Priest Bullpup SAFETY WARNING
I Have been watching the progress of this new pup and was hoping the production model was going to be different to the prototype they showed us a few months ago.
While the design of this pup interests me there is one aspect about it that scares me and is a very real potential safety hazard to users and modders.
I felt it was important to share it here.
The potential hazard I speak of is related to the regulator. Other than the obvious hazard of the bottle taking a good knock and breaking at the reg, those paintball style bottle regs are not at all suitable for this application.
They had an original design intention for use with 1200psi of CO2 pressure and a built in engineering safety factor to suit that pressure rating.
The have been pushed past the normal operating safety factor in a few cases with HPA with modified pistons and washer stacks but structurally they are still only designed for 1200psi.
Anyone familiar with these regs will know what Im saying, some of the reg bodies are paper thin and not designed to hold HPA pressure so I caution anyone swapping the reg out with a cheaper chinese reg, they often quote on Ebay and Aliexpress etc that they are suitable for 4500psi carbon bottles but the burst disks they come with are still only Co2 rated pressures.
It looks to me that the Priest boys have made their reg body from stainless steel? can anyone confirm this for me?
While the body of that particular reg may be strong enough to hold the 200 bar the alloy bottle on the priest is rated for in the event of a reg O ring failure but the thread on the gun end is still the std sub par paint ball thread designed with a safety factor for use with 1200psi.
The only other HPA powered factory made PCP that I can think of that uses this bottle reg setup is the Spanish Cometa lynx and even in .25cal it is very low powered (25ftlbs) for a good reason. Its reg is set to 1800psi and its burst disks are also very low ratings (2200psi on the low pressure side) so if any reg O rings leak they will blow before a potentially very dangerous over pressure situation occurs.
Personally I think these regs should never be used on HPA PCPs, bottle PCPs should be fitted with a long straight thread like the RAW or BSA guns anfd the regs should be built into the guns frame.
For those of you tempted to fit this pup with a carbon fibre bottle and new reg to fit the bottles thread (normally 18×1.5 instead of the smaller 5/8″x18tpi alloy bottle std) be sure to spend the money on a decent regulator too, do some research and see if you can fit the priests Stainless steel(?) reg housing onto a new reg with the bigger metric thread and set up the burst disks within its safe operating pressures.
Those cheap chinese regs are being offered in 130 and 150 bar for HPA now but often the burst disks are not correct for either operation and they only have 3 to 4 threads on the section that attaches to the gun.
For the correct safety factor for use in HPA for that thread size and pitch it would need a minimum of 7 threads tightened fully in the guns housing. Often you will see these regs with only 3 to 4 threads and they dont tighten fully before the valve opens and locks them up from pressure. This allowed the CO2 gauges and foster fitting etc to be aligned on the gun. On HPA they need to be tight before any air pressure is introduced to the threaded section regardless of where that may align/misalign the gauges/ foster fitting.
Dont be tempted to ever put 4500psi into a carbon fiber bottle on this gun, even though the bottle is rated for it the reg housing, threads and probably gun are not. It would only take a worn o ring for a potentially very dangerous situation to arise.
Personally Id like to see the Priest manufacturers change the thread in the gun with something more suited to cope with a potential 4500psi overpressure situation which will also stop people unknowingly fitting sub par weaker thin reg bodies with that scary 1200psi rated paint ball thread on the back. They should aso build an internal bottle reg so the bottle can be fitted flush.
Fine tuning this stile of reg is a big PITA as it requires fitting different sized shim washers so you will never have the same scope of fine tuning as a reg that has an adjustable seat.
In short, If you want to fit a carbon bottle and reg to suit, look for a good quality, thick bodied, 150bar min, 6 to 7 threads on the back of the reg with modest burst disks that will blow and a pressure just above the reg setting when the reg o ring fails. burst disks are cheap so keep spares just as you would with o rings.
Please be warned and be safe.
All Replies
My point exactly. Ive seen these mods all too often and I felt the need to share before someone does something stupid.
Jump on Aliexpress some time and take a look at some of the 4500psi input 2200psi output regs on offer from $10 to $20.. they are pictured with 6k and 4.5k burst disks and I can almost garantee the wall thickess and threads are out of spec… this is even before the buyer mods it further.
Wow, how did that reg ever got out of design phase is beyond me, did they do any stress simulations on cad? Probably not by looking the blue regulator thickness.
I have one vulcano pb bottle reg adjusted to 3000psi, by the previous owner but I have never dared to use it for anything. I think I’m going to burst test it some of these days and see where the limit is before the top goes out.
Got it with one used bottle for nothing, burst disk blanked and all. Some people are just waiting for good old Darwin.
Marko
I was just chatting to Huub a few days ago about making me a replacemet reg for a customers cometa lynx (same bottle reg set up) and he shares my veiws on this safety concern.
Sorry I cant recommend any good brands as I wouldnt want to put my name to any that could potentually be a hazard in this combo.
If you intend to mod this reg and bottle I recommend you do lots of reserch and find one with a good wall thickness, a short over all length and set it up with a burst disk rated just above the regs set pressure.
I guess that’s a fair point then, actually makes me wonder why we don’t hear more about PB bottle accidents as those things really do take some abuse – these were the first ones I saw. Why don’t you share with us the names of those good brands then? I checked Huma site and they do not have a PB regulator listed. I mean even if RTI made an improved “bonnet” for their regulator I bet there would be interest amongst other airgun enthusiasts for a safe solution. I forwarded this thread to Huub, let’s see if he has anything to say.
Im refering to the thread from reg to gun and the thread that splits the reg but also the thickness and structural integrity of the reg body that takes the load..
Like I said, there are a few good regs out there that can take the load but there are many brands that are nothing more than a flash name and pretty anodising on a very inferior CO2 paintball reg.
Paintball regs treated bad without issues you say… I know of a few first hand.
Heres a CO2 reg breaking off with only 800psi escaping.. Just picture what a 4500 CF HPA tank would do
I must say I don’t quite get it. Is the problem in the threads that attach the bottle to the frame of the gun? As you said they have been designed for 1200 psi (Priest seems to use 1800 psi) and PB people treat them badly on daily basis without issues. Or are you referring to the regulator to bottle connection? Again 4500 psi PB bottle/regulator combos are treated badly on daily bases without issues. If you refer to the thread within the regulator body, then I would say that depends entirely of the make of the regulator and Chinese cheap ones may indeed have a potential problem there. Does this mean that we shouldn’t buy from companies like JDS Airman either as they seem to offer only about 4 threads in the bottle to gun connection with output pressures up to 3000 psi? If that’s the case, I think a wider warning should be issued as there are countless QB and other conversions running normal PB regulators shimmed to higher pressure output.
Please let me be clear, I am not saying the Priest is a safety concern in its factory state, without having one in my hands to inspect and test I would not assume such things.
I am cautioning people who intend on modding this pup with aftermarket carbon bottles which would require having to purchase a new after market reg to suit the M18x1.5 std threads they all have. There are loads of paint ball regs out there and I would be confident in saying 99% of them are unsuitable for use on HPA at 300bar. Even at 200bar I wouldnt be happy with many of the 1200psi rated paintball regs out there labeled as 4500psi regs. The original design of this style of bottle reg was never intended to handle these kinds of pressures or side loadings on the the universal CO2 thread they all have. There are quality ones out there with longer threads now (6-7 instead of 3-4) but they are all pigs to adjust.
What I can say is after working on several Cometa Lynx .25cal PCPs with this same bottle reg set up, there is no way Ill be buying one of these pups.
If I did I would be opening up the thread in the gun to a longer and finer pitch and building a custom more solid reg housing like the RAW or fit a larger air cylinder to it like the Colibri.
Fitting a reg that extends into the bottle or the frame of the gun would be ideal and it would also pull the bottle further back with less load hanging of that thin housing and crappy paint ball CO2 thread.
Still not convinced? Take a look at every other bottle fed airgun out there such as the Airforce range, Air arms, Daystate, FX, Rapid Air Weapons, Theoben, BSA etc and you will see they all mount the bottle very close to the receiver and the mounting components are all solid steel not thin alloy.
Like I said the only other gun I have seen with this highly stressed minimal safety factor set up is the Cometa Lynx and the have detuned the gun considerably (20-25ftlbs) with very low reg pressures and a max fill pressure of 200bar. The wooden stock is also designed to “cradle support” the bottle and reg should it take a knock unlike the fully exposed bottle of the priest. I really hope for their sake they dont learn the hard way.
Its a cool gun with nice features but it could be so much better..
Heres a few other flush mounting reg options that RTI should really consider;
😐 Damn it…. I really want to like the Priest. Decisions, Decisions.
Can’t go wrong with a Cricket. Love mine.
OK, so… Serious question. Is this concern with the bottle enough reason for you to recommend that a person not buy it. The reason I ask is because I orginally had intended to get a Cricket .25 then I found the Priest and decided to wait for it. I liked the pound less that it weighed. I loved it’s super low bore axis. But now after hearing Ksfastman and this comment from Wing coupled with the fact the RL still hasn’t called me, I am considering calling them up tomorrow and telling them to switch me to a Cricket. I would appreciate whatever input you guys may have.
WOW, that’s Heavy !!!!!! :suprisedn: :suprisedn: :suprisedn:
And we all know that Wing knows his stuff.
Hi wingman
Get ready for the popcorn……ive always thought this gun looked very weak at the front were the bottle attaches…good safety call from yourself and i hope people take note of your warning,if they have seen.some of your builds ?they will realise you know enougj ab high pressure air and safety
Rgds steve
The RTI reg bonnet/top hat is not steel.
- You must be logged in to reply to this topic.
RTI should offer the gun with carbon fiber bottle and a safe regulated that does not whistle and just add to the price I’m pretty sure it’s a lot safer