Keyboard Jockey Attempts Two AR-15 Builds

I assembled my first upper receiver from parts. I got an 18" 223 Wylde barrel from Green Mountain, and fixed it to a vacant upper receiver. I put some blue loctite on the gas block screws. Put a little bit of hi-temp grease on the barrel threads, lined everything up. Admittedly I didn't torque it, but I do enough wrenching on my cars to know what 80 ft-lbs feels like. Backed it off to "season" the threads, and cinched down again. New BCG from PSA. Put a little lube on the sliding metal to metal contact points. Am I missing anything?

I'm nervous as hell thinking about shooting it though. It seems to go into battery fully. Anyone else been in this situation and how did you double check your work? I'm thinking about "remote firing" it a couple of times so I don't kill myself.
 
I assembled my first upper receiver from parts. I got an 18" 223 Wylde barrel from Green Mountain, and fixed it to a vacant upper receiver. I put some blue loctite on the gas block screws. Put a little bit of hi-temp grease on the barrel threads, lined everything up. Admittedly I didn't torque it, but I do enough wrenching on my cars to know what 80 ft-lbs feels like. Backed it off to "season" the threads, and cinched down again. New BCG from PSA. Put a little lube on the sliding metal to metal contact points. Am I missing anything?

I'm nervous as hell thinking about shooting it though. It seems to go into battery fully. Anyone else been in this situation and how did you double check your work? I'm thinking about "remote firing" it a couple of times so I don't kill myself.

Did you watch videos online to assemble it? I'd quickly watch a few and just make sure you.did everything correct.

Imo lube up the entire bcg and inside the upper. You can always clean excess but over lubing isn't really a thing unless you seriously go full retard. There is however such a thing as under lubed. I've quickly wiped bcgs and uppers then coated them in rem oil, clp, or whatever to the point they are dripping while reassembling them. It's not a problem, might be a bit messy. They certainly don't need to be dripping and I don't usually use that much but I like everything decently coated.

You can buy go & no go guages and check headspace if you want. Pretty easy to do.

Depending on your planned firing schedule, once you confirm it functions remove the gas block set screws and clean the blue loctite off of them. Gas blocks get too hot for blue. Some people use red but depending on your firing schedule that might be insufficient. I prefer rocksett, similar breaking strength as blue but holds up to heat. If you ever have trouble removing water breaks it down. Up to you, if you aren't going to be getting it that hot it might not be a big deal.
 
Did you watch videos online to assemble it? I'd quickly watch a few and just make sure you.did everything correct.

Imo lube up the entire bcg and inside the upper. You can always clean excess but over lubing isn't really a thing unless you seriously go full retard. There is however such a thing as under lubed. I've quickly wiped bcgs and uppers then coated them in rem oil, clp, or whatever to the point they are dripping while reassembling them. It's not a problem, might be a bit messy. They certainly don't need to be dripping and I don't usually use that much but I like everything decently coated.

You can buy go & no go guages and check headspace if you want. Pretty easy to do.

Depending on your planned firing schedule, once you confirm it functions remove the gas block set screws and clean the blue loctite off of them. Gas blocks get too hot for blue. Some people use red but depending on your firing schedule that might be insufficient. I prefer rocksett, similar breaking strength as blue but holds up to heat. If you ever have trouble removing water breaks it down. Up to you, if you aren't going to be getting it that hot it might not be a big deal.

Thanks. Yes, I watched a few videos. I was wondering about blue loctite being sufficient, and was worried the block might fly off under the stress.

This will be a target-shooting , light-duty upper; California Legal. I have different SHTF equipment for when the next earthquake/tsunami hits, or BLM comes to town.
 
Thanks. Yes, I watched a few videos. I was wondering about blue loctite being sufficient, and was worried the block might fly off under the stress.

This will be a target-shooting , light-duty upper; California Legal. I have different SHTF equipment for when the next earthquake/tsunami hits, or BLM comes to town.

Is the barrel dimpled for a set screw?

Do you have a something like a fat wrench to torque to 25 in lbs?

p_100012250_3.jpg


There are also knurled set screws if you wanted.
IMG_20191213_220836_111-1536x1536.jpg

These are like $2.
 
I assembled my first upper receiver from parts. I got an 18" 223 Wylde barrel from Green Mountain, and fixed it to a vacant upper receiver. I put some blue loctite on the gas block screws. Put a little bit of hi-temp grease on the barrel threads, lined everything up. Admittedly I didn't torque it, but I do enough wrenching on my cars to know what 80 ft-lbs feels like. Backed it off to "season" the threads, and cinched down again. New BCG from PSA. Put a little lube on the sliding metal to metal contact points. Am I missing anything?

I'm nervous as hell thinking about shooting it though. It seems to go into battery fully. Anyone else been in this situation and how did you double check your work? I'm thinking about "remote firing" it a couple of times so I don't kill myself.

My opinion, even if you put it together loose, (which you didn't) it shouldn't blow up. It might stick or separate the case.

Now if the barrel, bolt carrier and or receiver is is outa-spec and or junky shit, a blow up is always possible.

Just turn your head, or give it to a buddy to shoot first!

<Kpop775>

The hole going through the barrel is a fine pressure release mechanism if you think about it.
 
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I assembled my first upper receiver from parts. I got an 18" 223 Wylde barrel from Green Mountain, and fixed it to a vacant upper receiver. I put some blue loctite on the gas block screws. Put a little bit of hi-temp grease on the barrel threads, lined everything up. Admittedly I didn't torque it, but I do enough wrenching on my cars to know what 80 ft-lbs feels like. Backed it off to "season" the threads, and cinched down again. New BCG from PSA. Put a little lube on the sliding metal to metal contact points. Am I missing anything?

I'm nervous as hell thinking about shooting it though. It seems to go into battery fully. Anyone else been in this situation and how did you double check your work? I'm thinking about "remote firing" it a couple of times so I don't kill myself.

These are kinda idiot-proof. Chances of a headspace issue are pretty close to zero.

With torqueing, you go until the holes line up. Not a lot of choice there. I've always put grease (aeroshell I think) on the barrel extension that slips into the upper receiver. That might be more important for disassembly later than it is for performance.
 
All good points, thank you. @RerouteToRemain Do the knurled set screws eliminate the need to dimple the barrel?

I prefer a dimpled barrel. It really keeps alignment and even further prevents walking or shifting. The knurled screws on top of that are just an added bonus. Less likely to back out or allow walking.

A dimpling jig is only like $30. Or to get it done at a shop I can't imagine it being that much.

How was the gas block fitment on the barrel?

If it was a tight fit, the knurled screws properly torqued with red loctite or rocksett without dimpling and your firing schedule you will more than likely be good to go.
 
How was the gas block fitment on the barrel?

If it was a tight fit, the knurled screws properly torqued with red loctite or rocksett without dimpling and your firing schedule you will more than likely be good to go.

I'm going to disassemble it and double check everything. I might check into using Rockstet after seeing that, per the labels, blue and red loctite somehow had the same heat rating.
 
My word, thank you for the link. I always cringe at spending money for hazardous chemicals (loctite, etc.) or other one-time-use tools, knowing that I might use it once and have a bunch left over.

Yeah no problem.

I was hoping to find a much smaller bottle of rocksett. I've used it like 3-4 times on different builds and I still have like 98+% of the bottle lol. It will probably go bad before I can even use 5% of the bottle. But whatever it was like $15. That's another benefit of rocksett though it's non toxic, non hazardous, odorless, breaks down after soaking in hot water, etc.

But the .02oz single use packs of the 271 is an awesome option.

That is a really cool company. They have a ridiculous attention to detail on the stuff they do.
 
Ok, a little update. The knurled screws and loctite came. I took the upper apart, but could not get the gas block screws off. So I just blew through the barrel and tube, everything felt good and secure. Last night I got out to a range and only had an hour to work. The 18" + Rifle length tube did not cycle very well with my 4.2oz buffer; switching to a 2.1oz buffer, and she ran like a charm.

Shooting indoors with a mask sucks; my glasses kept fogging up. Will try to upload pics later.
 
Ok, a little update. The knurled screws and loctite came. I took the upper apart, but could not get the gas block screws off. So I just blew through the barrel and tube, everything felt good and secure. Last night I got out to a range and only had an hour to work. The 18" + Rifle length tube did not cycle very well with my 4.2oz buffer; switching to a 2.1oz buffer, and she ran like a charm.

Shooting indoors with a mask sucks; my glasses kept fogging up. Will try to upload pics later.

What buffer(s) are you using. 4.2 and 2.1oz sounds very unusual. Is it an adjustable weight buffer?

An 18" rifle length should cycle an H buffer without issue. But if it runs reliably I guess there isn't reason to change it.
 
What buffer(s) are you using. 4.2 and 2.1oz sounds very unusual. Is it an adjustable weight buffer?

An 18" rifle length should cycle an H buffer without issue. But if it runs reliably I guess there isn't reason to change it.

Pardon me, 4oz even, it's a Spikes T2 powdered tungsten buffer, I bought it for a very aggressively gassed 16" 5.56, carbine gas upper.
The light buffer is adjustable on the lowest setting. I have it for my 16" 300 Blackout upper; the good news is now I don't have to switch buffers now.

Ideally, I'd like to tune it, but with the 18" didn't have the harsh push-back of being over-gassed.
 
I've ran into an issue that I am not sure where to go with it.

My gas block is a .750 gas block. My understanding was that my barrel has a .750 gas block seat. I can't hand fit the gas block over it, it just stops and feels like you need a hammer to get it on.

I measure them.... the gas block is a .749 and the gas block seat?... .758. FUCK. I wonder if this is something a gunsmith could get to work by like working off some of the finish on my barrel or something.

@Roaming East you ever run into something like this? The gasblock is a BCM and the barrel is Rainier Arms so they're reputable companies. The gas block is close enough but the seat is off by 8 thousandths which seems pretty big when you start thinking about how tight these tolerances tend to be.
 
I've ran into an issue that I am not sure where to go with it.

My gas block is a .750 gas block. My understanding was that my barrel has a .750 gas block seat. I can't hand fit the gas block over it, it just stops and feels like you need a hammer to get it on.

I measure them.... the gas block is a .749 and the gas block seat?... .758. FUCK. I wonder if this is something a gunsmith could get to work by like working off some of the finish on my barrel or something.

@Roaming East you ever run into something like this? The gasblock is a BCM and the barrel is Rainier Arms so they're reputable companies. The gas block is close enough but the seat is off by 8 thousandths which seems pretty big when you start thinking about how tight these tolerances tend to be.
yeah, we see gas blocks that need to be put to the torch to heat them up, you mallet tap them into place, and as they cool, they contract tight unto the barrel. Normally only see that with like the primo stuff. about 200 degrees normally gets them on. And once they are on, they certainly dont ever leak.
 
yeah, we see gas blocks that need to be put to the torch to heat them up, you mallet tap them into place, and as they cool, they contract tight unto the barrel. Normally only see that with like the primo stuff. about 200 degrees normally gets them on. And once they are on, they certainly dont ever leak.
Awesome thanks.

I have a Rainier Arms ultramatch barrel and a BCM gas block. Glad this seems to happen.

Seen some guys suggesting throw the barrel in a freezer and then heat up the gas block both but that seems like a primo way to fuck up the barrel.
 
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