[dragon64]

You make the parts, and we will test them... Do you have a youtube channel to promote? As I rebuild my M28 and start a new series of videos on the rifle, I would like to give shout outs to your website and channel...

I found some archive video footage from Dec 2010, the month I received my M28, and posted it to my youtube channel... one of the first vids I made after doing some do-it-yourself mods... Don't know how I missed it... one of the few times that Alabama had such a beautifull snow fall... or any snow at all for that matter.

 

[dragon64]

I emailed Brian (Lead Service Tech) at ECHO1 USA about the zero trigger and matching piston, and his reply was that ECHO1 was having them made, and they have been trying to source materials and parts... no ETA on these new items.

 

[chaoticairsofter]

Dragon I have been watching your m28 vids since they came out Please do make new continious videos because I too want to get my m28 back in action but my hop up unit is terrible. I might take your advice and buy a new one.

 

[silentball]

The hop up unit issues is with the cast metal pin that the hop up lever pivots on.

Dragon, if you take a caliper you will find that the left side of the lever pin has a larger diameter than the right side. This is because the left side of the hop up unit needs to release from the mold and if the hop up lever point was completely parallel, it will bind coming out of the mold.

Mathematically you can calculated the exact angle of of hop up lever tilt from the measurements.

Thus the hop up lever will be canted a few degrees to the left, cause more hop on the left side of the buck, and a result shots hook to the left.

Solution - get a CNC hop up unit that using a real steel pin

 

[dragon64]

Dragon I have been watching your m28 vids since they came out Please do make new continious videos because I too want to get my m28 back in action but my hop up unit is terrible. I might take your advice and buy a new one.

Good for you CA. My wife asked me what I wanted for Christmas.. as ugly as it is, I may opt for the desert tan M28. We'll see. I have been watching the boneyards for a tan one to show up, it is at least worth half price to me if it comes with most of the accessories. More video will come once I have finished the rebuild.

The hop up unit issues is with the cast metal pin that the hop up lever pivots on.

Dragon, if you take a caliper you will find that the left side of the lever pin has a larger diameter than the right side. This is because the left side of the hop up unit needs to release from the mold and if the hop up lever point was completely parallel, it will bind coming out of the mold.

Mathematically you can calculated the exact angle of of hop up lever tilt from the measurements.

Thus the hop up lever will be canted a few degrees to the left, cause more hop on the left side of the buck, and a result shots hook to the left.

Solution - get a CNC hop up unit that using a real steel pin

I believe I lucked out on my recent purchase. I measured close to the base...

And closer to the top, and my pin is rather uniform...

The problem with the pin on this new unit, is that it does not extend to meet the other half of the hop-up shell. There is a 0.0625" air gap between the end of the pin and its mating side. I have a little more fitting and sanding to do, and then I casn re-assemble... not enough hours in the day.

 

[silentball]

You certainly lucked out . Mine was not uniform. These things are cheap so I may buy another one or go to the store with the calipers and pick a good one.

 

[dragon64]

The #1 Complaint With The M28... is the Dreaded Slam-Fire event. Until this issue raised its ugly head, the previous #1 issue with the M28 was the propietary assemblies, namely the cylinder group and the hop-up assmebly. This will be covered in more detail later; today's topic is the new #1 issue to plague the M28, and that is the slam-fire event.
Again, for those of you just starting out, the slam-fire event happens when you cycle the bolt, and when you go to return the bolt to its fire position (battery), the bolt slams forward... wala, you have the nasty slam-fire.
There are a number of theories out there about the exact cause with regards to the M28, I aim to describe the problem that caused my rifle to start slam firing. The issue with my rifle lies within original M28 trigger group. The major components that make up the assembly rattled back in forth inside of the housing. The parts, which are generaly cast pot-metal, were made with very loose tolerances. So loose, it was a wonder that the trigger sear ever held onto the piston in the first place. As seen in the next photo, the wear on the piston sear shows clearly the rounded edge...

The piston sear flopperd around so much that when the bolt was cycled, the slot in the bolt was cutting into the side of the sear. Notice also how the metal looks almost pewter or even the color of lead. Pot metasl equals bad material for airsoft, unfortunately it is how manufacturers turn out quick down and dirty clones...

Here is a brief video on my defective trigger group. Although the video is of poor quality, I am able to clearly show how bad the M28 trigger can be...

There is an easy fix for this issue; if you are experienceing the slam fire event, and you believe that your trigger group is the problem, simply rebuild the trigger group... The downside is, it will cost you at a minimum of $55 for the parts. For my rifle, I rebuilt the trigger group using Airsoft GI's VSR-10 trigger sears and springs. The cost was $55 plus shipping. There are other manufacturers that make after market trigger parts for the 45 degree piston sear set up, you just need to shop around. I liked the Airsoft GI rebranded parts, as it comes with excellent spring package. You will find that the springs in the M28 trigger group are sub par, and need replacing. Here is the link to the parts I used:
http://www.airsoftgi.com/product_info.php?cPath=362_364_651&products_id=5951
Note also, if you are not comfortable rebuilding your own trigger group, then Airsoft GI has a complete upgraded trigger assembly for the M28, just remove and replace (R&R). Here is the link:
http://www.airsoftgi.com/product_info.php?cPath=362_364_651&products_id=7694
For those of you who seek the adventure and want to know more about what makes your rifle tic, here is a simple video I made on re-assembling your trigger group after rebuild. It is good to note at this point, that a trigger assembly from most any VSR-10 rifle will work in the M28. This is a blessing, as had this been one of the propietary assemblies, our rifles would have been dead in the water with no fix relief. As it is, this is the only complete VSR-10 compatable assembly that works as designed in the M28. Here is the re-assembly video...

With any introduction of a new part, there is a break-in period, until the parts start to messh and begin working together. Give your new assembly some time, and it will work like it was supposed to in the first place. Brian at ECHO 1 USA has indicated in I video that I linked to, that there is a zero degree trigger and piston on the horizon... unfortuantely there is no release date set.
If you have found that your M28 is slam firing for a different reason, please feel free to share what the problem was, and how you went about fixing it.

 

[dragon64]

I'll float one more issue that contributes to slam firing. Inside of the receiver are two plastic rings. The front ring is complete, and the rear ring has a gap in it. The rings help keep the bolt assembly centered within the receiver. But I have noticed that the rings in my m28 are a very loose fit. I was ablt to cock my rifle, and with some slight upward pressure on the bolt from my thumb, I could lift the bolt and the rifle would fire. Essentially I could fire the rifle, beause the slack in the rings allowed me to lift the bolt and piston off of the trigger sear.

I fixed the rear ring by manicuring an old 35mm plastic film canister which I used to replace the rear ring. Cycling the bolt was a little tight at first, but it is wearing in now... Check it out:

 

[silentball]

Great idea with the 35mm film cans. Hope you have a supply for us because I have gone digital a long time ago and haven't touched a roll of 35mm since.

 

[dragon64]

I had to really dig to find the one I used... We used to have them in every drawer in the house it seemed.. not now, now the cannisters are a dying breed.

 

[silentball]

New product from Dragon64. 35mm cylinder sleeve kits coming soon....

 

[dragon64]

New product from Dragon64. 35mm cylinder sleeve kits coming soon....

One drawback to the sleeve, and it is not really that big of a drawback, and that is that the sleeve needs to broke in. Because of the material, the break in period can take a while. I guess what I am saying is, the bolt will be tight to pull back on, until the sleeve gets a little wear on it. Silicone grease really helps with bolt cycling.

The plus side of this modification; my bolt is not getting damaged anymore, and it is well centered inside of the receiver.

 

[MGunner]

http://backyardcacher.com/index.php?main_page=product_info&products_id=44

Fairly cheap.

 

[dragon64]

I wonder what their inventory looks like... The canister pictured in the link you provided will not work as it is the 35mm cannister with the screw on lid. You need the cannister with the pop-on lid. That way you can take advantage of the lip at the top of the can. I'll bet a call to the vendor when you order may net the cans you really need.

 

[bushes]

I think I may be able to offer some help to anyone trying to fit VSR cylinder parts in the M28 as this is how I finally fixed my personal slam fire issue.
Budget VSR pistons will usually fit in the M28 cylinder, though some, like the ASGI piston I used, may need some filing/sanding to make them fit since the M28 cylinder seems to be a bit narrower than a VSR. Once you get the piston in though you won't be able to pull the bolt back far enough to engage the sears. This is because the M28 spring guide is about a quarter inch longer than a VSR guide so the piston hits the end of the spring guide before it reaches the sears. All you have to do to remedy this is to cut the spring guide down a bit or just use a VSR spring guide.
A VSR spring guide and VSR piston will work or an M28 spring guide and M28 piston will work but they cannot be mixed.
In my case this seemed to boost my FPS since the shorter piston has more room to accelerate than the stock one but i cannot verify with actual chrono results.
Now all I have to do is figure out how to get her to feed consistently.

 

[dragon64]

I think I may be able to offer some help to anyone trying to fit VSR cylinder parts in the M28 as this is how I finally fixed my personal slam fire issue.
Budget VSR pistons will usually fit in the M28 cylinder, though some, like the ASGI piston I used, may need some filing/sanding to make them fit since the M28 cylinder seems to be a bit narrower than a VSR. Once you get the piston in though you won't be able to pull the bolt back far enough to engage the sears. This is because the M28 spring guide is about a quarter inch longer than a VSR guide so the piston hits the end of the spring guide before it reaches the sears. All you have to do to remedy this is to cut the spring guide down a bit or just use a VSR spring guide.
A VSR spring guide and VSR piston will work or an M28 spring guide and M28 piston will work but they cannot be mixed.
In my case this seemed to boost my FPS since the shorter piston has more room to accelerate than the stock one but i cannot verify with actual chrono results.
Now all I have to do is figure out how to get her to feed consistently.

For the miss-feeds, get the metal magazine... zero miss-feeds to date.

Interesting about the VSR-10 piston working. The one I tried would not engage, as the piston is nearly .25 too short, and just misses the trigger sear. When I installed the piston, I also used the associated spring guide, not the M28 guide... no joy.

I'm your has oulled through, no pun intended... I have wanted to try the Airsoft GI piston, but did not want to waste the money if I thought it would not work.

Do you have some pics of your psrts and set-up?

 

[silentball]

Make sure there is a return if it does not work. Those asgi pistons are made off shore for clone VSR10 cylinders, not M28. There was a confusion when the M28 was released was supposed to be 100% VSR but now we find out only the trigger is and that is also off spec.

 

[bushes]

Interesting about the VSR-10 piston working. The one I tried would not engage, as the piston is nearly .25 too short, and just misses the trigger sear. When I installed the piston, I also used the associated spring guide, not the M28 guide... no joy.
QUOTE]

Have you tried it without the bearings on the the spring guide. Someone earlier mentioned them being a problem. I think that the m28 needs the piston pulled back all the way back to the base of the spring guide, whereas the VSR has a bit more slop, so the bearings may get in the way. Make sure that the spring guide will fit all the way into the piston so that it is completely covered.

As for pictures, the rifle is currently in pieces since I've been using my BAR 10 of late due to the feeding issues, so theres not much to see. Hopefully one of these days I'll get her up and running with some of the metal mags you mentioned. Then I'll post some stuf.

Make sure there is a return if it does not work. Those asgi pistons are made off shore for clone VSR10 cylinders, not M28. There was a confusion when the M28 was released was supposed to be 100% VSR but now we find out only the trigger is and that is also off spec.

The ASGI piston looks good and has held up well but I would not necessarily recomend it in the m28. it needed a few hours worth of slowly sanding down the guide rings and steel lip to make it fit perfectly inside the cylinder.

 

[silentball]

Looks like Evike has a piston for the M28 but it also will work on a VSR10.

http://www.evike.com/product_info.p...35610&osCsid=5d5b61b3c1fadbbe508ccd29a04369d5

 

[~Ranger~]

The piston at Evike doesnt actually fit the M28. Evike is pretty clueless on what they sell. People for the last few years have been buying pistons they say will work, and then have pistons they cant use,lol.. My M28 pistons work, and I make them specifically for the M28. I make them to match the stock sears as well.