Sam Yang question…
Hello to everyone out there as this is my first post. I’ve been lurking for quite sometime and thought I’d like to participate.
Sam Yang Big Bore 44 909 Light Hunter
Sam Yang Big Bore 909S
Thinking about either of these and thought I’d like to get some feedback. What’s the difference between the two other than the obvious like one doesn’t have a pressure guage and one has 30 less fps.
Thank you,
Machine Gun
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Wow. Am I glad I found this place. I have been looking for info on tuning my 909S and I keep hitting stone walls from people that want to sell their information. Here is a free and open discussion. I just saved a bunch of money and time. Thanks.
Reached 390fpe with 465grains .458 flatnose.
make that 2 shots at 397fpe after new modification. 😛
from 3500psi to 2900.
Okay, I will try to smoth out the transfer channel next time
I have changed the spring inside the valve to at much weaker one, this gave about 24fpe. Maybe it can be even weaker, and still close the valve. I don’t know.
What is the optimal size for the valve? standard was 8mm, but 9,5 was far too much for the stock hammer and spring. Perhaps I should just leave it at 8, and focus on makeing the edges round instead.
Edit:
Hm… been working my butt off the last couble of days..
Startet out rounding off all sharp edges. But this resultet in the valve to become larger AGAIN, 8,5mm, which is too much for the stock hammer and spring. So I had to change it back to 7,5mm and the polish it up to about 7,8mm.
I made a new cocking handle, a bit heavyer than the original and a new valve of a hard kind of plastic. The new valve is more optimiced for air flow around it.
I also cut the closing spring for the valce a bit down, so it gives less resistance.
These modifications ended up giving a maximum readout of
Shot one 320fpe ~ 800fps
Shot two 300fpe ~ 772fps
Lee 456-220-1R 226grains
It’s using around 25bars per shot, and the stock is about 20bar per shot.
Drop is about 30fps from one to two 🙄
The 141grain .454 roundball is 900fps
I think it needs a longer barrel, perhaps I will get my hands on one someday.. It’ could also use a better trigger mechanism, but things doesn’t come eazy or cheap in DK.
I got no idea about the groups the gun can make.. and so far it has been all about how much power I could get out of it
smooth out any sharp edges and turns round the edges as much as possible doing so will help the air flow better
have u done anything to the spring in the valve i took the one in my 201s and cut it down a bit just enough spring tension to close the valve
First mod was transfer = 8mm instead of 6mm
It produced 237fpe with .454 roundballs 141grains
It produced 275fpe with .456 roundnose 226grains Lee 2-Cavity Bullet Mold 456-220-1R
We drilled the transfer up to 9mm, and the valve house to 9.5
The piece that goes into the barrel broke off, it seams that it was mounted with a thread. We made a new one with could handle 9mm.
first test gave 92fpe 🙄 with the 456-220-1R
It seems the valve was not able to open a high pressure.. when the pressure was down to 1800psi the power went up again to 216fpe with 456-220-1R. 9,5mm valve is to large for spring and hammer.
We attempted to make a costume made spring our self, but it did not make any big changes.. perhaps 20fpe more than the standard one.
So we had to change back the valve house to 8mm, but I got the idea to change the valve closening spring, to a weaker one.
Now transfer is 9mm except valve opening which is only 8mm.
It has a much weaker closening spring. standard hammerspring!
It produced these numbers
226grains 456-220-1R : 771,5fps – 299fpe
141grains roundball : 886,5fps – 246,1fpe
Does anyone have any idea of what else that could be changed in my gun.. I was hoping for a little more power about 870fps with 226grains – 380fpe.
The transfer channel, has a few sharp edges, like going directly from 8mm to 9,5mm just after the valve.. Does it have anything to say? or is this limiting the airflow alot? The transfer channel is not mirror smoth, quite the oppesite.
Does the design of the female part of the valve “the valve seat” have much to say? Now is more or less just a sharp edge of 8mm. the original designe was more like curved/round edge.
Pleace reply if you got any ideas of what im doing wrong, or right.
thanks butcher
I’ve have ordered a mold for a .456 220grain sludge, it’s round nouse, and has two “compression rings” Its the closest thing I can get my hands one right now.
Regarding the cockinglever… I broke it today, during the dismantling of the gun.. LOL
My goal is to reach about 370fpe and two shots within 20fps.. So I don’t have to holdover on a follow up shot.
In denmark, the largest possible animal to shot with an airgun, would be a fox or goose.. it require 200 joule at 100 meters. (E100 = 200joule)
I think the samyang would have no trouble with a fox 😛
I hope to have the gun ready by the 28. august, for a little airgun get together here in denmark and of cause the hunting season. I will post the final result and details on the gun before that 😀
I appologise for my english, I don’t know any better 😉
Kickeren, I’m happy to see that this post helped you.
I want to suggest that you try out the EPP/UG boolit design. It will go about the same speed as roundball while being slightly heavier, and is incredibly accurate. The .45Slim design is extremely accurate as well (shot a .45inch center to center 3-shot group off my steady stix at 50yards with it).
I consider the number of full power shots to be however many shots I can shoot while staying within a 20fps maximum variance. I’m getting up to 880fps with roundball out of my tuned 909, but only get three “full power” shots (within 20fps) using roundball. EPP/UG’s are much more efficient, and bump the full power shot count up to 4-5 shots. Most all of the boolits I shoot stay within a 15-20fps maximum variance for 4 shots (between 270-285fpe), so I don’t have to hold over to shoot very tight groups (under an inch c-to-c@50 yards being typical).
With my tuned 909, the low powered option when shooting roundball works best when using a 2200psi fill. I get about 5 tight shots around 740fps or so with that set-up. I need to start using that low power setting more often when punching paper.
Be careful with the hammer spring. The impact can crack your stock, and shorten the life of your cocking lever.
Might as well get ahead of the game, and fabricate yourself a new cocking lever or two. I’ve lost track of just how many of them I’ve broken so far, but the one I broke yesterday is the fourth or fifth one I’ve gone thru in the last 3 years.
I think I need one! lol
Very big squirrels in my area. 😆
I’ve got a tuned 909s and I LOVE it….I only get 5 full power shots but the first two are 300fpe+ and I hits like I’m throwing a rock at the target….so far the only victim of this gun has been a marmmit that was raising hell at my buddies place so we sat arround all day one Sat. Waiting for it to wander out and when it did I let a 170grn hollow point (courtesy of Mr.Hollowpoint.com ) fly and it damn near cut him in half at 50yrds…I wish I would have had my camera cause it was a mess….but all in all if you wanna hunt get the 909s if you wanna hunt paper get the 909s (more power is always better) since they do have the half cock feature allowing more low powered shots per fill…just make shure you’ve got an scba tank or a couple of scuba tanks to fill from…..Greg
I’ve got my samyang for nearly a year, and been woundering how to pump up the power.. then I came across this forum, and found this topic very helpfull. This week me and my brother dismantled the gun, and decided to start with drilling the transferport up to 8mm all the way from valve to barrel. My 909s is a never version, wich has a smaller connection piece between valve and “barrel housing”. This connection piece we had to make a new one of.
before the mod the 909 were shooting 181fpe MAX pushing a 141grain roundball at 760ft/s
Now it’s doing 237fpe with the roundball, pushing it down range with 870ft/s
I’m searching for a stronger hammerspring, and of cause planing to make the transfer 9mm. Perhaps make the valve rod a bit thinner, to allow more air to pass from the valve.
Any ideas/suggestions on my mod?
greetings kickeren
The 30 inch long smoothbore barrel wasn’t mine….the guy I corresponded with used it.
I shoot several designs of slug, and have a few favorites. Most are your basic 45ACP, or Cap+Ball cowboy-type designs.
This one was designed specifically for 909 air rifle barrels. Cast by BlackHogDown. The group is a typical one, shot at 50 yards off steady stix.
butcher45 i am intrested about your barrel (pic?) and what do your slugs look like?
I don’t know what the tune entails. It’s all Chinese to me.
I did send these instructions I received from a guy on the Yellow way back when, to a guy I don’t know that has posted on here. He found them useful.
“If you slot the sides of the valve body, ad weight to the hammer, open the transfer port to .360, open the .24 restriction where the barrel slides over the receiver as much as possible you get an even 300fpe with 200g ammo.”
Keep in mind, that Sam Yang at some point started using a narrower transfer port, and possibly a different valve sometime along the way.
Here are his responses over a period of time. He was tuning a 909S.
Hey,
I’m about ready with my tuning project!
There were problems along the way, but they are fixed. I had to cast (of chemical metal) strengthening to the end of transfer port (to that ending part which goes into the barrel) because it fell off when I was drilling it to 9 mm.
I think my gun is from newer edition and has smaller walls for its transfer port, but I managed to make enough room to get the port to the ultimate 9 millimeters. Some parts I first drilled to 8 mm and then ground manually to somewhat 9 mm, afterwards. It was quite a job… I also polished the transfer port pretty shiny and made all the curves smoother.
I also drilled the valve body to 9 millimeters. 9 mm is the maximum also there, because the valve (which is made out of plastic) is 12 millimeters with its brass coating/jacket; the plastic part is the gasket and holds the pressure, though the brass jacket could not hold the pressure: the system would probably leak, if one goes over that critical 9 millimeters.
The hammer and hammer spring are still original and in process (if I happen to do something with them).
It will be hard to put more weight to the hammer, because then I must make some modifications to the spring or other parts (because: just like with transferport, there are built in limits in hammer, spring and valve trinity, namely, not too much room for modifications). For example, if I’d grow the length of hammer, I should cut the hammer spring shorter or the whole thing grows out of picture and keeps the main valve open when in rest. It’s pretty much the way… if you add with one hand, you must take with the other…
You remember my 909S tuning process…?
I think it’s about ready, finally. I chronographed that strange 909, and got pretty fine numbers: 785 feet per second with 300 grainer slug, 405 FPE. And what the best I could get three shots with almost the same numbers. With 400 grainer I could get even better numbers, but that bigger slug is not as accurate as the 300 grainer…
Details of the gun:
Transfer ports are at least 8 mm everywhere (somewhere it’s over 9 millimeter), ports are grinded mirror-smooth, valvebody is 9 millimeter, and there’s stronger hammer spring. I had to make new bushings to the transfer port all along the way from valvebody to the barrel.
And, I changed longer barrel (over 30 inches long), it is smoothbore! I have designed special slug with which I could shoot one inch groups 55 yards (50 meters). One reason for smoothbore is that I could shoot shots with it, because I live in the town and near the town it’s better to shoot shots only (and hunt small pests), slugs could be shot far in the forrest only…
Sam Yang Big Bore 44 909 Light Hunter
Sam Yang Big Bore 909S
Thinking about either of these and thought I’d like to get some feedback. What’s the difference between the two other than the obvious like one doesn’t have a pressure guage and one has 30 less fps.
Thank you,
Machine Gun
The 909 is more versatile……more air for more shots, tighter fps variance in a shot string making for a better plinker/target gun. Still plenty of power for deer when using medium, to heavy slugs (especially when tuned). Can be tuned to 280+fpe.
The 909S is more powerful…..more of a dedicated hunting rifle with more variance in fps between shots (when tuned, anyway). Can be tuned to 350-370+fpe.
I have the 909, and plan on getting another one before this one wears out. Great gun. Mine is tuned to 260fpe, retaining the stock hammerspring.
hey butcher do you whats needed to up the power ? is it as simple as a porting the transfer port and fitting stiffer hammer spring or is it more complicated ?
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I am a gunsmith and I own a 909S.
OK, now that I have read everything I can find, I have some ideas. These are a compilation of the work of many 909S owners that were kind enough to share their knowledge along with some ideas of my own to enhance them.
I plan of doing these steps one at a time to make sure I dont overshoot the goal. If I hit the goal early I will stop modifications. Maybe I will never hit my goal!!
The goal? to have three shots that have a MV of 1000 fps using a .454 round ball using a starting 250 bar charge. As to what is left in the tank, maybe the FPS WILL drop, but it was only 750 in stock form!! Until it drops below 750fps I will call it a viable round.
1. It seems a great improvement may be had by putting a .050 shim washer under the end of the hammer spring. OK, so that is the first one to try. IT IS REVERSIBLE!!!
2. Making it breathe easier only requires making the air flow more open. The airflow around the valve cannot be changed unless the valve is redesigned. One person is doing that. For now, that is outside my talent. But making more air available is easy. The return spring housing has only one purpose, to contain the spring. It is far heavier than it needs to be for that purpose, the spring is not that strong. At least several ways to get more air into it have been designed. One is to slot the housing, another is to drill holes into it and in both cases the sides of the housing must be relieved so the air can get to the slots/holes. Most just file flats on opposite sides of the housing to get flow to the slots.
Drilling holes is the easiest and can be done one hole at a time until you have the flow you want. Another easier way is to open up the hole in the end. This is easy but care has to be used to avoid making it so large that the spring falls through!!! LOL My second step will be to open the end hole. My third step will be to chuck the housing up in my lathe and turn it down just a bit instead of filing flats on the sides. The reduced diameter has to be between the top of the threads and the end of the housing and must not go closer to the “O” Ring. Then I will drill holes slanted toward the valve seat, maybe three at a time around the perimeter, starting small and increasing the size if I see improvements. These holes will be easy to get to for deburing and polishing.
3. Another way to get more flow is to weaken the return spring. This seems to me to be risky because I dont want to make a modification that will cause the valve to “bounce” or even not seal, thus loosing air.
4. Polishing and opening up the holes from the valve into the barrel can also be helpful if still more is needed.
All these mods will be done on a “spare” valve that I purchased from Pyramid Air so if I screw up, my old valve will allow me to return to stock. The porting to the barrel will be last because that wont be reversible.
Comments will be welcome as I dont have a clue what I am talking about, just compiling all the ideas into one location and I have a valve I can hold in my hand and it helps me to visualize the problem.
Thanks for reading this far.