My Pseudo HK 243

[Bartok5]

Well, like many other black rifle aficionados here on CGN, I was very disappointed with the RCMP's decision to Prohibit the HK 243 on the grounds that it is simply too scary for Canadian public consuption. Figuring that where there's a will there must be a way, I started researching the various HK SL-8 conversions to more G36 styling. I wanted to stay non-restricted, which ruled out rebarrelling to a carbine configuration. That left me with the full-size G36E rifle to emulate. I didn't have the barrel re-profiled to a lighter weight, as the current match, heavy barrel is a real tack-driver and I didn't want to compromise the inherent accuracy by re-machining it. So, no bayonet lug and an overall heavier rifle than the genuine HK product. Albeit, with a match, MOA (or better) barrel capable of sustained fire due to its heavy profile. Not a bad trade-off.

I decided to go with a "Stock Block" conversion, which uses a new, machined aluminum receiver rear end to accept the unique SL-8 receiver closure method and the folding buttstock. This adds approximately 2" to the Length of Pull, which can be mitigated by using the 1" shorter HK G36C buttstock (which I did). The Stock Block conversion is the closest that you can come to a factory G36, aside from the actual receiver conversions done by Tom Bostik or "Chopstix Kid" in the USA wherein they graft a genuine G36 receiver stub onto your SL-8 receiver. I wasn't prepared to purchase a conversion of unknown quality off of Gunbroker for 3rd party importation, as there is no recourse if you buy a lemon. I also didn't want to try to wade through the paperwork required to ship my own SL-8 receiver to the States for conversion and return to Canada, nor did I want to wait 6 months to a year for the work to be done. This left me with the Stock Block conversion as the next best thing.

Most of the parts for the conversion came from 2 sources - HKParts.net in the USA, and RKS International out of Spain. The links are provided on page 1 of the SL-8 Conversion sticky at the top of this forum. The parts coming from the US have to go through a 3rd party importer, which drives up the price to almost double in the case of smaller parts. From Spain you are looking at long postage delivery timelines and expensive shipping charges. The cost of the parts themselves is pretty much the same between HKParts and RKS.

Enough chattter. Here are the pics:

Some food for thought, for those who had their heart set on an HK 243/G36. The Stock Block conversion process is not overly difficult and is completely reversible for those who might wish to return to the thumbhole stock (for some unknown reason). That said, it can be a lengthy undertaking not well-suited to those who are overly impatient. There is some minor sanding work required to the Trigger Housing in order to fit the SL-8 receiver, but that is pretty straightforward and is well-detailed in the sticky above. No special skills are required, although an understanding of how trigger mechanisms operate will be usefull when stripping and reassembling the trigger mechanism. Aside from all of that, the conversion process is not for the faint of wallet. The required parts are quite expensive to purchase and ship, which can be a bit much to bear on top of the $$ required to purchase a decent SL-8 base rifle for the conversion... But for those who must absolutely have something as close as possible to the G36, this is it. Short of a "Tom Bostik/Chopstix Kit" receiver conversion out the States, or one of the $10K+ genuine G36s floating around Canada, this conversion is as about as good as it gets. YMMV...

 

[Reaper of the apocalypse]

That's awesome. Two questions.

What was your total cost for the conversion including the price of the rifle?
What's it weighing in as configured in the pictures?

 

[vince514]

awesome job.

 

[Juster]

A great contribution, thanks!

 

[Bartok5]

I should have mentioned that the full-auto selector marking is purely cosmetic! The Trigger Housing is a polymer shell that holds the SL8 Trigger Group transfered over from the thumb-hole SL8 stock. When you do a Stock Block conversion you need a G36 Trigger Housing. You can get various pictogram markings on stripped G36 Trigger Housings from hklparts.net. I chose the 3-position markings for visual appeal and added authenticity. The painted symbols in no way alter the semi-auto function of the installed SL8 trigger mechanism....

 

[oenone]

Thank for sharing, it looks very nice.

I decided to go with a "Stock Block" conversion, which uses a new, machined aluminium receiver rear end to accept the unique SL-8 receiver closure method and the folding buttstock. This adds approximately 2" to the Length of Pull, which can be mitigated by using the 1" shorter HK G36C buttstock (which I did). . . . This left me with the Stock Block conversion as the next best thing.

The stock-block conversion renders the length-of-pull more appropriate for a Dinka warrior or a Dutchman due to the longer receiver on the SL8 as compared to the HK243 or G36:

(Image showing a "made in bedroom, just like you!" stock block conversion aligned with G36 receiver with G36 stock installed. Alignment is at the lower front push-pin hole and comparison point is the stock hinge. Approximately 2 cm of extra length are evident on the stock block conversion.)

The original G36 stock was also quite long, and in a sense even HK "admitted" that with the IDZ replacement stock:
26 cm original (not G36C length) vs. 23.5 cm (convex IDZ stock)/23 cm (concave IDZ stock) (fully extended):

(Image showing an original G36 stock aligned with a convex IDZ stock. A ruler is placed on top, with "0" aligned to the stock hinge. The fully extended IDZ stock measures to approximately 23.5 cm, while the original G36 stock measures to approximately 26 cm.)

Sadly, using a stock-block conversion severely limits the capability of SL8 to eject with the stock folded inwards.

I didn't have the barrel re-profiled to a lighter weight, as the current match, heavy barrel is a real tack-driver and I didn't want to compromise the inherent accuracy by re-machining it.

You have an AB date code SL8, which is likely one where the barrel nut was sealed with adhesive making removing your barrel without heating the chamber past boiling point very difficult and possibly terminal. So, in a sense you likely dodged a major head-ache with that decision.

The Stock Block conversion is the closest that you can come to a factory G36, aside from the actual receiver conversions done by Tom Bostik or "Chopstix Kid" in the USA wherein they graft a genuine G36 receiver stub onto your SL-8 receiver. I wasn't prepared to purchase a conversion of unknown quality off of Gunbroker for 3rd party importation, as there is no recourse if you buy a lemon. I also didn't want to try to wade through the paperwork required to ship my own SL-8 receiver to the States for conversion and return to Canada, nor did I want to wait 6 months to a year for the work to be done. . . . Short of a "Tom Bostik/Chopstix Kit" receiver conversion out the States, or one of the $10K+ genuine G36s floating around Canada, this conversion is as about as good as it gets. YMMV...

There are at least two people in Canada who can do the conversion, and at least one of them has performed the conversion on several SL8s. Finding them (should they want to be found) however is another story. There are also at least three "desporterized" (or is it "ergonomified"?) SL8's in Canada, which again, you would need to find and encourage their owners to sell them.

Where did you get the optic?

Oh, and nice AUG and HK G3/HK33/MP5 family rifle.

 

[Bartok5]

That's awesome. Two questions.

What was your total cost for the conversion including the price of the rifle?
What's it weighing in as configured in the pictures?

Reaper,

The all up cost of the G36 parts, Stock Block, and brokerage is approximately $1800 USD or $2300 CAD. I added it all up, and that's what it came to almost to the dollar. On top of that is the cost of having the barrel cut, crowned and threaded. Then you have the cost of the "donor" HK SL8 rifle, which costs $2100 CAD new, but can be had for around $1600 in excellent, used condition. So figure $2500 CAD for the conversion if you already have an SL-8, and $4600 CAD for a brand new rifle with conversion.

The basic weight of the SL-8 is 9 lbs. Add the aluminum Stock-Block at around 1 lb (very nicely machined, but chunky) and you are looking at 10 lbs. Heavy for a 5.6mm rifle, but the weight is mostly all in the barrel - the heart of the weapon and source of its accuracy. The way I have done the conversion, you basically still have a full-up match target rifle in G36 clothing. The Added weight of the stock block actually helps to balance out the front-heavy ergos of the SL8 due to its heavy match barrel.

If you were to swap the SL8 barrel for a true G36 barrel you would save approximately 1.5 lbs, but would add at least another $1000 (barrel cost) to your conversion - assuming that you have an early SL-8 which permits barrel swaps without the factory chamber-heating equipment. In order to get rid of the Stock Block (another lb), you have to find someone capable of performing major surgery - chopping off the back end of your SL8 receiver in order to graft on a genuine G3 receiver stub. That's assuming you can find someone skilled and trustworthy enough to chop your SL8 and seamlessly reassemble it by steel reinforcement, plastic welding, and autobody refinishing. Not to mention the trouble of finding a genuine Receiver Stub. HKparts is perennially sold out of those.

Oneone's post does a good job of pointing out the limitations of a stock-block conversion. The bottom line is that it is the best solution for me, not necessarily for you. G36 Conversions are on a sliding scale from the least expensive "Top Notch" all-in one lower receiver, to the full-up SL8 surgery. Figure another $1500 for someone to do all of that cutting and reassembly work, adding considerably to the overall conversion cost. At the top end of the scale are the handful of genuine G36 rifles and carbines floating around in Canada at the fabled $10K asking price. Below that are the chopped receiver conversions, worth about $6000 (and up). Next are the Stock-Blocks at about $4600 on a brand new SL8. Last are the "all in one" lower receiver kits such as the one manufactured by "Top Notch" (no longer in production) which cost around $500. Add one of those to a new SL8 and you are looking at a modest $2600 - assuming you can find a Top-Notch conversion.

I personally don't find the increased length of pull derived from a Stock Block to be overly long, but then I stood 6'2" when I still had legs. Indeed, the Stock Block LOP is still shorter than most of my "traditional" battle rifles (FNC1A1, G3, M14, AR-10). So it is really a matter of one's stature and personal taste. Aside from the HDPS Stock Block that is available through HKparts.net, HERA Arms also makes a Block that accepts ACR stocks. The ACR stock solves the longer length of pull that you get from a Stock Block conversion, but looks silly if you want the real G36 look. Instead, you are better off to use one of the G36 Retractable Stocks - either the IDZ version shown by Oneone, or the 4-position Collapsible, Folding G36 stock (which I have coming for another $350). Either style of G36 retractable stock will handily solve the Stock Block length of pull issue if you find it too long. As for the stock blocking the ejection port when folded, that is true of a Stock Block conversion. That said, I stopped firing my rifles with the stocks folded when I graduated high school...

Oneone:

My Hensoldt optic came from a private sale. They run about $400 if you can find one, but they are apparently pretty rare. You have a good eye picking up a few of the background "tell-tales" with my G3A3 and AUG. There are also an FNC1A1, M14, original AR10, Swissarms and Tavor hiding in there, among others.... ;-)

 

[Tiker]

Very nice. I had one thats converted just like your's. Bought it already converted off the EE. I think it was like $3600 or something.
Biggest problem I had with it is I just cant put up with the length of pull and also the height over bore of the optics really bugged me, so I got rid of it.

Really nice looking and good to have, but not practical imo.

 

[oenone]

The basic weight of the SL-8 is 9 lbs. Add the aluminium Stock-Block at around 1 lb (very nicely machined, but chunky) and you are looking at 10 lbs. Heavy for a 5.6mm rifle, but the weight is mostly all in the barrel - the heart of the weapon and source of its accuracy. The way I have done the conversion, you basically still have a full-up match target rifle in G36 clothing. The added weight of the stock block actually helps to balance out the front-heavy ergos of the SL8 due to its heavy match barrel.

The G36 original stock has a mass of about 290 grams, while the IDZ version goes over 500 grams. The IDZ stock may also help balance out the target barrel.

If you were to swap the SL8 barrel for a true G36 barrel you would save approximately 1.5 lbs, but would add at least another $1000 (barrel cost) to your conversion - assuming that you have an early SL-8 which permits barrel swaps without the factory chamber-heating equipment.

One cannot help but wonder if shooting a quick IDPA rifle match would provide sufficient heat to loosen the thread locking adhesive.

In order to get rid of the Stock Block (another lb), you have to find someone capable of performing major surgery - chopping off the back end of your SL8 receiver in order to graft on a genuine G36 receiver stub. That's assuming you can find someone skilled and trustworthy enough to chop your SL8 and seamlessly reassemble it by steel reinforcement, plastic welding, and autobody refinishing.

What kind of receiver grafting is this that it requires auto-body refinishing? A coat of duracoat or armacoat? Yes. Bondo or body filler or a nylon adhesive (Devcon II)? No. The nylon adhesive fails due to adhere due to the inherent oil in the receiver, so welding is the only way to go. Perhaps the necessity to sand down the welds so that the graft is imperceptible is what is referred to as "autobody refinishing".
The coat of duracoat is necessary due to the slight differences in tint between the receiver and the grafted end, or, if the receiver is a classic blue or grey receiver.

Not to mention the trouble of finding a genuine Receiver Stub. HKparts is perennially sold out of those.

Perhaps there is a firm in Canada that injection moulds stuff from glass-re-enforced nylon 66 or Zytel and would be interested in a pretty simple project?

Oenone's post does a good job of pointing out the limitations of a stock-block conversion.

Thanks!

I stopped firing my rifles with the stocks folded when I graduated high school...

What high school is this? It sounds like a great place to enrol an errant child.

My Hensoldt optic came from a private sale. They run about $400 if you can find one, but they are apparently pretty rare.

Yes, yes it is rare. And it is likely reaching its second decade. Which is why it caught the eye. From the 1999 SL8 manual:

Image showing a scan of page 40 of the HK SL8 manual dated to 1999. An image of an optical sight mounted on a rail on the receiver of the SL8 rifle taken from the left side is shown. It is captioned "Fig. 42 Optical sight". Above it is a section of text titled "Special purpose acessories" The only heading is "Optical sight". The text reads "Instead of the mechanical standard sight, the sight rail also accepts the 3 power optical sight available as a standard accessory." "The optical sight carries a reticle with range marks from 200 to 800 meters in 200-meter increments."

Image showing a scan of page 41 of the HK SL8 manual dated to 1999. An image of the reticle of the optical sight with numbers for all markings is presented. The image is captioned "Fig. 43 Reticle for optical sight". There is a list of descriptions corresponding to the numbered markings on the image below. It reads "1 200 meter lead mark*" "2 Circular reticle ⌀ 1.75 m at 300 meters distance" "3 Horizontal line to recognize whether the weapon is canted" "4 Lead mark appox. 400 meters" "5 Lead mark 400 meters" "6 Lead mark 800 meters" "7 man sized target of 1.75 m at range X" "*Weapon sighted in at 200 meters shoots 4cm high at 100 meters distance" "8 cm low at 300 meters distance"

It was the only accessory offered back then, item number 217 964. And instead of the proprietary receiver mountings that the carry handle optic mounts to, it mounts on a standard MIL-STD-1913 rail.
A historic artefact, one could say.