Author Topic: SS valve in the .22 Mrod  (Read 660 times)

Christopher

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SS valve in the .22 Mrod
« on: February 09, 2018, 05:52:59 PM »
Thought I would share my initial thoughts on the SS valve that I got from JSAirrifles. 

AS the title says, it went into a .22 Marauder, factory barrel, MDS hammer, .187 matched porting, .054" wire diameter spring (not sure of the pound rating, 10 lb maybe??)

Also I put a Huma regulator in it that I have had for a while. Just as a footnote I'm not an expert tuner and know nothing about using regulators. I say that because I know that others have done much better than this tune that I'm going to share.

The thing that hurts me the most here is the small plenum. The Huma reg has approximately 16cc of plenum and the best I could tell there is about another 4cc's in the valve. So, I'm working with a 20cc plenum here. i set the reg at 155 bar/2350 psi to help compensate for the smaller plenum. According to my measurements I have right at 200 cc of HPA capacity.

18.1 grain JSBs plateaued at 990 fps which happened at 7 turns of preload. 25.4 gr Monsters hit the plateau at 860 fps and I could tell it was going to be a airhog judging by the sound. 860 wasn't as fast as I would like to have it shooting so decided to go with the 18.1's and back it down to the knee at a 930 fps average. Yes, 860 with the Monsters is more energy than 930 with the 18.1's but I was tuning this for my son and he enjoys hunting and I this would help him with the trajectory shooting flatter at the normal ranges that he shoots at.

So, with a 3200 fill down to off the reg I'm getting 30 shots at 930. That works out in the neighborhood of 1.35 efficiency. Not stellar but far above shabby :)
Probably could have done better, but its a real pain to degas the gun, adjust, refill, test, and repeat when you hand pump so i just stuck with what i had the first time....

Some observations about the SS valve:
1. Cocking is easier. Had a TSS in the gun and took the inner spring out so obviously it's easier. Not a whole lot, but quite noticeable. Can't quantify it for you.
2. Seems to be pretty efficient for the air that it's moving, which is always a plus.
3. The most profound thing to me about the valve (with this tune) is how quiet it is. I mean it sounds like its shooting sub 700 fps. It is unbelievable how much difference it made. The MDS hammer has a hammer throw adjustment screw, which is metal. So which it slams into the valve stem that is now by far the loudest thing about the gun.

This isn't meant to be a thorough review of the SS valves capabilities but just my first impressions with the valve. And wanted to says thanks to Travis, Lloyd and the others that were involved in designing and making this part for the airgun community.

Chris


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oldpro

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Re: SS valve in the .22 Mrod
« Reply #1 on: February 09, 2018, 06:21:40 PM »
 If your going to regulate it and run that kind of power I would open the TP up on the valve and barrel to 80% of bore this will lower the regulator set pressure quite a bit and extend the shot count also. The other side effect will be less hammer strike and even less cocking energy. JMHO and thanks Chris for both buying and taking the time to share your experience.
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rsterne

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Re: SS valve in the .22 Mrod
« Reply #2 on: February 09, 2018, 06:41:02 PM »
Unless I misunderstood, he is already over 80% of bore, it's a .22 cal running 3/16" ports (85%).... I wouldn't go any bigger if that's the case....

Bob
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Christopher

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Re: SS valve in the .22 Mrod
« Reply #3 on: February 09, 2018, 06:55:18 PM »
Yes Bob....the barrel, TP and the valve are all .187".

Chris
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rsterne

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Re: SS valve in the .22 Mrod
« Reply #4 on: February 09, 2018, 07:13:03 PM »
I am surprised that is all you are getting with those monster ports at that pressure.... Have you tried adjusting the preload and recording a curve to see where the plateau and the knee are?.... My 2260 HPA shoots 18 gr. JSBs at 960 fps on only 1600 psi with only 0.166 ports on a modded Disco valve.... 24" barrel not 20" though....

Bob
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Christopher

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Re: SS valve in the .22 Mrod
« Reply #5 on: February 09, 2018, 07:19:41 PM »
I've got it wrote down somewhere. As soon as I find it I'll post it up for you to take a gander at......

Chris
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Christopher

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Re: SS valve in the .22 Mrod
« Reply #6 on: February 09, 2018, 07:35:42 PM »
All of these shots are of course regulated at 2350.  Shooting the 18.13 jsb

No preload:  891
1 turn: 933
2 turns: 948
3 turns: 964
4 turns: 966
5 turns: 971
6 turns: 980
7 turns: 977

Chris
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rsterne

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Re: SS valve in the .22 Mrod
« Reply #7 on: February 09, 2018, 08:13:13 PM »
With that plateau, your maximum usable velocity would be 948 fps @ 2 turns preload.... so anything in that 1-2 turn area should be fine.... I'm a bit surprised that your small plenum is requiring that much pressure to get those velocities.... I guess the shorter barrel is part of the reason....

Bob
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Dairyboy

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Re: SS valve in the .22 Mrod
« Reply #8 on: February 10, 2018, 05:44:53 PM »
Nice results! I am going opposite as you and instead of regulating going big power. So far on only .140 ports I can hit 40fpe with 18gr with only about 3 turns CW on stock hammer spring. I just got beasts in today and am going to test those out and see how accuracy is and then if there good I'll open up the ports and let it breathe!
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John 3:16

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oldpro

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Re: SS valve in the .22 Mrod
« Reply #9 on: February 10, 2018, 07:21:28 PM »
All of these shots are of course regulated at 2350.  Shooting the 18.13 jsb

No preload:  891
1 turn: 933
2 turns: 948
3 turns: 964
4 turns: 966
5 turns: 971
6 turns: 980
7 turns: 977

Chris
That doesnt seem right are you going by gun gauge or by tank fill gauge?
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Christopher

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Re: SS valve in the .22 Mrod
« Reply #10 on: February 10, 2018, 08:03:39 PM »
Travis,
Going by the gauge on the hand pump. Just a Benjamin hand pump. Probably not the most accurate, but I would put more faith in it than the gauge on Mrod for sure. As far as knowing about the setting on the reg, I just went by the little mark on the sticker and set it for a 155 bar. I was actually hoping that it would have pushed the 25.4 gr monsters in the 890-900 fpe range, but didn't for some reason  ::) Might tear back into one of these days but for now my boy is just loving it.  ;)

Just as a side note, JSA needs to look at having a quality 1" gauge manufactured to replace the factory ones that we all love to hate so much.

Chris
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oldpro

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Re: SS valve in the .22 Mrod
« Reply #11 on: February 10, 2018, 08:43:26 PM »
 I would open the jet up .005-.010 that should get your power up and lower the set pressure.
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Christopher

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Re: SS valve in the .22 Mrod
« Reply #12 on: February 11, 2018, 03:01:12 AM »
What size jet is in the .22 valve?

Chris
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oldpro

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Re: SS valve in the .22 Mrod
« Reply #13 on: February 11, 2018, 10:17:43 AM »
.037
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