Jury out on Scorpion: Trigger Reset Issues

[3guneric]

I agree that the opportunity is just hanging out there for: "Maybe one day someone will create a drop in replacement trigger/hammer set similar to an AR."

My replacement HBI spring due tomorrow: will update.

[DanT]

After upgrading to the HBI springs, I still found the trigger pull/reset rather long.  I fixed this in my gun with three shims, one to shorten the over travel (0.010" - front of the trigger), one to reduce the trigger pull (0.032" - rear of the trigger) and one to shorten the reset (0.016" - front of the disconnector foot).  The trigger post the safety "half moon" sits on top of needs to be filed down to accommodate the "pre-loading" of the trigger.

The HBI springs, a bit of trigger polishing in key spots to remove friction, and the addition of the three metal shims to shorten up the trigger travel really helped the stock trigger feel a lot better to me.

I really love the HBI long AK safety on the right, mini AK on the left.

- DanT  Phoenix, AZ

[3guneric]

Dan T:

Have read your very detailed postings here on the use of shims to further enhance the trigger.  Well Done!

[Dirty J]

Installs aftermarket parts. Gun doesn't work.

Gun is crap. 

[3guneric]

Initial press reports that the Chrysler XM-1 tank is  crap due to serious design flaws - after correcting these issues the renamed M1 tank has dominated for 30+ years.  (I was in Germany when they arrived and led a platoon of them.)

Anything mechanical faces these issues when new - how about the M16 debut debacle in Vietnam?

There are exceptions - the B-17 Bomber was really one of the few prewar designs that was of real value.  Look at the initial issues with the German Tiger 1 and 2's.  But once they were ironed out - wow.  Same with the German A4 (V2) rockets.

So be patient and learn from the process.

My latest Update:

Received my free HBI replacement springs.  Installed them and things were much better but the "shifting" of the spring off the arm did repeat itself - though not as often.

Contacted HBI and thanked them for trying to work this out but that my Scorpion did not seem to want to cooperate.  Told them I would send both spring kits back if they wanted to look them over but that I did not need or expect a refund.  Am still very pleased w/ the AK safety and charging handle.

They have offered to pay shipping both ways and want to examine my trigger pack, and install spring kit!  I have not answered them yet and am considering taking them up on the offer.  Have just been weighing the feel of my present OEM springs versus having the lighter kit.

The jury is still out.

[ShootersElement]

Initial press reports that the Chrysler XM-1 tank is  crap due to serious design flaws - after correcting these issues the renamed M1 tank has dominated for 30+ years.  (I was in Germany when they arrived and led a platoon of them.)

Anything mechanical faces these issues when new - how about the M16 debut debacle in Vietnam?

There are exceptions - the B-17 Bomber was really one of the few prewar designs that was of real value.  Look at the initial issues with the German Tiger 1 and 2's.  But once they were ironed out - wow.  Same with the German A4 (V2) rockets.

So be patient and learn from the process.

My latest Update:

Received my free HBI replacement springs.  Installed them and things were much better but the "shifting" of the spring off the arm did repeat itself - though not as often.

Contacted HBI and thanked them for trying to work this out but that my Scorpion did not seem to want to cooperate.  Told them I would send both spring kits back if they wanted to look them over but that I did not need or expect a refund.  Am still very pleased w/ the AK safety and charging handle.

They have offered to pay shipping both ways and want to examine my trigger pack, and install spring kit!  I have not answered them yet and am considering taking them up on the offer.  Have just been weighing the feel of my present OEM springs versus having the lighter kit.

The jury is still out.

If you've not done any kind of polishing the reset can be an issue or if you didn't use the shim in the spring kit that might be the cause.

If you're game for another option, we offer an install and polish option for the lowers that help reduce trigger pull, trigger reset and pull weight. The total package runs $93.94 (trigger, install, polish and spring kit). I'll test it out for you and see if we can get it running smoother, lighter and shorter for you.

I just wanted to offer another solution.

[3guneric]

To SE:

Thanks for your kind offer!  However am having very positive interactions with HBI on this and am taking them up on their offer to install and inspect. 

Am looking into polishing options as well though.

Thanks

[3guneric]

Mailed my trigger pack off to HBI today for them to look into my Scorpion.  Since they are going to have it have asked them to upgrade/install one of their triggers as well.

I had just about accepted that I would have to keep OEM springs.  We will see.

[ShootersElement]

To SE:

Thanks for your kind offer!  However am having very positive interactions with HBI on this and am taking them up on their offer to install and inspect. 

Am looking into polishing options as well though.

Thanks

Great people over there, I'm glad it's working out for you. Most important thing is to get that scorpion upgraded and working as you want it. That's why we all offer these products and services.

[3guneric]

Update:
48 hours ago I placed my trigger group in the post from Winchester, Virginia  to HBI in Arizona. (Their dime)  Earlier this evening received email that they looked over things (all seemed OK), installed springs, and USPS label created to return to me.  WOW that is service.

It looks like the install error was probably on my end. 

Will update after I test fire. 

[cocowheats]

I had reset issues after the HBi spring kit and a light polish job. After assuring the trigger roll pin was not rubbing in the lower, I found it to be a mix of poor relations between the sear to hammer and a bit under powered trigger reset spring. Gun would work fine until it got a bit dirty (I shoot mine primarily suppressed and noticed a fair amount of dirt in the trigger pack from doing so). When a bit dirty, the reset issue would occur with the HBi spring kit since it didn't have enough force to overcome the poor sear to hammer mating with the added dirt. Worked fine until dirty...this is with a polish job on all the trigger pack contact surfaces as well. If I'd reset the trigger slow enough after shots, it'd get stuck and I'd have to force it forward to reset it.

I ended up cutting a handful of coils off the oem trigger reset spring and stoning the disconnectors, hammer, and sear. MUCH smoother and no more issues since. I suggest looking at the relation between your sear and hammer while the trigger pack is dirty if you have reset issues. See if this is where your trigger is picking up the resistance during reset. Very easy to see if you work the trigger reset with the lower off. If you find that this is your hang up point, then you just need to take a bit off the back of the hammer and the underlip of the sear, polish, and perhaps mod the oem reset spring for slightly more forward oomph on the trigger shoe.

Basically, I had a little to much force being put on the sear from the hammer during trigger reset. I alleviated it by removing material and then polishing the mating surfaces so that the force was lessened allowing the trigger to reset easier. The cut down oem trigger reset spring was just for good measure. My trigger breaks at 4.2ish lbs with a tad bit of creep(like the Glock's gen 4 spongy creep that comes after pulling past the wall). Cleaning up the front of the hammer and disconnectors was just to smooth out the trigger pull, nothing to do with the reset issue.

It was a frustrating endeavor as I had to take a little off here and there at a time then test fit but the results are a gun that hasn't been cleaned in a few thousand rounds without trigger problems. I wish the trigger was crisper, but it ain't awful. It's just no Elftmann...

[3guneric]

Thanks for your info.  Never fired mine enough to get dirty yet!  Will update this weekend.

[bravo5two]

I agree that the opportunity is just hanging out there for: "Maybe one day someone will create a drop in replacement trigger/hammer set similar to an AR."

My replacement HBI spring due tomorrow: will update.

Actually CZ Custom already has a 'drop in' replacement trigger that has extremely short travel/reset:

https://czcustom.com/cz-scorpion-evo-3-s1/evo-custom-parts/cz-evo-trigger-pack-czc.html  Only $224 

There is a video of Angus showing the short of travel and reset CZ Custom trigger for Scorpion.  I wish I have the dough to acquire one

[3guneric]

That is true.

 IMO CZ should sell an upgraded Scorpion with the improved trigger out of the box.  Having just purchased a new gun I opted to go the spring upgrade route.  Didn't want to buy a new gun - order $200 + trigger upgrade, and place the old trigger pack in the spare parts bin.
(Also the added cost of the CZ enhanced trigger pushed total investment too high for me.  For that kind of money I would be in striking distance of a much higher quality gun.)

So we will see.

I had hoped to be posting my observations on HBI's spring and install but my trigger is currently in USPS limbo - storm in Memphis has delayed delivery.

[DanT]

Internal drag makes the reset less reliable, as the trigger spring needs to overcome this drag to do reset.

I have found the number one drag point is that long lever on the same roll pin as the hammer.  Thus lever rubs against the trigger side wall.  Polishing this lever on the side against the wall and polishing the wall relieves the largest source of trigger "drag" that keeps reset from working well.  I also a tiny bit of gun grease between the two. 

The number two drag point for me is the trigger hooks on the front side of the hammer.  I polish both the bottom side of the trigger hooks and the hammer shelf. However, those will not effect reset.

Likewise I would polish the rear hammer shelf and the bottom side of the disconnector hook that rides on it.  This would definitely affects the reset drag and thus makes the reset less reliable.

Thus for more reliable resets, clean up that lever, the wall it rubs against, the rear disconnector hook and the rear hammer shelf spot it sits on. A tiny spot of grease under the disconnector hook and the level side against the wall helps also.

Also, if you want, it is a "drop dead simple" thing to wind your own trigger spring using vice grips and a 1/8th inch drill bit as a coil form.  I normally use 0.039" music wire (a.k.a. spring steel) or the next step down 0.037".  I have a thread on trigger shim modifications, and that thread points to an earlier one that shows how to wind a trigger spring.  The wire thickness and the angle between the two legs sets the force of the spring.  Wider leg spacing = more force, less leg spacing = less force.

If you want to play with this, for $3 I can send you a foot of both 0.039" and 0.037" music wire.  A trigger spring maybe takes 1" to 1.5" of wire. Use your current spring to get an idea of the leg length and ballpark leg angle to start working from.

- DanT  Phoenix, AZ