steve-l

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    steve-l
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    I have made a bunch of these over the years and I have found that packing of any kind simply does nothing. It is simply false that any packing silences anything. What does work very well is outer tube-centric baffles. Inverted cone baffles work best, as opposed to flat discs with a central hole because they cause greater turbulence and energy absorption behind the pellet. Each section of the moderator effectively acts like a small expansion chamber which allows the propelling air to reduce pressure and air velocity one section at a time. The hard part is keeping these baffles fastened tightly at your chosen spacing without excessive weight and or consumption of chamber volume. It is also another old wives tale that close bore tolerance is a requirement……..it isn't, a clearance of moderator bore to pellet clearance of .020" (.5mm) works well without any chance of clipping.

    These are a lot of work to make just one. If you value your time, just buy one. I only make those things I cannot buy. 

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    steve-l
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    I have had the issue with other high pressure gas bottles both large and small. My solution is using a fork on a fork lift and cargo straps with ratchet tensioners. Just make as many wraps around the bottle and fork as you can and then tighten the ratchet. This works like a custom belt wrench, but you don't have to hold it. This leaves both hands to deal with the valve. This works very well, even on the largest bottles.

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    steve-l
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    I read threads like this and several questions come to mind.I own a Crown in .25 and I made a moderator that fits and works perfectly, but I too was concerned about the potential of clipping. Now I have capability that most here do not. I own a machine shop. So I made a precision rod that picks up the last 3 inches of the barrel bore and has an OD of .250" and is long enough to extend past the end of my 8" moderator in order to verify bore alignment through the stripper, shroud to moderator adapter and the moderator itself. I felt this tool was necessary to determine the required bore to baffle clearance in the moderator. I was pleasantly surprised as to the accuracy and alignment of all those parts.There was no measurable misalignment anywhere. I ended up using .020" clearance, but it could have been much less and clipping would not have been an issue.

     

    That short story was necessary to understand my doubt to the OP's clipping report. No offence to the OP, but how does he know he is suffering clipping? Because of my experience with the Crown, I find it really hard to believe. So before anybody fixes anything, it would seem prudent to make certain. The Crown is a superbly made air rifle with very high quality components. If you have a cracked gauge, why would you be thinking about changing from OEM. The OEM gauges work just fine.

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    steve-l
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    First, barrel droop is not important. Where the gun shoots is where the gun shoots. As long as it is consistent, it doesn't matter. Secondly, I don't understand why the barrel/ bottle band would not work better than shims of any material between bottle and barrel. The one I bought from Ohio Airguns works perfectly and my POI shift from session to session has completely disappeared.

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    steve-l
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    I'm waiting for these in 25 Cal.

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    steve-l
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    Comments????

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    steve-l
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    This is after all a top of the line, $2,000 gun. This flaw should have generated a factory recall…… It didn't. There are several ways FX can address this or not. They could just ignore the problem and hope it goes away or they could offer an "Upgrade Kit (Service)" at some cost to the customer. Let's see…….

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    steve-l
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    Blejda

    Do the newer crowns still have that problems?I heard that the changes were made to how barrel is atached.

    I just watched a video today and you are correct. I believe FX has recognized the flaw and the new barrel assembly is touted to be ultra light. The lightness of course had nothing to do with the fix. The real fix is the addition of a taper faced jam nut over the barrel threading into the receiver. This will snug up the barrel fit and register every time the same way in the receiver.

    So the question arises. Will FX offer to retrofit the older versions of the Crown with the new barrel arrangement? 

    • This reply was modified 1 month ago by steve-l.
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    steve-l
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    Sto,

    You can check the archives for the previous threads on this subject if you like. You will see the steps taken by myself and others than suffer this issue. I have a machine shop, so I have all the tools needed to check for sizes and fits. Several iterations of complete disassembly and reassembly checking size, lengths and torque applied to all fasteners, barrel and stripper as well as "O" rings. I also moved the extendable shroud to the rear most position locking the shroud in place. All to no avail. The barrel on my Crown is 600 mm add to that a 200 mm Moderator and you have an 800 mm multi-part assembly supported only on the receiver end. From an engineer's point of view, the design is truly frail, if not stupid. A reasonable fit of barrel to receiver of .001" clearance is difficult to achieve on every gun made on an assembly line and yet, even that clearance is too loose for consistent barrel location after every assembly. What is amazing to me is that only some of these Crowns exhibit the problem.

    • This reply was modified 1 month ago by steve-l.
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    steve-l
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    Wow…..don't be so lazy……Google is your friend……….. https://ohioairgun.com/

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    steve-l
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    My Crown is one year old and my problem has existed since new. Before I went to this clamp, I addressed all the other remedies and possible causes first. The issue has never been accuracy. The gun has been spot on, but every time you put in the case, transported it or bumped the barrel, the POI changed. I also do not believe that all braces or clamps would correct this. The space between the bottle and the shroud is slightly different from gun to gun and the bottles are not round nor are they all the same diameter. It is quite difficult to get the fit correct so the shroud fit has zero clearance and when the clamp is tightened on the bottle, no stress is applied to the shroud. The clamp I received from Ohio Airguns just works.  I was very impressed with the fit.

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    steve-l
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    That is a professional compressor and at the end of the day, it is the least expensive way to go for high pressure air. When I outfitted my bare Bauer pump, I had to acquire all the safety valves, high pressure fittings, stainless tubing and high pressure switch. I found sources in Australia that were pretty friendly, but the safety valve and the control switch were more $100 each. On top of that you have to build manifolds to house gauges and connectors,  a DC power supply and a power control relay for the motor. There are very good reasons why these compressors are expensive, but when designed right, they perform flawlessly for many. many years.

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    steve-l
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    zx10wall

     

     

    I think Derrick is almost correct, but I believe the conflict of the two stabilization forces he identified only occurs when the spin speed is incorrect for the sectional density of the pellet. If the observer throws an American football and the spin rate is correct, the football will pitch over when the football reaches its apogee, keeping the orgive perfectly centered in its flight path. If however, the football is over rotated, the football will not pitch over. In which case the air pressure below the football would be greater than over the top side and the football will attempt to fly and sort of float towards its destination. The same thing occurs with bullets causing vertical deviation over longer distances as the bullet encounters lower and higher air temperatures/air density along its flight path. With a pellet though, over rotation will cause the conflict of the two stabilization forces Derrick so eloquently identified and spiraling occurs.  

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    steve-l
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    STO is correct. The Crown is perfect the way it is. If you need more power, use a PB.

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    steve-l
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    Long_Gun_Dallas

    Simple fix.  Store it in a case that holds it firmly.  Once the gun settles in, zero is set.  If it's been resting on the barrel, pick it up, and gently push the barrel left right up and down so it settles back where it was.  

    Cold weather will affect zero.  Let the gun cool down to working temp.  Check zero.  If you bump the barrel in the field, gently push it left right up down.  It'll settle back where it originally settled.  That's why I love my 380mm barrel.  Never a worry about bumping it in the brush

    Consider yourself very fortunate. I have this issue and many others also have it too. It is not an accuracy issue, nor is it a temperature issue. Yes, it does settle back to another POI, but the issue is which one will it use today. I am a competent gunsmith and a machinist with my own machine shop. This problem is real and it affects many others as well.  I am not alone. This brace is very well made and I have much hope that it will solve the issue. The Crown barrel is a piss poor design that is very frail. This brace, if nothing else, is cheap insurance at $20 for a $2500 air gun. It certainly cannot hurt.

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    steve-l
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    L.Leon

    @steve-l, so how is the shroud attached to the receiver? The shroud on my Bantam screws into the receiver for a rigid fit. Just curious as to how it’s attached on your gun.

    My Crown is just a year old. The shroud  just slides on the barrel tube. It does not attach anywhere else and that's the problem. The barrel is 600mm long plus the moderator and that's one hell of a lever. It takes very little force to disturb it.

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    steve-l
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    Allen_wind has it right. There is Bauer and then there is everyone else in the PCP world as well. Bigragu has it right too, you don't find Bauer compressors in the classifieds very often and if you do the price is high. You do find them in the junk yards and then the price is scrap weight and a little bit. Bauer compressors are repairable. Parts are available. So finding a Bauer in the bone yard is a good deal in any condition.. I bought a bare pump 25 yrs. ago for $150 and sat in a junk pile in my shop until 3 yrs. ago when I got into PCP. I had to build a base, attach a motor and build, mount, plumb and wire in all the controls including sensors, gauges, power supply and electrical cabinet. I spent several days on the project. The biggest problem was finding, buying and waiting for delivery of all the parts. All in, it has cost me something less than $1,000. They can actually often be found in government surplus.

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    steve-l
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    I hope you know that here are pin wrenches designed just for this task. They don't cost much and they come with different sized pins. The pins fit into threaded holes in the tool with an M9 mm thread, so you can make your own pins if you have a lathe. My point being the correct tool is less expensive than screwing up your gun……..jus saying! Mickey Mouse appears to be alive and well!

    One more point. Taking the shroud cap off is easy. The standard pins on the pin wrench will not fit the DonnyFL adapter because they are too short, so I had to make longer pins to overcome the length of the 1/2"-20 male threads on the adapter.

    • This reply was modified 3 months ago by steve-l.
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    steve-l
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    The shroud on FX guns only provides sound suppression. It does not attach to anything on the gun, so it cannot provide any barrel support. Those "O" rings do nothing except possibly damping vibrations, which in fact on any air gun are either minimal or non-existent. Please remember the issue is shifting zero, not accuracy.

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    steve-l
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    As to what thread is used where, it is a crap shoot. I can tell you that the most common thread used in high pressure air is BSPP……….everywhere. That stands for British Standard Pipe (Parallel) as opposed to BSPT (Tapered). British threads use a 55 degree thread form. National Pipe Threads (NPS)(Straight) and NPT)(Tapered) and Metric threads all use a 60 degree form. All straight threads (NPS & BSPP) require a sealing ring or washer. The washer can be at the top or bottom of the thread and can be copper, aluminum, plastic or steel with rubber. The taper, if you care, on both NPT or BSPT is 3/4" per foot. Tapered threads seal on the thread and require a sealing medium like Teflon tape or thread sealant.

    The most common size for guns and small, not commercial, compressors is 1/8". Please note that even though the thread form is different between BSP(P)(T) and NP(T)(S), the threads per inch is just slightly different and one can thread into the other with light resistance, 28 TPI and 27 TPI respectively. So be very careful.

    Commercial high pressure compressors like the Bauer use both 1/8" and 1/4" fittings again in BSPP. Piping between stages and filters/dryers is heavy wall stainless steel tubing that use ferules for sealing with BSPP compression fittings. These are typically 3/8" and 1/2" BSPP. All connecting tube lines require a bent 360 loop to compensate for thermal expansion and contraction……very important.

    So, the question of how to determine what you have is the conundrum. The correct answer is a set of plug and go/no go gauges. However, these are expensive and only some shops will have them. I use my tap and die sets as test gauges when in doubt. You do not need a full set, as good sets are also pricey. For the air gun enthusiast, only 1/8" NPT, 1/8"NPS, 1/8" BSPP, 1/4" NPT, 1/4" NPS, 1/4" BSPP , 1/4" BSPT, M6. M8 and M10 Taps and Dies are required. These are affordable and well worth having.

    Another confusing issue is pipe sizing is based on the approximate ID and wall thickness is determined by its Schedule. Consequently, the OD of a pipe thread is much larger than the stated diameter number. This is opposed to tubing which is based on its OD with a separate wall thickness number. 

    • This reply was modified 3 months ago by steve-l.
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