GTA
All Springer/NP/PCP Air Gun Discussion General => Projectiles => Boolit and Pellet Casting => Topic started by: Hobbyman2007 on November 26, 2018, 08:43:26 AM
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I finally got the chance to cast up a bunch of these from the new mold I’ve had for nearly a month now . The mold is a 4 cavity aluminium of typical stellar NOE quality . I didn’t get the HP pin with this one . As cast they are dropping at .2604” in 40:1 rotometals lead. I’ve sized them to .2578” for the 1:14” TJ barrel I plan on shooting them from . They look like a shortened 257420 and I’m hoping to have them shoot just as good . Might get a chance to shoot later today . Will post pics once I get a chance .
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I have that mould as well, but have not cast with it yet.... It is a shortened NOE 260-86 FN, with the rear lube groove and driving band removed.... Originally I think NOE made the 63 gr. moulds by using the 86 gr. tool and simply not plunging it as far into the mould block.... but when they made the last run, they must have made a new tool, because you can now get a GC version....
Bob
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Finally got to test at 100 plus yards ...... I’m more than happy with the results . I’m not sure if I can feed this gun anything it won’t shoot well even the JSB 34 MKII . Anyhow here are a few pics of the groups . These were shot at an average of 910fps . Not quite sub MOA but with a bit of work sizing and more consistent mold temps should get me there. In the second last pic there’s a three shot group well inside 3/8” at the same distance , I did cherry pic that one and was ruined by a couple of flyers .
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Nice !!!
Bob
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That looks good, what's the length of those bullets?
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certainly for the first casting, sizing and sending is showing good sign... I think that barrel it likes to group...
what is nominal/actual bore on your rifles TJ barrel... is it the 25-20 liner? 250/257..?
not that I know what I am doing but some thing whispers try size the just the nose band down some like .252-.253 if set up for it.? ::)
What sort of chamber are you running... I have not read yet how wide the lands are I know there are 6... with that tall of rifling I am guessing a skinny bore/groove ratio...25% bore or less... just trying to imagine how much the round gets swaged by the barrel...
I would be happy with that as a first outing for sure...
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That looks good, what's the length of those bullets?
just a touch past half inch.
http://noebulletmolds.com/NV/product_info.php?products_id=4718&osCsid=14foppuc4p57caf0suhpbs6fd5 (http://noebulletmolds.com/NV/product_info.php?products_id=4718&osCsid=14foppuc4p57caf0suhpbs6fd5)
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I’m using a 1:14 “ TJ barrel . Specs give 257/ 250 , but I’ve slugged the barrel and I’m getting .258/251 . It could be the difference in micrometers. I cast another batch of 500 with a new PID controller on my lee bottom pour , it kept the temp of the lead at a constant 780F . The fill out was much better and had very little difference in weights .
Rkr , they are listed at .514 AOL . These would do well in your new conversion and fit your mag length .
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yeah 780 is were I like to run also but need to learn to run cooler to see if I can get the molds to drop a bit larger for some barrels...
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I’m using a 1:14 “ TJ barrel . Specs give 257/ 250 , but I’ve slugged the barrel and I’m getting .258/251 . It could be the difference in micrometers. I cast another batch of 500 with a new PID controller on my lee bottom pour , it kept the temp of the lead at a constant 780F . The fill out was much better and had very little difference in weights .
Rkr , they are listed at .514 AOL . These would do well in your new conversion and fit your mag length .
Unfortunately the old style .357 magazines have only .472" long drum as the "cuckoo clock" mechanism takes a lot of space. I could ditch the mechanism and rebuild the mag for lengthened .257 drum but that's a low priority project right now.
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I went an entirly different way thany you guys. I started with a .25 RS and converted it to .257.
the mag conversion was easy. Just plunge milled the mag to fit the .257's. worked perfectly, with little head ache. Big + was being able to keep the 9 rounds of the .25 mag.
to make the Mag longer, you can cut shims form thin material shaped to allow the mag to rotate easily. Place shims on back plate of mag, then screw mag back together. It will allow much longer bullets this way.
In fact, the probe retracts so much, that you could mill the rear of the mag slot in the block to allow quite a large shim to accommodate much longer bullets.
Enjoying this thread Guys!
would be very interested in a stronger dual spring combo. Let me know what you end up with. ;)
Mike/Knife
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The dual spring set up I’m using is much stronger than the factory supplied spring . I have it set up with the hammer in free flight with a .040” gap. I’m sure if I were to add preload I could get the velocity well over 1000 FPS but of course the shot count would suffer. We’re in the beginning of winter with close to 2 feet of snow on the ground already , further testing will be in below zero conditions .
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I use this type of dual spring setup in my bigbore Evanixes:
(https://farm5.staticflickr.com/4115/35774072825_6cabe3a44f_c.jpg) (https://flic.kr/p/Wvetv4)IMG_2324_zpsswiaecsi (https://flic.kr/p/Wvetv4) by abbababbaccc (https://www.flickr.com/photos/11843711@N08/), on Flickr
(https://farm5.staticflickr.com/4260/35732912186_efaab82c36_c.jpg) (https://flic.kr/p/WrAvSS)IMG_2323_zpslmqyfzwz (https://flic.kr/p/WrAvSS) by abbababbaccc (https://www.flickr.com/photos/11843711@N08/), on Flickr
It gives rather good air efficiency for a high fpe bigbore while still being easy to cock. When tuned for negative preload I got this 14 shot power curve from my Blizzard.
(https://farm5.staticflickr.com/4024/35774072225_21904dcf39.jpg) (https://flic.kr/p/WvetjH)Low-power-string_zpsc562a75c (https://flic.kr/p/WvetjH) by abbababbaccc (https://www.flickr.com/photos/11843711@N08/), on Flickr
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RKR , that string looks near identical to what I’ve tuned the 63 grainers to shoot at over 12 shots . Both the springs I’m using are in the hammer , yours appears to be one in and the other outside that rides the OD of the hammer . Either way whatever works with what you have on hand .
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Denis, what are the rates and sizes of these springs?
Mike
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Denis, what are the rates and sizes of these springs?
Mike
Knife,
The outer is a .480” x 2.5 “ x .063” with a 18lb spring rate the inner is what I think to be a 2240 spring . I did have to remove the spring guide section from the hammer spring tensioner and I made a replacement from delrin that rides in the inner spring .
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Humm, I have a few different rates for the Maximus here, I may turn down the tip of the guide and fit one and try it out.
thanks Denis!
Mike
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Ok now for my edificatioin. LOL, the longer spring is in full contact with the hammer, No? If so, how does it not contribute to hammer bounce.
Trying to learn here. ;D
Mik
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Ok now for my edificatioin. LOL, the longer spring is in full contact with the hammer, No? If so, how does it not contribute to hammer bounce.
Trying to learn here. ;D
Mik
Mike ,
Both of the spring season I use are the same length , not exactly sure on RKR’s set up but it looks like the inner spring is inside the hammer like factory set up and the heavy spring is on the outside set up with no hammer preload . I have a gap on mine of .040” very little hammer bounce if any .
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The outer spring pushes against hammer skirt while the inner one pushes against the hammer itself being inside it. Both are cut to have the same free ĺength. With adjuster I can then dial from free flight hammer to positive preload as needed.
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Thanks Guy's! Now let the tinkering begin. LOL!!! ;)
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Well, I got er did!
Used one of the springs you sent Daniel, cut it so that I had about 20 tho. free flight, and turned the spring guide down to accept 3/8" of the Maximus spring that was a 9 lb spring. Also cut for the same free flight.
Cold here with strong winds today, but did chron it at 30 35 fps less than spring for RS alone with its preload. Oddly enough, the fps was exactly where I wanted the 44 gr. NOE bullet to be from the get go. Woo-Hoo!!!
Went from 6 good shots, declining after #4 to a full mag, first shot 40 fps low, second dead where I wanted it, and the following 7 shots all within where I wanted to be. Very stable.
When weather permits, I will shoot until I see a real drop and see where she is.
20-25 mph head wind with gust to 35 today, + damp, grrrr!!! Did do a few mods the the Mag. It was slightly resizing the bullets, and I could feel a rough spot as it was cycling the bullet into the bbl. Pushed one back out, and it had a bad scrape on the side starting with a gouge or nick.
the bullets were getting cocked and shaved by the exit hole in the forward plate of the mag.
Accuracy had still not been where I wanted it to be. Well, after re-working the mag by polishing it out to .258 and replacing the tension springs that hold the bullets in the chambers with the correct 90 dro. O rings of rubber, all went very smoothly. No marks on the pellets at all.
The springs were also leaving sever scratches in the bullets. The O rings are smooth as butter, yet have no backing out under recoil issues. I normally lube with 10 wt silicone RC oil on all ag bullets. I will further test to see if the addition of the oil will cause the o rings and bullets to slip under recoil and jam the mag.
I tried 257420's in the mag a few months ago, and the tapered nose caused the bullets to back out under recoil and jam. Not loading a new round. I fashioned a thin back plate piece from very thin cutting board sheet that covered the main loading port, and this stopped the issue with the .257420. The spring was on the tapered nose, and pushed the bullets to the rear under recoil. The NOE's did not have this issue. No back plate interior cover when using them.
First group at 76 yards went into 3/4" in this wind. Second went into less than half inch. Now we're getting somewhere!
Daniel, I ordered 2 o rings just as an experiment. But like you did when ordering springs, I got a bag full. LOL.
Probably a bad time to ship here at the heaviest mailing time of the year, but If you would like to try the, I can sure ship! ;)
I think they are the same size used in the mags of the Diana Outlaw. One of the Outlaw owners suggested them, and they work very well indeed!
Size is Buna O-Rings # 023-90D /Item number is 162907167215
price is 1.75 per fifty, and shipping was a flat 3.00 usd.
Don't know if RKR can get them. Hope so. If not, I can ship after Christmas!
Mike/Knife
Oringsandmore.com Phone-804-437-5859
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Glad to hear that the twin spring set up worked for you . Hope the bullets you’re casting end up on NOE’s list of offerings at some point without having to modify / deck the mold . I’m wIting for the air speed to be delivered and am going to need some sub 40 grain HP bullets to shoot from it .
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Glad to hear that the twin spring set up worked for you . Hope the bullets you’re casting end up on NOE’s list of offerings at some point without having to modify / deck the mold . I’m wIting for the air speed to be delivered and am going to need some sub 40 grain HP bullets to shoot from it .
At the moment they are casting at 43.6 average Denis. I will eventually send the mold out to Eric at hollow point mold service. That will drop them by apx. 4 grains. ;)
Mike/Knife
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Hey Knife when you say 44g NOE are you talking about a decked TL 255-rf..?
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No Sir, it is the 84 gr Ranchdog fp. I use it un molested but with hp by Eric in the Talon?Dor. I already had the mold decked to throw at 60 grains for people with .257 condors, but without Doug's valve. Just shaved it a bit more. ;) I currently have two of these molds. One at full weight and HP, and one at the 43.6 wt.
Well, Denis, the valve gave it up today. GRRRRR!! I'm being very-very good there Santa! ;D
Mike/Knife
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No Sir, it is the 84 gr Ranchdog fp. I use it un molested but with hp by Eric in the Talon?Dor. I already had the mold decked to throw at 60 grains for people with .257 condors, but without Doug's valve. Just shaved it a bit more. ;)
Well, Denis, the valve gave it up today. GRRRRR!! I'm being very-very good there Santa! ;D
Mike/Knife
Snapped stem or chipped seal? Both seem to be rather common occurences unfortunately. Making a new one from HSS drillbit without o-ring groove and poppet from PET-P is recommended.
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RKR, I will be doing exactly that today. I have the PET-P on hand. Just wondering if there is something not exactly right with the actual seal lip in the valve body itself. GRRRR!!!
Knife
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RKR, I will be doing exactly that today. I have the PET-P on hand. Just wondering if there is something not exactly right with the actual seal lip in the valve body itself. GRRRR!!!
Knife
You mean the horizontally split o-ring type valve seat in the valve body? I really don't like it. It means you need to use bigger diameter poppet or it will squish itself in to the valve throat. In my .45 I ground off the o-ring thingie and used just a flat surface around the valve tunnel with reduced poppet diameter. Good enough for 300 fpe.
(https://farm5.staticflickr.com/4010/35732908286_ce59e7a9fc_b.jpg) (https://flic.kr/p/WrAuHC)valve_zpsfzujhqfc (https://flic.kr/p/WrAuHC) by abbababbaccc (https://www.flickr.com/photos/11843711@N08/), on Flickr
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Thanks for the suggestion RKR!
the issue ended up being the thru hole for the poppet stem was too large in dia., making for a sloppy fit. I selected a screw machine drill bit that was just able to fit thru without resistance. Made a PET-P poppet for it, and dressed the valve seat, as the wobby pin caused the metal jacket around the poppet to cause a cut in it.
Wish I had read your post sooner. When this one fails, I will plunge mill it with a 1/2 endmill and have a nice flat surface. ;)
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Do you have any issues with the valve leaking at low pressures with the flat seat?
End mill, or stone ground? If ground, how did you keep it square? (true)
Mike
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Do you have any issues with the valve leaking at low pressures with the flat seat?
End mill, or stone ground? If ground, how did you keep it square? (true)
Mike
It has kept pressure well, I think about one and a half year now with only few shooting session. I did it with a bench drill, took a fitting steel bar and ground the end flat and square against a sand paper. Then used fast glue to slap pieces of sand paper to the end and kept "drilling" the valve block until the "o-ring" was flat. After that finish with 600 grit paper at the end of the bar. If you grind that o-ring shape flat the normal valve should work as the rim won't touch the seat and it should also be easier to open. You should also get some extra valve opening as the valve sits a bit further in the block.
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Sounds like a plan RKR!
Thanks 8)
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Talked to Travis today, and he suggested another thing to try with the valve seat. Will be trying both.
I made the poppet too short, and it allowed it to crack at the end of the (tip) of the poppet pin. Will lengthen the poppet body today. ;)
Mike
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I posted a wrong photo, this is the actual valve I'm using as of now. Just a straight HSS drill rod piece as the shaft.
(https://farm5.staticflickr.com/4012/35774073185_d36780ee6b_c.jpg) (https://flic.kr/p/WvetBg)IMG_1973_zpsvq6ktmcw (https://flic.kr/p/WvetBg) by abbababbaccc (https://www.flickr.com/photos/11843711@N08/), on Flickr
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I did the same Ric. It is working fine so far. LOL!!! ;)
I did a simple plunge mill of the actual seat using a 1/2" carbide endmill. It was inserted into valve body to completely flatten it, then broke the edge with rubber abrasive and used the hand drill to pull the shaft of the poppet while pulling it tight against the seat.
Sealed fast, no leaks. 8)
Mike
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Finally, Success!
It's been quite a long road for this. Tiny issues kept popping yup. Never could get the accuracy wanted. Tried sizing, re-polish bore, crown, added set screws to the breach to hold barrel tighter. You name it.
As usual, it turned out to be the simplest of issues. The stock to action screw was bottoming ut. What felt tight, was in actuality, doing nothing at all. LOL! GRRRR!!!
I have Carbon Fiber tubing coming to stiffen the bbl. that should make quite a difference.
Thanks to Hobbyman, OneShot, and Hobbyman and Travis for keeping me after it!
Here are the initial results. Very worthwhile I think. Started at 2900 psi, and it grouped low. Once it reached 2700 psi, man, it was a laser!
The 5 shot group at 80 yards measures .390 X .309 inch. 8)
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the carbon tube came in. Very poor quality. both ends were shattered. They shippen in a trash bag, an in bubble wrap. It didn't survive.
I will order higher strength and thicker wall tube from Japan after the first. ;)
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The new Poppet an stem is holding up well. It has already passed the life cycle of the factory poppets when shooting bullets.
Got a couple thousand on it so far. Finger staying crossed!
thank Hobby, RKR, OneShot, and Travis for the advice on the spring setup, valve seat improvement and poppet construction. working well, and picked up another 20-30 fps at a lower spring setting. ;) While allowing more shots in the sweet zone. 8)
In fact, tried the NOE cast pellets again today, had to start at 2400 and shot several mags down to 1200 psi. No leakage! Now I enjoyed that!!! (And they shot well in the .257 19 inch barrel. Something they didn't do in the factory barrel). Odd thing is, the JSB's shoot great out ot the factory barrel, and poorly out of the .257. go figure! Guess I'll have to shoot those low cost, almost free NOE Pellets instead. ;D
Mike
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RKR, just incase your watching this thread, I installed a .25 non choked W/L barrel and sized the NOE's down. The 50 grainers.
Here are the results. And check out that nice mushroom shot into a one gallon water jug. 8)