Up first for mine is a barrel stabiliser, the ACR was famous for its barrel being wobbly.
As a note, you can tighten the barrel nut and barrels which helps, but being a nylon barrel still wobbles a bit.
I’ll print a stabiliser and then refine and reprint… until I am happy.
I will test soon and chrono to get a starting point.
I did this after buying and found it a bit lacking and inconsistent, and feeding was a bit ordinary, but documenting progress is key.
I have epoxied a 40cm alloy barrel in a tpiece, may get cut down to suit or may not… I’ll test with that, then go for a green o-ring, m90, 11v, cylinder head and nozzle and test again. Will give a good easy upgrade results I believe.
Later I may pilfer an MK CNC box from a gen9 o don’t use and do a bit of a thing
My only consideration is I might make it a bit more three dimensional, gas block looking and a bit thicker but as is works a treat and very easy install.
Good to see this thread… nothing wrong with the old blasters at all, and let’s face it, if you want a ACR /Masada gel blaster you’re either buying a Jin Ming J10 or a HEe ACR. So they’re still valid.
Mine is my first JM ACR, they just weren’t my thing years ago and I gotta say, I’m impressed with the build quality. Very solid. The nylon outer barrel is a bit of a let down but not a dealbreaker for me. The bolt hold open and functional release are a nice touch too.
I’ll probably forward wire mine too… plenty of room in that handguard and easier to access than the janky trapdoor arrangement in the folding buttstock.
Looking forward to seeing more in this thread… I’ll post up pre-mod chrono results and impressions and post-mod for my ACR as it develops. Still haven’t ruled out a full metal CYMA V2 yet.
Damn, you epoxy the tpiece to the barrel? In China all the techs use this kind of glue that comes apart if you twist really hard. I might consider epoxy on my MK47.
Are you drawing these stabilizers yourself or you get the 3D file from somewhere? Interesting as the J10 ACR is pretty rare these days in China as well.
I do yes, but I always get a spare tpiece! Quite often removing a barrel once epoxied does involve destroying the tpiece, but the seal is unbeatable.
I have seen some use hot glue so they can reuse the tpiece if wanting to change it later… hot glue is right there with sanding for me… I’ll do anything to avoid it I can! No reason other than I don’t enjoy doing it!
@Friendly_Fire you are motivating me to go for it too! Hopefully tomorrow I can get a green o-ring, cylinder head and nozzle and m90 in to see how it goes… For science!
Then I can swap out the mk box from my gen9 into the acr… and the nylon box will go into the gen9.
As for swapping to a metal V2, I did once get a singularity V2 box working in a gen9, similar externally to an ldt gearbox but much stronger…
From memory it was a bit tricky but not impossible. Imo the nylon gen9 box is best left with stock nylon gears and motor, and m90 11v and they just go forever. I knew a fellow that had an m100 in an acr with nylon gears and it went for a few years! My gen8 ump did the same for 10 months.
Thanks so much for starting this thread @RokSolid
I love my old school Blasters, and these ACR’s have been a favourite of mine since they were very first released, same as you have commented, was immediately impressed with their rugged bulletproof build design and simplicity.
Yup, standard JinMing lottery as to what you received, but I was lucky enough to have great 220-250FPS output with smooth feeding on each one that I tested/reviewed straight out of the box.
Can’t wait to see your results with this, but honestly take VERY little work to make them into a solid and reliable performance Blaster…same with yours @Friendly_Fire, always keen to see other people’s builds and results from these classic “old” models.
Regarding the different types of barrel stabilisers, I found them all to improve barrel rigidity much better than standard, along with using heavy Stainless Steel barrels, but my fussy standards still weren’t happy that they still allowed the barrel to be moved upward slightly if forced by hand to check the clearances.
Sure that the chances of the barrel moving upwards during normal use was highly unlikely, but to me, “stabilised” means ZERO allowable movement in ANY direction!
This was easily rectified by the addition of a bit of sticky back black high density foam tape above the barrel anyrate, so no big deal.
There was a time where if you could get 300fps reliably with 11v and not suffer breakages you were a god among men… the j9/10 and nylon gen8s really changed that to a normal level of performance in their day. Was a very exciting time for gel blasters!
The first time I picked up a j10 I bought one, the solid body and feel was something special in its day. And there are fields that still use them as rentals because they were so solid and reliable.
I believe I did something similar with my original acr to keep the barrel vertically stable.
The little thing I printed actually works well in all directions, no movement at all. It’s a little tight to get the handguard on but that’s better than still having movement. I am only going to modify it to improve aesthetics of it, even though it is largely hidden.
My ACR/R came with poorly shimmed metal gears in nylon box. Had it re-shimmed and it ran great after some work on the t-piece to ensure that it didn’t foul the front exiting wiring. Finally wore out the pinion as there isn’t any way to maintain pinion height and didn’t notice that the baseplate had come loose.
Have installed a stock gearbox with stock rear exiting wiring until I work up the inclination to go through the frustration of re-shimming the old gearbox - and I’ve spent too much time on this thing already
The inconsistent feeding from magazines is a real bug bear. Happens with both stock ACR/R magazines and J12 magazines and the retaining clips on the stock ACR/R mags break off when you try to clean the mags (or chase feeding problems)
Just yanked the inner barrel out of the upper receiver… surprised to see no spring in front of the t piece and the t piece quite tight in the outer barrel.
Unimpressed with the bruisemaster god level barrel M4A1 put in my mates and the hack job they did to fit a 3S Lipo suppossed “upgrade” package they were selling.
Oh dear bits and pieces of ACR on my bench for days.
Strip down, Gen 9 box out, nylon gears shimmed, o ring swap from shitty factory to green and piston spring swap for a slightly cut down M100, 7.5 alloy inner barrel.
Looking at around 250FPS on the chrono now… a gain of around 40 - 50, but surprisingly low given the mods. A few different trials with other springs seems to be in order.
Definitely more consistent and highest FPS using Ultra Elites, smaller gels sat at around 230FPS. The OEM ACR mag fed inconsistently, something it wasn’t doing before… CYMA mags constantly double fed and with mag out there was often two or three gels squashed into the collar at the top of the feed tube… hmmmmm. Gen 9 mags worked flawlessly.
Further fettling and investigation required, methinks.
I used to fit Pololu Voltage Step Down Regulators to the mag feed wires to be able to adjust the speed of some of the troublesome magazines.
Some mag motors ran too fast, jamming more gels into the feed tube and t-piece than the Blaster could physically fire, causing all these similar issues.
At first I thought that the mags couldn’t keep up with feeding enough Gels, causing the misfire issues, but it was actually the opposite, where too many Gels were being force fed into the works.
Mag motors should all operate at the same RPM, but its possibly the diameter of the feed wheels being slightly different that is pushing more Gels at any given RPM than other magazines.
The WELL PDW was the same from memory, and a couple of others that I can’t remember the exact brand/type… possibly a couple of SLR’s in that list as well?
This is just an example to give you an idea of these tiny little units and are available in hundreds of different voltage ranges to suit whatever power range requirements you are looking for.
