Holes in a shroud

Jump to latest Follow Reply
This is a contrarian opinion, but I have found holes in the shroud have always made the gun louder and never quieter no matter where they are placed. The more I put thought into it, it makes sense to me that the holes allow more sound to escape. A shroud with no holes increases the muffling effect. I think holes in shrouds are only really useful when designed as air strippers for improved pellet stability.
 
  • Like
Reactions: subscriber
Upvote 0
I was also looking at getting 6 more Baffles for my SynRod, and modifying them, by drilling the Marauder Baffles Bell Cone Area, small holes start with 1/16" 4 holes, so that the air in front of the baffle is pushed Backward into the newly drilled rear facing drilled holes, so it can redirect the air backward into the Shroud, toward the breech. I may use a magic eraser sponge, I will start with one, one inch piece, but I will make 3 pieces of one inch sponge. and try them all in there to see what the difference is and if there is any positive or negative changes. I would Like to use a Pitch gauge, and a DB meter, To see if the pitch changes and or does the volume of sound reduce/increase. I want to try this in several different configurations to see, or hear what works best. I may want to try this on my P-rod next if it works, and a Fortitude gen2 after that.
 
Upvote 0
My thought was to loosen the Rear shroud Mount, and slide it forward, starting with an inch, this would gain one inch more from shroud to barrel. test it, in one inch increments, first to see how much sound difference. But I am also trying to get a More accurate rifle by smoothing out the sound/pressure wave. So I will be testing for both Improved Accuracy, and Sound Reduction, to see what is any changes can be had.
 
Upvote 0
I have used the move shroud forward on a good number of guns. I have always done it on a baffle increment(s). It does require you to file a flat in the barrel for the shroud mount set-screw. One to keep it from spinning when you try to remove the shroud, but also to get the set screw low enough so it can screw on.

I can't say I know of a way to test uniquely for sound pressure related accuracy. The biggest issues you will have with accuracy with this method are poi changes, and to a lesser degree barrel harmonic changes. Of the three guns you are planning on, the Fortitude will be more susceptible to poi changes, but could see it on all depending how far forward you go. ie the Fortitude has the longest, whippiest barrel, especially in 22 cal. Using some thin foam in the barrel band can help support the shroud/barrel. I use it on my 25 cal Fortitude, even though that has 1/2" OD barrel. Harmonics, are very hard to predict, and basically can only do extensive before and after testing. Longer barrels and higher power tunes, would be more susceptible. LDC's change harmonics, to a small degree, as well.

When I did it on a Prod, it was like 4" further out. I didn't get any accuracy change. At the time, used the 1720T baffles, which are small and more expensive than Mrod ones. IMO, a LDC is a better approach on the Prod.






 
Upvote 0
Nation, 

For the guys that have Marauders, all new Generation 2 models do have the 4 holes in the front shroud support fitted to the end of the barrel, leading to no pressure inside the tubes. On an earlier version of the Gen 1, that was not the case. My Gen 1 shroud support has no holes in it whatsoever, and it did pressurize the tube creating shift due to extreme temperature swings. This is why I do recommend drilling a small hole somewhere on the shroud. My bad for not explaining it 100%.

Tom Holland 

Field Target Tech 
 
Upvote 0
 

The Gen 2 shroud spacer is the same part number as the Gen 1. While I only had a half dozen of Gen 1's apart, they all had the six holes, and have never seen pictures of one without. If you can post a pic of yours, wouuld like to see it. It was, and still is a common mod to make those holes larger. Basically, without those holes, the shroud behind the spacer would be unused/wasted. That being said, the very first 100 Mrods made, were unique builds. They built and released these guns, and got feedback, and made allot of changes to the Gen 1 full production gun. The stock (fatter pistol grip area), trigger (added lawyer spring), and a number of other changes. While I never heard of it, it is possible the shroud spacer was one. Those 1st 100, are fairly rare these days, and those that have them, should consider keeping them original. If you happen to have such a gun with one, and know that the heat pressurization is happening, just buy the current production spacer from crosman. They are very low cost and you can swap it back.
 
Upvote 0
Nation, 

For the guys that have Marauders, all new Generation 2 models do have the 4 holes in the front shroud support fitted to the end of the barrel, leading to no pressure inside the tubes. On an earlier version of the Gen 1, that was not the case. My Gen 1 shroud support has no holes in it whatsoever, and it did pressurize the tube creating shift due to extreme temperature swings. This is why I do recommend drilling a small hole somewhere on the shroud. My bad for not explaining it 100%.

Tom Holland 

Field Target Tech
Click to expand...

IF your shroud support had NO holes then there would be NO way for air to enter the tube and pressurize it. BTW - BOTH of my Gen 1 Mrods had supports with holes in them.
 
Upvote 0
Hi I have reximex throne gen 2. On the shrouded barrel I have holes all around. It's very loud. Can I make blind these holes?
IMG_20220328_212508.1648726572.jpg

 
Upvote 0
Make blind the holes? I am guessing you mean fill the holes or plug them up? Best way would be welding. If that is not an aluminum Shroud if it is you could try the cold welding for aluminum from the inside of the Shroud and use a marker to touch up the holes after filling. 

There is more pressure in the Shroud when you fire a round then you would think. So much so that on my Wildcat MK1 I have dense foam in my shroud with 4 3mm holes, it blows the foam out of the holes after a few shots. 
 
Upvote 0
Yes, yes sorry me bad English. Yes aluminium.

Holes plug the? I can?

But what happens to the excess air?
Click to expand...

If you remove the shroud and put a strong tape wrapped sticky side outward covering the holes, that should stop the air from escaping. The pressure pushes the same direction as the tape is pressed so the tape should stay put. The air pressure escaping is far less than at the muzzle, so this should work. Silver aluminum heat duct (3M brand is what I'm used to) tape should do the trick as it's very sticky and durable. Did the Throne come with these vent holes?
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu