Case prepping for LR
Paul Perez
In an earlier post I mentioned the iron-sight training aid that Mid Tompkins
was using during the last Palma team practice at Byers, Colorado.
Since I was going mostly to pull targets for the team, and second to that, get
in some more practice, I almost collected all the surplus long-range loads
left over from this season to expend them there.
Instead, I decided to run an experiment - instead of prepping cases the usual
way, use brand new cases w/o usual prepping procedures. Here's the setup:
rifle - paramount 1.5" receiver, conventional-bed w/ Devcon in a McMillan
fiberglass prone stock. 30" Krieger 1:13" barrel, .3075" x .298" free
floated. Barrel has ~2,900 rnds but still shoots within 1/3 minute of
call @ 1000 yards.
load - case: Winchester Palma (not '92, but new production)
primer: RWS large rifle, known good lot
powder: 44.6grs IMR4895, known good lot.
bullet: Sierra 155-gr MK, seated ~0.015" past land contact.
This was my standard load last year. It was a milder version of the
'92 load (~2910 to 2920 fps), but extremely accurate. This year I
experimented with N140, AR2208 and R15, and ended up coming back to
this load.
In order to compare apples to apples, I decided to compare new unprepped cases
to new prep'd cases:
usual prep procedure on new cases:
1. Uniform primer pocket
2. deburr/uniform flash hole.
3. Use a neil jones .3080" mandrel w/ appropriate neck bushing to uniform
necks.
4. Use #5 easy-out bit to "chamfer" inside of case mouth. Bart showed me
this trick that does NOT leave a sharp edge on mouth.
5. After loading, index the cases for concentricity. My runout averages
0.002" at the worst. I'd select 0.003" for 800 yards, 0.002" for 900
and 0.001" or better for 1000.
-----------------------
My average score over the Palma course is between 435 to 437. With the new
unprepped cases, my score was 439 - I'll take this to mean it fell in the
average.
Observations:
1. Load shot to call as well as prepped cases.
2. Vertical spread was consistent with prepped cases.
3. I did not spin or index cases for concentricity.
Caveats:
1. Winchester Palma cases are fairly uniform.
2. Paramount bolts are 4-lugged, so they supposedly generate less dispesion with
out of square square new cases better than 2-lugged actions.
3. The statistical sample (45 shots for record) is small.
Musings:
1. Bart got me started thinking about this back in June during the state long
range championships, when he did just this to "see how the cases would
shoot". I recall him doing very well, as always.
2. Several good long-range shooters (Johnny Franklin, Mitchell Maxberry among
others) told me this season that they prefer new cases because they're "more
accurate". It'd be interesting to measure the dimensional differences in
groups of 20 cases from new to FL sized, and track their long-run accuracy.
3. I think this behavior probably holds for "good" or "uniform" cases, to wit:
Remington BR, WCC '58 or '60, Winchester Palma, or any lot of brass that
happens to have "tight" (within a few grains) weight distribution and tight
variance in neck wall thickness. I wonder how much generic brass benefits
from prepping/sorting steps. I recall Precision Shooting performing just
this experiment, but I also recall their experiment was flawed in several
ways.
Any comments?
Donald R. Newcomb
Paul Perez <p...@hpfcla.fc.hp.com> wrote:
#load - case: Winchester Palma (not '92, but new production)
# primer: RWS large rifle, known good lot
# powder: 44.6grs IMR4895, known good lot.
# bullet: Sierra 155-gr MK, seated ~0.015" past land contact.
Sorry it this digresses from Paul's excellent discourse. I'd like to drop
back a bit and get some ground-work out of the way.
Just how do us guys who can't store 30 or 40 lbs of powder or who don't have
the ability to select from various lots of RWS primers assure that we are
using a "known good" lot of powder or primers. I have not yet finished
reading the recent PS article on primers which might help answer this
question.
--
Donald R. Newcomb * University of Southern Mississippi
dnew...@whale.st.usm.edu * "The God who gave us life gave us liberty
dnew...@falcon.st.usm.edu * at the same time." T. Jefferson (1774)
Bart Bobbit
: Has anyone done comparison testing between new brass and once-fired brass?
Yes. A few folks have done valid testing in highpower match rifles using
the same components, but the only difference being new and once-fired
brass as well as brass that's been fired a few times.
In a properly built rifle, the differences are rather small when the .308
Win. is used. Bigger differences have been observed when belted magnum
cases are used.
With uniform .308 brass, brass with very small tolerances in body and
neck wall thickness, as well as reasonably square case heads, new brass
can shoot ~.2 to .3-in. groups at 100 yards; about 10-inch groups at
1000 yards. This is with new, virgin brass that's had their necks resized
to uniformly hold the bullet. In the same rifles, the same loads have
shot bigger groups with those cases then neck-sized. When proper full-
length sized, those same cases typically produced slightly smaller groups.
After the same case was full-length sized three times, the groups tended
to be the smallest ans would remain small for many more shots per case.
When belted magnum cases were used, some interesting observations were
made. New, virgin brass with their necks resized to properly hold the
bullet, excellent sub-MOA accuracy at 1000 yards was attained. Neck-
sizing those cases produced much larger groups. Full-length sizing those
cases where the shoulder was set back no more than .001-inch, and the case
body was sized all the way back to the belt, produced equal or slightly
smaller groups. But when cases were full-length sized the traditional way
that set the shoulder back several thousandths of an inch (in some instances
as much as .020-in.), accuracy was not as good as with new cases.
Not very many folks can tell the difference between ammo that shoots
10 inches and ammo that shoots 7 inches at 1000 yards. Especially when
they're laying down prone and not using a rest.
For those whose experiences/observations differ from these, there is
a distinct difference with their equipment and/or processes compared to
those yeilding the above results. If there was not a difference, their
experiences/observations would be the same. Whatever equipment and/or
processes they get the best results with is what they probably will use.
BB
Paul Perez
: Stefan (sm...@ariel.lerc.nasa.gov) wrote:
: : Has anyone done comparison testing between new brass and once-fired brass?
: Yes. A few folks have done valid testing in highpower match rifles using
: the same components, but the only difference being new and once-fired
: brass as well as brass that's been fired a few times.
[snip]
: With uniform .308 brass, brass with very small tolerances in body and
: neck wall thickness, as well as reasonably square case heads, new brass
: can shoot ~.2 to .3-in. groups at 100 yards; about 10-inch groups at
: 1000 yards. This is with new, virgin brass that's had their necks resized
: to uniformly hold the bullet. In the same rifles, the same loads have
: shot bigger groups with those cases then neck-sized. When proper full-
: length sized, those same cases typically produced slightly smaller groups.
: After the same case was full-length sized three times, the groups tended
: to be the smallest ans would remain small for many more shots per case.
You'll recall that's what happened last year when we switched from neck-sized
to FL-sized brass in our Palma rifles...
: When belted magnum cases were used, some interesting observations were
: made. New, virgin brass with their necks resized to properly hold the
: bullet, excellent sub-MOA accuracy at 1000 yards was attained. Neck-
: sizing those cases produced much larger groups. Full-length sizing those
: cases where the shoulder was set back no more than .001-inch, and the case
: body was sized all the way back to the belt, produced equal or slightly
: smaller groups. But when cases were full-length sized the traditional way
: that set the shoulder back several thousandths of an inch (in some instances
: as much as .020-in.), accuracy was not as good as with new cases.
I don't have any magnum rifles, hence no experience. But several people
commented last season on how they like to use virgin brass in their magnum's..
-plp
Paul Perez
: back a bit and get some ground-work out of the way.
: Just how do us guys who can't store 30 or 40 lbs of powder or who don't have
: the ability to select from various lots of RWS primers assure that we are
: using a "known good" lot of powder or primers. I have not yet finished
: reading the recent PS article on primers which might help answer this
: question.
Don,
By "known good", I meant I'd used those particular lots (powder, primers) over
a whole season of long range with excellent results, at least results to my
satisfaction. This means that "known good" is subjective. I had tried them
again this year and found the performance to be the same.
For the record, I only had 24 lbs of IMR4895, not 30 or 40 :-) I ended up
sharing some of that with Bart.
I've always taken chances with RWS primers. I order 2,500 at a time, usually
when my current supply is down to half. When the new ones arrive, I'll shoot
a match with the new lot. If the load shoots ok, I consider the lots somewhat
equivalent. If the new lot shoots MUCH MUCH better, and I have enough of the
powder lot, I'll save it for important matches. If it doesn't shoot well, I
try to sell the lot to my good friend Dan Chisolm :-)
In a recent reply, Eric Obermeyer alluded to people over-emphasizing chronograph
results. I think that's probably true in a lot of cases. Come to think of it,
I haven't chrono'd a long-range load in a while. I just go out, shoot it at
distance, and check the vertical stringing compared to my calls.
Then again, if I ever build that 50-yard underground tunnel in my backyard,
maybe I'll start chronographing again :-)
-Paul
Stefan
#3. I think this behavior probably holds for "good" or "uniform" cases, to wit:
# Remington BR, WCC '58 or '60, Winchester Palma, or any lot of brass that
# happens to have "tight" (within a few grains) weight distribution and tight
# variance in neck wall thickness.
Has anyone done comparison testing between new brass and once-fired brass?
**********************
* Is the line ready? *
**********************
Scott Keszler
< much deletia >
} Then again, if I ever build that 50-yard underground tunnel in my backyard,
} maybe I'll start chronographing again :-)
} -Paul
Hey! I've had that same thought. Has anyone actually done this?
Scott
Paul Perez
: Scott
Actually, yes.
One occurrence is to be expected: The olympic trainint center in Colorado
Springs has two (i think) 50-meter indoor ranges for ISU competition. They're
used for smallbore rifle/pistol, air rifle and air pistol.
Another:
A good friend of Bart Bobbitt's built a 100-yard underground tunnel somewhere
outside Fort Collins, Colorado. The target stand is mounted on an electric
rail car. The shooting end of the tunnel has a fixed concrete shooting bench
with a small slit window for the muzzle/barrel of the weapon being fired. There
are bushings on the bench to attach ransom rests or any mechanical rest
devices. It is also a complete reloading room, so you can load & shoot. He
has a 3-screen Oehler chronograph installed, too.
It's real nice to be able to work up match loads during the off-season when
it's snowing outside :-)
-paul
Bart Bobbit
: Hey! I've had that same thought. Has anyone actually done this?
Yes, there's a few around the USA.
Sierra bullets had a 200-yard underground range at their plant in
Santa Fe Springs, CA. 'Twas used to test their bullet's quality.
A really neat place with machine rested barreled actions at each
firing point. I think their new site in Missouri has a 100-yard
undergound range.
L.E. Wilson, Cashmere, WA, also has a 100-yard underground range, or
one nearby it uses to test its reloading products and other stuff.
A friend of mine here locally has a 100-yard underground range I
helped build part of. It has a 4-foot diameter culvert with a track
inside for the electric=powered target cart to run on. Neat place
to shoot.
Not an underground range, but one built inside an old airplane hanger
in Texas exists. It goes to 100 yards. Benchresters use it to test
rifles and ammo in.
There may be a few other underground ranges; I just don't know where.
BB
Alan M Grossmeier
: Paul Perez (p...@hpfcla.fc.hp.com) wrote:
: < much deletia >
: } Then again, if I ever build that 50-yard underground tunnel in
: }my backyard, maybe I'll start chronographing again :-)
:
: Hey! I've had that same thought. Has anyone actually done this?
My neighbor has done exactly that. He had a 24 inch diameter culvert
buried between his basement and a pit beneath his garage. Actual range
is around 120 feet. His shooting bench is in a separate room in the
basement, he has a cable strung to place and retrieve targets, and a
light switch to turn on his target pit lights. Access to the pit is
through a trap door in the back corner of the garage. Works out real
well during the cold of winter. A 2 foot diameter block of 8 inch thick
styrofoam plugs the hole, when the range is not in use, so the house
stays warm.
good shooting,
al
Alan Grossmeier /`-_
Cray Research, Inc. { . }/ PREVENT FOREST FIRES
Chippewa Falls, WI \ / Register Matches
agr...@cray.com |___|
David A. Honig
#My girlfriend recently purchased a house with a crawlspace off one side
#of the basement that looks like the perfect place for some in-home shooting.
#
#When mentioning the possibilities of turning it into an indoor range, somebody
#mentioned the possibility of giving the house a bad case of "lead poisoning"
#
#Is there much of a danger of "lead dust" poisoning the house (and it's occupants)
1) Definately include a bigger-than-needed fan. This could be an expensive
waste of heat in winter in cold climes.
2) This might have to be told to potential buyers of the house in the
future. You might have to get the house assayed when selling. This will
probably put the homeowner off to it. Alas.
--
David A. Honig, informivore
Politicians prefer unarmed peasants without encryption...
The Rifleman
#When mentioning the possibilities of turning it into an indoor range, somebody
#mentioned the possibility of giving the house a bad case of "lead poisoning"
Lead contamination comes both from lead dust from the projectile and
lead styphenate from the primer. You can buy ammo which has a lead-free
primer and a TMJ (total metal jacket) to reduce (but not eliminate) both
of these exposure sources.
Yes, you should be concerned.
#Is there much of a danger of "lead dust" poisoning the house (and it's
#occupants) and would something like an exhaust fan at the target end help/be
#needed, etc? Any other health considerations? (I had already thought of
#an exhaust fan for byproducts of burning powder)
Yes, you should have an exhaust fan, ideally drawing air downrange away from
you. You should have a minimal air flow in cubic feet/sec. which someone
might know who has constructed a range.
You also need to worry about stray shots. Is this place completely
underground? Would an upward shot go through to an occupied room? If
so, manganese metal plate or somesuch should be installed to to provide
some protection against handgun rounds.
Also, DOES YOUR TOWN PROHIBIT DISCHARGE OF A FIREARM (unless lethal force
is justified)!?!? If so, FORGET IT! You'll get in gobs of trouble. Even
if it is legal, the noise might be a problem to your neighbors.
--
----------------------------------------------------------------------------
"Government is not reason. It is not eloquence. It is a force. Like fire,
a dangerous servant and a fearful master." --George Washington
---------------------- NRA Libertarian Party FIJA ------------------------
John Garrett
I know a guy who had an indoor pool. On one wall was a little door,
about 5' off the floor. Beind it was a 25 yd tunnel, about 3' in
diameter, with lighting and a motorized target hangar. Don't remember
if it was concrete sewer pipe, dirt, blown concrete or what. I think
there was a vent fan, and guess there was acess to the far end via
trapdoor outside, to facilitate changing lights. Pretty slick, and not
real expensive, if you have a backhoe in doing excavation for new
construction anyway.
John
Donald R. Newcomb
Bart Bobbit <ba...@hpfcla.fc.hp.com> wrote:
#There may be a few other underground ranges; I just don't know where.
#
If you have a copy of "Americans and Their Guns", look on page 82. You
will see a picture of a 100 yard underground range that ran under
Broadway in New York City in the late 1870s. Yes, that's right, there
was an underground rifle range in the heart of what is now "Gun owner's
hell." If you have seen any pictures of the original NY subway tunnels
(i.e. on the walls at Subway (tm) restaurants) it looks quite similar.
Could have been an abandoned section of subway tunnel.
Richard A. De Castro
#My girlfriend recently purchased a house with a crawlspace off one side
#of the basement that looks like the perfect place for some in-home shooting.
#When mentioning the possibilities of turning it into an indoor range, somebody
#mentioned the possibility of giving the house a bad case of "lead poisoning"
#Is there much of a danger of "lead dust" poisoning the house (and it's occupants)
#and would something like an exhaust fan at the target end help/be needed, etc?
#Any other health considerations? (I had already thought of an exhaust fan for
#byproducts of burning powder)
It bears some concern (but not paranoia). Contact the NRA, they have
range building information with ventilation requirements, etc.
--
============================================================================
deca...@netcom.com Warning: I am a trained professional. No, Really!
Rick N6RCX EMT-A ATP MA Do Not try this yourself - it could get ugly......
Richard A. De Castro - As long as the Government pretends to protect me,
I'll pretend to feel safe - NOT!
-Don't Tread On Me!-
============================================================================
Doug White
#
#Scott Keszler (kes...@rrnet.com) wrote:
#: Paul Perez (p...@hpfcla.fc.hp.com) wrote:
#: < much deletia >
#: } Then again, if I ever build that 50-yard underground tunnel in my backyard,
#: } maybe I'll start chronographing again :-)
#
#: } -Paul
#
#: Hey! I've had that same thought. Has anyone actually done this?
#
#: Scott
#
#My dad had a 50 foot small bore range in his basement. He ripped out the
#sidewalk from the house to the street, dug a trench with a backhoe, built
#a culvert out of scrap 55 gallon drums, a trap from boiler plate. This
#tunnel opened into the basement. Targets were carried to the end ofthe
#tunnel on a trolley made from model train parts.
#
#Send me a picture if you build one.
#
#Wes
The Caswell Equipment Company (which I believe was bought out by the Detroit
Bullet Trap people) used to have a 'Technical Bulletin' on building such a
range. You might try calling Detroit, and see if it's still available.
The one thing I don't think it addressed was the ventilation problem.
Unless you want lead vapor/dust and unburned powder blowing back into your
basement, you should put in a fairly healthy blower system.
Doug White
MIT Pistol and Rifle Club
Sanford E. Walke IV
: The Caswell Equipment Company (which I believe was bought out by the Detroit
: range. You might try calling Detroit, and see if it's still available.
: The one thing I don't think it addressed was the ventilation problem.
: Unless you want lead vapor/dust and unburned powder blowing back into your
: basement, you should put in a fairly healthy blower system.
An important point regarding blowers: IN at your end, OUT at the target end.
mark r rauschkolb
When mentioning the possibilities of turning it into an indoor range, somebody
mentioned the possibility of giving the house a bad case of "lead poisoning"
Is there much of a danger of "lead dust" poisoning the house (and it's occupants)
and would something like an exhaust fan at the target end help/be needed, etc?
Any other health considerations? (I had already thought of an exhaust fan for
byproducts of burning powder)
Mark
Wes Melander
: } -Paul
: Scott
My dad had a 50 foot small bore range in his basement. He ripped out the
sidewalk from the house to the street, dug a trench with a backhoe, built
a culvert out of scrap 55 gallon drums, a trap from boiler plate. This
tunnel opened into the basement. Targets were carried to the end ofthe
tunnel on a trolley made from model train parts.
Send me a picture if you build one.
Wes
JCCiccone
Bobbit) writes:
I'd like to find one where I can test a 45-70 to 500 yards, it would have
to have a hell of a ceiling.