GBB M4's: WA | Inokatsu | WE

[Kimbo]

The KJW looks like it has worse cooldown than both the WA and the Ino

[RacingManiac]

I am in the process of getting a used G&P GBB M4, I am told at the moment there are some issue with worned stock bolt carrier and such. I am wondering about the effect of upgrade parts might have on it. Specifically I am looking at the complete bolt assembly from RA-Tech, with steel carrier and aluminum nozzle. Should I be looking at replacing other parts if I were to get this, to prevent adverse wear of the steel bolt? How is the hop-up assembly on these stock G&P item, do they already have the G&P replacement hop-up(is there need for those replacement hop-up?). In terms of the bolt, how much of an impact to blow-back and rate of fire would the steel bolt incur, and how would that compare to say, the Airsoft Surgeon aluminum bolt? Whats the stock WA/G&P bolt carrier made of anyway?

[ujiro]

Don't know much about most of that, but I am 90% sure it has the upgraded hop up unit, which is a good thing. Apparently the stock one leaves something to be desired.

[ILLusion]

You can also consider getting RA-Tech's softer bolt catch. They have two - a steel one and a softer version to reduce wear on the bolt. It's cheap enough to buy several to replace as time goes on.

As far as ROF goes, gas consumption will go up and ROF will definitely go down with the steel bolt, but on my Inokatsu, I'm still getting about 817RPM on propane, which is still in the realm of real steel ROF. I'm also in the process of getting the RA-Tech plastic bolt/nozzle set, which should lighten the assembly while maintaining the harder steel bolt carrier. Blowback power goes WAY UP with a steel bolt, at the expense of higher gas consumption. Make sure you have the proper buffer spring to accommodate the added power.

The AS aluminum bolt will obviously have higher ROF and lower gas consumption with weaker blowback, but you will need to consider wear against it from harder parts such as the hammer, bolt catch and even the magazine.

[RacingManiac]

In terms of buffer spring, whats recommanded to go with the steel bolt? I figure if the gun I am receiving have issues with bolt and hop-up I might just replace both of those with RA-Tech item...

[ILLusion]

The hardest spring possible... RA-Tech summer spring would be fine.

[RacingManiac]

BTW, what stock dimension does G&P use? I don't know if it is the same as WA or Ino, I've heard both Commercial and Mil-Spec......

[bleaches]

rock a real steel AR buffer spring. iv heard it works well on WA/GP based guns