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PostPosted: Mon Jul 27, 2020 6:08 pm 
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Location: Thunder Bay,On.
This guy says he added 50fps to his Phantom.....I say no way..probably LOST 200fps... :shock:
https://youtu.be/UiJSf8oD1EQ

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PostPosted: Mon Jul 27, 2020 6:45 pm 
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Hard to say but I'm inclined to agree with you. I checked his channel and he never did a chrony test before/after the mod. He made a video of a shot through a wood board, but no details whatsoever on speed, distance or anything else: https://www.youtube.com/watch?v=5vRGo7unbPo

Interesting to note, Chevota left a reply in the comment section of the video you posted.

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PostPosted: Mon Jul 27, 2020 6:58 pm 
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Location: Mtl
While I wouldn't go and blindly drill the transfer port of my springer, I do believe that in some cases such a modification can increase the FPS :

I believe the non PAL Gamo Varmint has a short piston and full power spring, like you'd find in a Trail or Quest etc. I know that because I bought the Quest upgrade kit from scopes and ammo for my Benji Classic and got pretty much the same results with the upgrade kit and the Varmint spring. The piston is the same lenght, no bleed hole or anything, which leaves me to wonder how'd they manage to tune down the varmint without a weaker spring or modified piston ?


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PostPosted: Mon Jul 27, 2020 7:16 pm 
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airmec wrote:
Hard to say but I'm inclined to agree with you. I checked his channel and he never did a chrony test before/after the mod. He made a video of a shot through a wood board, but no details whatsoever on speed, distance or anything else: https://www.youtube.com/watch?v=5vRGo7unbPo

Interesting to note, Chevota left a reply in the comment section of the video you posted.


Quote:
Chevota left a reply in the comment section


And for once he was correct


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PostPosted: Mon Jul 27, 2020 7:17 pm 
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airmec wrote:
Hard to say but I'm inclined to agree with you. I checked his channel and he never did a chrony test before/after the mod. He made a video of a shot through a wood board, but no details whatsoever on speed, distance or anything else: https://www.youtube.com/watch?v=5vRGo7unbPo

Interesting to note, Chevota left a reply in the comment section of the video you posted.


Never noticed Chevota in the comments but yes thats him....you can tell its him by the encyclopedic
response....never a guy for short answers thats for sure....

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PostPosted: Mon Jul 27, 2020 7:33 pm 
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Ask ravengun. He drilled out the transfer port, then was asking the stock size. Because it lost FPS.


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PostPosted: Wed Jul 29, 2020 12:12 pm 
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Completely normal to lose FPS when going to larger port unless you have a huge 80mm plus stroke and short port....then you might get more out going bigger but risky.
Think Webley MK3..or Anshutz 335 both of them never able to compete for power with similar guns, entirely due to 4mm plus ports. 6mm in the case of the MK3 ..barely 35% efficient.
Think HW35 ...going down to a 3mm port improves the guns performance no end..
Very often, going in the other direction improves power....more pressure, less lost volume..
You can find out the volume of a TP by adding its length to the diameter....This then equals your lost volume.
A long port like HW35 rifles which is opened up in size will be a disaster because that extra diameter more massively impacts its volume because of its long length....don't ever do it.

A good safe port size for a springer is 3mm.
I once gained 30 fps by sleeving a stock Walther LP53 pistol port from its stock 4mm down to 2.8 mm and transformed the guns shot cycle..


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PostPosted: Wed Jul 29, 2020 2:27 pm 
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clarky wrote:
I once gained 30 fps by sleeving a stock Walther LP53 pistol port from its stock 4mm down to 2.8 mm and transformed the guns shot cycle..


How to? JB weld the port then drill open it again with the size you want?

And, does that apply on rifles too?

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PostPosted: Wed Jul 29, 2020 3:21 pm 
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Fairly easily. A great source is stainless steel hollow pins. They come in a range of sizes, or telescopic chrome radio ariels.
You can find the right fit, or drill out the TP to get the fit and then glue in with Red Loctite 638.
It will never come out and needs drilling out if you want it out.

I used a 4mm dia x 10 long stainless tube in the Walther. The internal dia. slightly under 3mm ..


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PostPosted: Wed Jul 29, 2020 3:37 pm 
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:thumb: That's a good idea~ Learned something new and will keep that in the knowledge database ~

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FWB300S Universal
HW30s / 35e / 40+Extender / P3+Kit Scope
HW45 with customized grips from UK
Russian Izzy 46M
2240+14" barrel
Camo Chaser long barrel rifle kit


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