Fx transfer port and prope mod.

I got the .25 dual TP Huma modded along with the OEM probe. It looks good to me as far as flow path. I didn't like the air crashing in to the top of pellet ring, so I cut off a

part of that section. I believe this should get me a little more over stock. Will be testing this and the dual valve spring setup soon. I am planning on filling in the small recessed part of the probe as well

The Huma dual port by itself had no improvement on my 22 cal Dreamline Classic. The ones they are shipping now are wider than the one shown by spyde82. In fact, it looks more like his modified one.

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I just received two Huma ports yesterday from Trenier Outdoors. They may be from old stock as they don't look as wide as the pictured mod or even close to that.

The one thing I do like about these Huma dual TP ports is that the O-ring groove must be shallower as the probe fits more snug. The OEM probe and port is very loose together. I just replaced the breech seal 100 shots back or so. I don't see now how air is not getting past the loose probe. It's been pushing 70 FPE in .25 cal, so not too terrible. I think the Huma will be better with the tighter tolerances.

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Just be sure it's not too tight. I recall reading a few slipped by that were tight enough to deform the pellet skirts on chambering. 

The Huma dual port by itself had no improvement on my 22 cal Dreamline Classic. The ones they are shipping now are wider than the one shown by spyde82. In fact, it looks more like his modified one.

Click to expand...

I just received two Huma ports yesterday from Trenier Outdoors. They may be from old stock as they don't look as wide as the pictured mod or even close to that.

The one thing I do like about these Huma dual TP ports is that the O-ring groove must be shallower as the probe fits more snug. The OEM probe and port is very loose together. I just replaced the breech seal 100 shots back or so. I don't see now how air is not getting past the loose probe. It's been pushing 70 FPE in .25 cal, so not too terrible. I think the Huma will be better with the tighter tolerances.

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Just be sure it's not too tight. I recall reading a few slipped by that were tight enough to deform the pellet skirts on chambering.

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Thanks! I did check that out beforehand and all is well there.

I have the Impact back together now. Can't tell much until I get it over the chrono, but it's still shooting very strong and on point.

I just took eight shots over the chrono. Boy is is hot out there. I got a high of 950 and a low of 947 for the eight shots. I had it tuned to 900 FPS with the 34gr JSB MKIIs before these two mods and I didn't touch any tuning screws.

I would say the mods are a success so far. I have maintained the typical 3 FPS ES and gained 60 FPS with adding the power plenum and another 50 FPS with these two mods. I do have to fine tune it now. The PW is currently set on minimum.

I just took eight shots over the chrono. Boy is is hot out there. I got a high of 950 and a low of 947 for the eight shots. I had it tuned to 900 FPS with the 34gr JSB MKIIs before these two mods and I didn't touch any tuning screws.

I would say the mods are a success so far. I have maintained the typical 3 FPS ES and gained 60 FPS with adding the power plenum and another 50 FPS with these two mods. I do have to fine tune it now. The PW is currently set on minimum.

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Excellent!

I just took eight shots over the chrono. Boy is is hot out there. I got a high of 950 and a low of 947 for the eight shots. I had it tuned to 900 FPS with the 34gr JSB MKIIs before these two mods and I didn't touch any tuning screws.

I would say the mods are a success so far. I have maintained the typical 3 FPS ES and gained 60 FPS with adding the power plenum and another 50 FPS with these two mods. I do have to fine tune it now. The PW is currently set on minimum.

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Excellent!

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This is with the reg set at 135 bar (1950 psi). I have no idea yet just how low I can go. It really likes the JSB MKIIs at 900 FPS.

All of this is in preparation for the .30 cal gun I actually bought. Working with the .25 cal gets me setup and familiar with the gun at a cheaper cost. I'll be switching back to .30 caliber and fine tuning eventually before hunting trips. I really don't know how much power I have just yet, but I can say it's a lot for an Impact.

I got the king heavies to 1000fps on 100bar with the valve wide open before. Theres more to be had TT. Such a fun platform to tune with IMO.

I got the king heavies to 1000fps on 100bar with the valve wide open before. Theres more to be had TT. Such a fun platform to tune with IMO.

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That's something there. I don't think I am quite there at 100 bar. The Impact has a couple of more components to it than the Marauder has, but I find it easier to work on than breaking down a Marauder. I really do like the external valve spring control, of course the rest of the external adjustments as well. I had no idea these guns were so easy to play with. I guess I read too much...Now I know firsthand. Experience trumps opinions every time. LOL, I bought my .22 Marauder at the height of the .22 cal Marauder bashings on the forums. It won the first competition I took it to against a lot of fancy big name guns.

I, too, opened up my 25 cal Huma tp and that alone gained me 21 FPS. Since taking ownership of this MK2 pre power plenum a little less than a month ago, all I’ve done is install the PP, then the Huma TP and probe, and finally a 700mm superior liner.

It’s gone from 882 FPS to 964 FPS with the JSB 34g King Heavy's. All knobs, adjustments, etc, still left untouched since I got it, as I’m still learning the gun. It came to me set at just a hair under 130 BAR Reg setting. 

Ive got a lot of catching up to do, lol.....

Nice work Big!

I did a little tuning today with my new Impact mods (modded dual Huma port with probe mod and PP added) With reg set at 135 bar (1950 psi), I can only get to the 950-960 fps range with the 34gr MKIIs sized to .251". Any more HS and it starts wasting air and fps drops a bit. That added hammer weight in the PP kit is a little too much weight for a 135 bar SP. I have it tuned with PW on MIN to 850 fps and PW 3 set to 900 fps. I can't go above PW4 without wasting air. I have the hammer spring backed all the way out. I can clearly set the reg lower for 900 fps with the MKIIs, Right now, with forty shots on a fill, it looks like I'll get at least 80 shots at 61 FPE on a full fill, so I will leave the 135 bar SP for now for .30 cal testing.

Trigger, after a whole mag of 28 shots, what is your gun pressure at? Mine is at 175 down from a 250 BAR fill, reg still untouched from how it came at just a hair under 130 BAR. 

I didn’t even put in the hammer weight from the kit. I went right to this brass one shown on left-

Trigger, after a whole mag of 28 shots, what is your gun pressure at? Mine is at 175 down from a 250 BAR fill, reg still untouched from how it came at just a hair under 130 BAR. 

I didn’t even put in the hammer weight from the kit. I went right to this brass one shown on left-

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It used 21.75 psi per shot on average for the 40 shots I took. 240 bar down to 180 bar.

My findings are similar

The stock PP hammer weight is 6.07 grams (hammer 18.34 gr and the spring 52.5mm), just measured these last weekend.

I did not order that brass HW yet, first I would like to add a 2-3 mm washer to the H spring (me same not able to higher the reg pressure timing without this mod) but unfortunately I don't have anything that fits in my drawers and ordering anything these days is becoming a gamble...



Edit:

Here we go, I just ran into a new post, we got a new kit to increase the power:

https://www.airgunnation.com/topic/fx-slug-power-kit

Anyone knows where I can find the pin probe working with Huma dual TP? Or it's no big difference than Huma probe? 

Anyone knows where I can find the pin probe working with Huma dual TP? Or it's no big difference than Huma probe?

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Looks like PA will be carrying them https://www.pyramydair.com/s/a/FX_Impact_Slug_Power_Kit/9604

Augie, that brass weight might be too much, the shoulder being thicker is going to add some preload alone and I imagine it's quite a bit heavier which will add more. What is the weight differences? You might end up having to back off the hammer spring knob and if it's still too much back off the adjuster screw. But... if your going for max power and are planning on cranking up the regulator you might be ok. 

I tried running the pre PP FX hammer spring a few days ago with the PP system installed and ended up having to do what I mentioned above. I didn't really need the extra hammer energy for my NSA 29gr slugs so I pulled it back out and re-installed the PP hammer spring. It'll shoot plenty fast at 120bar with the PP system inclusive. 

Jking

Augie, that brass weight might be too much, the shoulder being thicker is going to add some preload alone and I imagine it's quite a bit heavier which will add more. What is the weight differences? You might end up having to back off the hammer spring knob and if it's still too much back off the adjuster screw. But... if your going for max power and are planning on cranking up the regulator you might be ok. 

I tried running the pre PP FX hammer spring a few days ago with the PP system installed and ended up having to do what I mentioned above. I didn't really need the extra hammer energy for my NSA 29gr slugs so I pulled it back out and re-installed the PP hammer spring. It'll shoot plenty fast at 120bar with the PP system inclusive. 

Jking



the hammer weight is at 7.2 gr.

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I just took my Impact apart to make some changes. The new PP hammer weighs 18.64 grams. The extra weight weighs 6.05 grams. Together they weigh 24.69 grams. The original hammer weighs 19.30 grams.

The new hammer spring is 52.50mm in length. The original hammer spring is 56.50mm. The springs appear to be the same rating. The new shorter length difference appears to be just for compensating for the shoulder thickness of the added weight.

Next, I'm trying the original valve and hammer springs with the rubber ball cap and the new hammer without the extra weight added. It's super quiet right now, but low speed, too. Can't wait to see what adjustments I get with this arrangement. I know if I can get to 900-950 fps at max with the 34gr MKIIs while still at 135 bar on reg, I will have met my goal in .25 cal, if shot report sounds right and not overly stressed, and remains efficient.

I just put some shots over the chrono with a different arrangement of PP and original parts noted above. With the valve on the 4th line and PW on max, and with HS adjustment all the out to minimum and reg still at 135 bar, I started out at 912 FPS. It stabilized at 905 until pressure was down to 105 bar where it finally started dropping off the 900's. So that's more proof I can drop the reg down to at least 105-110 bar for shooting MKIIs at 900 fps. It sure is a lot quieter now with all of the extra hammer weight gone and not fighting the new valve spring and cap so much. I haven't even turn the HS in any yet. I suspect it would hit the 960 ceiling for the reg SP. I might try that after getting my scope issue sorted out. 

...I suspect it would hit the 960 ceiling for the reg SP....

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Yes, this what I got as well, maxed out at 960-965 with 126bar and no matter what else I do the speed gets slower. Not sure how to influence with longer spring or heavier H weight but I have no parts in my hands and cannot order neither.

and, btw, the two springs the old 58 and the new 52 mm are not the same specs. I cannot find it now but I saw earlier in one post somebody measured the deflection and pressure force on CNC and weight scale.