We're going to issue a recall of the 13.5X1LH barrel adaptors via email addresses on existing orders to all our direct consumer and business customers.  The product is de-listed until we can replace it with the longer better metric supporting model. The recall won't require return shipping of a part from anyone who bought it from us direct, we'll just be sending replacement parts to those people.  The people that purchased from dealers will have to contact us for an RMA.  We're going to contact dealers this morning to tell them to cease sales of the 13x1LH adapters for the interim period until we can replace the inventory they have in 2-3 weeks.  We appreciate the quick notification of the customer here, that was very helpful.  

We deeply apologize for the inconvenience.  

When designing the 13.5x1LH part we really wanted to keep the 9mm family short style, and we were looking at in CAD a model with .020" wall stock at the forward O-ring groove.  That wasn't a comfortable place to be- and that made it far and away the most marginal component of the family, but we thought it would work out and we shot and practically tested examples of it successfully to the recommended 20FT lb setting which we are not suggesting be changed for any of these products or the revised part comming.  CAD FEA suggested that would take ~36ft lbs of torque.  In testing this morning that part yielded and broke at 23ft lbs, and that showed ~.012 wall on that O-ring groove, and the reason for that is probably revisions to remove thread over-cutting and to fit the O-ring groove. That failure was shear separation of the forward half of the part due to the 3600lbs of force created by the 23 ft lbs of torque.

We tested all the other models (16X1, 578x28, 1/2x28, 14.5x1) to 45ft lbs today without failure- not to be construed as a recommendation of a higher level of torque.  Just to check and ensure they are not dysfunctional parts.  

I can't really underscore how challenging it has been to continue product development this year with 3 times the normal order volumes, and this product is really pushing the limits of what is possible with material strength, and CAD/CAM, and CNC manufacturing tolerances.  We are confident that we can maintain a high level of performance in the field, and this was just an example of how narrow that performance envelope was on that one part of this total system.  Getting that "magic" feeling into a product is unfortunately linked to these types of challenges.  

This is a first recall for us, and we will work to satisfy ever customer rapidly with a solution.

Thankyou for the positivity, we really appreciate the support of all of our customers.  We're going to resolve this very quickly, fortunately we have a great team, and the capabilities to quickly fix this.

We made the first 13.5X1LH barrel adaptor of the new design, and torque tested it to 45 ft lbs successfully on a VP9 barrel.  That torque is not recommended for the pistol barrel or the adapter, and we didn't test for geometrical yield at 45ft/lbs, just for no failure.  There was some slight deformation of the wrench flats at the corners from taking it up there with the socket wrench.  They have begun manufacturing them on second shift tonight.

We also made the first Osprey slotted universal piston.  With the slots are cut over the internal threads where there is more material.  We ran a pre-heat treat sample of it through some practical testing in a 9mm Octane with S&W M&P 2.0 in 9mm, and it did not fail.  The area that is made more thin by the slots isn't exposed to pressure because it is behind the sealing taper, it is only exposed to radial force at the thread, so it holding up made sense and conformed to the theory that got us to the point of wanting to attempt it.  

We don't have an Osprey here.  We're going to get one in to do more testing with an Osprey.

The easy way to mount it is dump it to the stop, rotate into resistance, maintain rotary resistance and pull away and the threads will mesh as they move into contact, rotating into tight connection.


There is about .013 of z motion across the entire thread lug,  and we wanted to center thread purchase so we are trying to use about .003 of that range which seems to be about ~+-.0002 on diameters of the taper of the barrel adapter.

To get it to turn in consistently without turning and pulling away, we probably would have had to increase helix by 30-50% and at that point it probably wouldn’t be able to be cut with the tool (running out of relief to support the angle / promoting insert failure), or at least would violate the thread form and begin to compromise the thread.  When you violate form, the thread will become very sensitive to slight changes in cut diameter.  Additionally, a greater helix would reduce mounting security which is currently about perfect.  Too fine- it will bind up and be far too secure, too coarse and there will not be any mounting security as pressure or force will want to translate into rotary motion and hand torque to get similar taper load with that reduced mechanical advantage with double helix would need to double.

The larger pitch thread profile we used (supporting more helix angle) the more diameter the thread consumed in the application.  So the problem we obviously ran into with the 13.5x1lh, would have impacted and removed the ability to support the flush mounted 1/2x28 on the next larger thread profile.

A large profile is a blessing and a curse because more coarse is more durable and eats more diameter in the application.  It becomes like silencer design where weight is Somewhat connected to short sprint durability, but weight is also negative attribute mass to carry around and less efficiently cooled with the same amount of surface area due to lower gradient at lower temperatures and greater stored energy at higher temperatures, making it more likely to promote a bright thermal signature or hold heat for a longer period of time causing things like having to wait a long time to leave a gun range safely.

I have a MK23 also.  I would kind of like to get one of the Surefire discontinued style MK23 rails from the HKpro group buy but I haven't logged in there for a long time.   I don't understand why the rail has to be manufactured to order on a second or third run.  If I was manufacturing that rail, we would just keep it in stock for people to buy when they wanted it.  The current group buy is at 30 so maybe in like 6 months they will run the rail.

It's kind of a shame HK had to be different with the rail, and also that no one produced any consumer LAM units or even lasers for it.  I think a Steiner TOR mini in red would be a cool addition- offering a red laser answer to not having night sights and the red laser could also be used with night vision.  When I was in high school I bought a Wilcox LAM unit for like $799 when I didn't own a MK23 to put it on.  I sold it later on the EE, for something like $750.  I once mentioned LAM units to Wilcox at Shot show a couple years back and they kind of laughed and said that was like 30 years ago.  I felt like Wilcox could make the original unit and probably sell them pretty well if the price was even remotely reasonable like sub $1400.  Maybe the reality is that nothing Wilcox makes is capable of being price competitive on the consumer market.  I have a RAPTAR and its Achilles heel is that it doesn't really hold a zero because they use this one screw picatinny interface that just pulls the plastic housing down on top of the rail.    

A RAPTAR that held zero would be pretty awesome, because electronically the raptar is pretty sweet.   I'm having bad luck with lasers currently.  My home defense primary MK1 has a CQBL which is a pretty sweet laser in that it retains zero, and keeps a low profile, and it just spontaneously stopped working- like totally mint condition- I went to check it after it had been sitting in the corner for a while selector on vis, button activated to off, and nothing.  I took the working 3V out of the Surefire and put it in the CQBL and no dice, so I had to grab a spare CQBL for now while I figure out how Steiner's warranty works.  It's pretty important for the laser to fire when the button is pressed.  That's the point of the system.

The distance required for each pistol model is different- like a SIG and a 1911 won't have the same amount of barrel travel with the slide before the barrel unlocks and stays put.  The mounts are made exactly like our former pistons, so they don't have any unconventional length relationship behind the muzzle.  We have never as far as I know had issues with customers except for guide rod contact to the piston retainer which could be resolved by clocking the can to put the retainer scallop in line with the guide rod.  This year we changed the piston retainer design slightly to give the retainer more clearance before the tool receiving scallops are reached.  I am not familiar with short cut Bear Creek Arsenal barrels.

This is the newer style piston retainer:

An elite unit solicited a system this meets the general scope of years ago- it was word of mouth from former members. The order was too small to really give it much serious thought and our ideas at that time were like booster housings designed around a 3 lug spring biased mount and we felt that was not very attractive as a concept and very gadgety.  We had no understanding of the price they were willing to pay for development so we were thinking in terms of what our products sell for off the shelf.  Maybe they will call?  I'd be happy to sell it to them.  We're not hard to contact. They probably have COTS credit cards they could buy this with.  It would probably be the most affordable thing they bought all year.

I envy your HK collection.  The HK45CT looks like an answer to most of the things unlikable about the MK23- the lack of a standard rail, the lack of night sights, and when carried, the size of the MK23.

@Gopherboy128 - Do you still use that SiCo Y-Mount?

I ditched mine for the much lighter and shorter YHM versions...

Mine was the military version with the IR and vis lasers.  They used to be on the market for like $750 and people just started flipping them again and again for more till going price was in the 2-4K range.  Now you'd worry what if it just stops working after spending that kind of money on one.  

I'd like to pick up a 45CT with night sights.  That looks like a good gun.  Agreed the MK23 is a really nice shooting pistol.  If I had the MK23 when I had the laser I probably would not have sold it.  The MK23's were going through a period where they were like $2000 at the time.