[DIY] Transfer port modifications what happened?

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Redick

Redick

Member
Nov 9, 2019
1,546
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Ohio, United States
I remember when the Impacts first came out and there was a bunch of DIY video's on modifications. One in particular was the transfer port and probe enlargement. The modification looked to be straightforward and effective. 

So what happened? Why is everyone running to get the dual port&probe when you can DIY for FREE!! Am i missing something about the mod? It just seems like the $70 for the parts can be used for other accessories like pellets or whatever. 

Well that's my rant for today shoot safe and be well


 
I think one of the main reasons for going with the dual port vs homemade is being able to cycle slugs with out worry of them falling into the transfer port.

On my Crown I have homemade TP on the 380mm barrel (only shoot pellets) but a Huma dual port on my 700mm for slugs.
Click to expand...

I'm sure the factory port can be modified as well to accommodate slugs i would think. Couldn't this be done by going oblong instead of oval. Right? Im going to modify my port and probe
 
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Hmmm you're supposed to elongate the port. If you do it right there is no more risk of projectile falling in than if you were using a factory port.



All my barrels and probes I ported myself. 0 feed issues. And have the same gains as the best gains reported from the dual port/modified probe. 75fps on factory 130bar tune 700mm. 50 fps same tune on 380mm barrel 
 
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Yes a little oblong towards the front and you should be fine. Always good to test along the way. There can be a bit of a fine line between best flow and going a little to far and then there’s no going back.

I think a few members went to far and had jamming issues. In some cases only certain weight/size pellets or slugs were a problem. For a few bucks the Huma’s solved that.

I found my modified TP just slightly outperformed the Huma. Great little mod to pick up an easy 40fps in my experience.





 
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Yes a little oblong towards the front and you should be fine. Always good to test along the way. There can be a bit of a fine line between best flow and going a little to far and then there’s no going back.

I think a few members went to far and had jamming issues. In some cases only certain weight/size pellets or slugs were a problem. For a few bucks the Huma’s solved that.

I found my modified TP just slightly outperformed the Huma. Great little mod to pick up and easy 40fps in my experience.




Click to expand...

Hmmm you're supposed to elongate the port. If you do it right there is no more risk of projectile falling in than if you were using a factory port.



All my barrels and probes I ported myself. 0 feed issues. And have the same gains as the best gains reported from the dual port/modified probe. 75fps on factory 130bar tune 700mm. 50 fps same tune on 380mm barrel
Click to expand...

Got any photos of how your port/probe ended up, or measurements?
 
Upvote 0
Hmmm you're supposed to elongate the port. If you do it right there is no more risk of projectile falling in than if you were using a factory port.



All my barrels and probes I ported myself. 0 feed issues. And have the same gains as the best gains reported from the dual port/modified probe. 75fps on factory 130bar tune 700mm. 50 fps same tune on 380mm barrel
Click to expand...

Same question to you sir. Got any photos of how your port/probe ended up, or measurements?
 
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Pretty much made a bellmouth with .30 inlet. Center of port is factory ID. Outlet is radiused, and egg shaped. Sides and back of port on the inside is factory. Front is elongated, and has a narrow taper forward so nothing can fall into it, but overall area is increased. As is the path of airflow smoothed.



Once the port was shaped, I just patiently and slowly cut the probe to match the changed port

Dont have a pic of the probe on this device. But there was considerable material removed from the area forward of the port on the bottom side of it. Actually a notch taken completely out, so it is like 75% of a circle with the bottom part gone
 
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Redick,

I also have positive results with the same mods on both my .25 Dreamline and .22 Impact. Elongation was 1mm on both. 6.5x5.5 on the .22 and 7.35x6.35 on the .25

Both Slugs and Pellets cycle without issue. I have heard some feedback on probes having to much diameter taken away ( 50% ish) has caused some feeding issues with certain pellets/slugs.

Gains in FPS will be seen, and, the tightness of those numbers will be influenced by the time spent smoothing out the laminar air flow between supply and projectile.

Take your time, have fun, share your results!



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1598656824_12932175435f4991389bfc32.87666117.jpg
1598656837_16935947695f49914508cc76.08985013.jpg



 
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