A friend of mine wanted to learn to shoot. One of the best tools for learning
marksmanship is the air rifle. Air
rifles are inexpensive to buy and shoot and require minimum space to use. They are quiet and have little to no recoil
so won’t mask any shooting errors. Mari
tried my Daisy multi-pump and liked it.
I don’t care for the quality of the current Daisy rifles plus I wanted
to cut the stock to fit her and that’s difficult with a hollow plastic stock. I also prefer a brass barrel on a multi-pump;
the current Daisys use steel.
I decided on a Crosman Benjamin 397 .177 caliber. Besides being virtually recoilless and easier
on scopes, the 397 is less expensive than the better break-barrel spring
guns. The multi-pump 397 also offers a
choice of velocities. Most of the
current break-barrel rifles are high-velocity.
The 397 has been getting good reviews online and has a wood stock and
brass barrel.
Mari liked the aperture sight on my .22 rifle so I ordered a
Williams 5D-SH receiver sight. I also
ordered a hard rifle case, some pellets, and some airgun oil.
When the rifle arrived we took it out to check the zero and
test fire. If there were any problems, I
wanted to be able to return it under warranty before I did any
customizing. The rifle functioned well
and the factory rear leaf sight was pretty much dead on.
The 397 is already drilled and tapped for the Williams
sight. On some older models the front
sight is too short for the Williams and doesn’t allow sufficient elevation
adjustment. A taller front sight or
modification to the rear sight may be required.
I degreased the mounting holes. Since the receiver is brass, and I didn’t
want to over-tighten the mounting screws, I made sure to use a bit of
Loctite. I looked through the aperture
and it aligned fairly well with the previously zeroed leaf sight so I was
reasonably certain I could get a good zero without any modification to front
blade or rear aperture.
Once I was sure the Williams sight was going to be fairly
close to zero without any machine work or modifications, I removed the leaf
rear sight. I removed the two windage
adjustment screws. I then put a punch
through the windage adjustment screw hole at the front of the sight. I put the muzzle of the rifle on a protected
solid surface. By pressing forward on
one side of the punch and tapping toward the muzzle on the other with a light
brass hammer, I was able to drift the sight clear of the two triangular base
grips. With the sight removed, the base
grips fell right out.
The trigger was reasonably consistent out of the box. Pull weight wasn’t bad so I left that alone
for the moment. I opened up the trigger
mechanism and didn’t see anything too grotesque. I made sure there weren’t any machining chips
or chunks or overly rough surfaces. I
hit all the contact points with some moly grease and left it at that. If, after some break in, the trigger needs
some refinement, I can go back in and polish or re-contour contact points or
lighten springs.
The factory stock was a bit long so I cut it off and fitted
the original buttplate.
A good way to get an approximate length of pull is to bend
your shooting arm 90 degrees at the elbow.
Now, take a yardstick and put it in the crook of the elbow. Grasp the yardstick with the shooting hand as
if it were the wrist of a rifle stock.
Bend the trigger finger as if pressing a trigger and measure the
distance from the inside of the trigger finger to the inside of the crook of
the elbow. This measurement should be
pretty close to the maximum comfortable length of pull (LOP) for you. It may be desirable to cut the stock even
shorter to allow for heavy clothing or just to make the rifle feel a bit
handier.
I measured the current LOP on the rifle and Mari’s LOP and
calculated the difference. Despite the
fact that you don’t want to exceed the maximum LOP for the shooter, it’s
generally a good idea to initially cut the stock just a tiny bit longer as you
can always remove material. Plus, if you
get a rough cut, you can sand back to the final dimensions.
I removed the plastic buttplate. Some manufacturers glue the buttplate in
place and it may be difficult, if not impossible, to salvage it. It’s a good idea, with a glued on buttplate,
to have a spare in hand in case the original is damaged while removing it. Fortunately, Crosman did not glue on this
buttplate.
I wrapped the buttstock with masking tape around the point
where I was going to make the cut. The
tape does several things. I can mark my
cut line on the tape without marking the stock.
The tape helps prevent tear-out and chipping when I make my cut. With the tape in place, I can grind the
buttpad to near final dimensions when it’s installed with minimum risk for
damaging the stock. Note that much of
this is irrelevant with an unfinished stock as you can grind buttpad and stock
together and then finish the stock.
I carefully measured and marked several points around the
tape from the butt to the intended cut point.
I then took a flexible straight edge and connected the dots so I had a continuous
cut line around the stock.
With my old shop, I had a jig for my table saw that would
allow me to mount the buttstock. I would
set the stock against the fence, set the cut angle on the butt (usually the
same as the current angle), and then set the fence for the depth of cut. Starting at the toe of the stock, as that’s
the most likely to tear out or chip, I’d make one pass and hope for a clean
cut. As I no longer have a table saw, I
used a Japanese pull saw with fine teeth to make the cut. I worked very slowly and carefully to
maintain my angle and make a straight cut.
You can start your cut with a needle file to prevent any false starts or
skips with the saw.
I got a good clean cut and it only took a bit of sanding to
get the butt flat. I used a straight
edge at several points and angles across the butt to make sure it was
flat. Again, this was much easier to do
with a bench sander but careful work with a sanding block, while slower, will
do the trick. If you use a bench sander,
again, sand from the toe of the stock to the heel as the toe is the most likely
to break away. By sanding back to the
final length, you can remove many of the small chips you may get while
sawing.
When you cut a stock, the original buttpad often ends up too
small for the butt. You can fit the butt
to the pad or get a new, oversized pad.
If the butt is finished and you don’t want to refinish the whole stock,
a new pad is the way to go.
Again, in my old shop I had a buttpad fitting jig. I would mount the pad to the stock and scribe
around the stock. Then, I’d mount the
pad to the jig and set the angle against the stock. Finally, I’d grind the pad back to the scribe
line on the bench sander. It was quick
and easy with no chance of damaging the finish on the stock. Since I’m no longer in my old shop, I have to
fit the pad while it’s mounted on the stock.
Slow and careful are the watchwords of the day.
I put the pad against the cut stock. The original pad was big enough to use. I picked a drill bit that was about the same
size as the shaft on the buttpad screws.
I didn’t cut off enough of the stock to eliminate the existing screw
holes. The existing holes were close
enough to the correct position for the pad so I just deepened them a bit rather
than drill new holes. If I had needed to
remove a lot of material, I would have scribed the pad and done the majority of
the fitting off the stock. As it is, I
only had to remove a little material in a few places.
With the masking tape still in place, I used a Dremel with a
sanding drum to match the stock contour and remove the unwanted material. By carefully working back to the tape, I was
able to get quite close without damaging the finish on the stock. I then removed the tape and remounted the
pad.
The toe on the pad requires a little more fitting which
isn’t a problem. The heel on the stock
needs a tiny bit of fitting and that is a problem. I can either order and fit another buttpad or
grind a tiny bit off the stock. If I
grind the stock, I’ll have to try to match the original finish. Either way, the rifle is currently functional
as it stands.
I removed the aperture insert on the rear sight to give a
ghostring effect. Mari used a similar
sight on my .22 to good effect. I was
able to get a three round cloverleaf at about 10 meters with the ghostring. Mari was getting good groups and hitting
targets out to about 20 meters with three pumps from the offhand position. Later, she had me put the aperture insert
back in. We had to bring the rear sight
up a couple of lines for a new zero.
Mari hasn’t needed any windage adjustment.
So far, the rifle has proven accurate, easy to use, and fun. It’s serving its purpose as a training piece
admirably.
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