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Campfire 'Bwana
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OP
Campfire 'Bwana
Joined: Nov 2010
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Good info.
My reamer was rented, headed home tomorrow. Hope they don't get too torqued up over ground down set screws. Without grinding them down, I couldn't have finished the project.
Oh well.
DF
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Campfire 'Bwana
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OP
Campfire 'Bwana
Joined: Nov 2010
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They must have engraved that same stone with factory 1-14 twists in many of the various .224's.... My CZ is 16 twist like the older Hornets. Wish it was a 12 or 14. At least it's .224 not .223. DF
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Sep 2009
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I'm not in it either DF, Poobs says I need to buy a smaller rifle. The Poobs is one of a kind, never to be duplicated...On the other hand, that may not be all bad... 😎 DF Yup,like a snow flake. That CZ is one sweet rifle DF. BWAAHAHAHA WORD, Men!!!!! ;]
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,226 Likes: 27 |
DF,
The 1-16 twist should still stabilize most 40-grain plastic-tips at your altitude. As I noted earlier, the Tipped Varmageddon is about the shortest.
The 45-grain TSX, however, is pretty much out of the question, so you probably won't be able to use your CZ K-Hornet for much stunt shooting....
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Joined: Sep 2009
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Sep 2009
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Hello Mule Deer, how on earth is my M-70 with I believe a 16 twist able to stabilize the 45 gr TSX, I'm getting nice round holes at 200 and shot length ways through a coyote at a bit less than 100 yards? just lucky? or the 2922 fps in a 24" barrel?
Thanks, Gunner
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,226 Likes: 27 |
I ran the numbers through the Berger twist formula, which is normally accurate, especially when it indicates there's no way a certain bullet will stabilize in X twist. But there are mysteries in twist that formulas can't answer, especially typos in manufacturers specifications--and the length I used for the 45 TSX came from the Barnes website. I don't have any 45 TSX's on hand. Could you measure one?
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Joined: Sep 2009
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Sep 2009
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Yessir, just got in from the shop, Wifey is pulling Axis deer meatloaf outta the oven right now , I'll eat and go back out and measure one.
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Campfire 'Bwana
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Campfire 'Bwana
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JB, if my calipers are on, the Barnes 45 gr TSX measures .697"
Will look forward to your spin calculations.
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
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Thanks. Should have also asked your elevation and typical temperature range when shooting.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Campfire 'Bwana
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OP
Campfire 'Bwana
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Gunner probably gets more Lil gun in a Hornet case than anyone. He uses a drop tube. There are loads and then there are gunner loads. He's probably off the chart with that 45 Barnes load. May not be able to explain gunner with facts, physics or formula....👀
DF
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Joined: Jul 2001
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
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LOL!
However, the 2922 fps velocity he provided in his post is right in there for the K-Hornet. On the other hand, extra velocity doesn't make nearly as much difference in bullet stabilization as most shooters believe.
The formula also is designed around boattail spitzers, and flat-based bullets with less-than-pointy tips also stabilize in slower twists than the formula indicates. Will see what it says with elevation/temp info.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,226 Likes: 27 |
Yep, and it's because the two opposing forces are the gyroscopic stabilization provided by the rifling, and air pressure on the front of the bullet: The faster spin resulting from extra velocity makes the bullet more stable, but the extra air pressure destabilizes the bullet. The effect of extra spin is only slightly more than extra air pressure.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Campfire 'Bwana
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OP
Campfire 'Bwana
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I've seen observed velocity to be a poor substitute for twist.
DF
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Campfire Ranger
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Campfire Ranger
Joined: Dec 2002
Posts: 22,274 |
Very interesting thread. I bought a #1B Ruger in the .218 Bee, figuring it would be a little better in a heavy single shot rifle - before discovering Bee brass is now unobtainium. I may have to revisit the K Hornet. Also good to hear about 300MP being useful.
"...the designer of the .270 Ingwe cartridge!..."
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Campfire 'Bwana
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Campfire 'Bwana
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Thanks. Should have also asked your elevation and typical temperature range when shooting. Elevation here at the farm is 555 ft asl, average temps fired in are 40-55 degrees, hope this helps solve the mystery.
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Campfire 'Bwana
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Campfire 'Bwana
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Gunner probably gets more Lil gun in a Hornet case than anyone. He uses a drop tube. There are loads and then there are gunner loads. He's probably off the chart with that 45 Barnes load. May not be able to explain gunner with facts, physics or formula....👀
DF A mad scientist in the loading room, huh?
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Sep 2009
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Very interesting thread. I bought a #1B Ruger in the .218 Bee, figuring it would be a little better in a heavy single shot rifle - before discovering Bee brass is now unobtainium. I may have to revisit the K Hornet. Also good to hear about 300MP being useful. Tex, the next time I see some Bee brass for sale here I'm gonna grab it then give you a call, if you don't buy it I'll be forced to buy a 218 Bee rifle somewhere. And that would be a dire shame ;]
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Campfire Ranger
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Campfire Ranger
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Thanks - you can find it on the auction sites, but they want $1.50+ per case, which is about what .475 Turnbull brass costs! versus ~$.25 for Hornet brass. I think I can make these from .32-20's without much trouble, which is probably what I will do in the future. The rifle shoots well, and easily beats 3200 fps with 40gr bullets and 14gr of Lil'Gun.
"...the designer of the .270 Ingwe cartridge!..."
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
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gunner,
It comes out closer now, close enough that the 45 TSX being a rather blunt-nosed, flat-based bullet explains the discrepancy with the program.
Now I'm curious if you've actually measured the twist in that rifle? Have run into a few older rifles where it varied some from "nominal," due to the primary method of rifling used for many factory barrels before WWII.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Campfire 'Bwana
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OP
Campfire 'Bwana
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JB, how much will 100' vs. 555' above sea level matter if the equation is already on the fence? Maybe I can get more Lil gun in a K Hornet case that gunner can squeeze into a Hornet case... I may get a can of 300-MP. Is 300-MP denser than Lil gun, as in getting more in a case? If it's slightly slower than Lil gun, I'm guessing maybe not. DF
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