If you are doing 16”, I suggest mid length gas system. It’s your build tho.


Sent from my iPhone using Tapatalk

Is mid length standard for M4?

What was the LE6920 carbine length? I'll do that.

Here is a good deal........ https://www.primaryarms.com/timber-c...ack-nitride-16


Sent from my iPhone using Tapatalk

16.1”

But I’m talking about the gas system. My suggestion is to get a “mid-length” gas system on your barrel choice instead of “carbine”. It’ll give the powder more time to burn and in turn be more reliable with different loads as well as be “cleaner” (less carbon build up on the bolt face).


Sent from my iPhone using Tapatalk

LPK minus fire control group.... https://www.primaryarms.com/cmmg-ar1...it-no-grip-fcg


Sent from my iPhone using Tapatalk

Thanks! I'll keep it in mind. Unfortunately, Primary Arms is being very slow to respond to my original order of the two lowers and other parts. So much so, that my bank took off the "temporary hold" from my account. I still hope the purchase is still valid. Furthermore, I got an email yesterday from Primary that said due to the flooding from Tropical Storm "Beta," there will be even further delays.



So, "hopefully," they will ship soon enough. I know the upper I bought on Gunbroker has already shipped and is expected for delivery on Sat. 09/26.



We'll see...

Yeah that sucks, they are usually pretty quick to ship under “normal” circumstances.


Sent from my iPhone using Tapatalk

Just received notification - The lowers and parts have shipped and are expected to arrive at the FFL on Fri, 09/25. So I'll get those quicker than the upper receiver that was shipped directly!

That’s great!


Sent from my iPhone using Tapatalk

Current Status: Upper received today. Looks good.




Barrel, lower parts kit and stock receiver extension on order.


Lowers, trigger group and other parts to arrive tomorrow at the FFL.


Now, what other parts do I need, especially to connect the barrel to the upper/lower assembly (i.e. including barrel nut, etc.)?


For the stock receiver, extension, I know I need a bolt buffer assembly and spring, etc. But how much weight I'm not sure, and I have no idea how it might affect recoil, etc. I also need the gas system as well (block and line).



I'm probably a bit tapped out for this month, but will be ready for the rest of the parts and the tools for assembly (vice block, etc.) next month.


Thanks all!

Next quick question: Buffers and Springs. I see both "Carbine" length and "rifle" length springs. But I don't see "mid-length" which my barrel is (16.1"). Do I absolutely need exactly a "mid-length" spring? Or will one of the other lengths do (carbine or rifle)? And what Buffer weight do I want for shooting XM855 Green Tip 62gr primarily?

Usually when you buy your hand guard it’ll come with the barrel nut. Question is. Are you getting a free float hand guard or old school M4 style?

I’ve always used a carbine strength/weight buffer and spring and have had no problems. I’ve shot 75gr Match with that set up.

The gas system depends on your answer for the hand guard question above. If running a free float HG, then you will need a low profile gas block. If your barrel is dimpled for proper alignment, then you won’t have any problems lining it up properly. If not you can use chalk lines to line the block up with the gas port on the barrel.


Sent from my iPhone using Tapatalk

I'm looking at the MAGPUL MOE M-LOK HG.


https://www.primaryarms.com/SSP%20Ap...0&resizew=2000Sorry for the pic size :D


I don't think it comes with a barrel nut, but I have this one on my "wish list..."


https://www.primaryarms.com/SSP%20Ap...0&resizew=2000
I actually have a YT video on how to dimple it for the gas block. but we'll see...


Oh, and my 2nd order shipped from Primary Arms today, including the barrel, lower parts kit and the receiver extension.


We're making some progress. I'll get back in another few weeks with the other part orders.

Building Confidence
 

That won’t work. That handguard is for the m4 style barrel but and “A” front sight. Stand by while I search for links on what barrel but you will need for that hand guard.


Sent from my iPhone using Tapatalk

Here is the barrel nut and delta ring you need.


https://www.opticsplanet.com/spikes-...arrel-nut.html

https://uploads.tapatalk-cdn.com/202...9ca898f6ad.jpg
https://uploads.tapatalk-cdn.com/202...e2156b3a9f.jpg


Here is the front sight/gas block you will need...


https://www.brownells.com/rifle-part...prod81261.aspx

https://uploads.tapatalk-cdn.com/202...9b165833d4.jpg
https://uploads.tapatalk-cdn.com/202...6bc8acbbad.jpg

Link to me the barrel you purchased.


Sent from my iPhone using Tapatalk

It's the one you suggested from Primary Arms.... And, yes, I got it "on sale."

Are there any alternatives to the above gas block with "A" frame front sight? That happened to be the one thing I disliked about the original LE6920 OEM1 I had. It had the front sight (with gas block) built into the barrel assembly. It's why I wanted an OEM2 for this project but can't get one.... I don't like the fixed front sight because it blocks the scope.



If my only option is that A frame front sight, then I might have to re-consider the HG.


Thanks.

Building Confidence
 

Ok so the barrel nut/delta ring and the front sight base I linked above is what you will need for that particular handguard. You will also need a “mid-length” gas tube.

PS: make sure the front sight base you choose is for a .750” gas block.


Sent from my iPhone using Tapatalk

Building Confidence
 

Stand by, I think there is.

Edit: Nope, I was thinking of something else.

Looks like you will need to go with a free float hand guard.

Edit 2: It is possible to cut off the sight part of the block but you will lose the ability to run a front back up iron sight.


Sent from my iPhone using Tapatalk

As it turns out, I was considering that for my original OEM1, but didn't feel confident enough to do it. I'll give it some strong consideration, this time, especially since I can always replace it with another one if needed.


I don't mind losing the "backup" sight portion of it. I'm strictly a "scope" man, m'self..... :D

So are you after this look? Ignore the colored furniture.

https://uploads.tapatalk-cdn.com/202...d76e397d5f.jpg


Sent from my iPhone using Tapatalk

Yes, but without the iron sights. I'm a scope guy.

Ok... let me think and research a bit. I have an idea.


Sent from my iPhone using Tapatalk

Thanks much!

:flagwave:

Problem solved.

You need one of these gas blocks or one similar..


https://www.opticsplanet.com/guntec-...-ALRHGB-GT750R

https://uploads.tapatalk-cdn.com/202...727181f70b.jpg
https://uploads.tapatalk-cdn.com/202...78e53567a5.jpg


You will need one of these as well..

https://uploads.tapatalk-cdn.com/202...b64a7bfc37.jpg

These items along with the delta ring barrel nut and you will be able to run the Magpul hand guard.

https://uploads.tapatalk-cdn.com/202...a3e54b6eb4.jpg


Sent from my iPhone using Tapatalk

With that block, you can install a folding front sight in case your scope fails.


Sent from my iPhone using Tapatalk

Wonderful! Thanks so much! :lama:

No problem.


Sent from my iPhone using Tapatalk

I use popup sights on mine in the unlikely event the Aimpoint Pro goes tits up

So I'm wondering, if you don't want the iron sight why then the A2 brushhanger gas block? There are a bazillion different low profile gas blocks out there?:confused:

Definitely a possibility... I gather I can mount them on the rails like any other devices, correct?

He wants to run the magpul hand guard.


Sent from my iPhone using Tapatalk

Yep. That’s why I mentioned the gas block with the Picatinny rail.


Sent from my iPhone using Tapatalk

Will pick up my lowers tomorrow and the barrel and other parts are also due to arrive as well.

Almost time to start building!


Sent from my iPhone using Tapatalk

Almost..... Still have some parts and all the tools left to purchase. I should be finishing all that within the next 3 weeks, after I get paid.


What parts I still have left to purchase:


1) Buffer and Spring;
2) Gas Tube (mid-length);
3) Flash Suppressor;
4) All the Furniture (HG, Stock, trigger guard, Main grip, forward verticle grip), etc.

5) Triangle End Cap... .750 (I assume I can get it from PSA)?
6) Barrel Nut

7) Castle Nut for stock.


And, all the tools, including:


1) Upper and lower vice blocks;
2) Vice itself (which I'll install on a heavy block of particle board;
3) hammers as needed (ball peen, soft/rubber, etc.);
4) Roll pin punch set;
5) Whatever else, I need.





One question. I assume the end of the gas tube feeds into the port on the BCG. I gather there has to be enough tolerance for the BCG gas port to insert itself into the gas tube after each action cycle. Correct? If so, then it needs to be aligned carefully.


For the 16" length barrel, am I using Carbine or mid-length HG? I recall using the Carbine HG for my LE6920, but it may not be the case, here.


Thanks much.

Building Confidence
 

You are going to need mid-length on both the gas tube and the hand guard. Those are determined by the barrel.


Sent from my iPhone using Tapatalk

Depending on its bolt pattern you may consider mounting/bolting your vise to a length of 2"x6", you'll exert a fair amount of torque/leverage tightening the barrel nut.

You're moving right along now, C aleb walked me through 2 builds and there were NO issues during or after the builds. On his recommendation I built a .223 Wylde and it's my favorite by far. :cool: http://www.cotep.org/forum/images/icons/icon14.gif

Well, right now, I'm just acquiring parts/tools. How they're put together is a whole 'nother story. And, although I have some good YT resources on how to assemble everything, I still have a few questions.


For example:


1) Gas Key on BCG: I gather that when the BCG is "in battery" with a round loaded, the gas key has to fit properly over the end of the gas tube, correct? If so, I'll need to ensure they're aligned properly.TBH, I'm amazed that it could stay "aligned" in that regard, especially in a "full auto" scenario.


Barrel, buffer tube and LPK arrived today. All look good. I'll be picking up the lowers and other items from the FFL tomorrow. Then I'll make sure I have sources for the other parts and tools so I can go to work in mid Oct, once all parts are ordered.