Making the .25 Edgun quiet, easily and inexpensively…
The key to the Edgun .25 making less noise is reducing the air pressure at the muzzle. There are a few ways to do this without engaging in exotic baffle designs, or spending money on an aftermarket shroud or moderator.
Here’s how it’s done:
The first step is to remove both the baffle cover, which is unscrewed counter clockwise, by hand, then removing the bottom shroud by removing the barrel bushing/vent nut. Then you can easily enlarge the existing vent holes at the rear of the Edgun shroud with a variable speed hand drill. I made my lower shroud vent holes 2.0mm in diameter:
You can go larger if you wish. If you go too large and begin to hear air “whoosh” out of the vent holes when firing, just wrap some felt around the inside of the shroud, behind the vent holes, to slow the air down. You can touch them up with the tip of a permanent ink black felt tip Sharpie. This is how they look when done, but before the Sharpie touchup:
The next step is to increase the air flow from the front of the Edgun to the rear of the shroud. Now on the R3 this is a bit more complicated because the shroud comes in two parts, so I will concentrate on the R3. Unscrew the top shroud, baffle cover, taking care to remove it easily because the O-ring can be damaged on the threads. Be sure to put silicone grease that O-ring before putting it back on. Note the bottom shroud, and barrel, are held in place by a 19mm nut with vent holes in it. It unscrews easily, counter-clockwise, with a common metric wrench:
After it is taken off, you then enlarge the holes in the nut with a variable speed drill. I went 2.5mm, you may choose to go smaller, but not much larger, as the hole diameter affects the strength of the nut.
After this is done, you simply replace the bottom shroud, then the barrel bushing, being certain that the bottom of the shroud is properly placed OVER the rim of the permanent cone shaped breech attachment. If you ignore this step, you will bend the bottom of the shroud when you tighten the nut…note the bottom of the shroud sitting flush against the cone shaped breech attachment in this picture. The hidden rim inside the shroud is about 1/8″ or so tall, but it must have the shroud placed evenly over it before tightening the nut. When you lift up and remove the bottom shroud, you will easily spot it, as the cone shaped breech attachment remains in place:
Finally, there has been much discussion regarding how much torque must be used to tighten the nut that holds the barrel and bottom shroud in place. This is not a difficult process. First you obtain a Russian Torque Wrench…see below picture:
Placing the 19mm wrench in this handy grasping tool, you tighten the nut to where it is snug against the shroud, then you go roughly 1/2 turn further. That’s all it takes. Remember, this is thin and fairly soft aluminum and will strip threads or bend rather easily. AND…if you have placed the bottom of the barrel shroud over the lip of the cone shaped breech attachment, you will not have bent, or dented, the bottom of the shroud.
Replacing the top shroud (baffle cover) is easily done, just be careful sliding the cover over the O-ring using a light downward pressure and clockwise screwing motion until it gets past the threads on the cover. Snug it up hand tight, no more.
That’s it! You can expect at least a 50% reduction in muzzle blast, which on the Long Edgun makes the hammer slap the loudest noise emitted when shooting the gun. It costs nothing, takes about 1/2 hour, a couple of metric bits, and a variable speed hand drill. Take your time. The existing holes will guide the bit if you proceed slowly, especially when starting the new hole.
Now, for that hammer slap…I’m still working on that one.
Regards,
Kindly ‘Ol Uncle H 😯 😯 t
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Very well. I plan on using it prairie dog shooting next spring. :5:
looks good..i was always concerned about stability with that tripod mount….how does it hold up?
I picked up a Caldwell Deadpod like H 😯 😯 t’s and they are a great light weight stable shooting platform for the price ($85). I added a Velcro safety strap because the std Cricket just barely fits on it at the shortest setting but it works like a champ – just ask about 6 sparrows. 😯
Hoot ,
Yeah, I did drill out the baffle nut:
Tommorow, I will try to shoot a few groups with the oem and NC setups.
Gabe
We need to remember these were both prototypes that Neil put together in a very short time, between filling his normal orders.
Neil has indicated he has made improvements on both the prototypes, including the one piece shroud, so how effective it is, compared to the prototype remains to be seen.
What I would like to see is an oversized shroud for the Edgun, 1.5″ OD, but that would entail making a concave bottom to fit over the air tube and that has got to involve some serious labor on his part. Another way to get oversized is a breech riser and extended hammer release for the trigger mechanism. Lacking that, the two piece seems to offer the most volume to disperse the air the .25 exhausts with each shot.
Gabe, did/have you drilled out the front barrel bushings on the Edgun? That is essential to getting maximum air flow to the rear of the shroud, and may account for part of your results with the one piece shroud. I drilled my front barrel bushings out to the absolute max, every hole was enlarged. The nut held up to being tightened, and I knkow at least twice the volume of air can now reach the back of the shroud.
Just a thought, but I feel a critical element in distributing the pressure to the right places on the shroud to lower the noise.
Hi,
I got a quick chance to try the one piece aluminum shroud Hoot sent me. The construction is superb. The powder coating is even. I compared it to my 30 ft lbs .22 cal cricket standard with 16 inch Clague carbon fiber shroud. I shot the cricket first then the r3 with shroud. I shot at a duct seal trap in my living room.
To my ears, the r3 seemed snappy and quite a bit louder than the cricket. This was with the one piece shroud. I removed the one piece shroud and put on the modified oem two piece shroud. Remember, I opened up the vent holes as well as drilling a row on new holes. With the modified oem shroud, I would say it is quieter than the one piece aluminum shroud. I was surprised at the results. But that is what I noticed.
Synopsys was kind enough to let me borrow his decibel meter and I should get it early next week. With the meter, I should be able to quantify my observations. I will shoot in under the same condition only changing the shroud systems.
IMO, there needs to be more volume up front to slow down all the air the .25 pushed out. That is why I think the two piece shroud will be more effective at sound suppression. A “can” up front can do this. Remember, the .25 cal is using more air than a .22 cal. The difference is what is most likely causing the difference in sound levels.
I didn’t test accuracy because I just don’t have the time yet. Maybe this weekend. I’ll definitely post my result ASAP.
Btw, my r3 is shooting .25 jsb kings at 890 fps.
Gabe
Good! It´s always nice to be properly dressed for the occasion. 😎
Not yet. No hurry, the parade isn’t till September 31st.
I never mentioned to anyone that I had drilled out the holes in the Edgun barrel bushing. The holes there are not very large, so I drilled them out to the max!
Your idea is better, and I agree from experience that more air in the back of the shroud is relieving pressure on the shroud baffles. This is positive proof that great minds travel the same roads.
However, I would suggest drilling out that front barrel bushing is still a very good idea.
Sounds (or maybe for this instance the lack of sound) like a very good idea. This may be the first fix that isn´t just a band-aid. Interresting.
That should help! 😉
KnifeMaker
You might wish to wrap a piece of felt, or fine wire mesh, inside the shroud where the air exits the holes. Several members have done that to slow/muffle the release of air.
Sir Ville had this same problem, but he had forgotten to replace the shroud over the barrel before he shot it!
Regards,
H 😯 😯 t
Hoot, that didn’t work, I already tried it, it seems there is not much air going back in the shroud so I will have to enlarge the front holes. but I designed something better to fit inside the back shroud to divide it into chambers & printed it already, lets see how this works.
Now you’re going all senile on me again, Uncle… You promised not to tell anyone about that little misshap i had in drugged haze (purple). I didn’t have any Bong on hand so i needed to use the shroud with its enlarged holes as a make-do. It would have worked well except i forgot to remowe the felt from inside it and got poisoned by the smoke.
I hope you’re happy – now everybody knows …
PS Got your T-shirts yet???
Sent from my iPhone using Tapatalk 2. This POS iPhone sucks though …
Interesting!
You might wish to wrap a piece of felt, or fine wire mesh, inside the shroud where the air exits the holes. Several members have done that to slow/muffle the release of air.
Sir Ville had this same problem, but he had forgotten to replace the shroud over the barrel before he shot it!
Regards,
H 😯 😯 t
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Hi,
I was able to take some sound measurement using a radio shack sound level meter. After reading the online manual, I was able to figure out how to use it… I think 😕
I was weird because the one piece aluminum NC shroud read at 67 decibel ( an average of five readings) and the modified oem shroud also read at the same levels but I swear the oem shroud is quieter. None, came close to my NC shrouded cricket. I came in at 62 dbs. I used duct seal as the back stop and shot in my back yard at a short 10 yards. I didn’t want the impact of the pellet to influence the sound from the blast.
I wanted to find out for sure which unit was quieter so I ask my kids to judge the sounds. I have four kids and I asked them to come down and tell me which one was quieter. To make sure they got a “real” report, I was able to come up with a way to change the shrouds rather quickly. I held onto the NC one piece shroud as i fired so I didn’t have to waste time tightening the set screw. For the oem shroud, I quickly attached it to were it was secure enough to fire it safely. The transition was quick. I fired three shots and then another with the different shroud.
All but three of my kids believed the oem shroud was the quietest. Oh my the way, my kids are young adults, one teenager, and a very mature 8 year old. I think the odd one out has hearing problems. Need to check her out 😆
Well those are my results with my limited experience using a sound meter. Actually it was my first time. I’m sure I can get more accurate measurements with more experience but I am satisfied with the results.
IMO, I think the 0em shroud with the mods I made are just as quiet or more than the NC one piece shroud. Results will vary with the degree of modifications done to the oem shroud. I believe Demp mentioned that there is a threshold between opening up the vent hole or adding more holes and lose of sound suppression. That being said, I think my oem shroud is at the point where it is working at it’s maximum at suppressing the sound of the air blast.
To truly make the edgun .25 long absolutely silent, I think there needs to be more volume up front in the form of a detachable LDC. The two piece unit that NC made for Hoot seem to be the ticket. On another option is to make the one piece unit longer or to modify the internals. That would take a lot of R and D and the cost of NC’s shrouds would probably lose their affordability. I am content with ordering one of NC’s two piece units. That way I can choose to add a big ass can upfront or a smaller one. In essence, I can tune the sound the gun makes to my liking.
I didn’t shoot for accuracy as I was not in my usual shooting spot. I will try to shoot some groups on Monday or maybe next weekend.
I like tinkering with my guns but to a certain point. I can become obsessive it I don’t check myself. It’s fun though :8:
Gabe