Mega Arms AR15 Pistol Build

[JohnC]

Call the manufacturer of the piston kit and see what they recommend. I am sure they answer this question all the time.

They have a list on Adams Arms website, but they fail to list in detail, if the gas block only fits outside the rail or also inside, etc.

For instance, obviously a 7in rail on a carbine gas system places the gas block in front of the rail. They will put, works with their gas piston system.

However, my gas system is pistol length, so while that rail might work on a carbine, it still might not work on a pistol length gas system because the gas block would be inside the rail.

So I've bee left Googling for info and searching forums for weeks....

[JohnC]

I finally found a rail that I can make work with the XLP and uses the mil-spec barrel nut (with some clearancing around the gas block). https://troyind.com/products/mrf-7-blk

Not as sexy as the high dollar Daniel Defense Lite II, but I'm tired of buying/being sold rails that don't work and searching endlessly, so I'm going with this.

This rail pictured is off my Colt LE 6920 that has probably 1,000 rounds or more down the barrel, so it's nasty and a little beat on. But for test fit purposes, here it is. KX5 is not tightened up yet either...

Going to order a new one for this gun and put this one back on the Colt.

Edited April 11, 2016 by JohnC
this rail ended up touching the gas block, so added that I had to clearance the rail.

[JohnC]

Test fired it yesterday.

Gun was so tight, it didn't cycle at first, but as I manually cycled it each shot, it started pushing the bolt rearward more. By the second 30rd mag, it fired and cycled like a champ!

With the SD3G, mag dumps were easy. With the AA XLP, it didn't recoil, so laying those rounds on target fast was easy. :up:

This was my first AR build and I'm very pleased with it. :D

[DT INC.]

I'm glad it ran great. It is a fine looking weapon for sure

[JohnC]

Said heck with it and just ordered a Law Tactical M-3 folding stock adapter for the Mega Pistol. Should make it a more concealable gun when transported.

http://www.lawtactical.com/ar_folding_stock_adapter_gen_3_m_p/99312.htm

I think now I want a buffer tube that will allow the Sig Brace to move forward about 3 inches. Anyone know of one? The Phase 5 Sig uses in the SB15 kit pushes the brace back, like I said, about 3 inches.

[JohnC]

Final build specs:

Mega Arms Forged Pistol lower
Mega Arms Forged upper
Mega Arms charging handle
Geissele SD3G Trigger
ALG Defense LPK
Hogue AR15  grip
Bravo Company forward assist
Bravo Company complete ejection port assy
Sig Brace with Phase5 pistol buffer tube kit
Law Tactical AR Folding Stock Adapter GEN 3-M
Troy Industries MRF, 7" -BLK
Adams Arms (PDW) Pistol Length XLP gas piston system with Nickel Boron Carrier
Spikes Tactical (FN) 8.1" CHF DCL 1:7 Twist Barrel - 5.56NATO
Noveske KX5 Flaming Pig
Samson Quick Flip Front & Rear Sight Package HK Front/A2 Rear
Spikes Tactical Barrel Nut
VDI Lifecoat Bolt Carrier Parts - 5.56
Magpul MOE Trigger Guard

http://www.megaarms.com/ar-15/lower-receivers/forged-lower/
http://www.megaarms.com/ar-15/upper-receivers/forged-upper/
http://www.megaarms.com/ar-15/accessories-2/charging-handles/mega-grip-charging-handle/
http://geissele.com/super-dynamic-3-gun-trigger.html
http://algdefense.com/ar15-m4-mil-spec-lower-parts-kit-less-trigger-less-grip.html
http://www.hogueinc.com/store/products/ar-15m-16-overmolded-rubber-grip-with-finger-grooves-black/156
http://www.bravocompanyusa.com/BCM-AR15-Forward-Assist-Assembly-p/bcm%20forward%20assist%20assembly.htm
http://www.bravocompanyusa.com/AR15-Ejection-Port-Cover-Assembly-p/ejection%20port%20cover%20assembly.htm
http://store.sigsauer.com/1-0000.html
http://www.lawtactical.com/ar_folding_stock_adapter_gen_3_m_p/99312.htm
https://troyind.com/products/mrf-7-blk
http://www.adamsarms.net/pistol-pdw-length-piston-kit-xlp-no-rail
http://www.primaryarms.com/spikes-tactical-81-chf-17-twist-barrel-556nato/p/kt-sb50810-pl/
http://www.noveske.com/products/kx5-flash-suppressor-w-crush-washer
http://www.samson-mfg.com/mm5/merchant.mvc?Session_ID=beec3e8da356e81b45181aff0ec944df&Screen=PROD&Store_Code=SM&Product_Code=QF-HK-A2-PKG&Category_Code=QUICK_FLIP
http://www.spikestactical.com/upper-parts-milspec-delta-ringbarrel-nut-kit-p-415.html
http://www.voodooinnovations.com/vdi-carrier-parts
https://www.magpul.com/products/moe-trigger-guard-polymer-ar15-m4

I think I've got everything listed there....

[JohnC]

Law Tactical folder finally came.

I have one issue with it that I am going to contact them about. The Bolt Carrier Extension part fits loosely in the Adams Arms BCG. I tested it on my mil-spec Colt LE6920 and it fit better.

That said, I think if I can find some o-rings that can take some heat, I can take-up the excess clearance.

I'll get a video in a second...

[JohnC]

Sorry for the crap video, but holding the camera one handed/between my knees to record wasn't easy. Lol



https://vimeo.com/148192344

I have the rail off right now because I'm waiting for the new one to come in. The one I tested that fit was the Troy MRF 7 off my Colt LE6920.


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Edited December 8, 2015 by JohnC

[JohnC]

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[DT INC.]

Very nice!

[JohnC]

Just an update on the rail fitment....

So I moved the old rail back to my Colt LE 6920 after I got the new Troy MRF-C 7 inch finally.

When I went to install the rail last night, it would not fit together. I looked and the top half of rail was sitting on the XLP gas block and needed to come down to be level.

So I had to break out the Dremel, take a sandpaper roll and remove material in the area around the gas block. Just taking the roll and placing it between the valley where the gas tube normally runs to trim back the corners on each side gave me the clearance I needed to fit the gas block.

I also noticed when trying to install the rail that my drive rod, the part that holds the spring and rests on the barrel nut, had a mark where it looked like it made contact with the rail when I was trying to install it. So I again took out the Dremel and clearanced an area from the barrel nut forward (just enough) to be sure no contact was made there.

Afterward, i got it all back together and everything fit and had plenty of clearance.

I just wanted to get that out there so you all would know before you got the Troy rail, that it will need a small amount of clearance to work to fit under the Adams Arms XLP gas block.

Mega Pistol build is DONE!!!!!!!!!!!!!! Edited April 11, 2016 by JohnC

[justincase]

How did you like the ALG LPK? I have had a hard time finding anyone that has used one or reviewed one..

[JohnC]

Quality, fit and finish seemed excellent to me, but keep in mind this is my first AR build, so I only have factory AR's to compare it to. :up:


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