Fast Twist Swift

[DennisPA]

I need some help finding out what I am missing. I would like to start shooting the Ridgeway VBR silhouette matches. They are a steel silhouette match shot at 850,900,950 and 1000 yards. My question is about caliber for this type of shooting. I currently have a 220 swift 14 twist rifle which I know in its current configuration would be completely inadequate for this discipline. I have contacted the match director to get some clarification on some of the rules and to get a feel for the caliber need to knock over the silhouettes. This match deviates from the NRA norm by not having a caliber minimum.

Per the director a common match caliber is 6 Dasher, he personally shoots a 260 & and 6.5 x 284. So I started looking at the numbers of retained energy, drop and wind deflection at the match distances, using the 6 Dasher as my baseline. I found some interesting data comparing the 6 dasher, 243(Director's suggestion), 308, 25-06,7 SAUM, 300WM, 223, 220 Swift fast twist just for fun.

By setting the minimum retained energy baseline at the 6 dasher I noticed that the Swift with a 90g Berger had about 240 ft-lb's more energy, is 500 fps faster, and has 35 inches less wind deflection and 225in less drop at 1000 yards then the Dasher. All of the muzzle velocities for these calculations were driven from loaddata.com's max loads -20%. I figured in order to get an accurate load I would more than likely not be a max. So from my list the only caliber that had less wind deflection was the 300wm and none of them had less drop then the Swift.

So when mentioning a fast twist Swift the director replied "You would be at distinct disadvantage". Why?? I know every time a fast twist Swift comes up people bring up that it's not what the caliber was designed for and such. Since when has what a caliber was designed for mattered to a wildcatter? Not that a fast twist Swift fits the definition of a wildcat but you get my drift, it a deviation from the 12 or 14 twist norm. If you look at the history of the swift a little deeper you'll quickly find the parent cartridge the 6mm lee navy was designed for 75 to 100+ grain bullets. So why is it such a stretch to put a 90 grain bullet with a higher BC then the 6mm lee navy could have ever dreamed of in a swift?

I'm not concerned with barrel wear unless anyone has experience taking a fast twist swift deep into the round count in a competitive environment. I have competed with my 14 twist for the past 2 years and have personally passed the 2000 round mark, and it is shooting the best groups I have ever shot. I personally think a lot of the Swift barrel burner myth is just pour cleaning.

So what am I missing? Any advice would be greatly appreciated. Thanks in advance.

 

[wc872]

I don't think that you are missing anything. If you want a 7 twist 220 Swift go for it. While I have not had a fast twist Swift I have had a 7 twist 22-250. I did not explored a maximum load as it shoots just fine with a real world speed of 2970 fps avg. with a 10 shot string. Excellent accuracy & after 370 rounds there is virtually no throat erosion. The throat erosion is far less the I expected. I check the erosion with my bore scope every time I clean. The bbl. is a 7 twist Kreiger.
Semper Fi

 

[DennisPA]

WC872 what grain bullet are you able to push 2970? Also how far have you shot it?

 

[wc872]

The bullets are 90 gr. Berger VLD w/factory Moly. We have very limited long range access this time of year due to all the rain we have been getting, but I have shot it @ 980 yards. The best groups so far have been 5.375" & 7.250" 5 shot groups. The rest of the groups were anywhere from there to 14". I did primer testing at 980. Loaded up ammo with the load that showed the best accuracy & then went back with that same powder & bullet combo changing only the primers. I let the holes in the paper tell me which primers I should use.
Semper Fi

 

[DennisPA]

By setting the minimum retained energy baseline at the 6 dasher I noticed that the Swift with a 90g Berger had about 240 ft-lb's more energy, is 500 fps faster, and has 35 inches less wind deflection and 225in less drop at 1000 yards then the Dasher.

I got my Berger Book out and looked at the velocities in there and re-ran my numbers. I think this looks a little more realistic but still favors a fast twist swift.

At 1K yards. The FTS (Fast Twist Swift) has 71.7 in less drop, 11.8 in less wind deflection, 207 more FPS, and 13 ftlbs more energy. Compaired to the Dasher.

Just for fun I ran a FTS Ackley Improved even more interesting compaired to the 6 Dasher. 99.5 in less drop, 16.3 in less wind, 311 more FPS, and 84 ftlbs more energy.

Not a night and day differance but not a disadvantage either.


WC that is some very incouraging news. I was thinking if I could hold 1 MOA at 1K yards I'd be competitive. But getting close to 1/2 MOA would be awsome. Thanks for the info.