[DKL]

Does anyone know (have you tried and it worked) if a SP89 trigger group will "drop in" (just remove pins on factory SP5K, remove HK SP5K trigger group, and install SP89 group, pins back in, shoot)? Further, has anyone used a clipped and pinned MP5K compatible clone trigger group in their SP5K yet? I have done a search and got several bits of intel but wanted to know if/who has actually done and any issues if can be done as simple drop in as I am considering purchasing the SKU HKP16442 from HKParts for my SP5K SBR. Thanks

 

[bystok]

SP89 housing is clipped different than the SP5K.....need a housing that fits the SP5K shelf.......a SEF or Ambi pack from your SP89 will work fine, it is the housing that must be clipped to fit the SP5K

 

[DKL]

SP89 housing is clipped different than the SP5K.....need a housing that fits the SP5K shelf.......a SEF or Ambi pack from your SP89 will work fine, it is the housing that must be clipped to fit the SP5K

Thanks!

 

[F0x_hound]

I noticed this to I have both sp89 and sp5k , cannot get it to fit the Hk sp5k the sef grooved trigger housing .
A lot of modification is needed to the grip .
A lot of small things Hk changed to the sp5k
Hkparts is coming out with a sp5k sef trigger housing specifically for it .
Trigger pack is also different .

 

[Slaine777]

Slightly related question, MP5K uses small push pins all around, including the top of the end cap, correct?

 

[retrodog]

I noticed this to I have both sp89 and sp5k , cannot get it to fit the Hk sp5k the sef grooved trigger housing .
A lot of modification is needed to the grip .
A lot of small things Hk changed to the sp5k
Hkparts is coming out with a sp5k sef trigger housing specifically for it .
Trigger pack is also different .

I was sizing mine up this past weekend. I have the C&P SEF lower with my sear pack that I've been using for 8 years. Thought it would mount right on the SP5k but wouldn't. After further examination, it appeared that the part that rests on the shelf could be filed down (or up, depending on your persepective) and make it work. It looks like the SP5K shelf is sitting about .5-1mm higher than the SP89 shelf.

Is there something else that changed and I'm missing?

 

[Mr.Maim]

It looks like the SP5K shelf is sitting about .5-1mm higher than the SP89 shelf.

I wonder why HK decided to do this.

 

[retrodog]

I was sizing mine up this past weekend. I have the C&P SEF lower with my sear pack that I've been using for 8 years. Thought it would mount right on the SP5k but wouldn't. After further examination, it appeared that the part that rests on the shelf could be filed down (or up, depending on your persepective) and make it work. It looks like the SP5K shelf is sitting about .5-1mm higher than the SP89 shelf.

Is there something else that changed and I'm missing?

Just got home and measured it. My earlier estimate was a bit off, probably because the difference was exaggerated by the extended position where I was looking at on the side. Looks like the actual difference is .012" (.3mm) difference on the height of the shelf.

 

[Mr.Maim]

Just got home and measured it. My earlier estimate was a bit off, probably because the difference was exaggerated by the extended position where I was looking at on the side. Looks like the actual difference is .012" (.3mm) difference on the height of the shelf.

Three tenths of a milimeter and your SEF lower doesn't fit? Is there something else preventing it? Seems like that would be just the difference between 'snug' and 'real snug'.

I'd be curious of the measurement between the bottom of the receiver and the top of the shelf compared to say an SP89.

I'm really curious about this. I can't see any good reason why HK would change the shelf height. It's not like they're going to make a ton of money or selling all new grip housings to those that already have them that are now incompatible with the SP5K...

 

[hk21man]

It is the width that is the main difference.
MM

 

[retrodog]

It is the width that is the main difference.
MM

Which part, the shelf itself or something else?

 

[SEAINC]

Slightly related question, MP5K uses small push pins all around, including the top of the end cap, correct?

Correct

 

[hk21man]

Which part, the shelf itself or something else?

The shelf width left to right.
Instead of a solid block cut into the sheet metal (9X and SP89)
it is a thin wrap around shelf to cover the pushpin bushing hole.
Far superior for us than the old way.
MM

 

[Mr.Maim]

The shelf width left to right.
Instead of a solid block cut into the sheet metal (9X and SP89)
it is a thin wrap around shelf to cover the pushpin bushing hole.
Far superior for us than the old way.
MM

Ah, understood. Thank you sir.

 

[Slaine777]

Correct

Thank you

 

[retrodog]

Photos from the other thread:

The modified carrier:

Didn't take a picture after bluing it but it looks pretty nice now. The chemical bluing matches the finish on the carrier pretty well, as if it matters. Used Birchwood Casey stuff that I've had for over 20 years. Still works great.

The blocking pin:

The shelf:

Some weld photos:

 

[Anthony.L]

The shelf width left to right.
Instead of a solid block cut into the sheet metal (9X and SP89)
it is a thin wrap around shelf to cover the pushpin bushing hole.
Far superior for us than the old way.
MM

So the push pin hole is actually there intact, just covered on both sides by thin metal? That sounds like WAY easier to do the paddle release mod.

 

[retrodog]

So the push pin hole is actually there intact, just covered on both sides by thin metal? That sounds like WAY easier to do the paddle release mod.

It doesn't look like thin metal to me, but I havne't tried to penetrate it. If I were guessing, just by looking at it, I'd estimate it at about 1/8" thick. Maybe that's considered thin.

 

[retrodog]

It doesn't look like thin metal to me, but I havne't tried to penetrate it. If I were guessing, just by looking at it, I'd estimate it at about 1/8" thick. Maybe that's considered thin.

My bad. I just examined it again and it is indeed a thin piece of steel. About .05" thick. Interesting design.

 

[Klaustrophobia]

Every time it shows up in pictures, I just can't get over how stupid that arrow looks.