TM G17 fps issue
 

Hi all,

I have a TM G17 with a PGC slide and Guarder high output valves for my TM mags.
I'm only getting 280 fps on green gas. Is it normal? I would like to get 330.

Also, do anyone knows a good gun doc in the Montreal area for AEG and GBB?

Thanks for your help

Did you replace the slide and the hi flow valve by yourself?

No, I didn't. I paid a gun doc.

Have you ever checked the fps b4 replaced these two new parts? Your gun doc should give a reasonable answer if he is good enough. I'm not a gun doc but as you only get 280 after upgrade, seems a bit low. Talk to ur gun doc!

I know some of the parts may just good for some brands. Based on these two new parts installed, there are some points you may check by yourself and see.
Between the new slide and the lower, holding the lower and use other hand to pull the slide up see any gap space? Usually has a bit, remember the space size, then insert the magazine in, once the mag hits the nozzle but before the mag got locked, keep an eye on the space I talked about, slowly push mag up and lock it, have you seen the slide slightly got push up and that's the mag and nozzle tightly sealed is good, and now there should have no up-pull movement between slide and lower. If it still has some allow to to pull the slide up, means the slide may not good fit to TM model. You may have gas escape through ejection port or under the slide.
And also you may check the new hi flow valve if it sits in right? Not to deep in, sometimes.
Like I said, I'm no gun doc but this is the way I do the diagnostic for my airsoft, hope it helps!

The slide fits perfectly. Well, I guess from the test you suggested. My knowledge on GBB isn't great. I cannot shoot more than 2 times each mags before I ran out of gas... It seems like there's a problem! Also, the slide doesn't block when shooting the same mag a 2nd time.

Fyi, I don't know the gun doc myself. I went to my local airsoft shop and ask for one. I never met him.

You have the hi flow valve and full filled mag could only finish just two full bb mag load is normal since the as consumption is higher, means less bb can be shot. If the slide can't b elocked close to the end of the second mag could be normal too as the gas pressure is not enough to perform full travel blow back.
How about the nozzle, is it original one? The marui nozzle contact to mag is round shape design, not like WE one is flat. If you have a new nozzle that may not have perfect round shape together the best contact sealed, it might drop your fps too. Check it out

Do you know what weight your BBs are?
If your shooting with a heavier weight BB the FPS is going to be a lot lower.

I have the original nozzle. My bbs that I used to test it are 0.20 g and my chrono was an xcortech.

From personal experience my Chrono has a difference of between 10-15fps higher than the Xcortech. This could be a possibility as to why you maybe getting a lower reading.

How many magazines are you using? If your using just one try a few different magazines to see if you get a different result.

I'm using 3 mags. But I only tested one. I'll test it again tomorrow.
My local airsoft shop told me by email that's it's not really possible to upgrade. So, I hope it will work!

Thanks!

The only way you can increase FPS is via a new inner barrel.

I run a 6.01mm or 6.02mm [I forget its a male leaf] tightbore on mine and I get about 320fps

I'm imagining your running a stock barrel which might be bigger than that so you'll be getting a lower fps reading for sure.

Also if you dial your hop up correctly you may increase FPS as well. I found from experience if there is no hop I get very low readings.

Its worth a shot looking into to see if you are actually having issues.

If you're using a hi flow blowoff valve, you MAY need to upgrade that hammer spring as well.

A stock one may not be able to consistently open your valve. A hi flow valve is much harder to crack open than the stock one. And if it opens, it closes faster with a full tank of gas.

and... welll... You can kinda fill in the blanks here...

...just a thought is all..

Ok so I'll check for a tight bore inner barrel and an hammer spring. Is it the 150% one that I need?

If you want higher fps, a tightbore such as PDI 6.01 with a new hop up rubber will help. Also, based on my experiences, the seals between the piston head and nozzle and nozzle with gas bucking need to be tight or else you will get a lot of gas leakage. This also helps with the gas efficiency