Shotgun/Inserts/Choke ?

[JPope]

When using a smaller guage insert (chamber insert only, not a full barrel type insert), 20 guage in 12, . 410 in 20, for example, is the pattern going to stay the same?

You are sending a smaller amount of shot down the barrel with the insert, but the barrel/choke cross section is now larger in comparison than the insert guage, so would the pattern act more open OR has the shot stream opened up to accomodate the barrel and then the choke acts the same giving the same pattern?



Thoughts, experience, technical facts, appreciated!!!!!

 

[B.G. Smith]

My thoughts only, no experience with this but I would guess the pattern is going to be adversely affected. bgsit is s

 

[A Johnson]

Thought only.



It will probably depend on the particular shell more than anything. I say this only because you can get modified patterns out of a full barrel or full out of a modified depending on how the barrel and charge interact. At least I think I read that somewhere. I have no experience with sub-gauge inserts.



Let us know how it works out.



A Johnson

 

[RBSOB]

There was a fairly good article in Shotgun Sports Magazine on the sub gauge inserts within the last 4 mos. If I recall correctly, the inserts were pattern tested and actually performed pretty well. If you intend to do anything other than casual practice with them, it would be a good idea to pattern them in your particular gun. Try to find the article on-line or I will re read it and report back over the week end. Have Fun, Jim G.

 

[SRadke]

Interesting question. I work part time at a sporting clay range and I've seen many diffrent combinations of shells, chokes, and shotguns. One thing I have never seen is a chamber only insert. Several guys have titanium tube inserts that run the full length of the barrel but I've never seen or heard of what you're describing.



With that said here's my thoughts. As soon as the shot leaves the insert (still inside the barrel) the wad will no longer have tight clearance with the barrell. This will allow a couple things to theoretically happen.

1. ) The pressure will be able to leak around the wad thus causing the pressure you're using to accelerate the shot to escape. Because od this you've effectively got a barrell that is only as long as your insert.

2. ) The wad and shot will begin to separate because it is not being accelerated as rapidly so you'll have shot rubbing on your barrel. Not a problem with lead but I wouldn't want to try it with steel.



To strait out answer your question I would guess you'll have a pattern similar to whatever gauge barrell you are using. Maybe not even as good because of how the shot will try to spread then gets pushed back together. I just don't see it working very well. My $. 02



-Scott

 

[JPope]

"There was a fairly good article in Shotgun Sports Magazine on the sub gauge inserts within the last 4 mos. If I recall correctly, the inserts were pattern tested and actually performed pretty well. If you intend to do anything other than casual practice with them, it would be a good idea to pattern them in your particular gun. Try to find the article on-line or I will re read it and report back over the week end. Have Fun, Jim G. "



Thanks for the site, the Nov. 2003 issue has the article that would help!! Their internet ordering does not appear to be working so I will call their 800 number. Of course found several other issues that have interesting information also!!!!

 

[Mr.Goat]

JPope



There's a reason chamber gauge inserts are not that popular with the clay target folks. And thats because the performance of the shot shell fired from a chamber insert compared to a full barrel insert is poor.



On average the wad/shot load has reached it's full velocity from the burnt powder gases within the first 12" to 16" of barrel length. This is assuming the wad being it plastic or fibre is making a tight seal against the walls of the barrel. This tight seal allows the gases from the powder charge to fully act upon the shot load to give it the maximum velocity from that particular powder charge. Hence in the old black powder arms the use of the patch between the powder and ball, it prevented the gases from escaping prematurely past the ball reducing it's velocity accordingly.



For example if one used a 410 chamber insert in a 20 ga. The little 1/2 oz. of shot expelled from the 410 would attain lower than normal velocity as a result of gas blow by. Also that little 1/2 oz. of shot is now slowly rumbling down a much bigger 20 ga. barrel. The combination of lower velocity and small shot load in the 20 ga. barrel will greatly effect the shots down range performance.



The 410 is already handi capped to shorter ranges due to the small shot load. This would reduce it range even further. Of couse some experimentation with various loads and ranges would prove of what practical use the chamber insert would have if any.



Hope this is of some help. Pete

 

[RBSOB]

JPope, Iwill try to find the Nov. issue and report the details. If you are into shotgunning of any type, check out a free issue of the Mag. Very good articles every month. JimG