I'm working on a model 6 Remington rolling block .22 rifle and have
another extractor question. The extractor is in the barrel, not the
rolling block. So there is a cutout in the breech for the extractor to
sit in. This cutout is .135" deep while the extractor is .110 thick.
This means that the face of the extractor sits .025 below the face of
the breech. I would think that the extractor face should be flush with
the breech face or maybe 1 to 3 thou. below the breech face. I haven't
been able to find online or talking to folks who should know just how
far below the breech face the ectractor face should be. Also, the spec
for the depth of the chamber for the rim of the .22 round appears to
be anywhere from .043 to .050, though most of the drawings I have come
across have the max depth as .046 or .047. Measuring several .22
rounds, shorts, longs, and long rifles, I find that the rims measure
..040 to .042 thick. Does this mean then that the only thing that
prevents gas from coming out of the breech is the shell expanding
against the chamber walls? And that if the block face doesn't lay
exactly flat against the breech face it won't make any difference to
how much gas comes out of the breech? I want to make a new thicker
extractor so that it is closer to being flush with the breech. The
extractor for this rifle is pretty eroded so it really either needs to
be built up by welding and re-machined or just replaced. The barrel is
in place and I crowned the muzzle using the 11 degree crown. The crown
is concentric with the liner bore to less than .0005" TIR. I
accomplished this by using a "cat head" to hold the barrel in the
steady rest. I couldn't steady on the barrel OD because the liner bore
runs out to the barrel OD by about .007".
Thanks,
Eric

On Wed, 05 Aug 2015 19:47:20 -0700, wrote:

I'm working on a model 6 Remington rolling block .22 rifle and have
another extractor question. The extractor is in the barrel, not the
rolling block. So there is a cutout in the breech for the extractor to
sit in. This cutout is .135" deep while the extractor is .110 thick.
This means that the face of the extractor sits .025 below the face of
the breech. I would think that the extractor face should be flush with
the breech face or maybe 1 to 3 thou. below the breech face. I haven't
been able to find online or talking to folks who should know just how
far below the breech face the ectractor face should be. Also, the spec
for the depth of the chamber for the rim of the .22 round appears to
be anywhere from .043 to .050, though most of the drawings I have come
across have the max depth as .046 or .047. Measuring several .22
rounds, shorts, longs, and long rifles, I find that the rims measure
.040 to .042 thick. Does this mean then that the only thing that
prevents gas from coming out of the breech is the shell expanding
against the chamber walls? And that if the block face doesn't lay
exactly flat against the breech face it won't make any difference to
how much gas comes out of the breech? I want to make a new thicker
extractor so that it is closer to being flush with the breech. The
extractor for this rifle is pretty eroded so it really either needs to
be built up by welding and re-machined or just replaced. The barrel is
in place and I crowned the muzzle using the 11 degree crown. The crown
is concentric with the liner bore to less than .0005" TIR. I
accomplished this by using a "cat head" to hold the barrel in the
steady rest. I couldn't steady on the barrel OD because the liner bore
runs out to the barrel OD by about .007".
Thanks,
Eric

Assuming that the primer, in a center fire cartridge or the rim in a
rim fire doesn't rupture that you are correct the case expands when
fired and provides a seal. In fact P.O. Ackley did considerable
experimentation with a lever action Winchester and it seems that the
expanding case serves to actually withstand the pressure when the gun
is fired. It has been a long time since I read his book but I seem to
remember that he ended up firing a Winchester lever action with the
locking lugs completely removed and it didn't blow up.

Extractors quite frequently don't fit exactly although if the firing
pin strikes the rim in the extractor area it is good to have the
extractor support the rim to avoid getting miss fires.

--
cheers,

John B.