from the same box of
20. And target #3 was shot a while back with the same load data, but a different
box of ammo.Why
is it important?
There
has been a lot of discussion about the barrel pivot pin. Some think it has
little or nothing to do with accuracy. The following article is an open honest
attempt to show with pictures what we are talking about when it comes to proper
fit.
The
following targets were fired at 25 yards from a rest. The were fired within
about 5 minutes of each with the only thing different was the “Frame” and
“Barrel Pivot Pin”
The
weather was cool, and not a breath of wind. The ammo is reloads with the three
shots from both targets coming
from the same box of
20. And target #3 was shot a while back with the same load data, but a different
box of ammo.
In
fairness to this test, I used a new factory pin in my frame, and Richard’s pin
in his frame. I will show in my frame what a first-over pin will do to increase
the accuracy beyond a factory pin in picture #3.
Picture
of target #1 was fired first with a new factory pin in my Old Contender frame.
It is a 12 inch 357 Mag rechambered to 357 Max. It is scoped with a 4X32 NcStar
Scope. The loads are using 180gr Hornady HP/XTP. Being pushed with 27grains of
Accurate 1680. Being ignited with CCI 450
Small Rifle Mag primer. With new Remington 357 Max brass. With a
Picture
of target #2 was fired next with the same loads and only about five minutes
after target #1 was shot. Just long
enough for me to put my
barrel on Richard’s frame. Using his Old Contender that has had many thousands
of all kinds of different calibers and barrels used through the years and has
ended up with a frame that is just worn out. The pin is worn a little but the
left and right sides of the frame where the pin goes are very, very worn. The
right side is beyond the use of the second oversized pin. Without making a
custom pin and reaming the barrel and frame which would only make this frame and
barrel a unit, I recommended he return it to
I could have shot more
than three rounds at these two targets, but with the comparison of these to
target #3 that was shot months ago in my frame with a FIRST OVERSIZE PIN, I
wanted them to compare to my three shot group. This was shot from the same rest
with the same reload data. The only difference is the ammo was from another box
or reloads I did earlier and shot up. But can see for yourself what a difference
of having a tight fit on the barrel and frame can do to improve your accuracy.
The data on target #3 is .550 raw. With the bullet deduct it is .193 which
relates to .772 at 100 yards. In my book that is ¾ MOA, and good enough to get
the job done, if I do my part.
This
may not be useful to all, but if you are going crazy trying to get that tight
group, take a good look at your PIN FIT.
To
summarize, if you want ¾ MOA you must have a tight pin fit. If you are happy
with the ease of pushing the factory pin out with your fingers, and switching
barrels, you can still have fewer than 2 MOA. Or if you old frame is getting
very worn, and your rounds are not grouping anymore, you might just have one of
those 3 and ½ MOA rigs.
Jim
L. “Shots” Hendershot Sr.