Accuracy and the shrouded barrel

by B.B. Pelletier

This experiment came at the request of Pyramyd Air. They noticed that people on the chat forums were saying that a shrouded barrel made a gun more accurate, and they asked me what I thought. I thought (and still think) that a barrel shroud has little or nothing to do with accuracy, but I said I would try an experiment to see what happened.

Talon SS
Since the Talon SS has the prototypical shrouded barrel and is the rifle that gave all the other makers the idea for shrouding in the first place, I decided to use it for the test. All I had to do was remove the muzzle cap to shoot the gun without the effects of the shroud – or so I thought. I used 50 yards as the range because the SS is so accurate that anything closer might not show a difference.

First – with the end cap installed
My SS is .22 and shoots JSB Exacts best. The first group of five measured 0.599″ between the centers of the two widest shots. The next group was a carbon copy of the first – another 0.599″ – but I had adjusted it to the center of the bull. Those two groups proved the rifle was shooting well, so I removed the muzzle cap.


A nickel will cover the 50-yard group of 5 JSB Exacts made by the Talon SS with the muzzle cap on.

With the end cap missing
The next group began like the previous two, with pellet holes touching. Then shot four went wide to the left. Shot five went to the right of the initial group, opening it up to 1.117″. I was surprised but figured it was a fluke, so I settled down and shot another group. This one was even more open, at 1.182″. I was very discouraged after this group because there were only three holes in the target. Four of the pellets went into the same two holes, but those holes were far apart!


Take the cap off, however, and the story is different! Shots are blown all over the place.

End cap reinstalled
I put the end cap back and shot a group measuring 0.820″. It was larger than the first two but back on the good side of the inch mark.


The chamber of the Talon SS may focus the muzzle blast back into the pellet’s path.

Conclusion
If you remove the end cap from a Talon SS, your groups will get bigger. I don’t think this proves that shrouded barrels are more accurate, because the plain Talon barrel that has no shroud is just as accurate as the shrouded SS. What I think this experiment demonstrates is that the muzzle blast can affect accuracy if it isn’t permitted to escape. With the cap off, the deeply recessed muzzle spews air against the wall of the receiver, where it rebounds against the pellet for the first four inches of flight. With the cap in place, the same air is prevented from following the pellet through the hole in the cap. What happens in the chamber before the pellet emerges through the hole in the cap apparently does not have any lasting effect.

14 thoughts on “Accuracy and the shrouded barrel

  1. For whatever it’s worth-I put a 24″ barrel on my Talon SS (.22 cal) and decided the gun was now a little too loud for my semi-urban location so I made a shroud out of PVC pipe, installed a brass end cap and cut the noise significantly. In the process I did briefly check the accuracy of both versions and found no significant difference at 50 yards. Unfortunately, this was some time ago and I did not record the exact measurements so I cannot give those results. I have been using Logan Predator pellets pretty much routinely.
    CWI


  2. The 45 acp springfield XD I just bought feels great. I had a chance to try out a fellow shooters sig suar p226 while he tried my XD. Great grip on the 226. It didnt even feel like a gun at all, it felt like another limb. As if it was made to fit my hands perfectly. The weight of the 226 didnt put a drag on my draw. Great pistol.

    After I went to the range I drove further and visited a wallymart in salem, Oregon. I saw a shadow 1000 going for 124.98. I purchased it. I just got finished pushing a a tin of Crosman Hyper velocity wadcutter. They shot all over the place the first 2 shots or so. I didnt clean the rifle becuase I have no AirRifle Cleaning Kit. So, I decided to shoot all the gunk out. It tightened up real nice. I grouped 6 shots .54 at 11 yards with open sights after 100 shots or so.



  3. B.B.
    I would really like to shroud the Crosman 2250 that I just ordered to quiet its report, but opinions about shrouds, silencers, moderators, etc. and their legality (in the U.S.) are all over the board. What’s the letter of the law concerning them, constructing your own and CYA so the BATF doesn’t come a callin’? I was planning to build a non-removable shroud with a removable end cap. Would that suffice legally?


  4. AirForce 45,

    I understand from Pyramyd Air that Tom Gaylord has written an article about this very subject. It should be up on their website soon.

    B.B.


  5. Any moderator that can be modified to fit a firearm is considered a firearm. It is illegal. THE BATF wont even allow airguns with built in moderators to be imported into the country. Do not bother producing your own. It is illegal. You dont want a felony charge, do you?




  6. CWI,

    WE don’t have to justify anything. AirForce has already done this. They have a letter from ATF that says the SS doesn’t violate the law. Their shroud is the frame of the gun. If ATF were to try to outlaw it, which they cannot because they have no authority over airguns, they would also outlaw most 10-meter rifles that are shrouded, too.

    Also, the TX 200 and Pro Sport both have built-in silencers that ATF has never had any problem with.

    I read the Beeman article, but there is more personal opinion than law there. I’d wait to see what Gaylord’s article says, becauase I understand it gives you the exact laws involved.

    B.B.




  7. No idea.

    Accuracy update of my shadow 1ooo: I sighted at 15 yards and got groups that averaged .60 of an inch. The trigger is a little stiff. :)

    I shot down a crow from 48.2 yards out. I used my Range Estimating Leapers scope to figure out my the distance. At 9×40 i placed the center of the reticleright above its head. The shot hit it on the neck from the front. I am really confident about this Shadow 1000. I’d suggest a shadow over a quest ANY DAY!


  8. Cesarf25s

    The ATF itself has published the conclusion that a silencer that is fixed to an airgun is legal because removing it with a hacksaw and modifying it to attach to a portable firearm constitutes their definition of “making”. I have no intention of being a felon, which is why I will submit my design to the ATF before building it.
    Next time get your facts straight and don’t jump down someone’s throat for asking an innocent question.


  9. “I was planning to build a non-removable shroud with a removable end cap. Would that suffice legally?”

    You did not say anything about presenting your plans to the BATF&E.

    Sorry, it was more of a warning. Its better to play it safe then to take your chances.


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