If you read the first in this series you will see the GnZ AR has changed considerably over the last few weeks. It began life as an SPR type build which was very popular about 5 years ago. The build looked to be modelled on a Knights Armament special purpose rifle.   These became very popular after the Lone Survivor film came out. I bought the rifle on the second hand market at a very nice price. The first thing I noticed was the weight.. It was well over 10lb with scope – Way to heavy for anything other than static prone shooting. Shots from standing became a test of endurance after about 2 minutes!


The original SPR build – great for prone but not much fun standing.. Notice the height of the scope.

The changes made so far:

Replace KAC handguard with Rainier Arms Evolution 15″
Replace A2 flash hider with Rainier Arms mini compensator.

In this article we look at buttstock, grip and scope mounts. Can they be improved upon and made lighter? We find out with a visit to Orion Firearms training in Wales (a regular favourite here at GnZ).

Scope Mounts.

The rifle came with A.R.M.S. quick release mounts. These have proven to be very reliable and extremely sturdy. I particuarly wanted a mount with 20MOA built in as the last time I had taken the AR out to longer range I ran out of elevation at about 900 yds. I had to use the reticle markings to reach out to 1000yds (80g SMKs single loaded as they are too long for a pmag).  I began to look for a canted mount which would also give me a weight saving.

American Defense Mfg – AD-Recon 20MOA scope mount.


One of the problems with standard type mounts on an AR platform is that of eye relief. If you are thinking of running a scope for longer range shooting then you might find it sits to far back forcing your head back and thus effecting your shooting position. This can be mitigated by increasing the length of pull to a degree but it is not the ideal solution. American Defense Manufacturing (which I shall refer to as ADMFG) produce a range of cantilever mounts which solve the problem completely. The rings are set further forward allowing correct eye relief with a large scope. The scope I am mounting is a Leupold 4-14x with a 30mm tube. ADMFG have a dazzling array of options for the AD-Recon mounts. They offer different colours, rings sizes from 1″ to 45mm, and built in cant of up to 30moa if required. I opted for black 30mm rings with 20moa of cant which should allow me to reach out to 1000yds without having to aim off.


The Recon mounts weigh 8.4oz which is less than the A.R.M.S system being replaced (8.67oz).The Recon uses a quick detach system which works very well indeed. The levers clamp down on the picatinny rail really solidly and lock in place. You can even adjust the setup to cope with picatinny which is not regulation size. Not a huge problem for most of us but nice to know it can be adjusted if nessecary.

The rings split vertically which usually is not my preference but I have to say these were simple to set up and install. I just sat the scope in them and put the bottom screws in lightly (just enough to support the scope). I then dry fired the rifle adjusting scope position until I was happy. Then just tighten down the bottom screws to your preferred torque setting and do the same with the four top screws. The whole process took about 15 minutes.

Once everything was tighted down the scope was rock solid. The Recon mounts bought the scope lower than the old A.R.M.S. system which is great news for those who don’t have or want an adjustable cheek piece buttstock (of which there are limited options). Due to the lower scope height I would now be able to comfortably run a collapsible buttstock which gives a big weight saving over the Magpul PRS that was originally installed.

First impressions of the ADMFG Recon mounts are superb. Lighter, added cant (increased scope range), lower scope height and high quality engineering along with a brilliantly simple design combine to make an excellent upgrade.

Cost wise the Recon comes in at around 190USD depending on the options selected. That works out cheaper than the old system (The A.R.M.S. system was around 250USD). The bottom line is you are never going to find presicion engineered components at rock bottom prices. As my old shooting friend always tells me “Buy once, cry once”.


The Recon mount keeps the Leupold 4-14x nice and low negating the need for a raised cheek position.

Magpul CTR buttstock and MOE grip.


Quickly despatched by Mark at Bradley Arms. Buddha seemed very happy with them.

The PRS buttstock is a heavy old beast at 1.68lbs. Being as we are looking to lighten the rifle and the lower scope mounts allow I decided to swap it out. The PRS went onto the Presicion rifle build which I think will benefit from a bit of added weight in the butt (insert pun here…) The replacement buttstock needed to fill two important criteria. I wanted something lighter than the PRS but it had to lock up SOLIDLY. I have used a variety of buttstocks which felt sloppy and heard various fixes mentioned (taping the buffer tube ect) from friends. Wobbly might be acceptable on a battle rifle but is not cool if you are reaching out to 800-1000yds (something we do regularly here at GnZ). I settled on a CTR from Magpul. The CTR is touted as a beefier version of the MOE buttstock with a secondary locking mechanism. Magpul marketing suggests the CTR locks solid. I am in the UK so Magpul stuff can sometimes be hard to come by. Luckily Mark Bradley of Bradley Arms was able to send the items immediately as he carries a lot of Magpul stock and has it at the shop (unlike many who say they have stock and often leave you waiting weeks or months). Mark sent a CTR in FDE, a buffer tube kit and an MOE grip also in FDE. The old grip was a black Fab Defence which would also end up going on the PR build. The fitting was easy and I must say the buttstock locks up very solidly. No play or wobble at all. The buttstock and kit were Milspec version. The MOE grip was equally simple to install and just as solid. The rifle became noticeably lighter and very easy to handle – the CTR weighs 0.55lbs, a considerable weight saving. The collapsible stock would also give more options in different positions and environments. Both items are ergonomic and very comfortable. The MOE grip feels good in the hand and is a good deal smaller than the grip that came off. It saves a few grams in weight which is good and allows storage (which personally I never use).

In Use.


Stunning scenery and an amazing range at Orion firearms training in Wales.

I took the AR along to Orions range in Wales. Steel targets stretching out to over a mile and the ability to shoot in multiple positions from barricades and structures. I kept things simple ammunition wise and packed a couple of hundred rounds of 5.56mm Nato from GGG and FN.
The first job was sighting in as the mounting system had changed. I dropped the scope a couple of full turns below the old 100yd zero as I now had a 20MOA cant to account for. The targets were standard silhouettes at 100yds plus a mixture of small round steels and clays. I took a shot at the first target in the prone position off a bipod. The bullet splashed into the dirt at 11 ‘o clock a couple of inches off of the steel. Second shot hit the left shoulder and a further scope adjustment saw the third round strike centre. After a few easy steels and clays I moved to 200yds and tried sitting and standing. The steels pinged away, the rifle was comfortable to shoot and felt nicely weighted.


The CTR allowed me to adopt more comfortable standing and kneeling positions and really get the butt tight into my shoulder. I checked the Recon mounts every few shots for signs of movement but they remained completely solid. The CTR also stayed as steady as a rock. I managed some consistent standing shots out to 370yds and finally ended up smashing a few clays out to 800yds in prone.


The old rifle hitting the same targets at Orion. The new version proves just as capable without the heavy weight.

Overall the new accessories are a huge success. I seem to have lost no accuracy at all yet shed around 2lb in weight which is no small thing in the shooting world. The current build is a lot more adaptable than the last as it can be used comfortably off hand and still retains accuracy for long range prone work. It can also be used comfortably by my lovely lady and guest shooters of small and large stature.

In the next article I will be looking at the standard AR trigger and discussing why it is a poor choice for long range target work and what can be done to improve things.


Previous Articles.

AR15 on a diet part 1 – rainier evolution handguard review/install

AR15 on a diet part 2 – rainier arms handguard and muzzle brake testing


American Defense Manufacturing – http://www.americandefensemfg.com

Magpul – https://www.magpul.com

Bradley Arms – www.bradleyarms.com

Orion Firearms Training – http://www.orionfirearmstraining.co.uk/

Rainier Arms – http://www.rainierarms.com