I will apologize in advance . . .
Borderline Stabilization... at long range - Yeah we need some more of that down here in AZ!:mrgreen:
:Fire:
:coffee:
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I will apologize in advance . . .
Borderline Stabilization... at long range - Yeah we need some more of that down here in AZ!:mrgreen:
:Fire:
:coffee:
You brought a grin to my face.... It didn't last though...... I grieve for you folks down there close to this mess.
I am ashamed of this Administration for sitting on their prat on this! Where's a "Black Jack" Pershing when you need him!
Sorry for the rant........ Eutectic
Experimental Determination of the Effect of Rifling Grooves on the Aerodynamics of Small Caliber Projectiles
"This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States."
I found the whole paper, but it's "payware" despite the non-copyright status.
http://www.aiaa.org/content.cfm?pageid=406
Anyone have the contact info for:
Otherwise, anyone interested in a "group buy" to defray the costs for the non-copyrighted material?Quote:
Sidra Silton, Weapons and Materials Research Directorate, ARL, Aberdeen Proving Ground, MD; David Webb, Weapons and Materials Research Directorate, ARL, Aberdeen Proving Ground, MD
AIAA-2006-6009
AIAA Atmospheric Flight Mechanics Conference and Exhibit, Keystone, Colorado, Aug. 21-24, 2006
Edit: I found the email address for David Webb. I'm going to shoot him an email.
I made a PDF of this one but it's just a bit too big to attach. Posterity -- shoot me a PM if this link ever dies.
On another note, lots of really cool stuff was discussed at YPSE-06:
http://www.aiaa-baltimore.org/YPSE-06/Titles.shtml
Excellent! It also answers my question about the S&W twist, I knew it was faster then 1 in 20" but could never find figures. It has been a LONG time since I had a 29.
What is wrong is that twist would be perfect for heavier boolits but the S&W can't take the recoil with inertia of parts. The S&W should be 1 in 20" and the Ruger 1 in 18". Overlap with boolit weights seems to be OK though. After all, it just takes a small change in velocity for a good match.
44man, Larry....
It seems S&W used to put 1 in 18 3/4" twist in everything from .32 to .44 caliber for their revolvers.
Smith .44's have shot pretty well for me with cast... But it isn't my most accurate .44. That spot goes to a Colt Single Action Army in .44 Special. The twist is 1 in 16" ??
I have a super accurate K-38. Super accurate using 148gr hollow base wadcutters. Does almost as well with 125gr cast. 158gr loads display yaw at the target and 2" groups become its performance at 25 yards.
A friend has a Colt Python .357..... IT IS ACCURATE! We shot 158gr Semi-wadcutter loads one day loaded down in .357 cases to about 850fps. They would touch each other at 25 yards.... The Python has a twist of 1 in 14".
Years ago, I shot competition with an old gentleman that had a Colt Officers' Model target revolver in .38 Special... Very accurate... I wish he was still with us as I'd like to test more 38 Special loads in Colt's 1 in 14" against S&W's 1 in 18 3/4"...
I tend to agree with the thought of a 'little tighter' twist in some of my revolvers.
Eutectic
Here's another spin-off - so to speak: Spinning .40 cal bullet on iceQuote:
The last few posts seem to 'spin' off some to my thinking....
http://www.youtube.com/watch?v=foZlciP6gUQ
At first i thought "No way!" but it actually seems to be a real phenomenon.
the fast twist in pistols seems to go against the formular for twist rates.My experince with short bullets has shown they will not be acurate in fast twist rifle barells,I have found that bullet lenth and slowing velocity is the only way you can get a 50ca BP rifle to shoot with a 1 in 20 twist rate,why is this difrent in a pistol
It's not "different" in a pistol. Most would shoot the shorter, lighter bullets better out of slower twists if the velocity got high enough. Ooooops, might be why the shorter, lighter pistol bullets shoot better out of the slow twist carbines and rifles.
Larry Gibson
It still does not make sence to me when I checked the optum stability for a .684 long .429 groove diameter 240gr 44magnam traveling at 1000fps it stated that the twist rate should be 1-29.8,and from experince I know that a faster twist in a rifle (same caliber ,same velocity gives terible acuracy)am I missising somthing
Other things contribute to inaccuracy in rifles vs handguns. The use of a magnum load in a rifle for instance. Many times the PB cast bullets that shoot fine out of the handgun produce too much velocity out of the rifle for good accuracy. Has to do with the limitations on the PB. Shooting magnum loads with Kieth bullets cast of WWs + 2% tin at 1400 fps out of a 6.5" barreled revolver produce 1600+ fps out of a 10" Contender and 1800+ out of a 20" rifle. Accuracy is excellent out of the revolver yet poor with the Contender and rifle unless I back the velcocity off to 1400 - 1500 fps. However, load a GC'ed SWC (429244) with the same magnum load and it shoots very well in all 3 firearms. Not the twist there, just the limitations of a PB bullet. Cast the Kieth bullet really hard and accuracy can be good in the Contender but just ok in the rifle.
Larry Gibson
That's correct, 44man! Latest issue Ruger rifles are 20 twist; Winchester rifles 26 twist. ... felix
I am testing that is why I can not make sence of it .The rifle tested was a Uberty 44-40 with a 1 in 36 twist rate ,sluged at .429,I got very good acuracy with it at 100 meters yousing a 200gr bullet at 1200fps.Now to be so I could judge the diffrence twist rates make I loaded My 44magnum super blakhalk revolver so the velocity was 1200fps,acuracy was terible with the faster twist rates,I then loaded 240gr,270gr &300gr bullets in it trying to stay close to the same velocity,results were the longer the bullits the better the acuracy as I expected,the only way I could get the shoter bullets to shoot was drop the velocity,so my conclusion is (I am proberly wrong) is if you want to have acuracy with a 44magnum with 240gr bullet the twist rate has to be changed to a slower rate or you drop the velocity(which does not work on the 300meter rames)all bullets were plain bass hard cast,the fast twist rifles that I tested were a Armi Sports 44 Rusian with a 1 in 16 twist ,a Armi Sports 45 colt with the same twist ,acuracy was terible till the velocity was droped to 300fps,and to be fair to Armi Sports I tryed there 44-40 with a 1 in 36 twist(in my opinuion the proper twist rate for this cartridge)and it was very acurate
Google this...
Reports_of_Experiments_with_Small_Arms_f
It's a copy of an 1850's US gov report on small arms development. It includes info on the spin causing the curve at long range.
Only a few of your observations are right. The SBH with a 240 gr bullet needs more velocity and the XTP needs 24 gr of 296, the Hornady silhouette bullet is better with 23.5 gr.
1200 fps is too slow.
The 270 cast would work with 22 gr and the 300 cast might be better with 22 also. The 320 gr cast is best with 21.5 (1316 fps) and the 330 cast uses 21 gr.
These are based on the Fed 150 primer. Now be careful because the heavier boolits from 270 to 330 gr are CAST so if you use a 300 gr XTP you only need 20.5 gr of 296. I can't tell you what load to use for a 270 gr jacketed.
The SBH does NOT like light bullets under 240 gr.
You can't compare the 44-40 to the .44 mag. You are too confused over twist rates because you are working with other calibers with vast velocity differences and boolit weights. You are also trying rifles and revolvers expecting the same results from the same loads and bullets.