[TsukiKanade]

Disclaimer 1: My account is still too new for links, so my sources will likely be text URLs that'll clump stuff up. Apologies!
Disclaimer 2: I'll try and put up a source for my claims as much as I could so there's a basis for where I'm pulling info from.

Hello! So I have recently procured for myself a TM Samurai Edge High Grade. The purpose of this post is to ultimately clarify some information I have about using the gun and how I can prolong its life, as the usual upgrade of "changing to a metal slide" would not work due to the custom slide. Yes, I know, novelty gun and all, but that's kinda the whole kit I'm going with. As a background, it would be used frequently as a primary in a CQB environment and secondary in fields along the temperature ranges of the US west coast. I have access to both propane and duster, so I can use either, but I'd like to stick to propane if possible.

1.
Now, as far as I'm aware, TM has upgraded their newer M9s to the 15mm BBU that I hear works better with propane/green gas compared to the previous M9 models (couldn't find a source for this unfortunately). Though this entry in the stickied "The ESSENTIAL Guide for Gasses for Gas Guns" makes me think M9s are still iffy for TM:
https://www.airsoftsociety.com/thre...gasses-for-gas-guns.30800/page-3#post-1008218

Granted, the age of the post may make it outdated.

Additionally, knowing Marui is in Japan and that they have a mandated limit, I know TMs are pretty much designed around duster/HFC 134a gas. Though reading this,

https://www.airsoftsociety.com/threads/tm-samurai-edge-m9-hi-grade-gbb.133915/#post-1626669

I'm lead to believe that green gas usage is discouraged? Despite the multiple posts I see that say TMs would be fine on propane, although they may be referring to other guns in TM's lineup.

Not sure what to make of the information above really so if someone could clarify, especially the 15mm BBU bit, that would be great.

2.
Going through the manual and with my limited Japanese understanding, they seem to warn against using the gun at 40 C/104 F temperatures. With the assumption that they were basing the gun's usage with HFC134a, and based on this:
https://www.engineeringtoolbox.com/r134a-properties-d_1682.html

Tupper operating tolerance of the gun would be around 10.1648 bar. With propane, you could reach that pressure around 32 C/89.6 F based on:
https://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html

With that info in mind, this guideline I found on reddit seems to have some merit:
https://www.reddit.com/r/airsoft/comments/1mlx10/_/ccah9f2
Should I pay any attention to the above info? Considering the California heat during summer, this tells me to either bring a different sidearm or just load it with duster. Or should I just completely scrap it cuz I'm probably overthinking things.

3.
Now with wanting to preserve the slide as much as possible, I came across this thread:
https://www.airsoftsociety.com/threads/gbb-spring-stiffness.159825/
Especifically this response: https://www.airsoftsociety.com/threads/gbb-spring-stiffness.159825/#post-1808371

where could one find a 120% recoil spring for the M9? All I could find are 150%, which, looking at the thread, has a higher chance of cracking the nozzle. Or would this fall under the whole "unnecessary upgrades"? I do have a recoil spring from a KJW M9A1 boneyard that I could try and use (pending comparisons).

If you made it this far, thank you for your time reading it and sorry for the whole mess I've created. And apologies if I misused any terms/committed any heresies. Feel free to correct me if I did.

TL;DR: This is probably another "will it run on propane" thread.

 

[aotsukisho]

Should I pay any attention to the above info? Considering the California heat during summer, this tells me to either bring a different sidearm or just load it with duster. Or should I just completely scrap it cuz I'm probably overthinking things.

I think since you've already done the legwork finding pressure curves for the different gases, I'd graph/chart both of them and find temperature ranges where the performance will be acceptable and refer to that chart whenever you're out at the field.

Now with wanting to preserve the slide as much as possible, I came across this thread:
https://www.airsoftsociety.com/threads/gbb-spring-stiffness.159825/
Especifically this response: https://www.airsoftsociety.com/threads/gbb-spring-stiffness.159825/#post-1808371

where could one find a 120% recoil spring for the M9? All I could find are 150%, which, looking at the thread, has a higher chance of cracking the nozzle. Or would this fall under the whole "unnecessary upgrades"? I do have a recoil spring from a KJW M9A1 boneyard that I could try and use (pending comparisons).

The preservation of a plastic slide has more to do with the design of the slide, as you said. However, the reason why stronger recoil springs work is that the spring absorbs the force of the slide traveling rearward, and limits the force applied to the slide when it finally hits the buffer at maximum rearward travel. This impact is what we need to solve, the shock transferred to the slide depends on speed (kinetic energy) and impulse (how long the 'hit' transfers that energy to the frame)

Slowing down the slide is usually solved with a stiffer recoil spring, the spring's increased stiffness will absorb more of that kinetic energy before it gets transferred to the frame. The problem with this is springs store energy, they do not dissipate much of it under normal operation. That increased kinetic energy will as a result slam the slide forward proportionally harder, as you know with nozzle damage.

You can increase the weight of the slide to require more energy to move and achieve similar end result, although I think this increases gas consumption more due to the gas pressure being used to move the slide, and I think that increased inertia will have more of an effect than a stiffer recoil spring.

I'm not too experienced in blowback unit tuning, but if you redo the tracks with JB weld or something similar you can hit the valve knocker reset sooner which cuts the amount of time gas pressure is pushing on the slide and thus its maximum kinetic energy.

To increase the impulse time you can use a softer buffer that will 'squish' longer and extend the amount of time the same amount of kinetic energy is applied to the frame. Longer impulse time will blunt the peak impact force.

Another potential combination solution that will remove the slide lock function is using a 150% recoil spring but short stroking the gun with more soft buffers. I am not familiar with the TM M9 design (only thing similar I own is a KWA M93R) so I am not sure how much short stroking is possible. Limiting the travel of the spring will limit the maximum stored energy, if 120% recoil springs are recommended then a 150% limited to 80% of the compression distance should be roughly equivalent.

 

[adas1223]

ideally you should use duster gas and a stock TM gun.

If your main concern is logevity on propane, personally, i would: increase spring rate and get a high power nozzle. (less gas to BBU)

the increassed peed upon return IMO is negligible

 

[Guges Mk3]

Our just put a buffer on the spring guide to mitigate rearward shock.

Rule of thumb is this for TM.
75 degrees or less run Propane
76-90 degrees run 134a
91 degrees plus run R52 - Duster

 

[TsukiKanade]

Thanks for all the input! To take aotsukisho's and Guges' suggestions, how can I put a buffer on the gun? And wouldn't this cause the issue of the slide not locking back?

 

[Guges Mk3]

You have a few mm's to play with...a small rubber band to soft urethane washer works well as a buffer.

 

[TsukiKanade]

I do have these o-rings that are used to dampen mechanical keyboard keys. Let me give them a go!

For those coming across this in a future search, no, KJW M9A1 recoil springs are not the same length as this TM one; it's like an inch shorter. They feel like they have the same tension, but due to the length, the stock spring should be able to absorb more of the rearward force.

Edit: Using a portable baggage weight (like those ones with a hook) and an empty M9 slide, I made a really crude spring tension tester. The stock TM and KJW had the same reading of 2.9 lbs despite the length difference. A spring I got from a WE M9 was at around 4.0~4.2, which effectively makes it close to a 150% spring (138%~145% if you want to be a lil more precise).

 

[aotsukisho]

I do have these o-rings that are used to dampen mechanical keyboard keys. Let me give them a go!

Let us know how long they last. My mechanical keyboards only get the orthodontic band treatment lol

 

[TsukiKanade]

Not an update to its durability (and RIP like a dozen of these o-rings due to clumsy fingers). Using calipers, these o-rings measured at 1.43 mm. I placed three of them, since four with the stock spring seemed to disable the slide lock when mag empty feature when the mag was less than half full with propane. Duster did not lock back at all, but it's like 65 F up here.

Now to come back after using it when fields open up in my area..

 

[TsukiKanade]

Update:
I was able to use my guns again and I noticed an issue. I'm not sure if this is due to lack of maintenance on my part or if something is up with my gun. Every so often, on either duster or propane, the slide would lock back even if the mag was not empty yet. It tends to happen when the mag is just filled (and settled to room temp) with duster, and sporadically with the propane mags. Based on this, and from findings from searching the forums, I've gathered some points that may suggest the cause of the issue:

1. The gas is too strong and it's triggering the slide catch (this logically doesn't make sense, but the evidence seems to support it)
2. The slide catch is wearing down (I haven't used the thing since my tests last year... that was quick. Edit: Definitely makes no sense since the slide would no longer lock if this was the case, as per Guges)
3. Slide is not properly lubricated (I admit, I haven't relubed; it still has the factory grease on it. Not sure if this is actually a factor)

For now, I took off the buffers to test. I haven't had the issue trigger with the o-ring buffers yet but I also don't have consistent repro steps.

Edit:
I forgot point #4: grip. I may be accidentally nudging the slide release lever, which may be causing the issue, and my hand tends to try to ride higher on the gun with the higher powered gas. Will try and investigate more.

Also found out one of my mag's feed lips is cracked, though the issue occurred on different mags. Definitely have more variables to play with now.

 

[Guges Mk3]

If a slide catch is worn, it wouldn't lock back.

Your Grip may be an issue. Are you a lefty? If you are not a lefty, fire the pistol single hand and see if the slide still locks back.

Another test is take the slide off and put a mag in. If the follower on the mag is working correctly, it should be lifting up the slide stop on an empty mag. With a loaded mag it won't.

 

[TsukiKanade]

Your Grip may be an issue. Are you a lefty? If you are not a lefty, fire the pistol single hand and see if the slide still locks back.

I'm a righty actually! I did a few more tests with just one hand and made sure no appendage was anywhere close to the slide release lever
Mag 1 (with broken feed lip): Slide locked on 2nd shot and midway through the mag
Mag 2: No issue
Mag 3: No issue

Granted, this was only one pass. I'll try again later when I can.

Another test is take the slide off and put a mag in. If the follower on the mag is working correctly, it should be lifting up the slide stop on an empty mag. With a loaded mag it won't.

I did this last night as well. Mag follower is lifting up properly when there's no rounds left, but not when it's loaded on all mags.

Would this be better left in a new thread instead of continuing in what was supposed to be a research and info thread?

 

[Guges Mk3]

I'm a righty actually!...snip

I did this last night as well. Mag follower is lifting up properly when there's no rounds left, but not when it's loaded on all mags.

snip...

That is operating within normal parameters.