Author Topic: Can I neck down a .220 swift to use a .204 bullet??????????? (Read 1930 times)

rickabristol · « **on:** February 09, 2005, 06:09:35 PM »

I have a Ruger M77 .220 swift. It was made in 1977. Can I put a .204 barrel on it(And machine to accept .220 swift with .204 bullet) This would be a super fast .204. Could something like this work or would there be too much cup pressure due to the small neck? If this works it would be the fastest rifle on earth!!!!!!!!!!!!!!!

5Redman8 · « **Reply #1 on:** February 10, 2005, 03:52:47 AM »

In a word....YES it can be done. Would I advise it...NO WAY....TOO MUCH OVERBORE....for me. Now if you are willing to go to the trouble of getting full custom dies and building a 20cal on a shortened Swift case....I could see that.

Or find out what othe cases have the same bolt face as 220 Swift and build a 20 cal from one of these cases.

I would recommend a 20BR Which is a 22 Benchrest Remington necked down to 20 cal. Would have the same bolt face, so no extra work for the bolt. Simple necking and dies are available.

Kyle
topboss8@yahoo.com

Graybeard · « **Reply #2 on:** February 10, 2005, 05:01:30 AM »

Just because you can does not mean you should. Even the .204 Ruger is over bore for a .204" bore. Using the Swift case woud gain you little if any over the current factory round and barrel life would be poor. Plus you'd have no pressure tested load data to go on and would be flying by the seat of your pants. If you have to ask such a question you are clearly NOT an experienced enough wildcatter to be flying by the seat of your pants on such a project.

Varminter · « **Reply #3 on:** February 10, 2005, 05:36:16 AM »

fast doesn't always mean accurate

rickabristol · « **Reply #4 on:** February 10, 2005, 01:52:51 PM »

Your right I dont know much about wildcats. What is OVERBORE. I have heard it thrown around however I dont understand it.

Thanks,

5Redman8 · « **Reply #5 on:** February 10, 2005, 02:23:43 PM »

OVERBORE is a term to describe a cartridge that is not efficient....or overly inefficient.

Meaning, you are burning MORE powder than needed to reach a certian velocity. Pretty much reaching and going beyond the point of deminishing returns.

If you want a 20 cal on your current rilfe, the 20BR is a good option. Find a gunsmith familiar with small calibers and have him do a rebarrel and chamber job. As far as load data, you might try going to www.saubier.com this is a sub caliber specialty board.

Kyle
topboss8@yahoo.com

onesonek · « **Reply #6 on:** February 14, 2005, 02:04:09 AM »

Sorry I was gone awhile unexpectedly. While catching up, this post caught my attention.
Hmm, where to start. Well I agree and disagree here. While a 20-220 would be inefficient, there are other in use equally so. The 7STW and 30-378 come to mind, and the 6-.284 isn't far off. But this is definately in the realm for a 28"-30" barrel in my mind. If you have the time and money, it is your choice. Personally, I agree with the accuracy part. For the most part, more speed is desired for longer range work. Small calibers and lighter bullets can be fickle in a mild breeze at long range. More speed isn't always the answer. Accuracy is or should always be #1. Also, the more inefficient bore , generally speaking, need to be cleaned more often to maintain peak accuracy. But one never knows untill one tries either.

As far as load data for such a round. Well, there are a couple excellent computer programs that brace that issue. With those, caution still needs to be used as with any other reloading data. The critical part is "pluging in" the correct information to start with.
Your proposed round will be burning quite abit of powder in relationship to bore diameter. But if you don't get it too hot, life of the barrel won't be any shorter than those mentioned above. Just don't shoot so fast between shots.
Dave

Catfish · « **Reply #7 on:** March 02, 2005, 03:24:42 PM »

The larger the case the smaller the returns. I once talked to a fellow than necked a .50 BMG round down to .243. Would it go fast?, about 5,000 fps. Was it worth it? He didn`t think so. With all of the powder he was burning to get that speed, not to mention the cost of the smith work and dies.
If you`ve never played with wildcats I would recomand that you spend alot of time studying internal and external blistacs charts befor you spend alot of money on a custom gun. I`m thinking of haveing a .20BR built, but if I do it will have a very fast twist and set up for 50 grn. bullets. I got to check the Berger 50 grn. bullets to make sure that they are of high enough quality to make it worth the gamble. If I go with it, it will be a bench rest gun rebarrel. With the barrel costing around $150, another $150 in smith work and dies at about $125 I want to be sure I`ve got a good chance of it being a shooter.

Blygy · « **Reply #8 on:** March 04, 2006, 06:56:15 AM »

check out www.woodchuckden.com I believe they have dies for the 20-220 swift.

Blygy