cold weather

[wyattwolf]

Hello
Just had my TM SOPMOD upgraded to shoot at 34ofps and using our chrono to check the fps and using .25 BBs I was only getting 290 approx...does the cold weather affect the fps?

[Sabbath]

Re: cold weather

COld weather can effect the electronics but not to a major degree

[jagillham]

Re: cold weather

Your FPS reading should be with a .20 BB.

Using a .25 will give you an artificially lower reading. But yes, cold causes things to contract. So I'd expect the air seal may be less perfect than on a hot day - probably not making that much difference though.

[Discoshrew]

Re: cold weather

was the gun upgraded to shoot 340 with .25's or .20's? theres always gnna be +/- so 290 could spit upto anywhere around 300 on said .25's. remember the velocity changes with weight not power (Y) chrono it on .2's & you should be hitting your 340 mark

[wyattwolf]

Re: cold weather

It was upgraded to shoot 340fps with .25s as they said it would be more accurate with that weight.

I'm fairly new in this world of airsoft and physics not something that clicks with me I'm afraid lol...I thought I only had .20s originally but when I got home I checked the BB bottle and its .25s.

[rossy02]

Re: cold weather

290 FPS with a .25 is roughly 325 FPS with a .20 which is a good FPS.

If it was upgraded to 340FPS with a .25 it would be 380ish FPS with a .20 which is too high for pretty much all sites in england.

290FPS with a .20 is a good fps. Why would you want it more powerfull than that ?

[jagillham]

Re: cold weather

340 with .25's... that would make it unusable on the majority of UK airsoft sites.

Edit: Beaten to it by a ninja!

[psirus101]

Re: cold weather

I'd go with Discoshrew on this, I reckon the gun is 340 with .2s and the 290 is due to the heavier bbs.

If this isn't the case then the gun really need downgrading again or being locked to semi-auto only.

[rossy02]

Re: cold weather

340 with .25's... that would make it unusable on the majority of UK airsoft sites.

Edit: Beaten to it by a ninja!

LOL

Sorry Jag Im to slick

[No1_sonuk]

Re: cold weather

I would assume they set it up for 340 on 0.2s, but advised you to use .25s.
340fps with 0.2 = 1.061J
1.061J with 0.25 = 304fps

Those are "sterile" calculated numbers. 290-ish is within practical calculation/measuring tolerance of the 340 figure. i.e. real-world factors would affect the final numbers.

[wyattwolf]

Re: cold weather

I hope I haven't been messed about with this upgrade

[Jon Bon]

Re: cold weather

I dont think you have mate, by the sounds of it its firing about right. As the other guys have said, your fps reading should be with .2s so 290 with .25s is about perfect.

[wyattwolf]

Re: cold weather

All sorted, I nabbed the team chrono and a bag of .20s...

so with 2 mags filled with .25s I was getting about 290fps approx
2 mags with .20s I was getting about 330fps

My mate was paying more attention than I was and says I've gotten mixed up...I thought it was still shooting the same fps as before, but I reckon it must of been 260fps with .25s and 290fps with site chrono and BBs...lesson learnt

so I should be ok...would be gutted if it was going to be too hot for The Outpost on the 12th!