HK SL8 Conversion?

[Danimal247]

What's it take to convert an SL8 to something like this cosmetically?

Non-restricted status is great, but having a gun that looks like this is too cool

 

[mr_trout]

Wolverine supply has that top rail.
Dlask has the smaller rails for the hand guard.
sl8.de makes the folding stock for the SL8, but they no longer export them.

The sL8 sticky at the top of the black rifle page should have the details.

Edit: Also NEA mentioned the idea of a stock kit. I encourage all SL8 owners to let it be known that there is a market for such a product, especially since sl8.de and HERA are reluctant to sell to us.

 

[john@]

Also notice that the rifle pictured has a shortened gas system and a shorter thinner barrel. Probably from a G-36 K. If you cut down and re-contour the hbar from an SL-8 it can not be shorter than 18.5 inches, otherwise you've created a prohib. If you want the shorter barrel look, you need to replace the barrel with a factory made, either from a G-36 K or C. Those can be pricey.

 

[oenone]

Also notice that the rifle pictured has a shortened gas system and a shorter thinner barrel. Probably from a G-36 K. If you cut down and re-contour the hbar from an SL-8 it can not be shorter than 18.5 inches, otherwise you've created a prohib. If you want the shorter barrel look, you need to replace the barrel with a factory made, either from a G-36 K or C. Those can be pricey.

The gas system on the pictured rifle is not shortened. Do not kid yourself, it is just the hand-guard that is from the G36K. The rest of the barrel has just been profiled and shortened to 16 inches. All federal laws apply, it is your responsibility to know the legalities regarding the over-all and barrel length of the firearm.

 

[AJCrowley]

I've been going through this process myself recently. Be prepared to do a lot of searching for parts, and be prepared to sink a lot more money into your rifle.

You don't have to lose your non restricted status for this.

If you look at the picture, there's a home made grip and stock on it, I guess it depends how much of a perfectionist you are, but if you can find one, you're much better off getting a genuine H&K G36 lower. You can get a CNC machined aluminium adapter to attach the lower and your folding stock to. Avoid the cheap plastic ones, as they break, and the home made hacked together solutions never look quite right. Once you've got your aluminium adapter block and your lower, you'll need another push pin to attach the lower to the adapter, your stock, and a roll pin to attach the stock to the adapter block.

The rifle in the picture also has the G36K handguard with heat shield, I like these, since they expose the front of the gas system, which looks pretty good in my opinion.

Also worth considering is a G36E barrel - long enough to keep your non-restricted status, and usually comes with a flash hider and bayonet lug, and possibly a mag well adapter. Ideally, you could just get G36 mags, but they're a hard find, and pricey, you're better off going with the AR mag well adapter and just getting some P-Mags (plus you can then use the 10 round LAR15 mags).

I guess it's also worth mentioning the bolt carrier. If you get a G36 FBI lower, the trigger group is slightly different, and there's a piece that prevents the hammer from falling before the bolt has reset. This is for full auto, even though the FBI lower is semi auto only. You can take this piece out easily enough, or you can replace the bolt carrier. The bottom of the SL8 bolt carrier has two straight grooves on it, but the G36 version has a little sloping piece at the end of the groove that disengages the hammer lock when the bolt has reset and it's ready to fire again. I guess this part isn't important, since it's not critical to the function of the rifle in any mode but full auto, which we can't have, and if you just take the lock out (a matter of removing a single pin, taking it out, then replacing the pin, not exactly hard work), and it's not a visible part, I just thought it was worth noting.

Also, take a look at the stickied thread, there's a wealth of knowledge in there, and I think it's also worth mentioning the ESB2. This is not a standard part of either the SL8 or the G36, but is in my mind a very worthwhile piece of kit. One of the problems with these rifles is that there's no quick bolt release. When the bolt is locked back, the only way to unlock it is to pull back on the cocking lever, which isn't a very economical or fast way of doing it. The ESB2 just extends the bolt hold down a little into your trigger guard, so as well as pushing it up to lock the bolt back, you can push it down to release the bolt. If those paper targets are ever coming at you in volume and you need to change your clip, it could save you a valuable couple of seconds, and we all know how nasty paper cuts can be.

After typing this all out, it's occurring to me how much time I've spent researching, sourcing parts, and wincing at the sight of my bank balance.

Anyway, good luck, and be patient, these parts can all be had, but be prepared to work hard for them.

 

[Kevin M.]

Awesome gun, but be prepared to sink your time and money into it unless you buy a completed conversion off the EE.

Here is mine.

 

[john@]

Oops, you are correct on the gas system. Had to pull out my SL-8 to check, thought it was longer.

Now for the 16" barrel, I thought if you shorten a non-restricted barrel to less than 18.2 or something inches, that makes the rifle a prohib? In other words you can not make a restricted out of a non-restricted (WRT the barrel) unless you use factory made parts. Is that not correct?

The gas system on the pictured rifle is not shortened. Do not kid yourself, it is just the hand-guard that is from the G36K. The rest of the barrel has just been profiled and shortened to 16 inches. All federal laws apply, it is your responsibility to know the legalities regarding the over-all and barrel length of the firearm.

 

[CNADNSL8-5]

It's a US gun in the pic, so they go by the 16" rules. In Canada you can cut it no less than 18.5 inches (470mm) for a semi-auto center fire. To still be legal and restricted it can be originally manufactured less than 18.5.

 

[oenone]

I guess it's also worth mentioning the bolt carrier. If you get a G36 FBI lower, the trigger group is slightly different, and there's a piece that prevents the hammer from falling before the bolt has reset. This is for full auto, even though the FBI lower is semi auto only. You can take this piece out easily enough, or you can replace the bolt carrier.

You cannot replace the bolt carrier on an SL8 with anything other than the SL8 bolt carrier. You cannot use the G36 bolt carrier in the SL8 without modifying the receiver. Do not modify the receiver. You will go blind (it's a feature to prevent tampering unique to Heckler & Koch). If you get a replacement lower, from a G36 or whatever, always replace the entire G36 fire-control-mechanism with the SL8 mechanism. Semi or whatever group you get, replace the entire thing, all the pieces, especially the hammer, the fire selector, and the slide. And the catch-release is removed and never spoken of again.

The bottom of the SL8 bolt carrier has two straight grooves on it, but the G36 version has a little sloping piece at the end of the groove that disengages the hammer lock when the bolt has reset and it's ready to fire again. I guess this part isn't important, since it's not critical to the function of the rifle in any mode but full auto.

This part is very important, because it interfaces the bolt carrier with the hammer, releasing the hammer when the bolt is fully forward and locked (usually something else catches the hammer like the sear as well). It is not present on the SL8 because this is only necessary for the purpouses of dropping the hammer when the bolt-carrier is fully forward and the sear is not there to prevent premature hammer-release, as in the case of automatic fire.

In short, do not take short-cuts. Replace the entire trigger group with the one from your SL8. The only bolt-carrier that should be in your rifle is the one that is came with. Bolt-carriers do not wear, you should not have to replace them, so there is no excuse not to have your original bolt carrier in your rifle. Do not modify the receiver. Other than that, have fun, and enjoy your rifle!

 

[AJCrowley]

Good to know, thanks for the info oenone. Probably just as well that I didn't drop a bunch of money on a G36 bolt carrier.

I'm curious as to why it's important to replace the trigger group, as once the hammer lock is removed, it fits, and all things short of a test fire seem to indicate that it *should* work.

Referencing the literature that came with my lower, it says:

Further modifications are necessary in order to fit the SL8 internal parts in the lower (I do recommend replacement of ALL G36 parts, even the FBI lower as the hammer from the full auto G-36 is there and safeties are different).

So, I understand that it's worth replacing the trigger group, and I will do it, but I'm just curious as to why - the parts seem to fit together, the bolt does reset the hammer, and the hammer is striking the firing pin. I guess I was hoping to avoid having to drill that extra hole in my nice new lower.

 

[RaTa]

The problem with most conversions is that you end up with a LOP that is way too long which makes the rifle pretty unwieldy.

I'm a big fan of the Tbostic stock modification, it completely changes the feel of the rifle and keeps it inline with its target/precision setup.

 

[mrsmitty]

That is why you put a G36C stock on the rifle to make the length of pull very nearly the same as a standard G36

 

[RaTa]

That is why you put a G36C stock on the rifle to make the length of pull very nearly the same as a standard G36

Yea there is a collapsible option too but when I had my SL8 they were both pretty well impossible to find.

 

[oenone]

I guess I was hoping to avoid having to drill that extra hole in my nice new lower.

It is highly unlikely that you will find a G36 bolt-carrier, but if you do, I'd really like to check out what other things the source is selling.

Ok, I'm assuming that you have gone ahead and read this.

There has been a lot of discussion on whether you need to drill the 4th hole and install the locking lever. The general opinion is that you should do a 100% swap, meaning that you drill the hole and you install the pain-in-the-neck-to-install locking lever. This is ideal.

But what if you have no drill, or are lazy, or whatever? The locking lever, is, in my opinion, a vestigial part from the G36, that serves no purpose in the SL8. Sort of like your appendix. In the G36, it is required for bust mode. Nor the S-1 lowers, nor the S-1-F lowers have them, only the S-1-3-F lowers have them. Thus, I, and many other people, believe that the locking lever is not necessary. So I am five-nines sure that if you don't drill the hole, and you don't install the locking lever, but all your other parts especially the hammer, slide, & fire-selector are swapped with the SL8 and the catch-release is removed, you will have no problems. The catch-release engages the G36 hammer, but the SL8 bolt-carrier will not release it, so you should change that or you get a bolt-action firearm. The slide works with the fire selector to give you the two, three, or four positions in your lower.

If you just remove the catch-release and leave the rest of the lower as is, your lower will have all the positions except the safe be single-shot only. So you will have either S-1-1 or S-1-1-1. This can be a neat party trick at the range, but you don't want bubba calling the gendarmerie on you because he doesn't get it.

 

[TRG-42]

If you get a replacement lower, from a G36 or whatever, always replace the entire G36 fire-control-mechanism with the SL8 mechanism. Semi or whatever group you get, replace the entire thing, all the pieces, especially the hammer, the fire selector, and the slide. And the catch-release is removed and never spoken of again.

This part is very important, because it interfaces the bolt carrier with the hammer, releasing the hammer when the bolt is fully forward and locked (usually something else catches the hammer like the sear as well). It is not present on the SL8 because this is only necessary for the purpouses of dropping the hammer when the bolt-carrier is fully forward and the sear is not there to prevent premature hammer-release, as in the case of automatic fire.
QUOTE]


Actually you want to replace the SL-8 internals with the G36 FBI lower ( 2 position ) since all the G36 trigger groups ( except for the relatively rare factory DMR / Sniper version ) have horrible trigger pulls.

You can leave the FBI lower internals and you MUST remove the catch, not because of some leagality, but rather the gun will not fire since catch will not be released by the SL8 bolt carrier . This is the method I used on 2 of these builds.

You do not want a 3 position or 4 position ( burst ) because the SL-8 bolt will not trip catch as mentioned above and IF YOU REMOVE CATCH the rifle will get you thrown in jail . Not only is it obviously illegal, but also dangerous since there is nothing preventing firing out of battery. Since the sear will not catch the hammer, the hammer essentially follows the bolt home

Since everyone wants a 2 position lower, they are far more expensive than the 3 position...go figure. You can always buy a 3 position / 4 position burst and swap out internals with SL-8

Problem is selector marking does not line up. I prefer the clean way of using a full FBI 2 position lower

No reason not to since at the end of the day, the lower price is a small portion of the conversion cost

 

[TRG-42]

The problem with most conversions is that you end up with a LOP that is way too long which makes the rifle pretty unwieldy.

I'm a big fan of the Tbostic stock modification, it completely changes the feel of the rifle and keeps it inline with its target/precision setup.

You are bang on. Even with the shorter G36C stock it is still doesn't feel right

If you are not use to ARs with collapsible stocks you may never notice. If you are use to shooting with nose close to CH on an AR you still won't like the G36C stock. To exacerbate the situtation, the std SL-8 barrel is relatively heavy

This makes for a very unbalanced rifle. I have reprofiled / cut down SL-8 barrel and I would highly suggest you budget for that as well

On my person SL-8 trying hard to look like G36 I didn't bother. The only reason I have this rifle is for non restricted gopher shooting so it always wears a bipod anyways

 

[AJCrowley]

More great info.

Yes, the lower I have is the FBI (S-F) lower. I have removed the hammer lock (catch), as it seems to make no difference in the 2 position lower - the sear prevents the hammer from following the bolt home anyway, just as it does in the SL8 lower. The catch seemed more like a vestigial part of the full auto system, which this lower doesn't have anyway.

I'm going to play with it a little (when my G36C stock arrives at least), and figure out what works and what doesn't work. For now, I'm wondering if swapping the hammer out of the SL8 lower will be adequate, since that's the only part (so far as I can tell) that interacts with the rest of the rifle and is different, though the SL8 bolt seems to reset the hammer without issue. I haven't tried firing a live round yet, but it appears that the hammer should have no problem striking the firing pin.

Anyway, lots of good advice so far, and I appreciate it. I'm just going to try different configurations, and see what works best for me, it's just in my nature to tinker

 

[AJCrowley]

You are bang on. Even with the shorter G36C stock it is still doesn't feel right

This is actually something I was wondering about.

Because I'd heard of people cutting down their G36K stocks to be shorter, I figured I'd get around this by just getting a G36C stock. However, then I was worried that I'd made a mistake.

Let me start by clarifying my understanding of "length of pull", because if that's wrong, then my whole theory is shot, so please correct me if I am. Length of pull is the distance between your shoulder (where the butt sits), and the trigger - correct?

Anyway, if this is the case, then a proper adapter block should correctly replicate the LOP, as the lower and stock will sit in the same position they would on a G36, the only way the LOP would be changed (if you're using an original H&K lower and stock) is if the block that holds them together spaces them differently than a real G36, right?

The distance from the centre of the lower securing pin to the centre of the stock roll pin on my adapter (which seems like it should be the useful measurement in this case) is only 60mm, which should coincide pretty closely with a "true" G36, meaning that the LOP should be true.

Am I misunderstanding something here, or does the LOP issue not apply to my setup?

 

[CNADNSL8-5]

Using a stock block conversion will increase the LOP because the roll pin for the folding stock is about 1" farther back from the trigger. The SL8 receiver is longer than the G36 receiver.

 

[oenone]

Comparison of G36 length of pull vs. length of pull of an SL8 "stock-block" conversion:

The trigger lock numbers are exactly 2 cm across, so the SL8 conversion is roughly 2 cm longer than the G36. Note that the full-size stock is pictured. The C stock is about 2 cm shorter than the full size stock.