Upgrading question

[Sniper Steve]

Ok, well I will be upgrading my TM M16 A2 by this spring during the winter. Bellow is a list of the upgrade I intend to buy.

• PDI 150% spring
• Gear box shims
• 6mm stainless steel bushings
• TN 6.04mm tight bore barrel
• G&P M16 A2 metal body

What I would like to know is, will I have problems I the tight bore barrel because it is quite long in full auto? and would you suggest any other brands than these?

[vondnik]

don't use a PDi crappy spring.... try guarder, systema or top power springs.... PDI springs are inconsistent as hell... i have some pdi 130 that shoot 380 fps some pdi 150 that shoot 330 or 475....

[CDN_Stalker]

Agreed, PDI springs are way outta whack these days! I've put several PDI 150% springs in team guns over the past 10 months and all range from 350fps to 450fps with .2g. Problem being, the lengths vary a LOT (6 3/8" for a 350fps gun, to 7" for what would spit out well above 450fps), and Bruce mentioned the thickness of the spring wire as being an issue as well (I got a new PDI 150% spring a couple months ago, put it side by side with my 350fps PDI 150 spring, the true 150% measured 6 3/8" long and was made of ~0.75mm wire, the new one measured 7" long and was made from ~1mm thick wire, and was damn impossible to put in my mechbox. After cutting a few coils off the spring and installing it, the performance was so bad that every couple shots in semi the anti-reversal latch would fail and you'd hear the gears unwinding from the spring pressure.

Go for any spring that ISN'T a % spring. A lot of the other springs you'll find are graded in meters/second. Google "Unit Converter" and plug in the number (say a GP110 would be 110m/s) and get the output as feet per second and that should give you a basic idea what the spring you want will put out at. Add in a tightbore and/or a bearing spring guide, the fps will be somewhat higer, say 25fps higher than the spring with stock spring guide and stock barrel.

Illusion's spring guide chart fond on ASC is an invaluable resource for this type of thing, but yo umust read the fine print that the velocities recorded were done with the best BBs available, the gun was upgraded with a tightbore and bearing spring guide as well as other goodies. So what you see there, if yo uplan a basic bushing and spring upgrade, could be 25fps less or so (depending on your barrel length as well). M16 with a 509mm barrel will put out a bit higher than an MP5 with a 229mm barrel.

[Sniper Steve]

Thanks for the heads up guys. It was much appreciated. Well, I checked Rangers Airsoft and the smallest spring they had listed on their site was a M120 spring. Now according to a post above that works out to 120m/s or 393fp/s. Now from what I read, anything more than about 350fp/s is too much for a standard "metal bushing upgrade" and I was wondering if the M120 spring was ok or if they make a M110 spring that will bring me to about 360fp/s.