I'm currently building the lightest weight piston powered AR15 I can without sacrificing reliability and function. I'm pretty sure most, if not all of everything I bought is the lightest I could buy without going with polymer or carbon fiber receivers. If there anything I can improve upon then let me know.  I'm going to list every part and keep this thread updated until I get range time.


DISCLAIMER: A few parts were chosen specifically because I'm left handed

First pic:



Progress Report 1:





What's in the latest pic:
- DS Arms A3 Enhanced Flattop Forged Upper Receiver (w/ FA, Brass Deflector, & Feed Ramps) - $79.99
- 2A Armament Balios-Lite Billet Lower Receiver - $279.99
- MFT Battlelink Minimalist Stock -$59.99
- PWS Enhanced Buffer Tube Mod 2 -$104.95
- AR15Xtreme CA Reversible Mag (Lock) Release -$15.99
- Elftmann Tactical Push Button Speed Ambi Safety -$39.95
- Varmint Light X-Shim (removes remaining upper/lower play) -$9.99
- V7 Ti KMR Barrel Nut -$57.00
- V7 Ti Trigger/Hammer Pins (Geissele 0.155) -$17.00
- V7 Ti Grip Screw -$5.00
- V7 Ti Buffer Detent -$7.00
- V7 Port Door Rod (6061 Al) -$8.00
- V7 Ultra Light Port Door (7075 T6 Al) -$37.00
- V7 Ultra Light Forward Assist (Minimal) -$37.00
- V7 Ultra Light S7 Bolt Catch w/ kit -$31.00
- V7 Lightweight Castle Nut ("Super Al") -$22.00
- V7 QD Endplate (7075 Al) -$27.00
- V7 Ultra Light TD/Pivot Pin Set ("Super Al") -$24.00
- IVI Captured TD/Pivot Pin Detent Springs -$9.99
- Taccom Ultra Lightweight Carbine Buffer -$22.95
- Hogue Soft Overmold Pistol Grip -$26.95
- Hydra-Fire Roller Cam Pin (may Replace) -$28.00
- Wolff Reduced Power Buffer Spring -$14.99
- Elftmann 3-Gun Drop-In Trigger Group  -$279.00
- AXTS Raptor Ambi Charging Handle -$89.95 (going to replace, see below)

What's missing in the pic, but in my closet:
- VG6 Epsilon Ti Hybrid Compensator (no longer available, clone available on eBay) -$129.99
- Superlative Arms Mid-Length Retrofit Piston Kit (0.750) -$289.99
     - KNS Perma-Pin Firing Pin Retainer -$9.00
     - V7 Ti Firing Pin -$23.00
     - Sharps NP3+ Relia-Bolt (may replace) -$89.99
        - Springco Enhanced 5-Coil Bolt Extractor Spring kit (w/ black insert) -$4.95
        - Adams Arms Bolt Spring -$5.00
- BCM KMR13 Free Float Hanguard(OG) -$269.99
  - V7 Ti KMR Clamp Block -$35.00

What's missing:
- 14.5" Mid-Length Evo Ultra Lite 0.750" C.O.R. VDI Barrel(In Process, awaiting replacement) -$299.00
- Strike Industries Arch Latchless Charging Handle (awaiting release) -$??.??

Roughly $2,530.50 MSRP before shipping price. Estimated shipping price for each product combined: $100-150.

Added up all the weight and it should weight roughly 5.3 lbs before sights are added.

It's a 14.5 pencil. The lightest .750 available. I'll probably just slap on an Aimpoint t2 and the Troy HK style sights I have laying around. Those things are sexy.

SBRs don't count bro lol. But yours is a great build.

Build looks good!

If you're going for reliability, I would swap out the Relia-Bolt for a Colt or DD bolt.  In the Henderson Defense high round count thread, one of those bolts didn't make it past a week on the line while the DD and Colt bolts go for tens of thousands of rounds before breaking.  He has good things to say about PSA bolts too.

I was considering an LMT enhanced bolt for my SA piston kit build, but when Colt and DD bolts are lasting that long...makes you think twice about spending ~$170 when you can have 2 Colt or DD bolts for less.

I really like the KMR and V7 Ti parts!!!

I was going to say I MAY change out the Relia-Bilt for the LMT or JP. However Sharps had a bad batch that broke so they did a recall. So I'm banking on that. I do know there's another bolt that is apparently really amazing but I can't find it. I remver reading about it like six months ago.

We can have SBRs in CA.  However I can't really change that. I don't want one.

If you had your build and put my parts in it your probably have like a 3 lbs AR.

Only other bolt I can think of is the KAC E3, but that requires KAC's proprietary chamber

Let us know how the Relia-bolt runs if you do decide to use it.

I've already ran the Relia-Bolt on my AA XLP Piston. Runs great. No malfunctions.

I found some more bolts.
-ARP Superbolt
-Kac E3
LMT looks to be the best.

Also when you mentioned spending $170 for a bolt, I agree. However I spent like a crap ton on those V7 and Lightweight parts. Over $100 just for a buffer tube.

Roger that, always good to hear from actual users!




Yup...the bolt and barrel are two places I don't mind spending more $$$, especially since they are the core components of a build.

I'm a sucker for spending $100 on our ghtweight parts.

Anyhow, I'll probably replace the bolt with the LMT. I heard that the dual springs and lobster tail make extraction issues extremely unlikely.

@Keith1980

Just spoke to Tony from Superlative Arms. Told me that there is a batch almost done with CNC and then Ionbonding afterwords for their new Lightweight piston carriers. He told me after everything they should weigh about 7.4 oz for a stripped carrier. Rainier Arms bought the entire batch. So be on the lookout.

Once they become available I'll purchase and add to my build.

Updated OP w/ prices and links. Currently the build is Roughly $2,530.50 before shipping price. Estimated shipping price for each product combined: $100-150.

This is MSRP pricing. I'm sure I spent a little less because of coupons, and different websites who offer the product at a lower rate.

Updated OP. Changed the Geissele SD3G for Elftman 3 Gun, Hogue Overmold Grip w/ Beavertail for Hogue Overmold Grip, and JoeBob's Adjustable Grip Screw for V7 Titanium Grip Screw. Since the trigger is a drop-in, it raised my weight about .3 oz.  Pics below.

I'd hate to say it, but this Elftmann trigger is levels above the SD3G. Very impressed.

It's almost done. Just waiting on the SI Arch Latchless handle, but I'm looking for good, functional sights. I have some but they're pretty heavy. It will be anywhere between 1-3 oz for the sights.  Just wait till Superlative Arms comes out with their LW carrier.