Cartridge neck thickness

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Big Gun
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Joined: Thu Feb 13, 2003 8:35 pm
Location: Dakota Territory

Cartridge neck thickness

Post by Big Gun »

Anyone have any experience with thinning the brass of a .40 caliber case neck? A cutter for inside the neck? I would like to get from about 0.0105"-0.0110" per side down to about 0.0095" per side and take the brass off from the inside...or am I wasting my time? Shiloh chambers don't leave any wiggle room.
rdnck
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Neck diameter

Post by rdnck »

Big Gun--The Shiloh 40-65 that lives at our house requires a neck diameter of .430 or less, or it won't go. Trimming case necks was not something I wanted to do, and it was not necessary. What I did was use Remington brass, and a .408 diameter bullet. Careful adjustment of the seating die yields a loaded round with a neck diameter of just less than .429 and a cartridge that drops into the chamber with this combination.

I tried several different bullets that went .409 to .411 and they simply won't work. Shiloh recommends a .408 bullet, and we got good results when we followed their recommendation. Shoot straight, rdnck.
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Kelley O.Roos
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Post by Kelley O.Roos »

Big Gun:

If you must, you can neck turn and get the same results. You can buy all the tools for neck turning form Forster and ahve them grin the mandrel to fit inside the csae mouth for a snugg fit.


Kelley O.
Kelley O.Roos
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JAGG
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Post by JAGG »

Yes a foster neck reaming reamer ! I ruined a bunch of cases ! do as RDNK said ! Life is easier that was and cheaper to boot ! JAGG
JAGG
Bill C.
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Post by Bill C. »

Hey JAGG,

Do you HAVE that Forster reamer? What dia.? Want to sell it?
Bill C.-Shooting Birds in Oregon
RR
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Location: Nebraska

Post by RR »

Bill C.

I am new to the list. I shoot a Shiloh 40-70 SS for BPCRS. I have for several years now. You are not kidding about the no wiggle room in Shilohs chamber. I use the reformed 30-40 Krag brass form Buff Arms and had to inside neck turn all of this brass to keep things on track. I use the Forster trimmer and cutting tool with very good results.
RR
MikeT
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Post by MikeT »

Gentleman,
How thin can a case neck be, before it is TOO thin? To me 0.011 looks mighty thin. Maybe another way to phrase the question is, how much free space does the catridge neck need to let go of the bullet properly? If that maximum "free space" is exceeded, does accuracy go to hell?
Keep on hav'n fun!
MikeT
ffffgdave@yahoo.com
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Location: helena montana

neck turning

Post by ffffgdave@yahoo.com »

years ago i bought a target 22 250 dies made by (lee ?)that came with inside neck turner.. really nice.. i wanted one for my 300 mag so i would not have the donut where you cant turn past the neck angle.. i looked for years and was tralking to the rcbs custom departmant and they said they will make them custom for your gun, caliber, , much better and more accureat than outside turning and no donught.. have not tried rcbs iside neck turner yet,, but the (lee ?) was tremendous.. dave
Smokin
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Post by Smokin »

MikeT,

For comparison, my Starline .45-2.6" brass measures .009" at the mouth; some .45-70 Starline brass measures the same thickness. A randomly pulled W-W 45-70 case measures the same. A randomly pulled R-P of the same nomenclature measures .010". These are all many times fired cases and were measured with a dial caliper that zeroes. There were the excursions to +/- .0005" but I generally disregard that variance with a dial caliper. Were I a good machinist with a practiced thumb on the friction wheel, maybe the little numbers would mean something. One of my uncles, who was a model maker for the Mayo Clinic and later IBM, looked with rolling eyes at my handling of a micrometer, thus my opinion that it makes little difference when I see 3-5 tenths one way or another on a dial. Particularly when if I push that wheel a bit I can get things to whole numbers.

To a carpenter, they're only fancy C-clamps which adjust really slowly, Bruce
Smokin

Member in tall standing of the Frozen Tundra Chapter, Flat Earth Society.
MikeT
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Location: Saint Cloud, MN

Post by MikeT »

Smokin,
Have you calculated the clearance in the chamber with the .009 case necks e.g. chamber dia, minus the loaded cartridge neck O.D.? If so, inquiring minds need to know!
Keep on hav'n fun!
MikeT
Smokin
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Post by Smokin »

MikeT,

The only close scrutiny I have paid a rifle's chamber is to my .40-70SS #4 Ballard. It invited my attention when rounds loaded with similar care and the same bullets as my .40-65 wouldn't chamber. With a few "well, isn't this interestings" I hastened to get a telescoping gauge to measure the chamber. Others would probably counsel me to have cast a Cerro Safe plug of the chamber, but I had neither the material nor any experience with that technique. The cartridges didn't lie; the chamber was too small for them.

The other rifles I own have never exhibited similar head strong tendencies, thus I have had no occasion to plumb those depths. However, it would be an easy thing to do for an inquiring mind. I promise not to skew the data even if I'm looking to show well at the Freeze-Your-Parts-Off Shoot coming up all to soon. Are you gonna be there? Do you have a specific cartridge/rifle combination about which you are most greatly curious? Bruce
Smokin

Member in tall standing of the Frozen Tundra Chapter, Flat Earth Society.
MikeT
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Post by MikeT »

Smokin,
I'll be there at the Freeze-Your-Parts-Off Shoot cause it is a long cold winter if you don't get some shooting during January. Which one of the dozens of rifles in your safe is going to get the call?

I am curious about .40 caliber chamberings specifically, but any .45 caliber info would probably be good too. The amount of room in the neck area has got to have some minimum & maximum demensions for best results.

Hey, got another subject: Do you think the guys at Harris will go the BP or Pyrodex ONLY route? I shoot only BP so it makes no difference to me, but Ralph is nervous. I would guess that a 40-65 with BP is pretty much done after 800 yards.
Keep on hav'n fun!
MikeT
Woodcutter
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Location: Fort wayne, IN

Post by Woodcutter »

Big Gun:

I would rather use a bullet diameter that fits my bore than fit the bullet dia. to the case for ease of loading (unless by adjusting bullet hardness I could get the case fitting bullet to shoot accurately). Neck turning or inside reaming either one will do what you are wanting. As has been said Forster makes outside neck turning equipment and L.E. Wilson makes inside reaming stuff. If Wilson doesn't list the size reamer you want I am sure they will make it since they made a .40-65 case holder for my trimmer.
All that said, my Shiloh .40-65 has a tight chamber and I have been successful using R-P cases with .409 -.4095 bullets without resizing the cases. I just bell the case mouth and seat the bullet. There isn't any slop in the fit to the chamber but the rounds chamber easily. I consider it about as close to a match chamber as I would want.
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