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The Range
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reloading .220 swift
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<blockquote data-quote="bfoster" data-source="post: 972108" data-attributes="member: 85"><p>1. It depends on the use to which the rifle is being put.</p><p></p><p> I'll assume that this is a varmint rifle, initially capable of about 0.5 MOA, and that you'd want to replace the barrel when accuracy degraded to ~1 MOA. If so, and if you're running really hot loads in a 416R stainless barrel, life will be on the order of 800 to 1000 rounds. Backing off 5-7%, say to 3650 FPM with a 55 grain bullet has nearly doubled the service life for me.</p><p> </p><p>Unlike the 308 where many rifles will do about as well with a powder like 4895 as they will with 4064, I've never known anyone who was able to secure top accuracy with 4895 in the Swift. The trouble with 4064 is that as you approach the maximum pressure a very little more powder, say 0.2 grains, can make a BIG difference in pressure (and therefore temperature).</p><p></p><p>In this cartridge as you add powder in the 55000 CUP region a graph of 4895 showing peak pressure vs. charge weight is close to linear, that of 4064 is curved, as the maximum load is approached each 0.2 grains of powder added to the charge produces a BIGGER increase in pressure than did the previous addition of 0.2 grains to the base charge. This is why backing off ~2 to 2.5 grains from the maximum charge can produce a greatly reduced combustion temperature and longer barrel life.</p><p></p><p>A Swift built on a bench rest action with a top barrel may well prove capable of 0.15 -0.2 MOA; at this level of accuracy barrel life will be unfortunately short say 400 rounds.</p><p></p><p>A cautionary tale: a friend went east to rural Ohio to hunt groundhogs. He found a large pasture that contained more than he could count. 30 shots in about 12 minutes destroyed the barrel of his 22 Cheetah. The same thing will happen to any rifle shooting a fast varmint cartridge if the barrel is allowed to get hot.</p><p></p><p>2. I've thought about a book, but I doubt that the audience/market is there today. With the exception of the section on primers which is now obsolete, and also covering advances in bullet design, I could add little to Earl Naramore's Principles and Practice of Loading Ammunition, 952 p, Stackpole, 1954. Starting from scratch, and adding the graphics that the contemporary audience would expect, I estimate that such a book would run to perhaps 1400 pages. Adding a section on shotgun ammunition would add another 600 pages. The situation there is far worse; there's been no really good shotshell reference since the work done by Charles Askins Sr. in the 20's and Burrard's Modern Shotgun, Volume II, which mostly dates from the 30's.</p><p></p><p>I posted a <em>lot</em> on the long gone talk.shooters.com board along with a couple other gents who had been there and done that, "OKShooter" and "Sarge" (one may prefer anonymity, the other has passed away). I haven't seen an archive of those threads in years. I'm reluctant to put the effort into something as fleeting as a web site- even were it my own. Sic transit...</p><p></p><p>Bob</p></blockquote><p></p>
[QUOTE="bfoster, post: 972108, member: 85"] 1. It depends on the use to which the rifle is being put. I'll assume that this is a varmint rifle, initially capable of about 0.5 MOA, and that you'd want to replace the barrel when accuracy degraded to ~1 MOA. If so, and if you're running really hot loads in a 416R stainless barrel, life will be on the order of 800 to 1000 rounds. Backing off 5-7%, say to 3650 FPM with a 55 grain bullet has nearly doubled the service life for me. Unlike the 308 where many rifles will do about as well with a powder like 4895 as they will with 4064, I've never known anyone who was able to secure top accuracy with 4895 in the Swift. The trouble with 4064 is that as you approach the maximum pressure a very little more powder, say 0.2 grains, can make a BIG difference in pressure (and therefore temperature). In this cartridge as you add powder in the 55000 CUP region a graph of 4895 showing peak pressure vs. charge weight is close to linear, that of 4064 is curved, as the maximum load is approached each 0.2 grains of powder added to the charge produces a BIGGER increase in pressure than did the previous addition of 0.2 grains to the base charge. This is why backing off ~2 to 2.5 grains from the maximum charge can produce a greatly reduced combustion temperature and longer barrel life. A Swift built on a bench rest action with a top barrel may well prove capable of 0.15 -0.2 MOA; at this level of accuracy barrel life will be unfortunately short say 400 rounds. A cautionary tale: a friend went east to rural Ohio to hunt groundhogs. He found a large pasture that contained more than he could count. 30 shots in about 12 minutes destroyed the barrel of his 22 Cheetah. The same thing will happen to any rifle shooting a fast varmint cartridge if the barrel is allowed to get hot. 2. I've thought about a book, but I doubt that the audience/market is there today. With the exception of the section on primers which is now obsolete, and also covering advances in bullet design, I could add little to Earl Naramore's Principles and Practice of Loading Ammunition, 952 p, Stackpole, 1954. Starting from scratch, and adding the graphics that the contemporary audience would expect, I estimate that such a book would run to perhaps 1400 pages. Adding a section on shotgun ammunition would add another 600 pages. The situation there is far worse; there's been no really good shotshell reference since the work done by Charles Askins Sr. in the 20's and Burrard's Modern Shotgun, Volume II, which mostly dates from the 30's. I posted a [i]lot[/i] on the long gone talk.shooters.com board along with a couple other gents who had been there and done that, "OKShooter" and "Sarge" (one may prefer anonymity, the other has passed away). I haven't seen an archive of those threads in years. I'm reluctant to put the effort into something as fleeting as a web site- even were it my own. Sic transit... Bob [/QUOTE]
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