| We have got many questions
about the use of extension tubes in smallbore, and I decided to
share some of my experiences with them.
I first heard about tubes in 1992 and it was by the late 90's
World Champion in 300 meter prone Bengt Andersson. He was experimenting
with tubes to get a better sight picture and to get better accuracy.
He made me a copy of his tube that I tried during that season. The
tube was pretty much just a long tube with a
"hose-clamp" in the end.
The biggest difference I saw then was that it always looked
worse than it was. By having the tube, the movements seemed to
increase and it was hard to get a perfect shot - but the only
difference was that I saw the movement more and what seemed to be
bad shots often stayed inside the ten-ring in prone. The problem I
had was that it was very hard to always put the tube on the same
way every time. I sometimes ended up out in the 4-5 ring after
putting it on again. Therefore, I decided to always leave it on
the rifle.
It worked perfectly and I shot some great prone scores during
the beginning of that season. After a while the accuracy just got
worse and worse and sometimes there were a big flame coming out
when I shot..... I didn't think of all the unburned gun powder
that lined the inside of the tube. By not cleaning the tube regularly
there was a build up of the powder that eventually burned by
itself. The layer broke of in small chunks and ended up in my
barrel and really hurt my accuracy. After the drawback, I stopped
using it for a few years.
An example of a high tech tube, that allows the
shooter to adjust the length of the sight line by moving the front
sight on a rail.
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When I finally started to
look back at tubes again, I decided to go with a professionally
made tube that I could take off and put on without changing the
zero-point too much. By drilling a small hole on top of the barrel
and having a small pin sticking up and a matching groove in the
tube I was able to have a good line up.
I started to clean the tube after each time I shot. I got a
cleaning rod for a shotgun and one of the metal circular brushes
that I ran through a several times after each match/training and
then I used a gun cleaner and sprayed in there once a week. This
kept the accuracy at the same level all the time.
The tube can be both a help and a disaster for accuracy. By
putting something on the barrel, you will alter the frequency of
the barrel and it will alter the accuracy. Ammunition that was
super without the tube might have shotgun groups and a medium
ammunition might start to shoot extremely well. Therefore, it is
important to try around and see what's working. I had a rifle with
a barrel that it was so hard to find good ammunition for, I tried
pretty much any brand and lot that was out there. Finally I
started to experimenting on attaching barrel weights and a tube
and finally I found ammunition that was good.
At the same time as it changes the frequency, it will also
alter the balance of your rifle as you add weight to it far out
from your body. Therefore, there are many shooters that use the
tube in prone, but shoots without it in standing and kneeling.
When you use a tube, you will have to get a larger aperture. I
used 3.8 in smallbore without the extension tube and a 4.4-4.6
with a 8 inch tube.
Try the extension tube and see how you like it, it is the
prefect for some shooters, while others do not like it at all.
Good Luck!
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