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Discussion Starter · #1 ·
I released a few Beta test triggers into the wild, and got great reviews on the trigger functionality, but got lots of constructive criticism of the selector lever I designed. So I redesigned the shape, and re-machined the selectors (these are all aluminum). Then the anodizer was backed up, so there was a delay, so I took them to a different anodizer .... I finally got them back, so the first batch of triggers is released.

First triggers started shipping yesterday - some by express mail, so they should be arriving today. I expect we will start seeing range reports soon.

I will get into the shop today and will get some pictures of the trigger with the new selector - I got rid of the stepped design, so it looks a lot more like the original HK selector.
 

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Nice! I just looked on your site and realized you鈥檙e in Cincinnati as well. Are they readily available to order now?
 

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Super stoked about the Heckfire! My is scheduled to arrive Tuesday. The new selector looks fantastic IMHO.
 

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Discussion Starter · #7 ·
Nice! I just looked on your site and realized you鈥檙e in Cincinnati as well. Are they readily available to order now?
In stock, and shipping. I don't have a store front - just a machine shop, so it is not pretty, but if you want to stop in - just call to make sure I'm there.
 

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Got mine today. They look great! Now just need to transfer over the ejectors from my SP5 and SP5K-PDW factory packs, and should be GTG.
 

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Discussion Starter · #12 ·
Looking for feedback specifically on:

1. Ejector fit. I have 2 ejectors. One fit fine, the other had a slight bend to it and rubbed at one end, so I had to adjust the ejector. I'm thinking next batch I'll make the slot just a little wider so it is more forgiving. How did everyone's ejector fit?
2. Housing fit in the lower. There seems to be some variability of the width of the lowers. I measured the 5 that I have (4 HK and one MagPul), and got inside widths ranging from .875 to .900. My housings are .873, so they will fit everything without having to jam it in, though I have had 2 comments that they seemed loose. I think I have a shim solution, so you can self dial the fit. On my test guns, the upper clamps the trigger pack once you assemble the gun, so this might be a non-issue, but I'd like to hear from users.

Thanks,

Art
 

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Installed today in the SP5K-PDW lower. There was a slight bit of drag in the ejector lever, but the same was also there when the same ejector was in the factory trigger pack. Doesn鈥檛 seem to make any difference in the function as I can see the ejector come up as the carrier comes back. I just put some oil on the sides of the ejector. As far as the width goes, your trigger pack is a hair looser fit in the lower than the factory pack, but I don鈥檛 think it鈥檚 an issue. I鈥檝e had some variation in packs in lowers with various MP5 types I鈥檝e owned over the years anyway. Aside from the upper clamping the trigger pack as you mentioned, the safety levers also keep the pack from moving sideways.

The only thing I鈥檝e noticed is that the safety levers don鈥檛 completely cover the holes in the SP5 ambi lower all the way around. Some of the red of the trigger box is visible in places, like where there are notches in the circular hole to be able to pull out the factory safety, which aren鈥檛 needed with yours since the safety levers are screwed on. The polymer factory ambi safety levers have a flange that鈥檚 wider than the safety axle to cover all of the hole.

Also, can you verify that the little clip on the end of the ejector axle pin needs to be removed? I don鈥檛 see it mentioned in the instructions, but it was mentioned in a thread here. TIA.
 

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Discussion Starter · #14 ·
Yes, the selector levers need to be made a little bigger to fully cover the hole. That's already on the list for the next iteration.

The little clip on the ejector axle does need to be removed, otherwise it seems to jam when you insert the pin. Some of the clones don't use the clip at all - the lower traps it, so it can't come out.
 

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If you鈥檙e doing new safety levers, a suggestion is to allow a bit more clearance on the right side one. When the screw is tightened, the lever drags against the outside of my SP5 polymer lower. The left side lever is fine and doesn鈥檛 rub. On mine, I backed off the screw a hair and used some Loctite.

Will the new bigger levers be available for current owners?
 

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I finally had a chance to install the trigger pack.
The pack went in with minimal play between the sides of factory SP5 housing. Once installed back on the receiver it was perfect.

Like mentioned in another comment , the selectors don鈥檛 quite cover the holes on the housing. No big deal for me. The trigger is fantastic. If the selector levers are being reworked, I wouldn鈥檛 mind having a set of those as well.
 

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Discussion Starter · #18 ·
Trigger just started shipping last Thursday, so nothing arrived in time for the weekend, in time to make a range trip.
 

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Looking for feedback specifically on:

1. Ejector fit. I have 2 ejectors. One fit fine, the other had a slight bend to it and rubbed at one end, so I had to adjust the ejector. I'm thinking next batch I'll make the slot just a little wider so it is more forgiving. How did everyone's ejector fit?
2. Housing fit in the lower. There seems to be some variability of the width of the lowers. I measured the 5 that I have (4 HK and one MagPul), and got inside widths ranging from .875 to .900. My housings are .873, so they will fit everything without having to jam it in, though I have had 2 comments that they seemed loose. I think I have a shim solution, so you can self dial the fit. On my test guns, the upper clamps the trigger pack once you assemble the gun, so this might be a non-issue, but I'd like to hear from users.

Thanks,

Art

I'm happy to see that you're reaching out and listening to our feedback to make this product even better. Here's what I found when I test fitted the Heckfire on a PCS MP5 clone (SBR), HK SP5K, and HK SP5K-PDW:

The trigger pack did fit loosely in a few of my HK German housings. The receiver helps tighten it up a bit when fully assembled, but I did find an interference issue that made the lower not want to seat onto the receiver all the way. It made it difficult to get my stock or brace back on. There also seemed to be some binding of the action when cocking the bolt rearward against the hammer but I haven't figured what's causing it. It's getting late where I'm at and will have to look into this later.

Here, you can see an exaggeration of the corners of the pack making contact with the flange of the receiver (HK SP5K):


You can see the contact points where the finish was disturbed on the corners:


Here's an HK Ambi (0,1,F converted to semi) pack overlaying the Heckfire. Notice how the HK pack has a notch cut out, which is just enough to provide clearance from the flange of the receiver.


The Heckfire making contact with the flange on the PCS MP5 clone. The lower is as forward as possible:




The ejector lever on mine rubs and feels a bit gritty but I think it can wear in. The channel that the ejector sits in on the Heckfire has more surface area (and potentially more contact area) than the HK pack, more specifically the inner wall. I'm wondering if this could cause some issues where dirt/grime/carbon/etc creeps in there and interferes with the action of the ejector lever. I'm just thinking hypothetically of course, but thought I'd mention it in case you were planning on making improvement in this area.

I removed the clip on the ejector pin but it didn't want to go in all the way flush. It felt like it went in as far as it could. Since the pack fits loosely in the housing, this didn't really cause a problem however:




You mentioned that you're working on a new safety lever. Aside from what everyone already mentioned, I was wondering if it's possible to have it roughly the same shape and aangle as the factory ESSL (extended) levers. The Heckfire's lever, when on Safe, seems a bit high. The round shape of the receiver kind of gets in the way of your thumb when you're reaching to move the lever to the Fire position.


 

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Discussion Starter · #20 ·
Excellent feedback, and timely. Thanks. I'm going in today to set up the CNC to run more housings. Obviously, adding a cut to the rear of the housings is easy. I wonder if that is a clone thing - as I do not recall seeing that rear cut on the HK housings I own.

The ejector slot is something I am working on, both to make it wider overall, and also to remove some of the inner wall in the front. I obviously need both sides to the wall where the pin goes through, but if the ejector has a slight curve to it, the leading and trailing edges will be where the rubbing takes place, and in looking at the HK pack, the inside front of that slot is absent, so I'll copy that.

I had not noticed that the selector lever was uncomfortably high in use, but I'll pay closer attention - again, duplicating HK is an excellent starting point.

Love the feedback - keep it coming. Most companies go do these developments in a silo, but since forums have evolved on the internet, I think this access to the user base is an excellent opportunity to get product design feedback, especially since I CNC parts and do relatively small batches, so the feedback can be incorporated into the design even after product rollout. The good news for me is that there has been no negative feedback on the actual functionality of the trigger.

Art
ShootingSight llc
 
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