I'd say 40fpe is rather simple. Maybe 55fpe to be wrung out of it sans any heavier efforts such as a plenum
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Benjamin Gunnar listed on PA now.
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Two more small questions for you, what spring or type of spring should I be looking for to use for the hammer spring and where would I begin looking at plenums for that rifle?
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Let´s take the last Q first.
Short reply is that if you want to keep it within realms you could use the reg pressure gauge for entry port, it just needs to be enlarged somewhat at the seal for use as entry. Gauge port is on thread M10*1mm
Me, i´m always conservative as *ell when it comes to pressure vessels in as much that i basically use steel only, and then high pressure steel tubing. Ie; stuff made for the task at hand.
Yes. I´m more than capable of making the pts needed out of aluminium, it´s just.. suspenders n belt. Point being that aluminium has a finite life while correctly designed steel does not (this is defined as 10 million cycles).
In short i use steel as that way i´ll most likely never have someone walk up to me down the line to tell that one of my plenums didn´t make it and that there´s bodily harm involved.
Silly? Call me whatever.. that´s just me.
That being said i guess most pressure vessels you´ll run into ARE out of aluminium. As such i´d say 6086 or 7075 (both as T651) is what to go for. Know many of the chinese mans use 6082, which i honestly feel is so-so at best and that being said knowing all to well that there´s TONS of such bottles and what not on the market that works perfectly fine.
What many fail to realize is that the entity of a plenum can be regarded in many more ways than one and often times the volume arrived on is therefore a matter of personal prefs. So called standing waves and what not CAN come into play and god knows what more..
Having established that rambling.. for a 100J gun go for something along 60-70cc´s for starters i´d say. Seeing that the stock "plenum" on the NYX/Gunnar is hoovering around 20cc´s (if memory serves, did the math but it´s been a while..) anything added will sure help.
There´s those claiming that 10cc´s will support 10fpe and then there´s those claiming that every 10cc´s will support 20fpe.
Me i´m of a different notion and having done the math the truth as i regard it is that the curve we´re talking about is logarithmic to sense. Thus, the more power we´re to extract the larger the plenum needs to be, and that NOT in a linear fashion.
None the less. A rather reasonable 60-70cc´s should get you well under ways and most likely satisfy your power hunger, and then some.
Using the reg pressure port (underneath the gun/main block) might look a tad off but truth be told it´s by FAR the easiest way "in" for the novice. Point being that the diameter and the threads used will take the abuse, within limits of course, why as long as you protect said plenum from absolute mayhem as far as external force you´ll be just fine.
Spring then.
Here i believe MANY cross the bridge for water cause as been touched on in the current Notos thread you can sure get lost on this one... and no matter if you do the math the real question is if you´re really all that much for the wiser.
Me i´m an engineer and that crap is sorts of "engineer 101" together with doing the math for pressure vessels and so forth. Doesn´t help more than point the right direction as the issue in itself can be rather complex.
Thus.
For the novice i´d say look springs up based on wire diameter, outer diameter of spring and No of coils vs length. Don´t bother getting into so called K values and what have you, just as a piece of friendly advice.
However.
That means that springs by NO measure have to be something "pcp specific" as there really is no such thing. Get the stocker out of the gun and bring that with you for your local hardware store to see what they can come up with. Try the thing-s for size.
Chrono never lies and nor does consumption of air.
That said please be aware that there´s no such thing as free lunch. Granted, the NYX/Gunnar sports a 500cc bottle but no matter as... as power goes up you will consume more air and at a certain point will run into a shot count that simply ain´t acceptable to YOU.
Sure.
Hammer bounce and so forth sure doesn´t help, but again.. as long as not "dead locked" a matter that carries an absolute array of amounts of evil.
But by all means, read up on hammer bounce and its effects. That´s just healthy seeing what you ask.
Believe there´s even sorts of tutorial vids on YT on the matter. Just be aware that there´s very, not so say extremely, little that´s either black or white as far as this. Most of it is different shades of grey
Short reply is that if you want to keep it within realms you could use the reg pressure gauge for entry port, it just needs to be enlarged somewhat at the seal for use as entry. Gauge port is on thread M10*1mm
Me, i´m always conservative as *ell when it comes to pressure vessels in as much that i basically use steel only, and then high pressure steel tubing. Ie; stuff made for the task at hand.
Yes. I´m more than capable of making the pts needed out of aluminium, it´s just.. suspenders n belt. Point being that aluminium has a finite life while correctly designed steel does not (this is defined as 10 million cycles).
In short i use steel as that way i´ll most likely never have someone walk up to me down the line to tell that one of my plenums didn´t make it and that there´s bodily harm involved.
Silly? Call me whatever.. that´s just me.
That being said i guess most pressure vessels you´ll run into ARE out of aluminium. As such i´d say 6086 or 7075 (both as T651) is what to go for. Know many of the chinese mans use 6082, which i honestly feel is so-so at best and that being said knowing all to well that there´s TONS of such bottles and what not on the market that works perfectly fine.
What many fail to realize is that the entity of a plenum can be regarded in many more ways than one and often times the volume arrived on is therefore a matter of personal prefs. So called standing waves and what not CAN come into play and god knows what more..
Having established that rambling.. for a 100J gun go for something along 60-70cc´s for starters i´d say. Seeing that the stock "plenum" on the NYX/Gunnar is hoovering around 20cc´s (if memory serves, did the math but it´s been a while..) anything added will sure help.
There´s those claiming that 10cc´s will support 10fpe and then there´s those claiming that every 10cc´s will support 20fpe.
Me i´m of a different notion and having done the math the truth as i regard it is that the curve we´re talking about is logarithmic to sense. Thus, the more power we´re to extract the larger the plenum needs to be, and that NOT in a linear fashion.
None the less. A rather reasonable 60-70cc´s should get you well under ways and most likely satisfy your power hunger, and then some.
Using the reg pressure port (underneath the gun/main block) might look a tad off but truth be told it´s by FAR the easiest way "in" for the novice. Point being that the diameter and the threads used will take the abuse, within limits of course, why as long as you protect said plenum from absolute mayhem as far as external force you´ll be just fine.
Spring then.
Here i believe MANY cross the bridge for water cause as been touched on in the current Notos thread you can sure get lost on this one... and no matter if you do the math the real question is if you´re really all that much for the wiser.
Me i´m an engineer and that crap is sorts of "engineer 101" together with doing the math for pressure vessels and so forth. Doesn´t help more than point the right direction as the issue in itself can be rather complex.
Thus.
For the novice i´d say look springs up based on wire diameter, outer diameter of spring and No of coils vs length. Don´t bother getting into so called K values and what have you, just as a piece of friendly advice.
However.
That means that springs by NO measure have to be something "pcp specific" as there really is no such thing. Get the stocker out of the gun and bring that with you for your local hardware store to see what they can come up with. Try the thing-s for size.
Chrono never lies and nor does consumption of air.
That said please be aware that there´s no such thing as free lunch. Granted, the NYX/Gunnar sports a 500cc bottle but no matter as... as power goes up you will consume more air and at a certain point will run into a shot count that simply ain´t acceptable to YOU.
Sure.
Hammer bounce and so forth sure doesn´t help, but again.. as long as not "dead locked" a matter that carries an absolute array of amounts of evil.
But by all means, read up on hammer bounce and its effects. That´s just healthy seeing what you ask.
Believe there´s even sorts of tutorial vids on YT on the matter. Just be aware that there´s very, not so say extremely, little that´s either black or white as far as this. Most of it is different shades of grey
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Hey do you know,can you convert an fx impact m4 from 30 up to 35? I know you can take the 35 down to the other calibers. But I'm wondering if like I said, you can go up with em ..
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Give that a second thought.
The Throne, both versions, sure lacks plenum volume as well
Unit sports what Reximex call a "pre-chamber" stock, but that thing is like the original plenum on the Impact, along 20+cc´s and that sure won´t cope.
So as you can see in the picture i enlarged that with one by me out of steel that´s on approx 100+cc´s, which sure did the trick.
However...
Reximex is as far as i´m concerned a Turkish manufacturer on the move. Their latest designs the NYX per above and in turn this.
The Meta Premium. Comes in that roller flight case you see in the picture. The thing is that the Meta Premium is an upscale piece of kit vs the Throne it isn´t even funny and no doubt build quality as well as material choice and design is right up there. Just, still with a very reasonable hang tag (about half of what an Impact will run you)
It carries loads of features, some to expect and some not.
It sports a 90cc plenum stock. A 700mm barrel. 480cc tube (when aluminium, they offer carbon fibre ones too) and what not.
In turn this anti bounch device... wicked!
What it does NOT is sport transfer ports enough to really make the thing haul, this is where YOU the end user come in.
Mine there is a 25cal right so when drilling the transfers out what i didn´t account for was "breaking into water" (cutting into another hole).
Well. I did.
As it turned out there´s a small hole for a spring and detent for the mag and as i went past 6mm by any margin for the transfer i broke into that hole and couldn´t for the LIFE of me figure out where that leak was at that made the rifle loud, down on power and so on.
Well. Right there.
Remedy was REAL simple. I threaded and shoved an allen stoppie down that hole set with Loctite and then, as can be seen, yet another allen stoppie at the end of said hole.
Presto.
Where this unit is at it´s tossing the max length 25s the mags will take, which is 42 grains, at an easy 1050-1070. It´s currently setup "stffer" than my M3 even, and sure hands the M3 a run for the money no doubt.
Caveat to the Meta is that you´ll have to enlarge the transfers yourself. Stock they´re on something like 4 mills, and that´s not even CLOSE to what the design will take. Put the suggestion to Reximex why not just set a "performance online shop" up where they for instance offer main blocks so modified. No doubt there´s money to them in that too.
Since i´ve talked the situation over with Reximex (the lack of mag depth - for even heavier fudder) but as of current do not know where they´re at on this. Again.... an aftermarket main block is called for
See. The point here is that Rex and Kral are under the same owners right and it just so happens that the Kral mags are absolute deadringers for the Rex ones. In other words all that´s needed is for Rex to walk across the yard and ask Kral for their mags and then change ONE measurement on the CNC that makes the main blocks and we´d be there so to say.
On my own there in the pictures, as i keep heavy machinery i´m giving thought to just picking 2 or 3 Kral mags up and set the main block on the mill of mine and be done with it already.
None the less. The Meta Premium is an absolute *rapload of gun for the money.
Sans flaws then?
No. Of course not, but the thing is they can all be handled - which is more than can be said for many many other pcp´s out there.
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Thank you for sharing your experience with us, Mr. Racing. The Reximex brand has not penetrated the U.S. market yet, so there is little first-hand knowledge to be shared. I feel my Tormenta is lacking a bit in stock form for a .25 cal. My unregulated gun runs from 205 bar to 200 bar - then it falls off the cliff. I do get about 40 shots within reason and that is perfect for my pest control efforts. 4 full mag and a full load of air = about 2-3 hours of pest control.
I am pretty comfortable with the Kral designs, but have not done much exploratory surgery on the Rex, yet. Thanks again for posting about your findings.
I am pretty comfortable with the Kral designs, but have not done much exploratory surgery on the Rex, yet. Thanks again for posting about your findings.
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So far I took your advice and I added a slightly smaller diameter spring into my stock hammer spring. I could tell right away that fps was up and also I have a very good suspicion that now the valve open for a tad longer when I take a shot. Very noticeable difference! I haven't gone any further yet, but I do enjoyed shooting a stronger gun all weekend. Thanks again racing!Give that a second thought.
The Throne, both versions, sure lacks plenum volume as well
Unit sports what Reximex call a "pre-chamber" stock, but that thing is like the original plenum on the Impact, along 20+cc´s and that sure won´t cope.
So as you can see in the picture i enlarged that with one by me out of steel that´s on approx 100+cc´s, which sure did the trick.
However...
Reximex is as far as i´m concerned a Turkish manufacturer on the move. Their latest designs the NYX per above and in turn this.
The Meta Premium. Comes in that roller flight case you see in the picture. The thing is that the Meta Premium is an upscale piece of kit vs the Throne it isn´t even funny and no doubt build quality as well as material choice and design is right up there. Just, still with a very reasonable hang tag (about half of what an Impact will run you)
It carries loads of features, some to expect and some not.
It sports a 90cc plenum stock. A 700mm barrel. 480cc tube (when aluminium, they offer carbon fibre ones too) and what not.
In turn this anti bounch device... wicked!
What it does NOT is sport transfer ports enough to really make the thing haul, this is where YOU the end user come in.
Mine there is a 25cal right so when drilling the transfers out what i didn´t account for was "breaking into water" (cutting into another hole).
Well. I did.
As it turned out there´s a small hole for a spring and detent for the mag and as i went past 6mm by any margin for the transfer i broke into that hole and couldn´t for the LIFE of me figure out where that leak was at that made the rifle loud, down on power and so on.
Well. Right there.
Remedy was REAL simple. I threaded and shoved an allen stoppie down that hole set with Loctite and then, as can be seen, yet another allen stoppie at the end of said hole.
Presto.
Where this unit is at it´s tossing the max length 25s the mags will take, which is 42 grains, at an easy 1050-1070. It´s currently setup "stffer" than my M3 even, and sure hands the M3 a run for the money no doubt.
Caveat to the Meta is that you´ll have to enlarge the transfers yourself. Stock they´re on something like 4 mills, and that´s not even CLOSE to what the design will take. Put the suggestion to Reximex why not just set a "performance online shop" up where they for instance offer main blocks so modified. No doubt there´s money to them in that too.
Since i´ve talked the situation over with Reximex (the lack of mag depth - for even heavier fudder) but as of current do not know where they´re at on this. Again.... an aftermarket main block is called for
See. The point here is that Rex and Kral are under the same owners right and it just so happens that the Kral mags are absolute deadringers for the Rex ones. In other words all that´s needed is for Rex to walk across the yard and ask Kral for their mags and then change ONE measurement on the CNC that makes the main blocks and we´d be there so to say.
On my own there in the pictures, as i keep heavy machinery i´m giving thought to just picking 2 or 3 Kral mags up and set the main block on the mill of mine and be done with it already.
None the less. The Meta Premium is an absolute *rapload of gun for the money.
Sans flaws then?
No. Of course not, but the thing is they can all be handled - which is more than can be said for many many other pcp´s out there.
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Can you explain to me more about porting?@ Derick.
First up you need to get a feel for the unit and how it´s put together.
That does not by default mean that you have to rip the entire thing apart, it means that you need to get familiar with the basics.
Basics in this case for instance, how to get the rear stock off (which you do by unturning that massive castell nut at the base of it vs the main block).
There you´ll notice the plug for the hammer spring.
Other end of the block is where the regulator pressure is adjusted.
Btw.
As soon as you rip into the HPA side of the gun ALWAYS "de-gass" it. Remove the bottle (screwed on) and then use the onboard little allen stoppie on the block that keeps the Foster fitting and main pressure gauge to relieve the gun of the rest of its pressure.
Never EVER get into the high pressure side of a pcp that still retains air.
First tip is simple as pie and very very easy to handle.
The stock plug for the hammerspring, that thing needs a hole and a thread to make the thing adjustable. I opted for M8 (if memory serves) and i used an allen stop screw on said dimension where i made like a "shelf" on it out front to fit/center a washer. This rather large washer is in turn what acts vs the spring, not the screw in itself. I of course did this on a lathe but it can just as well be done rather crude using a file or a die or bench grinder.
Presto, adjustable hammer spring pressure.
So. Use an as long such M8 stoppie as you can get a hold of (if in the US feel free to go 5/16 thread, might be an idea to make that UNF even). Then.. turn it in and keep doing until the gun won´t cock. Back off 1 to 1,5 turns and put the unit over the chrono. You should see a marked difference in pellet speed.
Stock spring is rather meek and can sure (should) be replaced by any generic spring that hands more power/force. Pick your poison.
It being a side lever brings it´ll take quite a bit of spring need be without turning "Godzilla" to cock the unit.
Next up to be honest is porting the unit. When doing so keep the old "truth" at the back of you head, that you should never even give thought to going larger than caliber for regulated guns. Fact is, for starters keep it at like 5mm for a 22 and 5,5mm for a 25. Mind you, this then my OPINION and in essence mainly said to keep you on the safe side.
Porting is done using regular drill bits.
One absolutely imperative part to that though is that ALL holes affected by the drill bit HAS to be deburred when done. Any burrs left will eat o-rings alive in a heartbeat.
One caveat here is the power adjuster. The entire flow path of course needs to be ported, and Kral n Rex typical power adjuster can come to present an issue as those need to be drilled through together with the rest of the flow path.
When you do make sure the o-rings on the power adjuster are removed. The power adjuster, its clicks, is cotrolled by a small spring n ball bearing. These come to the letter rushing as you let go of the small allen stop screw that comes in from the front of the block to be able to remove the adjuster. Be aware of this so you won´t have to spend 3hrs on your knees finding that small ball and spring.
On my particular one there i went up in size on the adjuster and made the hole for it 10mm flat by use of a reamer. This as i ported it as large as i did and wanted to regain resolution on the dial. Thus i of course turned new inserts for the adjuster on the lathe to boot. But for lesser degrees of porting the stock thing will suffice just fine.
That should get you going at least. For reg pressure this both can and should be raised together with more intense hammerspring (as any other PCP really) and i´d wager that sans an external plenum that thing of yours when the above is done and done right will come to a rest around 170bar and approx 70J using either generic 25,4´s in 22 or 33,95´s in 25. The latter with the upper hand power wise.
Why around 70?
This is in essence a matter of LACK of what´s called plenum volume. An entity of air AFTER the regulator. Regs sure don´t flow worth a damn, which is why higher horsepower setups always sport plenums, installed one way or another.
To hand an idea another puff i´ve been working on lately. A rather old design by now, the BSA R-10. This one in 177cal. Seeing its age it´s rather cumbersome to the build but that being said one thing´s for *amn sure and that´s that the design was never intended for any higher horsepower applications. Thus what i did was fab me a rather "small diameter" plenum (25mm outer) that wouldn´t completely turn the beautiful design of the R-10 bonkers. The added plenum is that smaller tube right besides the barrel in the picture.
Word of advice on external plenums and the fabrication thereof though, never EVER get even close to that if you´re not 100% in the loop and know what you´re doing. Mistakes at that level can be lethal even, pressures we fool around with here are NOT to be played around with. So no. External add on plenums is NOT something to put together with a MIG welder on a vise.
Just to be blunt and very clear on the matter.
Anyways.
That BSA is now, as a 177, tossing H&N´s 20 grainers around the 1060-1070 mark at will, then handing approx 70J. So yes, the 177 can sure be had to perform too.
Accuracy won´t really be affected by any of the above, and with the reg pressure together with the now adjustable hammer spring you should soon enough find a new benchmark for the unit where it´ll hand really good accuracy.
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@ Derick.
What do you want to know?
For the most part enlarging the so called transfer ports, which entails the exhaust port on the valve and the barrel entry too, is rather straight forward. Just use a drill bit of choice and common sense.
The drill bit to rest though... follows what´s just as important and that is to deburr all them new holes free from flash n burrs. This HAS to be done or them will eat the o-rings in case for breakfast.
I tend to do this with a small round "diamond head" file on the Dremel tool. Works great. Just make sure the block et al is secure on a vise and that you have good lighting so you see what you´re doing and you´ll be fine.
Can´t recall if yours is a 22 or 25, but as it´s a regulated piece of kit i say start with 5mm for a 22 and 5.5mm for a 25. You can always climb up from there. Harder to redo the material back on there..
Word of advice is that you never go beyond caliber as far as transfer port diameter. That is NOT for the novice. Actually, if a 25 i´d say stay at 6mm tops.
As you can figure though, if the hobbyist in case isn´t all thumbs and is able to pick the rifle apart to that degree.. he will surely be able to drill the ports at home (and deburr) in his garage too.
Nope. There´s no "magic" to this what so ever.
What do you want to know?
For the most part enlarging the so called transfer ports, which entails the exhaust port on the valve and the barrel entry too, is rather straight forward. Just use a drill bit of choice and common sense.
The drill bit to rest though... follows what´s just as important and that is to deburr all them new holes free from flash n burrs. This HAS to be done or them will eat the o-rings in case for breakfast.
I tend to do this with a small round "diamond head" file on the Dremel tool. Works great. Just make sure the block et al is secure on a vise and that you have good lighting so you see what you´re doing and you´ll be fine.
Can´t recall if yours is a 22 or 25, but as it´s a regulated piece of kit i say start with 5mm for a 22 and 5.5mm for a 25. You can always climb up from there. Harder to redo the material back on there..
Word of advice is that you never go beyond caliber as far as transfer port diameter. That is NOT for the novice. Actually, if a 25 i´d say stay at 6mm tops.
As you can figure though, if the hobbyist in case isn´t all thumbs and is able to pick the rifle apart to that degree.. he will surely be able to drill the ports at home (and deburr) in his garage too.
Nope. There´s no "magic" to this what so ever.
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