CA94 and clone plastic cocking lever support

[flashlightining]

Did you buy a standard MP5 cocking tube support or a .40/F model support? It is my understanding that the F cocking tube support is larger in diameter than a standard MP5 cocking tube support. Instead of having the detent and spring at the muzzle end with a fixed cocking handle the F support has a spring tensioned "L" shaped cocking handle.

Or maybe a little bit of weld were the cocking tube is welded to the receiver that has burned through. I'd take the end cap off and look through the cocking tube for any obstruction. The cocking tube support in my converted 94 is fairly snug. I have a CA89-40 and the plastic support is pretty sloppy. I need to get around to replacing it.

Scott

9mm, 10mm or 40 cal cocking lever support is the same for MP5A2/A3/SD, as per HK parts list part number 205906
MP5K takes part number 206423
thanks
scott

[flashlightining]

Are you measuring the cocking tube or the support? A factory new cocking tube I.D. varies between 0.727" and 0.730" (probably because they are extruded). After welding, I ream just past the welds to 0.730". A factory demilled cocking tube measures close to 0.734" in the reamed area.

I just miked the support and it turns out that it is 0.721" relatively true the length +/- 0.0005" and is 4.9960 in length.
Chopstix,
The 0.734" is ID of the tube?
thanks man
I am pretty sure that the 9mm, 10mm and 40 cal take the same support. It has the same part number in the HK manual....
thanks

[flashlightining]

chopstix,
I'm busting your pills man!! You're right.
flash, try to get your hands on an actual reamer in the size chopstix stated. If not, make one.......just have to be alittle creative!
Dj

Here's an idea....get some emery cloth and cut into a 3/4" strip about 6" long. Insert that into a bore cleaning rod and bend the emery in half wrapping it around the rod. Insert the rod in a drill and Insert wound up emery through the butt end of the GUN and into the tube.
Spin it up for a sec sliding up and down the tube and check, do this repeatedly until the support is still tight, but will cycle with the hand.

What do you guys thing about that?
Thanks for all your help and conversation.

[DJF]

flash,
Just make sure you have theat receiver clamped up really tight, You don't want'er to go for a ride!!
Sounds like it might work.....just be patient. ream, fit, ream, fit, ream, fit....you get the idea! A reamer will work alittle better because it cleans it out & also slightly re-sizes it/trues it!
Dj

[flashlightining]

flash,
Just make sure you have theat receiver clamped up really tight, You don't want'er to go for a ride!!
Sounds like it might work.....just be patient. ream, fit, ream, fit, ream, fit....you get the idea! A reamer will work alittle better because it cleans it out & also slightly re-sizes it/trues it!
Dj

where would I get the right size reamer?......0.73 there about...
thanks

[barfythebum]

Man, you can feel the suspense of this discussion! I'm really curious to find out how you do this, because I, too have a CA94SD and will eventually replace the cocking support. I would have just run a piece of emory cloth/sandpaper through the tube with a drill motor by now, but if you get a reamer, that would be the best. Good to know that the I.D. specs were off, and you don't have to sand down the HK support!

[Chopstix Kid]

I just miked the support and it turns out that it is 0.721" relatively true the length +/- 0.0005" and is 4.9960 in length.
Chopstix,
The 0.734" is ID of the tube?
thanks man
I am pretty sure that the 9mm, 10mm and 40 cal take the same support. It has the same part number in the HK manual....
thanks

Yup... but only up to where the welding stops. As mentioned, a brand new German MP5 tube has an I.D. variance of 0.727" - 0.730". I guage pinned a couple of German demills, and they come in at around 0.734" through to where the welds are.

I think we're splitting hairs. I've reamed the few that I have done so far to 0.730" with no binding problems. An additional 0.004" DIA is not going to change anything. Resonably, you could probably ream it as small as 0.727" annd still be good.

As for technique/method, if you do not have access to the correct size reaming shank (they are expensive) then you can try to find a resonably priced 12" drill bit at the correct size. Which ever you use, I would do it by hand as the walls are thin and of you dont get it centered well, you don;t want to run the chance of side cutting through the wall of the tube.

[jason934]

I just finished my CA89 SD's HK cocking tube and it was a b*tch! About 2 hours of grinding and finessing back and forth but finally got it. Much improved feel and I no longer get the hesitation on the return. With this mod I have now replaced every moving part of the SD with HK/RCM parts, with the exception of the rear sight assy. Gun runs great now, lost count of how many rounds I've gone without a failure, but at least 10 50rnd boxes. Here's to another 10.

CA Plastic and HK side by side:

[flashlightining]

As for technique/method, if you do not have access to the correct size reaming shank (they are expensive) then you can try to find a resonably priced 12" drill bit at the correct size. Which ever you use, I would do it by hand as the walls are thin and of you dont get it centered well, you don;t want to run the chance of side cutting through the wall of the tube.

A 12" bit would not be quite long enough, will have to use a extension that does not have a large attaching shank.
thanks

[flashlightining]

I just finished my CA89 SD's HK cocking tube and it was a b*tch! About 2 hours of grinding and finessing back and forth but finally got it. Much improved feel and I no longer get the hesitation on the return. With this mod I have now replaced every moving part of the SD with HK/RCM parts, with the exception of the rear sight assy. Gun runs great now, lost count of how many rounds I've gone without a failure, but at least 10 50rnd boxes. Here's to another 10.

CA Plastic and HK side by side:

Since you have them there to compare like I did, their diameters are slightly different even seen without miking them....