This is related to
misfires also, but this article addresses the unlocking problem, why it happens
and what to do about it.
locking bolts do not engage into the frame's "locking table" very far, and from
what I have seen over the years, if they only engage just enough to release the
hammer block safety and permit the frame to fire, this minimal engagement will
wear and thus round the forward edge of the locking table. Once the locking
table is rounded, it will be more prone unlocking when fired. If after what
follows here has been addressed, a barrel or barrels still fly open, then send
the frame back to TC for inspection and probably replacement.
minimal engagement will be caused either by the height of the locking bolts
being too high for the given frame or it will be caused, as you noted, by cases
sticking out of the chamber too far due to not being sized correctly. (This is
one reason why I harp on the subject of size die adjustment and highly
discourage neck sizing for these break open guns. Continued firing of rounds
that interfere with lock up can cause undue wear on the locking table.)
is to either get a set of undersize locking bolts from TC or learn how to adjust
a size die to get the correct headspace. The latter is a pretty simple concept,
but the majority of shooters have been dumbed down by what they read and hear
and just can't quite put it together in their minds. I don't mean this in a
disparaging way, since I have also "been there, done that" trying to figure out
what in blue blazes is going on. Look at it this way. I have probably made just
about every mistake you guys can make and then some, and I also have a pretty
good clue what your problems are getting through puzzling situations.
to go through a process of elimination. With the barrel empty, you can get some
idea, though not 100% conclusive, about the engagement by holding the hammer
back and pulling the trigger with the barrel closed. If the hammer block safety
is not dropping... you got a problem, and need lower locking bolts.
because the hammer block drops, this does NOT mean you have adequate engagement.
For one, the mating surfaces between the hammer block and the interlock (the
little butterfly shaped gipper the locking bolts turn when the barrel is locked
up) can be worn and permit the hammer block to drop when it shouldn't, as in
when the barrel is not fully locked up.
need to degrease the tops of the locking bolts, ink them with a felt tip pen,
and then open and close the barrel in a normal manner several times. This will
leave a "signature" on the locking bolts by marring the ink where the locking
bolts are in contact with the locking table. This marring should show on the
locking bolts approximately 1/32" forward of the "U" shaped notch in the locking
bolts. It need not extend to where the main locking surface meets the angled
surface forward of it, but it should be close to it.
marring goes all the way to the way to this angled surface, it may also indicate
the top surface of the locking bolts is too low, and the lock up may not be
tight enough. So don't get alarmed if the marring does not take up the entire
engagement surface on the locking bolts. But it must be noticeably forward of
the "U" notch.
has been made elsewhere that the locking bolts should be left dry, and this is
true, especially in marginal situations. But if the locking table surface is as
it should be and the locking bolts themselves have not been polished, lubrication will not cause
the barrel to open. Face it, day in and day out I test fire barrels that go from
the lathe to the parts cleaning tank, which is a combination of some diesel fuel
and lots of oil. For mostly rust preventive qualities, I add some cosmoline and "STP" like goop to the diesel fuel. Locking bolts that come
out of the wash tank are well lubricated. But I cannot remember now when the
last time was that a Contender flew open test firing it. While the locking bolts
are best left dry, LUBRICATION ON THE LOCKING BOLTS IS NOT
THE CAUSE OF THE BARREL FLYING OPEN.
engagement as described above, if the barrel will unlock when fired, oiled or
not, then either the locking table is worn and the frame needs to be replaced,
or the tops of the locking bolts have been "dinked with" and are either polished
too smooth or the top "draft angle" on the locking bolts has been altered to a
more vertical plane.
words....DO NOT POLISH THE TOPS OF THE LOCKING BOLTS WITH
THE IDEA OF GETTING IT TO UNLOCK EASIER, ETC. The tops of the locking
bolts can be lowered to get a proper lock up engagement and easier unlocking ok,
but the surface should remain textured, not polished.
locking bolts in good condition engaged into the frame adequately and the
locking table in the frame in good condition, mechanically, there is no reason
for a barrel to unlock unless the loads being fired are excessively hot, but
even hot loads will not necessarily cause the barrel to unlock. With things
mechanically "right," the cause of unlocking frequently is then due to cases
being too long from head to shoulder and interfering with lock up.
all sorts of ideas about how the barrel feels or sounds when it is snapped shut
"guesstimating" whether the size die is set right or not, but the only way to do
it, in my opinion, is to first find out what the barrel to frame gap measures,
then with the barrel OFF of the frame, drop a sized case into the chamber and
measure how far it sticks out compared to what the actual barrel to frame
measurement is. Do the same thing with loaded rounds. Seating bullets out to
contact the rifling creates a round that is too long also, and can interfere
with lock up.
summary, we have all done things with Contenders particularly for years that
were rather dumb, or at least ill advised, and gotten away with it, sometimes
with great success. But it is a lack of understanding of what is going on that
rears its ugly head and causes problems such as misfires and barrels flying
open, the continuing bain of those who have not looked quite far enough into how
these guns work. Hopefully my efforts will help get the word out and make these
problems a thing of the past.
Final comment. One nice thing about Contenders and Encores is that the standing
breech, small as it is, acts as a shield that deflects cases flying out of the
chamber up over the top of the shooter's head. While it definitely gets your
attention, usually the worst it does is nick the top of your cap as it does its
"auto eject" thing flying by. However, someone standing directly behind a
shooter when a barrel does fly open could be at risk if a hot flying case hit
him in the eye. They come out with some force, but usually not enough to cause
severe damage unless something like an eye is hit. A barrel flying open is NOT a
good thing, and definitely not something to permit continuing to happen, but it
is not normally a severe hazard either. I have had it happen a number of times,
once while being filmed for television even. Talk about embarrassing. So, yes, I
have "been there, done that."