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Old February 12th, 2014, 20:30   #8
turok_t's Avatar
Join Date: Feb 2009
Location: Toronto, Ontario, Canada
Originally Posted by Trixshooter View Post
Deeply appreciate your time and expertise mates!

How did you do the hammer/sear modification you describe?
I thought that filing the stock parts could only shorten the hammer stroke?

Answer to Q,
my two weeks old stock TM is bad bad bad everywhere so I did not have the fortune to compare part by part. Thats why I had to get a hole pile of stuff to save it.

If you looking for details and backstory...
My stock Marui has a cracked slide, it cannot hold a rear sight and the nozzle-returnspring bends and turns to mush if slide is cycled. It also has severe problems with spraying gas back over gripping hand and so forth...

Slide needs replacement and I had 100% advice to replace with metal slide.

Metal is obviously heavier than metal so I went for the lightest slide I found.

All my mates run TM 5.1's, theirs rock'n roll 24/7,
my 5.1 since new is as reliable as a bipolar g/f blowing off steam.

Deduction, get a complete setup of vital gas-parts foodchain.

About the advice of knowing what I'm doing and taking it slow, I dont have much choice but to try myself if I want it fixed/repaired. And about the slow part and how I approached the so called drop-in slide fitting I don't mind sharing the details if you're interested...

Here I am,
Started on the slide, it would not slip on even using a sledgehammer.
Filing description,
1/ Cleared all metal burr's out (The frame is obviously casted) on frame.
2/ Filed off casting burrs adjacent to the slides dustcover.
3/ Black marker - then slide on/off to se where it rubs fixed!
4/ Fitted slidestop by Assemblying barrelsin+out&hopup, put it in gun (without slide). 7mm off, adressed and filed corresponding surfaces to fit hopup lock-lugs & frame to slidestop pin.
5/ Adressed outer barrel lockup movement (as in the outer barrel moves "up" to engage the slide lugs) but the outer inner barrel became a solid one-piece when assembled. Cause, the frame squezed the outer and inner barrel (underside) so it froze solid. Sorted this out by filing correct surfaces.
BUT later assembled in slide I'm having some issues with this.
5 and a half/ Rail cuts on slide ends to early, cut off 5mm from the front frame rails but it still needs rounding off to allow full rear motion of slide without hookup. I round off all frame rails except the rear that's visible. Diamond tool them and mirror polish.
6/ Tried slide lockup by entering only outer barrel. Used calipers to fit lockup. Rounded off the sharp edges of slide lugs. Removed two purposely high points at right and left side of slide port, apparantly meant to squeeze fit the outer barrel hood in the slide port.
7/ Assembled slide and tried on frame. Needed fitting of dustcover (tried to do it as nice as I could with bad tools as I prefer no wear marks on the dustcover from the framechannel.
8/Barrel was angled upwards and last 35mm prevented slide from moving forward in lock position. I also drew the ocular conclusion the nozzle/hopup penetration could use a subtle slack. Adressed issues with file.
9/Paused here and gave all adressed issues a thorough cleaning with diamond tools for mirror finish.

Assembly and testfire, one shot leaked all gas out the barrel (one shot/misfire)

Assessed and concluded that about the last 5mm slidetravel before lockup has to much resistance.
Further the hammer presents more slide resistance than the original slide, even hanging up slide through contact points hammer/bjhousing hunchback.
Counter tried all original parts with the new parts consequitevly to compare any and all differences.
There is an hilarious amount of slack in the stock plastic slide.
I decided next to give the aluminium slide just a tad slack to check function.
Re-did everything above again and cleaned out with diamond tools.

Now I got 15 shots out of a mag (Stock I could get +60 bb's out of a single mag on one refill)

I then tried to
10/ break lug edges and adress the lock-up in particular. Experiment with springs to see how it affected the last 5mm barrel/slide lockup.
11/ Polished hammer and examined the surfaces hammer/bjhousing and the resistance issue
12/ Mirror polished all contact surfaces again, rounded off edges and so forth. Pretty much re-did all points.
13/ swapped the RA-tech bucking with stock, and then back again. The out-sticking part of bucking clearly build the width of the assembly. Shaved the outstanding part away from the hopup. Smoother lockup motion followed.
14/ Tried different inner barrels. Adressed casting marks/spots on outer barrel. Lubed everything.

Got 17 rounds off... Slide hangs up on bjhousing knob at the last 17 round. I even get 3-5 bb-less farts off. Although those last poofters demanded manual cycling, it is still better than before. Now it appears it does not leek gas like a mel brooks western any longer.

Here I'm stuck...

If I get +60 BB's off stock, how many should I look to expect from a metal slide upgraded?

Advice how to fix it up and get her running comes deeply appreciated mates!

Thanks for the detailed description re: each step. You indicated that you removed burrs from here and there, filed off rubbing parts etc. How do we know if you have removed too much than required which may affect the performance of the slide? For instance, what if you removed too much than required causing the slide to sit to high resulting in a decrease in gas efficiency? We don't know that because we dont have the gun in front of us.

You indicated that you "testfire, one shot leaked all gas out of the barrel (one shot/misfire)" and you further inspected the hammer and the bbu and how they hung up. Maybe the air nozzle of the slide isn't aligning with the gas route?
Maybe the air nozzle in the new slide is sitting higher causing gas to leak and not entering into the air nozzle?

I feel like you are doing A LOT of mods, filing, using diamond tools. If you feel that all these mods, filing is not solving the problem, you should STOP, and try to diagnose the problem more conservatively. Obviously, your assumption of the surfaces, or bumps is not solving the problem. So before you do anymore grinding, sanding and turning your parts into a pile of dust, try to come out with a different theory on why the gun isn't working.

Your problem seems more of a floating valve/nozzle/gas efficiency issue. Did you check that the piston head makes good seal with the nozzle? How did you check to ensure that the air nozzle is making a good seal with the gas route? How do you know that the slide is not prematurely tripping the disconnector resulting in less gas output.

Are you sure you understand what every internal part of the gun does and its role throughout the cycling of the gun? I feel like from your description, you are just removing material from places that appear to be "stuck" but aren't investigating deeper into the functions of the gun and why its behaving the way it is.
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