Poor FPS - Need Help!

[DieselPower]

Right, I recently got some new parts for both my CA M15A4 RIS Sportline and G&P M16A3, but after installing these new parts I have not noticed an increase in FPS, which is confusing me to no end as after milling over user reviews of the SP90 it was reported to be firing in the area of 330 FPS but this isn't the case for me.
I installed a new Guarder SP90 spring and Systema hop buckings in each of the AEG's as well as a Guarder air nozzle and a DeepFire H-nub in the CA, and a DeepFire 6.02mm TB in the G&P.
but the FPS hasn't budged, it's around 280 in the CA, and 300 in the G&P after cronoing, I have tested the compression on both of them and it's bang on.
Both are pretty much stock except for the parts mentioned, the trigger mechs (AWS Raptor and ASCU), the hop unit in the G&P and the piston head in the CA.

Any help would be great.
Thanks.

[SAS Scott]

Re: Poor FPS - Need Help!

Did you check your airseal before you put the gearbox back together?

[DieselPower]

Re: Poor FPS - Need Help!

Yes, hence why I said I tested the compression before reassembly.
everything is tight, But I may try the stock CA nozzle in the CA as the guarder one sometimes doesn't provide an airseal (It does when it warms up oddly enough.)

[DanEly]

Re: Poor FPS - Need Help!

Sounds a bit silly but are the hops off when you chrono them?

[WonderBoy]

Re: Poor FPS - Need Help!

Check the hop, if not battery?

Even the pro's make schoolboy mistakes sometimes!

[BioSniper]

Re: Poor FPS - Need Help!

Guarder SP90's for me always kick around 270-300fps depending on quality of air seal.
If you want higher than that you will need an SP100 or SP110. All older reviews of the Guarder springs indicate that they run hot, but that doesn't seem to be the case any more and I've found that their number should be literally converted to feet from meters to give an approximation of FPS output.

As already said, ensure your hop is off, if you don't already, installing a bearing spring guide can increase FPS a little due to the greater compression of the spring. If you have a SORBO pad installed expect to loose a little.
Ensure that you have installed the spring the correct way round (tighter coils on the spring guide rather than piston).

Other than that, SP90 is about right for those FPS. It's why I love them for CQB guns, you get a nice ROF boost from the softer spring and their FPS is very sensible if you are sticking 20+RPS down field, you won't hurt anyone too badly.

[crasstoe]

Re: Poor FPS - Need Help!

Have you checked the seal with the hop rubber against the inner barrel? Blow in one end whilst covering the end where the rubber sits (with the rubber fitted), is there an air leak?

[dadio]

Re: Poor FPS - Need Help!

ditto the m100 spring for the 330fps mark m110 350fps mark the performance you'r getting is what i'd expect for an m90

[keithhibbert]

Re: Poor FPS - Need Help!

Guarder SP90's for me always kick around 270-300fps depending on quality of air seal.
If you want higher than that you will need an SP100 or SP110. All older reviews of the Guarder springs indicate that they run hot, but that doesn't seem to be the case any more and I've found that their number should be literally converted to feet from meters to give an approximation of FPS output.

As already said, ensure your hop is off, if you don't already, installing a bearing spring guide can increase FPS a little due to the greater compression of the spring. If you have a SORBO pad installed expect to loose a little.
Ensure that you have installed the spring the correct way round (tighter coils on the spring guide rather than piston).

Other than that, SP90 is about right for those FPS. It's why I love them for CQB guns, you get a nice ROF boost from the softer spring and their FPS is very sensible if you are sticking 20+RPS down field, you won't hurt anyone too badly.

totally agree. Just fitted a SP90 to my MP5 and getting 270-300 depending on hop. Exactly what I expected.

[DieselPower]

Re: Poor FPS - Need Help!

Thanks for the replies everyone, i'm putting the SP90 springs back in the bits box and trying some of these other springs i've got.
But I've got the CA up to a consistent 330 FPS with a DeepFire MS100, now to replicate the results with the G&P!