Since I recently built an AR from scratch, I thought it would be a good idea to rate the individual parts on the build so people can see opinions if they were deciding on building one themselves.
Picture of the build:
SI Defense Billet matched upper and lowers: A+
I couldn't ask for more out of receivers. As I was building this rifle, a buddy of mine was building two. This rifle was night and day easier to put together due to the receivers, all the difficult parts are simplified. You don't have to worry about damaging the trigger guard area because the trigger guard is milled in. The bolt stop is held in by a set screw instead of a pin, making it cake to install. Likewise, the forward assist is also held in by a set screw, although using a pin on that is not difficult. The ejection port cover pin has a stop to the rear of it, no need for a stop ring. The fit of the upper and lower when I got them were perfect. After several hundred rounds and associated cleanings, there is a minute amount of wobble. However, I just now discovered that there is a set screw underneath the rear takedown pin to tighten things up. All in all, these receivers were my single best decision on this build.
Geissele SSA-E trigger: A
I have never been impressed with any AR trigger I've used until this one. I still prefer a nice tuned M14 trigger, but this one is at least in the same ballpark. The break on the SSA-E, while no benchrest trigger, is still very good. Perfectly acceptable for precision shooting. Likewise, the trigger has excellent reset and isn't super sensitive, so I would be comfortable using it for rapid fire or home defense.
WMD NiB-X BCG: A-
I was going to give this a lower rating because I never really liked it until I realized I've never had any real problems with it and it works as it's supposed to. It is extremely smooth in the receiver. If I pull the bolt and just run this inside my upper receiver by hand, I definitely notice how much smoother it is than a mil-spec BCG. It cleans incredibly easily too, most of the time I can just wipe it clean. When I received my Douglas barrel, it came with a matched mil-spec bolt and I can tell the NiB bolt doesn't get nearly as dirty, and clean much more easily. I initially disliked it for some unknown reason until I thought about it and figured it out: the stupid packaging with the tactical toolbag on the front.
Diamondhead VRS-T rail: B
I REALLY like this rail, but it needs some refining. The installation of it is a breeze and looks and feels great. I had to do some machining on it to get it to fit my oversized upper receiver, but that's not a fault of the rail. In fact they've taken billet uppers into account and designed the anti-rotation tabs so they are easy to work on.
It could use a little refinement however. There are no slots to guide the gas tube on the barrel nut (hence why it's so easy) so the gas tube wiggles around in the upper a bit. For me, it's an annoyance to hear it, however the cloverleaf on my upper is tight enough to not cause functionality issues. Others have run into problems with the loose gas tube not going into the gas key correctly because it was too loose. A simple fix would be for diamondhead to include thin metal sleeves to shim the tube and the upper. The rail itself is not easy to add attachments to. For me specifically, a front mounted sling is very important, and for these guns, I prefer them mounted on the left side. While technically they make rail sections that fit the sides, they look terrible and are not flush at all. I ended up adding a longer rail to the bottom and using a 90 degree offset mount for it. I will post an update picture when I get home.
TIS slip cuff AR sling: B
The sling feels flimsy and does not adjust quickly, but it works. There is a tab on it that is supposed to allow quick tightening or loosening of the sling, however it's just too tight to use while the rifle is on me. However, when using the sling as a shooting aid, it's excellent. I was able to hold just over MOA using the sling from prone, not bad.
Magpul UBR: A
I don't like plastic on guns. While the skin on this is plastic, the internals are metal. It's heavier this way, but since I have a relatively heavy barrel, it balances the rifle very nicely. I don't baby my stuff, so when I read the buttstock comparison involving a drop from 3 feet, I definitely went for the UBR. The stock breaking from being dropped from 3 feet is unacceptable to me and the UBR was the only one that survived repeated drops. Some of the others broke in 1 drop.
JP silent captured spring: A+
This thing makes ARs enjoyable to shoot for me. I hate the sprong sound an AR makes, and I tried everything from high $ buffers to CS springs on my other ARs and could never fully get rid of the sound. This time, I bought what I really wanted the first time, and couldn't be happier. Seems to make the rifle run a little smoother too.
Wilson Combat Adjustable gas block: C
It works, but is a pain to adjust. The adjustment is on the front using and allen key. It's locked into place using a set screw taking allen key of the same size. The idea is that I would unlock the set screw, and the insert the allen key through it into the adjustment screw, turning both at the same. In practice, this is a terrible idea as I can not get the key into the second screw easily. If I put pressure on it as I turn to try to find it, it sometimes turns the adjustment screw instead, thereby changing the gas flow unintentionally. It would be much easier if the adjustment screw was smaller so I could unlock the set screw with the larger key and use a smaller one for the actual adjustment.
Once I got it set right though, it works perfectly. Since the JP SCS is a little lighter than a normal buffer spring, I reduced the gas and in turn smoothened the operation. Shooting this AR next to a standard one is a night and day difference in smooth operation.
JP Rear tensioning Screw: A
This locks the upper receiver down instead of pushing it up like an accuwedge. With this in place, the upper and lower are rock solid and feel like one piece. It doesn't affect function, but definitely gives the rifle a nicer overall fit and finish feel. It does take a longer and requires tools to disassemble though. The primary drawback on reviews for it is the requirement of threadlocker on it. I found that teflon tape works just as well, and does not make the mess of threadlocker.
PSA LPK: ?
I got this with a package deal with the trigger from PSA. However since all the parts used in the build are non-standard, I didn't use a lot of the parts in the kit. The trigger guard, buffer pin, detents and springs, trigger pins, etc. were all not used due to the other parts I chose. I could have spent the same money and gotten nicer looking parts for the ones I did use, but that's just cosmetics. I did not rate the kit because I don't have anything to compare it to.
BCM charge handle: A
It's much easier and quick to charge using the left hand instead of the right. This charge handle feels like quality and has performed so.
BCM 18" 410SS 1-8 SPR Barrel: C-
I had all sorts of accuracy issues with this barrel and finally replaced it. Currently trying to send it back to BCM, but as I bought it new from a forum, I may be SOL as they require an order number. This barrel would occasionally pull and MOA group at best with the best ammo. However most of the time it was 1.5+ with good match ammo, which is unimpressive to say the least.
Douglas 18" stainless 1-7 CLE Barrel: B-
The jury is still out on this one, but it definitely shoots better than the BCM. With my handloads its .75-1 MOA and factory match is consistently MOA. I was hoping for better as factory semi-auto rifles can meet or exceed that, but I'm not dissappointed either.
I have noticed the barrel is not very smooth while cleaning it. As I pull or push a patch through, the force required is not consistent throughout the length of the barrel. I some spots, it seems looser than others. Likewise, velocities from this barrel are all over the place. 80ish FPS ES from reloads and match ammo with up to 300! FPS ES from FMJ ammo. This is a problem when shooting at range.
AAC Blackout Flash Suppressor: C
I wanted a flash suppressor instead of a brake since I tend to think brakes at the range are obnoxious. I picked this one because I'd like to mount a suppressor on it in the future and there are not make FS with a QD sound suppressor mount. There are many brakes with one however. I gave this a C because it makes an annoying ringing sound during firing and pretty much any time the rifle touches anything. It's basically a tuning fork. The CS at AAC when I called with a question was also not pleasant. It sounded like I was talking to a lawyer.
Troy Micro Tritium BUIS: C
I bought these based on recommendations from ARF and once again was disappointed. They are solid sights, and good for closer range shooting, but clearly not designed for a rifleman. There is no elevation adjustment on the rear sight. Instead, I have to turn the front sight post with a tool. Precision shooting with irons at range will instead require holdover. I got the tritium version because they were the same price as the regular where I got them. The front tritium works well, the rear tritium is useless because they are too close to the eye and just blur out. I find the front sight post exceedingly thick as well. Probably about 4 times as thick on target as my .062 NM front on my M1a. Part of it may be the tritium housing, and part may be because it's closer to my eye on the smaller rifle. In any case, I'm looking to replace them, maybe with KAC sights that actually have elevation adjustments.
Bobro Scope mount: A
This thing is solid and returns to zero when removed. Can't really ask more than that.
SWFA 1-6X24 HD: A-
This thing fits this rifle very well. The reticle is effective at 1X close range as well at 6X. Rare for a FFP scope, but they nailed it. If I could change anything, it would be to make the center dot slightly smaller, but that's about it. At 24 ounces, it's on the heavy side for what it is as well. I feel this scope should come around at 20 or under. The Leupold Mark 6 1-6 uses a larger 34mm tube and is only 18 ounces.
I figured I'd review these parts in case anyone was interested. If anyone has done a build of their own, please feel free to do the same.
Picture of the build:
SI Defense Billet matched upper and lowers: A+
I couldn't ask for more out of receivers. As I was building this rifle, a buddy of mine was building two. This rifle was night and day easier to put together due to the receivers, all the difficult parts are simplified. You don't have to worry about damaging the trigger guard area because the trigger guard is milled in. The bolt stop is held in by a set screw instead of a pin, making it cake to install. Likewise, the forward assist is also held in by a set screw, although using a pin on that is not difficult. The ejection port cover pin has a stop to the rear of it, no need for a stop ring. The fit of the upper and lower when I got them were perfect. After several hundred rounds and associated cleanings, there is a minute amount of wobble. However, I just now discovered that there is a set screw underneath the rear takedown pin to tighten things up. All in all, these receivers were my single best decision on this build.
Geissele SSA-E trigger: A
I have never been impressed with any AR trigger I've used until this one. I still prefer a nice tuned M14 trigger, but this one is at least in the same ballpark. The break on the SSA-E, while no benchrest trigger, is still very good. Perfectly acceptable for precision shooting. Likewise, the trigger has excellent reset and isn't super sensitive, so I would be comfortable using it for rapid fire or home defense.
WMD NiB-X BCG: A-
I was going to give this a lower rating because I never really liked it until I realized I've never had any real problems with it and it works as it's supposed to. It is extremely smooth in the receiver. If I pull the bolt and just run this inside my upper receiver by hand, I definitely notice how much smoother it is than a mil-spec BCG. It cleans incredibly easily too, most of the time I can just wipe it clean. When I received my Douglas barrel, it came with a matched mil-spec bolt and I can tell the NiB bolt doesn't get nearly as dirty, and clean much more easily. I initially disliked it for some unknown reason until I thought about it and figured it out: the stupid packaging with the tactical toolbag on the front.
Diamondhead VRS-T rail: B
I REALLY like this rail, but it needs some refining. The installation of it is a breeze and looks and feels great. I had to do some machining on it to get it to fit my oversized upper receiver, but that's not a fault of the rail. In fact they've taken billet uppers into account and designed the anti-rotation tabs so they are easy to work on.
It could use a little refinement however. There are no slots to guide the gas tube on the barrel nut (hence why it's so easy) so the gas tube wiggles around in the upper a bit. For me, it's an annoyance to hear it, however the cloverleaf on my upper is tight enough to not cause functionality issues. Others have run into problems with the loose gas tube not going into the gas key correctly because it was too loose. A simple fix would be for diamondhead to include thin metal sleeves to shim the tube and the upper. The rail itself is not easy to add attachments to. For me specifically, a front mounted sling is very important, and for these guns, I prefer them mounted on the left side. While technically they make rail sections that fit the sides, they look terrible and are not flush at all. I ended up adding a longer rail to the bottom and using a 90 degree offset mount for it. I will post an update picture when I get home.
TIS slip cuff AR sling: B
The sling feels flimsy and does not adjust quickly, but it works. There is a tab on it that is supposed to allow quick tightening or loosening of the sling, however it's just too tight to use while the rifle is on me. However, when using the sling as a shooting aid, it's excellent. I was able to hold just over MOA using the sling from prone, not bad.
Magpul UBR: A
I don't like plastic on guns. While the skin on this is plastic, the internals are metal. It's heavier this way, but since I have a relatively heavy barrel, it balances the rifle very nicely. I don't baby my stuff, so when I read the buttstock comparison involving a drop from 3 feet, I definitely went for the UBR. The stock breaking from being dropped from 3 feet is unacceptable to me and the UBR was the only one that survived repeated drops. Some of the others broke in 1 drop.
JP silent captured spring: A+
This thing makes ARs enjoyable to shoot for me. I hate the sprong sound an AR makes, and I tried everything from high $ buffers to CS springs on my other ARs and could never fully get rid of the sound. This time, I bought what I really wanted the first time, and couldn't be happier. Seems to make the rifle run a little smoother too.
Wilson Combat Adjustable gas block: C
It works, but is a pain to adjust. The adjustment is on the front using and allen key. It's locked into place using a set screw taking allen key of the same size. The idea is that I would unlock the set screw, and the insert the allen key through it into the adjustment screw, turning both at the same. In practice, this is a terrible idea as I can not get the key into the second screw easily. If I put pressure on it as I turn to try to find it, it sometimes turns the adjustment screw instead, thereby changing the gas flow unintentionally. It would be much easier if the adjustment screw was smaller so I could unlock the set screw with the larger key and use a smaller one for the actual adjustment.
Once I got it set right though, it works perfectly. Since the JP SCS is a little lighter than a normal buffer spring, I reduced the gas and in turn smoothened the operation. Shooting this AR next to a standard one is a night and day difference in smooth operation.
JP Rear tensioning Screw: A
This locks the upper receiver down instead of pushing it up like an accuwedge. With this in place, the upper and lower are rock solid and feel like one piece. It doesn't affect function, but definitely gives the rifle a nicer overall fit and finish feel. It does take a longer and requires tools to disassemble though. The primary drawback on reviews for it is the requirement of threadlocker on it. I found that teflon tape works just as well, and does not make the mess of threadlocker.
PSA LPK: ?
I got this with a package deal with the trigger from PSA. However since all the parts used in the build are non-standard, I didn't use a lot of the parts in the kit. The trigger guard, buffer pin, detents and springs, trigger pins, etc. were all not used due to the other parts I chose. I could have spent the same money and gotten nicer looking parts for the ones I did use, but that's just cosmetics. I did not rate the kit because I don't have anything to compare it to.
BCM charge handle: A
It's much easier and quick to charge using the left hand instead of the right. This charge handle feels like quality and has performed so.
BCM 18" 410SS 1-8 SPR Barrel: C-
I had all sorts of accuracy issues with this barrel and finally replaced it. Currently trying to send it back to BCM, but as I bought it new from a forum, I may be SOL as they require an order number. This barrel would occasionally pull and MOA group at best with the best ammo. However most of the time it was 1.5+ with good match ammo, which is unimpressive to say the least.
Douglas 18" stainless 1-7 CLE Barrel: B-
The jury is still out on this one, but it definitely shoots better than the BCM. With my handloads its .75-1 MOA and factory match is consistently MOA. I was hoping for better as factory semi-auto rifles can meet or exceed that, but I'm not dissappointed either.
I have noticed the barrel is not very smooth while cleaning it. As I pull or push a patch through, the force required is not consistent throughout the length of the barrel. I some spots, it seems looser than others. Likewise, velocities from this barrel are all over the place. 80ish FPS ES from reloads and match ammo with up to 300! FPS ES from FMJ ammo. This is a problem when shooting at range.
AAC Blackout Flash Suppressor: C
I wanted a flash suppressor instead of a brake since I tend to think brakes at the range are obnoxious. I picked this one because I'd like to mount a suppressor on it in the future and there are not make FS with a QD sound suppressor mount. There are many brakes with one however. I gave this a C because it makes an annoying ringing sound during firing and pretty much any time the rifle touches anything. It's basically a tuning fork. The CS at AAC when I called with a question was also not pleasant. It sounded like I was talking to a lawyer.
Troy Micro Tritium BUIS: C
I bought these based on recommendations from ARF and once again was disappointed. They are solid sights, and good for closer range shooting, but clearly not designed for a rifleman. There is no elevation adjustment on the rear sight. Instead, I have to turn the front sight post with a tool. Precision shooting with irons at range will instead require holdover. I got the tritium version because they were the same price as the regular where I got them. The front tritium works well, the rear tritium is useless because they are too close to the eye and just blur out. I find the front sight post exceedingly thick as well. Probably about 4 times as thick on target as my .062 NM front on my M1a. Part of it may be the tritium housing, and part may be because it's closer to my eye on the smaller rifle. In any case, I'm looking to replace them, maybe with KAC sights that actually have elevation adjustments.
Bobro Scope mount: A
This thing is solid and returns to zero when removed. Can't really ask more than that.
SWFA 1-6X24 HD: A-
This thing fits this rifle very well. The reticle is effective at 1X close range as well at 6X. Rare for a FFP scope, but they nailed it. If I could change anything, it would be to make the center dot slightly smaller, but that's about it. At 24 ounces, it's on the heavy side for what it is as well. I feel this scope should come around at 20 or under. The Leupold Mark 6 1-6 uses a larger 34mm tube and is only 18 ounces.
I figured I'd review these parts in case anyone was interested. If anyone has done a build of their own, please feel free to do the same.
Last edited:
