Springs

A

Aaron.l

Members
Joined
Mar 14, 2022
Messages
7
Reaction score
0
Hey guys,

Bought a specna arms sa e19 as my first airsoft gun from patrolebase. (I'm still noobish). Haven't had chance to play about with the hop up or optic yet.

Just wondering if anyone knows what spring is in it (I'm guessing m90) and what spring I can use for max fps based on the UK site laws.

Cheers

 
Yes, it should be an M90, with a spare M120 in the box (although it may be in an opened "M90" wrapper).

The M90 should be usable, and notionally an M100 should get to close to UK limits.  However, it's entirely down to air seal and to some extend the BB weight you're using and whether your local sites chrono sensibly, or with 0.2g.  You may be lucky and get close enough as it is, or want a 95, 100, or 105.

I'd play with it first and see what it chronos at with the BBs and hop that you'll want to use, then take it from there.  A cheap chronograph will save you a wasted day if you come out a bit spicy.  It's easy enough to cut a spring down once you know what it's producing.

 
This is the weird thing about measurements in The UK. Springs are measured in metres but we chrono in feet. I have an aquarium, it's 4ft wide and holds 300L ?

 
Yeah I thought it was supposed to come with a spare spring but it didn't, thats what I thought was weird.

I read that the orion gearbox is supposed to mean I can change the sprung power without having to do any work on the internals, which is one of the reasons why I bought that gun.

If I'm using .25 bbs then is an m95 still probably over the 300fps or am I better aiming for an m100? I'm looking for ideally between 300 and the 350fps limit.

 
What Rogerborg said above ... You won’t know until you chrono it , with the bbs you will be skirmishing  . Borrow or buy a chrono - worth every penny . 

 
Indeed, I'm all for it. "M" ratings are intended to be helpful, but given the wide range of variables (air seal, cylinder to barrel ratio, BB mass) they're really just a relative scale, and only within a manufacturer's own range.

The Silverback springs just give a single Newton value - I'd assume (by which I mean hope) that it's at the compression of a fully cocked and locked SRS or TAC-41.

Even at that, with a 100N spring in mine, it doesn't feel like I'm lifting 10.2kg to pull the bolt.  Hmm, that would actually be measurable though... ?

 
Last edited by a moderator:
As Roger said, the fps for a particular spring depends a lot on the gas flow efficiency so you can never say exactly what fps you'll get with a certain spring.

I've made a simple contraption to measure spring power in Kg which will help get an idea of the fps you'll get from your particular rifle.

PM me if you want to buy one (£10)

View attachment 88808View attachment 88809

 
Last edited by a moderator:
Classic army m24 ltr is amazing stock for anyone looking for a cheap alternative, not fully upgradable tho so don't expect some insane performance after upgrades.. nice exterior too.

 
EDcase said:
As Roger said, the fps for a particular spring depends a lot on the gas flow efficiency so you can never say exactly what fps you'll get with a certain spring.

I've made a simple contraption to measure spring power in Kg which will help get an idea of the fps you'll get from your particular rifle.

PM me if you want to buy one (£10)

View attachment 88808View attachment 88809
Click to expand...
Click to shrink...
A gunsmiths trigger pull tester is very similar. 

 
EDcase said:
Yeah, same principle I guess.

It does work quite well and testing a few springs you can make a chart of Kg vs resulting fps for a particular rifle.

With enough samples from various rifles it should be possible to predict rough fps in general.
Click to expand...
Click to shrink...


I built myself one of these a couple years ago, handheld not fixed, but every time I pulled back a spring it gave different reading.  Do you get much variation in readings?

 
ak2m4 said:
I built myself one of these a couple years ago, handheld not fixed, but every time I pulled back a spring it gave different reading.  Do you get much variation in readings?
Click to expand...
Click to shrink...
It varies by a few grams each time.  I pull to a marked line then press the 'Hold' button to save the reading so I don't have to look at it while pulling.

 
Rogerborg said:
Even at that, with a 100N spring in mine, it doesn't feel like I'm lifting 10.2kg to pull the bolt.  Hmm, that would actually be measurable though... ?
Click to expand...
Click to shrink...


Well, shows what I know.  Using a cheap and admittedly uncalibrated luggage scale, with a Silverback 100 "Newton" spring with about 4 loops cut off, I'm seeing a 17kg (166N) peak from a slow, careful pull, and nearly 25kg (245N) peak from a more realistic sharp pull.

It still doesn't feel anything like that, mind, because it's a short, smooth pull.

Makes me want to try a Rapax 2J+ spring which claims a lighter pull for the same boing.  Out of stock at Skirmshop, of course. £21 delivered from Serbia... except if I get mugged for VAT, and the mugging to pay for the VAT mugging.

 
You must log in or register to reply here.
Back
Top