I thought some ppl might like to read about these products now that they can be readily had by Canadian shooters. First off, let's look at the HERA ARMS Gen 2 lower being sold by Wolverine (and possibly others?).
This photo shows the lower with the fire control group installed. The lower is designed to accept the SL8 fire control group, but and semi-only G36 assembly should also fit. What might not be obvious before you order is that it is actually assembled from two halves that are clam-shelled together and secured with hidden recessed socket head cap screws. You might ask why this was necessary with modern CNC machinery, and I would counter that I believe it is because the lower is made of aluminum (I think it's 6061-T6) and the fire control group pin holes are re-enforced by machined re-cesses inside the lower with hardened steel liners pressed in to ensure the pins never egg out. Nice touch, and not really doable unless the lower was made in halves and later mated together as HERA has done.
Now another problem the first batch of Gen2 lowers had is that the inletting for the ACR stock was not machined properly and owners had to modify (file material off) the top of the ACR stock tang to get it to fit into the lower. It looks like either Hera (or Wolverine?) listened to these early complaints and my lower came refitted by milling away enough material that the ACR stock was a drop-in fit. It's clear this was done post-manufacture as the anodizing was removed and the milling cuts colored with black marker to re-darken them. It's in an area that's invisible when assembled, so not much of an issue.
Another design choice is that because the parts were mated after anodizing, the screw hole for the pistol grip is fresh-cut aluminum owing to tapping only being possible post-assembly. I expect HERA desided it would be too expensive to assemble the lowers, tap this hole, then disassemble them to send off to anodizing. That this means is that the threading may be on the soft side, so do not over-torque the grip screw. Instead use a drop of blue loctite when you are ready to do final assembly of the pistol grip. I feel HERA should add this to the install manual, which while pretty and in color, is lacking (at least in English?).
You do have to remove the recoil buffer plate and buffer from your SL8 and re-use it in the HERA lower. The manual makes NO MENTION of this fact, it only alludes to the white rubber buffer being removable with a pair of needle nose pliers. This is true, but totally useless information since you should not remove the buffer. The whole plate has to come out and is moved over with the buffer in place. So take note - don;t flog your old SL8 stock while you wait for your HERA lower to arrive unless you remove the buffer assembly first!
Next, there is some marketing smoke and mirrors from HERA with respect to the grip. Ad copy claims that any AR grip will fit. A true-er statement would be that most AR grips can be MADE TO FIT. Hera grinds part of the MOE grip tail off and mills out some of the inside of the grip so the selector piston has room to travel. In a G36 or SL8, the piston goes into a hollow in the lower, but the HERA does not have an integrally moulded pistol grip so this mod is necessary to provide clearance. It looks to me like they did mine after quite a few Schnapps with a dull dremel gouge, but it's serviceable and not visible when assembled. In this photo I already cleaned it up a little with a file, it was sloppier before.
At this point I need to mention the ACR stock. When you google ACR and HERA, a few internet posts will advise you that there is a rubber buffer plug in the tip of the ACR stock and people talked about cutting it off, pulling it out with needle nose pliers, etc. All of these answers are WRONG. I'm ashamed to admit I stupidly tried to pull it out with pliers and bunged up the buffer a little before I applied rational thought to the problem, thank goodness I was going to bin that part anyhow. In this photo you will see a small roll pin below the bushed hole in the ACR stock tang. If you drift this pin out, the rubber buffer will virtually fall out the front of the stock. A small but important piece of advice
Here we see the HERA trigger guard next to an SL8 trigger guard (actually a PSG-8 lower, but it's the same stock forward of the pistol grip). Note the trigger guard on the HERA lower is wider. This will become important later below.
Next, here we see the HERA lower with the SL8 FCG installed. Be forewarned - the HERA manual "borrowed" pictures from the internet to make their instruction manual. I have great eyesight and these tiny pictures just do not have enough detail to assist anyone who has never installed (or removed) an SL8 or G36 fire control group. Seriously. It's that useless. I would suggest you maybe take pictures first if you aren't confident assembling a G36 trigger group - and how it goes together is WAY less obvious than, say, an AR15 fire control group.
I found this by accident after I had done mine (I had worked on a couple G36's before and WISH I had found this website my first go-around!), but here is the site HERA "borrowed" their SL8 FCG photography from. The pictures here are click-able and are actually helpful when blown up.
http://alpinetek.netfirms.com/guns/SL8/breakdown/
Now we move onto installing a SPUHR G36 magazine well adaptor. Why am I discussing the SPUHR? Well, if you are just installing it on a stock G36, jump to the end and ignore the next few paragraphs. If you have an SL8, or even better yet, an SL8 with a HERA lower, read on. THE SPUHR UNIT IS DESIGNED FOR A G36 - NOT AN SL8. It can be easily made to work with an SL8, but it is not really a drop-in fit if you want reliable action cycling. That being said, having now tried the old RKS adaptor, the NEA adaptor and now this adaptor (I have not yet seen an HK416 adaptor in the flesh), I can say the Spuhr adaptor, once fitted, is the single best upgrade I have ever seen for the SL8 rifle. But I digress...
Now here is the first challenge you will face with the HERA lower. When you install everything for the first time, it will *almost* all line up, but the push pin will not go in. You will scratch your head. Except you won't because you read this article first REMEMBER it is made for the G36 with a fixed pistol grip and trigger guard that is much narrower than the HERA trigger guard and the interference prevents the magazine well from seating the last 1 or 2 milimeters.
The fix is some light filing on the SPUHR adaptor (not the anodized aluminum lower) until it fully seats. On my spuhr, I also had to file the casting flashing line off the inside of the round hooks at the front of the adaptor so it would seat a few thou further forward as well.
Next thing to note is that to ensure reliable bolt hold-open, you need to use the included SPUHR extended/tactical magazine release. This thing is how the G36 mag release should always have been made. A truely excellent upgrade to the SL8 that would be at home even if you did not buy the mag adaptor. That being said, it is flawed for the SL8 as-received. Both the SL8 AND Hera lower have the same dimensions at the front of the lower and a G36 has SLIGHTLY more clearance. So if you install this bolt hold-open without modifying it, you will have to really come on to to the lower receiver to get the push-pin holes lined up. It is not the lower's fault - what is actually happening is the SPUHR bolt holdopen is pushing on the underside of the bolt. In some cases, the BHO might actually catch the bolt lugs when dry-cycling if you get the pin forced in. In all cases I have seen (3 guns), the BHO at a minimum pushes hard on the underside of the bolt carrier slowing it's cycling and making the gun cycle rougher in general.
The fix is pretty simple. there is a slant section of the anodized aluminum portion of the bolt release that sits inside the front of the lower receiver. This slant section bottoms out in the lower limiting its downward travel (upward travel is limited by the BHO retention pin that also serves as the hammer spring pin). Once you trial fit the extended bolt release, aggresively work it up and down in the lower a few times. Do this BEFORE installing the trigger, sear and hammer assemblies because you will be taking the BHO out a few times to trial fit it. Take the BHO back out and observe where it is hitting the front of the slit in the lower it passes through into the trigger bow. This area needs to be releived between 1 and 2mm with a small round file. The idea is you want the bolt holdopen to sit about 1mm lower when not engaged by an empty magazine. Go slow and trial fit this a few times - remember you can't put material back onto the BHO! Once the lower will fully close on the receiver WITH THE BOLT CARRIER IN, cycle the action slowly a few times to ensure the BHO is not dragging along the underside of the bolt carrier. It only has to clear it by a few thou. Once you are in the clear, finish assembling the lower and re-assemble the rifle. You're ready to go!
The Spuhr adaptor is made of similar material to the SL8 upper and is very light. Since it's molded, there is a minimum of material used to provide a sturdy part. Also, the ambidextrous mag release is ingeniously designed and 100% reliable on both sides of the magazine well. The BHO, once fitted, works 100% of the time on all mags I tried, to include Gen 1 and Gen 2 Pmags, LAR15 mags and USGI Okay Industries mags. The down side is that it costs twice as much as any of the aluminum offerings.
Oh, and in case anyone was wondering - yes, you can fold your ACR stock with this setup and still get reliable ejection.
My closing thoughts on this setup as I transition away from a PSG-8 lower. I REALLY like the quick LOP adjustment. The cheek piece ended up in the same plane as my PSG or SL8 stock with the factory cheek piece and one riser spacer when in the raised position which is perfect for me using TPS High rings and a 30mm tube 50mm objective lens scope. I use this gun from a bipod for target work and I wanted adjustable LOP to accommodate winter clothing, while the folding stock makes this already big rig fit a MUCH smaller range bag. I believe though, that someone looking for a G-36-ish conversion project who cuts the bbl to 18.5 and re-contours to a G36E profile would equally love this rig. It is genuinely a better stock arrangement than any of the OEM G36 folders.
Now for the CONS:
1) HERA needs to teach their G-code man about contouring. The edges below the selector and around the trigger guard circumference are basically unbroken edges and are un-necessarily sharp. One extra operation with a radius cutter on some of these edges would have dramatically improved the end product.
2) HERA needs to re-write their manual. Period. Less gloss, more content.
3) the front pin hole on the HERA should copy the SL8 lower pin hole layout. The HERA pin hole design is not the same and on my rifle, as a result, required a few file strokes to properly line up the push pin without having to resort to the rubber mallet to install it. If they had copied the SL8 pin hole layout with one hole more oblong than the other, this would not have been an issue.
4) SPUHR should redesign their BHO with more clearance on the forward underside edge so that it works equally well in an SL8 and a G36 without needing to be relieved. This is a minor complaint really, but not everyone will apply the proper fix. Some people will just notice their SL8 jams more due to bolt drag and not be able to figure out why. Or maybe they will go back to the stock BHO and live without the BHO feature, while 30 seconds with a file could remedy their issues. This is not only a HERA lower issue, I had the same problem when I trial fitted it in a stock SL8 lower.
This photo shows the lower with the fire control group installed. The lower is designed to accept the SL8 fire control group, but and semi-only G36 assembly should also fit. What might not be obvious before you order is that it is actually assembled from two halves that are clam-shelled together and secured with hidden recessed socket head cap screws. You might ask why this was necessary with modern CNC machinery, and I would counter that I believe it is because the lower is made of aluminum (I think it's 6061-T6) and the fire control group pin holes are re-enforced by machined re-cesses inside the lower with hardened steel liners pressed in to ensure the pins never egg out. Nice touch, and not really doable unless the lower was made in halves and later mated together as HERA has done.
Now another problem the first batch of Gen2 lowers had is that the inletting for the ACR stock was not machined properly and owners had to modify (file material off) the top of the ACR stock tang to get it to fit into the lower. It looks like either Hera (or Wolverine?) listened to these early complaints and my lower came refitted by milling away enough material that the ACR stock was a drop-in fit. It's clear this was done post-manufacture as the anodizing was removed and the milling cuts colored with black marker to re-darken them. It's in an area that's invisible when assembled, so not much of an issue.
Another design choice is that because the parts were mated after anodizing, the screw hole for the pistol grip is fresh-cut aluminum owing to tapping only being possible post-assembly. I expect HERA desided it would be too expensive to assemble the lowers, tap this hole, then disassemble them to send off to anodizing. That this means is that the threading may be on the soft side, so do not over-torque the grip screw. Instead use a drop of blue loctite when you are ready to do final assembly of the pistol grip. I feel HERA should add this to the install manual, which while pretty and in color, is lacking (at least in English?).
You do have to remove the recoil buffer plate and buffer from your SL8 and re-use it in the HERA lower. The manual makes NO MENTION of this fact, it only alludes to the white rubber buffer being removable with a pair of needle nose pliers. This is true, but totally useless information since you should not remove the buffer. The whole plate has to come out and is moved over with the buffer in place. So take note - don;t flog your old SL8 stock while you wait for your HERA lower to arrive unless you remove the buffer assembly first!
Next, there is some marketing smoke and mirrors from HERA with respect to the grip. Ad copy claims that any AR grip will fit. A true-er statement would be that most AR grips can be MADE TO FIT. Hera grinds part of the MOE grip tail off and mills out some of the inside of the grip so the selector piston has room to travel. In a G36 or SL8, the piston goes into a hollow in the lower, but the HERA does not have an integrally moulded pistol grip so this mod is necessary to provide clearance. It looks to me like they did mine after quite a few Schnapps with a dull dremel gouge, but it's serviceable and not visible when assembled. In this photo I already cleaned it up a little with a file, it was sloppier before.
At this point I need to mention the ACR stock. When you google ACR and HERA, a few internet posts will advise you that there is a rubber buffer plug in the tip of the ACR stock and people talked about cutting it off, pulling it out with needle nose pliers, etc. All of these answers are WRONG. I'm ashamed to admit I stupidly tried to pull it out with pliers and bunged up the buffer a little before I applied rational thought to the problem, thank goodness I was going to bin that part anyhow. In this photo you will see a small roll pin below the bushed hole in the ACR stock tang. If you drift this pin out, the rubber buffer will virtually fall out the front of the stock. A small but important piece of advice
Here we see the HERA trigger guard next to an SL8 trigger guard (actually a PSG-8 lower, but it's the same stock forward of the pistol grip). Note the trigger guard on the HERA lower is wider. This will become important later below.
Next, here we see the HERA lower with the SL8 FCG installed. Be forewarned - the HERA manual "borrowed" pictures from the internet to make their instruction manual. I have great eyesight and these tiny pictures just do not have enough detail to assist anyone who has never installed (or removed) an SL8 or G36 fire control group. Seriously. It's that useless. I would suggest you maybe take pictures first if you aren't confident assembling a G36 trigger group - and how it goes together is WAY less obvious than, say, an AR15 fire control group.
I found this by accident after I had done mine (I had worked on a couple G36's before and WISH I had found this website my first go-around!), but here is the site HERA "borrowed" their SL8 FCG photography from. The pictures here are click-able and are actually helpful when blown up.
http://alpinetek.netfirms.com/guns/SL8/breakdown/
Now we move onto installing a SPUHR G36 magazine well adaptor. Why am I discussing the SPUHR? Well, if you are just installing it on a stock G36, jump to the end and ignore the next few paragraphs. If you have an SL8, or even better yet, an SL8 with a HERA lower, read on. THE SPUHR UNIT IS DESIGNED FOR A G36 - NOT AN SL8. It can be easily made to work with an SL8, but it is not really a drop-in fit if you want reliable action cycling. That being said, having now tried the old RKS adaptor, the NEA adaptor and now this adaptor (I have not yet seen an HK416 adaptor in the flesh), I can say the Spuhr adaptor, once fitted, is the single best upgrade I have ever seen for the SL8 rifle. But I digress...
Now here is the first challenge you will face with the HERA lower. When you install everything for the first time, it will *almost* all line up, but the push pin will not go in. You will scratch your head. Except you won't because you read this article first
REMEMBER it is made for the G36 with a fixed pistol grip and trigger guard that is much narrower than the HERA trigger guard and the interference prevents the magazine well from seating the last 1 or 2 milimeters.
The fix is some light filing on the SPUHR adaptor (not the anodized aluminum lower) until it fully seats. On my spuhr, I also had to file the casting flashing line off the inside of the round hooks at the front of the adaptor so it would seat a few thou further forward as well.
Next thing to note is that to ensure reliable bolt hold-open, you need to use the included SPUHR extended/tactical magazine release. This thing is how the G36 mag release should always have been made. A truely excellent upgrade to the SL8 that would be at home even if you did not buy the mag adaptor. That being said, it is flawed for the SL8 as-received. Both the SL8 AND Hera lower have the same dimensions at the front of the lower and a G36 has SLIGHTLY more clearance. So if you install this bolt hold-open without modifying it, you will have to really come on to to the lower receiver to get the push-pin holes lined up. It is not the lower's fault - what is actually happening is the SPUHR bolt holdopen is pushing on the underside of the bolt. In some cases, the BHO might actually catch the bolt lugs when dry-cycling if you get the pin forced in. In all cases I have seen (3 guns), the BHO at a minimum pushes hard on the underside of the bolt carrier slowing it's cycling and making the gun cycle rougher in general.
The fix is pretty simple. there is a slant section of the anodized aluminum portion of the bolt release that sits inside the front of the lower receiver. This slant section bottoms out in the lower limiting its downward travel (upward travel is limited by the BHO retention pin that also serves as the hammer spring pin). Once you trial fit the extended bolt release, aggresively work it up and down in the lower a few times. Do this BEFORE installing the trigger, sear and hammer assemblies because you will be taking the BHO out a few times to trial fit it. Take the BHO back out and observe where it is hitting the front of the slit in the lower it passes through into the trigger bow. This area needs to be releived between 1 and 2mm with a small round file. The idea is you want the bolt holdopen to sit about 1mm lower when not engaged by an empty magazine. Go slow and trial fit this a few times - remember you can't put material back onto the BHO! Once the lower will fully close on the receiver WITH THE BOLT CARRIER IN, cycle the action slowly a few times to ensure the BHO is not dragging along the underside of the bolt carrier. It only has to clear it by a few thou. Once you are in the clear, finish assembling the lower and re-assemble the rifle. You're ready to go!
The Spuhr adaptor is made of similar material to the SL8 upper and is very light. Since it's molded, there is a minimum of material used to provide a sturdy part. Also, the ambidextrous mag release is ingeniously designed and 100% reliable on both sides of the magazine well. The BHO, once fitted, works 100% of the time on all mags I tried, to include Gen 1 and Gen 2 Pmags, LAR15 mags and USGI Okay Industries mags. The down side is that it costs twice as much as any of the aluminum offerings.
Oh, and in case anyone was wondering - yes, you can fold your ACR stock with this setup and still get reliable ejection.
My closing thoughts on this setup as I transition away from a PSG-8 lower. I REALLY like the quick LOP adjustment. The cheek piece ended up in the same plane as my PSG or SL8 stock with the factory cheek piece and one riser spacer when in the raised position which is perfect for me using TPS High rings and a 30mm tube 50mm objective lens scope. I use this gun from a bipod for target work and I wanted adjustable LOP to accommodate winter clothing, while the folding stock makes this already big rig fit a MUCH smaller range bag. I believe though, that someone looking for a G-36-ish conversion project who cuts the bbl to 18.5 and re-contours to a G36E profile would equally love this rig. It is genuinely a better stock arrangement than any of the OEM G36 folders.
Now for the CONS:
1) HERA needs to teach their G-code man about contouring. The edges below the selector and around the trigger guard circumference are basically unbroken edges and are un-necessarily sharp. One extra operation with a radius cutter on some of these edges would have dramatically improved the end product.
2) HERA needs to re-write their manual. Period. Less gloss, more content.
3) the front pin hole on the HERA should copy the SL8 lower pin hole layout. The HERA pin hole design is not the same and on my rifle, as a result, required a few file strokes to properly line up the push pin without having to resort to the rubber mallet to install it. If they had copied the SL8 pin hole layout with one hole more oblong than the other, this would not have been an issue.
4) SPUHR should redesign their BHO with more clearance on the forward underside edge so that it works equally well in an SL8 and a G36 without needing to be relieved. This is a minor complaint really, but not everyone will apply the proper fix. Some people will just notice their SL8 jams more due to bolt drag and not be able to figure out why. Or maybe they will go back to the stock BHO and live without the BHO feature, while 30 seconds with a file could remedy their issues. This is not only a HERA lower issue, I had the same problem when I trial fitted it in a stock SL8 lower.
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