The SL8 Mods, Info and FAQ Thread

I am an SL8-5 owner & new to this site. I will try to describe a very unusual problem I have been having with the gun at the range for the last few weeks.

Prior to going to the range, I disassembled the gun & cleaned & lubricated it as much as possible. The next day, at the range, I used American Eagle & Winchester .223 55 grain cartridges & shot 2 boxes (40 rounds) without any incident. I did rest in between so as not to overheat the gun. for your info I have 2 sets of the HK 5 cartridge holder mags.

However, it started jamming after that & what I & the range warden discovered was unusual. It seems like the reason the gun jams is because it literally slices the shot cartridge in half around the waist (halfway) & ejects only the lower portion of the cartridge. The top portion somehow gets stuck in the chamber & when a new cartridge is inserted into the chamber to be shot, it gets stuck inside the previously sliced upper portion of the cartridge. It's almost like the fresh cartridge is wearing the sliced cartridge like a sweater. This resulted in the gun to malfunction & jam. after ejecting the jammed cartridge, when I insert a new mag, it will shoot a couple & jam again.

The other thing I almost forgot to mention was that when we picked up most of the spent cartridges, almost all seem to have a mark around the waist showing a line where the cut seems to be happening.
I did take pics of the cartridges & sent an email to H&K Repair Department to show them what's happening. Unfortunately, since I am new to this forum, I still don't know how to attach the pics to my message. When & if I do, I will surely post it to show you guys.

I can't figure out how & why this is happening & a few of the guys at the range were also baffled by this. Almost all claimed that they have never seen anything like this. Considering the reputation of the SL-8 rifles, I am at a loss as to why this is happening

I very much appreciate any input on this matter, or if any one has encountered a similar situation.
 
Glad to see you found us. :) If you like you can email me the pics you sent to HK and I can post them here. (I'll send you a PM) Or you can use photobucket or imageshack to link pics to. I hope someone here can help with the problem. I have never heard of this type of issue before.
 
First off, which bolt head are you using? SL8 bolt head or G36 bolt head? I know firsthand that if you use an SL8 bolt head with double stack magazines you will damage the rounds and possibly you and the rifle. The Sl8-1 bolt head is missing an extra lug so that you can't use doublestack mags(damages the rounds when trying to feed) hope this helps somewhat.
 
Paletiger13 said:
First off, which bolt head are you using? SL8 bolt head or G36 bolt head? I know firsthand that if you use an SL8 bolt head with double stack magazines you will damage the rounds and possibly you and the rifle. The Sl8-1 bolt head is missing an extra lug so that you can't use doublestack mags(damages the rounds when trying to feed) hope this helps somewhat.
Click to expand...

IF you are in Canada or the rest of the world, you can ignore this completely. Single-stack bolts in the SL8 is something only found in the United States.

In any case, I am strongly of the opinion that this is an ammunition problem, where the casing is rupturing. Have you tried other ammunition?

There should be nothing in the chamber that could cause a ring of stress around the brass as you describe, unless this has been an ongoing thing where there is a ring of carbon built up in the spot that causes shear stress on the brass upon firing. But brass is soft and I am at a loss to imagine such a thing.

I would clean the firearm and especially the chamber, and try some different ammunition.
 
Anybody knows where I can find a Harris bipod swivel stud that would fit in the SL8 handguard threads? There is one available at Fabsports but it is for YHM handguards and I'm not quite sure it will fit.

Thanks

YHM-262.jpg
 
considering doing a SL8-G36C conversion in the near future:

Question:

- Is there a mag well made to fit the SL8 receiver that will accept G36 mags? I am looking for something like the one that was just offerred recently that will take AR mags. I know that G36 mag well do not interface with the SL8 receiver.....this is true only if no modifications are made to the notch in the SL8 receiver....correct?
 
rajczak_kashka said:
I know that G36 mag well do not interface with the SL8 receiver.....this is true only if no modifications are made to the notch in the SL8 receiver....correct?
Click to expand...

The G36 magwell fits just fine to the SL8. For the entire world, except the US which were hit with a rather silly set of laws regarding magazines and importation, there is no difference between the G36 and SL8 mag well.

There are two tabs that restrict using the G36 mags in the SL8 receiver that just need to be removed to allow the use of the longer mags. 10 min with a small chisel and you're done:D.

PM me if you want and I'll send you some pic of where but I believe the info is already in this thread.

Edit: I had some extra time and was able to dig up this pic of after the dremel and before I finished up with the chisel to leave a clean shiny finish. If I where to do it again I'd just use the small chisel... it's easier and has more control with a better finish.

PC090378.jpg
 
coldupnorth said:
Anybody knows where I can find a Harris bipod swivel stud that would fit in the SL8 handguard threads? There is one available at Fabsports but it is for YHM handguards and I'm not quite sure it will fit.

Thanks

YHM-262.jpg
Click to expand...

A harris #2 bipod adapter will work on an SL8 handguard. It will also thread into the factory screw holes on the handguard for the accessory rail. The have the same thread.

Do you know the thread pitch of the YHM stud? If you can find the thread pitch for the harris adapter or the handguard you can see if they match the YHM.

I don't have that info on me right now.
 
Magazine catch installation

I was asked about an easy way to install a magazine catch and this is what I came up with. Thought I'd share it.

I cut a 5/32 drill bit so it was the same lenght as the magazie catch.

I then put the spring in the catch and put the cut down bit through the catch and spring. (This holds the spring in place and keeps the spring lined up with the holes when you put it in place in the reciever.)

Put the catch in place in the reciever and line up the holes in the reciever with the catch.

Then put the factory pin through the reciever hole and drive it right through to the other side. This will push out the drill bit while keeping the spring in place.

Keep the pin hand for the next time you need it.

DSCN2292.jpg
 
CNADNSL8-5 said:
A harris #2 bipod adapter will work on an SL8 handguard. It will also thread into the factory screw holes on the handguard for the accessory rail. The have the same thread.

Do you know the thread pitch of the YHM stud? If you can find the thread pitch for the harris adapter or the handguard you can see if they match the YHM.

I don't have that info on me right now.
Click to expand...

Thanks for the info. I just checked the thread pitch on the SL8 handguard and it is M5X0.8. I'll try to find out the pitch on the YHM stud, hopefully it is the same (cheaper!!!). If not, I'll just get a #2 adapter.
 
CNADNSL8-5 said:
I was asked about an easy way to install a magazine catch and this is what I came up with. Thought I'd share it.

I cut a 5/32 drill bit so it was the same lenght as the magazie catch.

I then put the spring in the catch and put the cut down bit through the catch and spring. (This holds the spring in place and keeps the spring lined up with the holes when you put it in place in the reciever.)

Put the catch in place in the reciever and line up the holes in the reciever with the catch.

Then put the factory pin through the reciever hole and drive it right through to the other side. This will push out the drill bit while keeping the spring in place.

Keep the pin hand for the next time you need it.
Click to expand...

Thanks for that! I spent an hour getting the bloody thing to reinstall. It was horrible. Will make sure to use your method next time.
 
guys, whats the favorite handguard??? I spent the money on the rails and gave them to a machinist so he could size and build me an adaptor for my TRG bipod.... F***er has fallen off the map. Thinking about just going with a whole new "pretty" handguard rather than buy the rails again. what kind of experience have you had?
 
The B&T RAS and the KAC RAS both have rails that cover all 4 sides. Both are high quality and expensive. Or you can get longer aftermarket rails to fit the factory handguard. The aftermarket rails are much less expensive than the factory HK rails.
 
I actually far prefer the stock handguard. It's easier on the hands and has all the mounting points required. Plus it maintains the 'look'. I haven't come across an aftermarket fore end that maintains the essence or function than that or the original.

Just an opinion though:D
 
incorrigible said:
I actually far prefer the stock handguard. It's easier on the hands and has all the mounting points required. Plus it maintains the 'look'. I haven't come across an aftermarket fore end that maintains the essence or function than that or the original.

Just an opinion though:D
Click to expand...

I like the stock handguard because it very nicely integrates a bipod. Sure, one could mount a bipod on rails, but that would be an uglier solution to the very nice proprietary low-drag HK solution.
 
We are getting close to the point where we are going to run a new lower for the SL8 that will allow it to take AR grips.

One of the ideas we are tossing around is to make the stock adapter modular, like the XCR. That way it can be made to take the new folder system we are launching for the XCR, 858 and 870, which would allow the installation of a folding AR or Skelleton stock.
 
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