]

Well, they miraculously managed to ship the barrel the same day, so the real count down starts.... due on Tuesday!

[Brian Pfleuger]

Alrighty... well, good and not so good news... I got the barrel and got it assembled!... sort of:



A particularly astute observer may notice that the bottom of the Sierra3BDX scope actually hits the rail in the Leupold mount... so I need a different mount. That's annoying.

Unfortunately, the scope failing to mount correctly proved to be a positive note when the gun jammed *hard* on a fired case. Note that this is with factory Hornady Black ammo. I had to mortar it out. (I did clean the barrel and chamber before firing.) The chamber really doesn't look bad, but the brass does show scratching all the way around, none of it I would guess deep enough to prevent extraction, say nothing of jam the gun solid... although when I see it up close now it looks worse than it did last night.
One might be forgiven for thinking that a $500+ AR barrel would be smooth.

My intuition is nudging me that the brass and primer look over-pressure, to be honest, but the fired brass dimensions seem like the barrel is closer to over-sized than under.

Here is a shot of both sides of the same brass:

[Brian Pfleuger]

Well, some experimenting seems to indicate that the culprit is (at least mostly) the Hornady ammo. I believe my intuition about the brass was correct.
I loaded a couple of my own rounds with slightly below Quickload indicated starting load of AA2495 under 105gr Hornady. QL says 25.0 would be just about 58k psi, so I loaded at 22.0.

First round, with gas block full open, extracted but jammed against the upper... more or less as expected. According to QL, this is only a 34k psi load.

2nd round, I closed the gas block to see if there was any sticking. The round ejected by hand normally.

It would seem that not only is the Hornady ammo over-pressure, but dangerously so.

[Metal god]

It would seem that not only is the Hornady ammo over-pressure, but dangerously so.

No not necessarily , First when adjusting an adjustable gas block for the first time you start with it closed then open it in half or full turn increments firing a few rounds each time until the gun cycles properly . This allows you to keep track for future reference . It would be reasonable to expect any gas gun to be over gassed with the "adjustable" gas block wide open . They are designed to deal with either issue under or over gassed systems .

The vertical scratches on the brass are likely from mortaring it out . The horizontal rings are likely tool marks from the chamber .

I've had similar marks on a poorly cut chamber . I took a bore mop and some polishing compound and buffed it out with it attached to a drill . That said my barrel was $99 not $500

[Brian Pfleuger]

Originally Posted by Metal God

It would be reasonable to expect any gas gun to be over gassed with the "adjustable" gas block wide open . They are designed to deal with either issue under or over gassed systems .

Ok, but the action locks solid with that ammo whether the gas block is full open or full closed.

Plus, if it were over-gassed, wouldn't that throw the brass to the next county, not lock the action?

I just went out and fired two rounds at 23gr with the block full open. First one didn't budge the action, but extracted by hand, requiring more force than expected. Second one jammed the action and had to be mortared.