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MagPul PTS MASADA ACR

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I've not had any issues my ACR since getting it in 2010, however I got around to chrono'ing it over the last few days and with 0.2g bb's its been smashing them out at 410 fps!! The only changes I have made have been a new motor and thats it. Comparing it to my M4 which did 340fps on an M100 I swapped springs around between the guns and found the M100 from the M4 was pushing 420fps in the ACR and the spring from the ACR was pusshing 328fps in the M4. Strange! Now to cut down the springs to 370fps in the ACR and a bigger spring for the M4!

 

Sounds like you have an air seal issue in your M4 more then a spring issue. I think the M100 should easily be pushing 365-380fps if everything is air tight. Might be as simple as changing the bucking out. Going up in spring rate just puts unwanted stress on your gb. IMHO

 

What Motor did you install when you changed out the stock one?

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@sacairsoftsn00py: I just got hold of my ACR today. However, the bolt catch doesn't lock (no big deal actually) and I see some wear on the post that supposed to hold the dummy bolt. Is there any way I can fix this or a remedy perhaps? Though, I haven’t started working inside the gearbox. I am still waiting for the parts from RedWolf HK.

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You can square off the post and/or bend the part of the dummy bolt that catches onto it. When I lock the bolt back, I pull the bolt catch down first then slowly let the charging handle/bolt assembly go forward. When closing the dummy bolt, pull charging handle back, push down on bolt catch, then slowly let the charging handle/bolt go forward. This minimizes wear and tear on the pot metal bolt catch which is super soft.

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However, the bolt catch doesn't lock (no big deal actually) and I see some wear on the post that supposed to hold the dummy bolt. Is there any way I can fix this or a remedy perhaps?

 

I just took it apart, and using some pliers i bent the ejection port cover very slightly, just so it would make a more positive contact with the release/lock post.

 

Worked perfectly, just bend the corner a little.

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You can square off the post and/or bend the part of the dummy bolt that catches onto it. When I lock the bolt back, I pull the bolt catch down first then slowly let the charging handle/bolt assembly go forward. When closing the dummy bolt, pull charging handle back, push down on bolt catch, then slowly let the charging handle/bolt go forward. This minimizes wear and tear on the pot metal bolt catch which is super soft.

 

Yah, that technique would really help minimize wear of that soft metal post.

 

I just took it apart, and using some pliers i bent the ejection port cover very slightly, just so it would make a more positive contact with the release/lock post.

 

Worked perfectly, just bend the corner a little.

 

Thanks guys! for now, at least, the bending stuff seems to work.

 

And since I have the AEG unit right now, will try to find out if I can fit a Version3 bearing spring guide in it. I really don't care if I’ll lose the ability to dynamically change springs, never been a fan of it anyway. Though, it might require some modifications. In any case, will keep you posted.

Edited by snake_pliskin

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Final configuration of my magpul pts masada akm:

 

Jg mosfet

Ars sorbo pad

KWA v3 cylinder head for g36c

Tm piston head (ported with 8 holes)

Tm 6.08mm x 317mm inner barrel

Systema turbo motor w/ pinion gear off of the stock motor

Prometheus soft type purple hop bucking

Shs sector gear delay clip

Guarder sp100 spring

 

Angle of engagement correction with sorbo pad. Tappet plate sanded down. Air nozzle forward tappet retainer lip tapered. Front of the gearbox/nozzle area inside was tapered to allow nozzle to move farther forward. Heat shrink tubing shims added on top of hop bucking.

 

Compression components lubes with team associated green slime.

 

Perfect seal between hop bucking and air seal nozzle with the nozzle and piston all the way forward. Determined by zero air leak blowing into the inner barrel. Battery was unplugged.

 

Gun is shooting in the 320 fps range with a high of 327 fps using toytec .25g bbs. Hop was set for the said weight of bbs prior to checking the fps using an xcortech chrono at 3:00pm.

 

Rof is 20.5 rps with a 7.4v 1600mah 35c Lipo battery fresh off of the charger.

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sn00py, glad to see the KWA v3 head works. As I mentioned in a previous post, I have an AUG cylinder head that seems to work well too. I like your idea of mod'ing the tappet plate to allow for a better seal. I'm putting in a new micro switch in a few days and will try that as well.

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in case your ACR's tappet plate retires, you can actually fit in a V3 tappet plate. right now, just installed Prometheus Hard Tappet Plate Ver.III with a little filling on the bottom part of the tappet plate. i just want to make sure that it won't make contact with the micro switch. tomorrow, will try fit in a Systema V3 spring guide, though the quick change spring feature will be lost. i really don't like it anyway.

 

Here are the list currently installed in the gearbox with NO modifications.

 

Prometheus Stainless Hard Cylinder Type B for Marui AEG

Prometheus Piston head POM NEO for Marui AEG

Prometheus Aero Cylinder Head Ver. 3 for Marui AUG/SIG 552

Prometheus Double Torque Gear Set

Systema Anti-Reverse Latch

 

also, i still have to do a little filling on the Prometheus Reinforced Hard Piston for Max Torque; filling on the part that makes contact with the gearbox piston guide/rail guide.

Edited by snake_pliskin

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okay, i just did a little mod on the V3 tappet plate, a little filling job on its tail part. it’s a little bit thicker compared to the stock one. however, the V3 bearing spring guide do fit but it’s a PITA setting the spring in place, so discarded it for now. the promy piston works great after a little mod though. and finally, the wii tech air seal nozzle was a ######. it leaks and i mean big. surprisingly, the stock air nozzle seems air tight compared to the wii tech. i think it has something to do with the poor quality of the o-ring installed on the wii tech air seal nozzle. ill get someone to custom made a silicon o-ring for that wii tech air seal nozzle and see if it improves.

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utilizing SHS Version 3 Spring Guide, i managed to fit it in with some minor grinding and filling, of course. now my ACR has railing and trailing bearings to prevent or at least minimize stress on the spring. and surprisingly was able to retain the quick change spring feature. i finally completed the necessary adjustments i can think of to this gearbox.

post-69911-0-68625400-1330581793_thumb.jpg

post-69911-0-42987500-1330581893_thumb.jpg

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New to the forum. Just wanted to post results from all the info I gathered from this thread. All of you have been a great help in getting my Masada running in top form. I've recently installed SHS 13:1 gears, corrected AOE with rubber washers, and installed a red element piston(which is a great fit in the GB, no binding whatsoever). With an SHS M100 I am shooting consistently in the low 350 fps range...perfect. However, I'm running into some feeding issues....mags not keeping up or not feeding correctly. From what I've read, i might have to modify or replace the tappet plate and/or sand down the nozzle. Here is a video with my results. The mag was almost empty at this point and battery wasnt at full charge. Let me know what you think. Happy Holidays!

 

http://www.youtube.com/watch?v=jCttl0MzG9E

 

A little bit unrelated but my SHS M100 spring shoots 393 FPS with .20g Tracer rounds from AONW in a Tokyo Marui G36C with a stock barrel, bucking, and compression parts. Hop has already been set for .25g BBs. I am using a 3/16" sorbo pad to adjust my angle of engagement.

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OK so first post, specifically to find out as much as possible about my Masada.

 

Bought a 2nd-hand one, about 5 months old but only used twice. All I've done is install a PDI 150% spring and a Madbull blue hop (had these parts lying around at home).

FPS is 365 - 370 FPS and range is approx 50ms, so I'm pretty happy with it, but not 100%.

 

Firstly, the Madbull blue hop only has an effect right at the very end, but I am ordering the PDI W-hold hop, so hopefully that will make a better difference.

Secondly, I'm wondering if the Prometheus 6.03 TBB 380mm made for the Masada will make a difference?

Thirdly, after scouring this thread for a few days, I can't really put my finger on what GB upgrades are absolutely essential. Any help in this would be greatly appreciated.

 

For info sake, I'm not the type of Airsofter to lob tons of bb's downrange and hope I hit something, I like to take controlled bursts with relative accuracy. I'm not interested in high-speed setups or 400FPS (our field limits in South Africa) setups, I just want something as accurate as possible. And yes, before anyone asks, I can shoot :)

 

Many thanks in advance.

Mav

Edited by Maverickus

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Someone of you may have already noticed that a computerized mosfet with active braking is bad idea. It doesn't work with micro switch. I can confirm this. Everything works fine with a basic mosfet.

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I have tried an active breaking MOSFET and it works really well for me however there are some caveats with me saying that!

 

When the mechbox was out and on the table the active breaking didn't work, all the symptoms you would expect. However when it was back together it is perfect. I wouldn't like to use it on full auto all the time as I feel this would be pushing your luck but in it's current setup with a 4 round burst I can't fault it.

 

For reference I have hardwired a basic MOSFET and then used a plug and play micro computer with active breaking so I could re-use if it didn't go to plan.

 

It also has a sorbo pad on the cylinder head and a thin piece of rubber on the piston head for that extra bit of padding. Maybe it is this that's 'letting me get away with it'

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.

For reference I have hardwired a basic MOSFET and then used a plug and play micro computer with active breaking so I could re-use if it didn't go to plan.

 

I also have used a plug and play micro computer w/AB and have never had any problems with it.

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OK. So what issue and/ or problem does this Wii thing address? What improvement does it provide?

 

All genuine questions. I'm up for after market improvements.

 

You can use a regular nub with the masada with this kit. in the stock hup-up arm the only nub that could fit there without modification is the stock nub, which is terrible.

Edited by V3RTIGO

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