Is there any real reason this case has not been used as a basis for wildcats in the contender?

This type of wildcat would have minimum case taper --a difference of 0.012" from base to shoulder. If pressure is kept to 45-47000 psi max.(Accurate Reloading Manual has the 6.5 JDJ Max. pressure @ 47,600 PSI--375 JDJ @ 45,100 PSI), it should work well. It would be an intermediate between a 225 Win (30-30 Win) and a 444 marlin case. With minimum taper the case should "cling" to the chamber walls and have no more back thrust on the action than a 225 Win case (same rim diameter). I believe, based on rim diameter, it should actually have slightly less back thrust on the action than a 30-30 Win case would, at the same pressure. It would definitely have less back thrust than a 444 Marlin case. All of these cases, 225 Win, 30-30 Win and 444 Marlin are commonly used.

I realize it may not be the most efficient case for 12" or 14" barrels but as barrel length increases so does the ability to burn more powder, otherwise a 30 Herrett would still be a better round in longer(14") barrels, than a 30-30. On the other hand it is 0.020" shorter and 0.025" narrower in diameter than a 444 Marlin case that I guess is considered efficient in this length of barrel.

I heard before that it would have to be loaded below factory pressure. All wildcats are loaded however the reloader feels like it. Many people load 30-30 cases over factory pressure. I'd bet many people load it (30-30) over 50,000- 60,000 PSI (not for long hopefully). --------By the way 225 Win SAAMI pressure is 50,000 CUP or 60,000 PSI,----------- 307 Win SAAMI pressure is 52,000 C.U.P. or 62,000 PSI, --------220 Swift SAAMI pressure is 54,000 CUP, or 65,000 PSI.

After all of this, the only reason I can come up with why the 220 Swift isn't a common platform for contender wildcats is-- maybe the brass doesn't show pressure as well as other cases??

By the way I was thinking of 6.5mm thru 8mm for this case.

Any other ideas?

[ 07-14-2003, 04:38: Message edited by: RAS 323 ]

There's a lot more to safely chambering a round in the Contender than factory published figures in psi or cup. Without going into lengthy details, I'll try this:

Case configuration, case head size and capacity figure prominently into the backthrust against the frame. You can safely fire a 50000 cup round like the little .17 Remington but can't do so with a 48000 .257 Roberts. Anything with a .223 case head size, including the rounds based on the rimmed 5.6x50 brass, can be run full throttle. Cartridges based on larger case head size must be kept closer to the 40,000 cup range (but again, there's more to it than sheer pressure figures).

[ 07-14-2003, 05:26: Message edited by: Bobby Tomek ]

Bobby Tomek--
I realize there is more to chambering a contender than "factory pressure." Obviously, with a wildcat there is no factory pressure limit. However with some factory cartidges pressure is the key ..ie 250 savage, 300 savage and 30-40 Krag.

I also realize that if you double the head size of the 17 remington-- you increase back thrust on the frame by 4 times.

Based on what you said --Case Configuration, case head size and case capacity-- The 220 swift type wildcat should work (minimum taper--Ackley like-, case head size 0.445" (rim diam 0.473") same or less than a 250,300 savage and less than 444 Marlin, and case capacity less than a 444 marlin) I'll also throw in 45-47000 psi max.

I'm just curious why it isn't used in contender wildcats? I'm guessing it the brass.

I know my 416 VVCG with 56 gr of RL 10 and Win (or starline) 45-70 brass and 270gr speer shows very flattened primers and sticky extraction with one shot. While the same load using shortened 376 Steyr Hornady brass --shows the primers are very much rounded and can be neck sized (41 mag die) up to 5 times and still be pulled out with my finger nails (no extractor)after that I need a cleaning rod to tap it out.

Take Care

I've shot .257 Darts in a Contender, which is formed off of the Swift case. I realize that many question the safety of 45,000 psi loads in a TC, but I haven't experienced any problems to date. I also did a Contender barrel in .401 Bobcat, which is again based on Swift brass.

Lee Martin
www.singleactions.com