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If Elmer didn't say it, it probably ain't true.
quote:Dr.John....If you shoot hot loads too fast and for too long without letting the barrel cool then it will burn the throat and barrel as will any larger volumne case/shell.....but I have a P64 Mod 70 Winchester in 220 that is 40yrs old with orig. bbl and it has throat wear in the light barrel but with modern mollyed bullets and 4064 in new cases it shot a .585group of 3 shots the last time out and less than that with another BR bullet but had horizonal stringing that I'm working on now.....good luck and good shooting with a grand old caliber/cartridge.....!
Originally posted by Dr. John:
is the 220 swift really a barrel burner. I have considered picking one up in the ruger m77 varmint lam. stock target type. do they burn barrels only after many repeated shots? what is the deal. seems like an excellent caliber/cartridge.
I don't know how many rounds my father put through it, but I've put over 3,000 through it, and it still groups 1/2-3/4 moa. I used 4064 with 50 gr Ballistic Tips for years, but have now switched to Barnes 50 gr VLC bullets and Viht N140. They group excellently, and the blue coating gets you another 100 fps without excessive pressure. I can get 4,010 fps with them, no problem.
I clean thoroughly every 25-30 shots. I never take more than five shots without letting the barrel cool to ambient temps.
I have a Ruger like you are talking about getting it is a very good rifle. It is very accurate have killed a coyote over 440 yards with it . I don't think the swift is a barrel burner . Barrels are made out of a lot better metal than they used to be .
the rag writers run the Swift down 95% of them never shot a swift . It is the top of varmint rifles will out shoot the 22-250 by 100 yards. my .02 worth
I have been shooting a Swift for a while and have on the order of 2000 rnds through a Shilen Select Match Stainless Barrel and erosion is not evident. The loads that have been put through it have been as high as 4500fps but never under 4000fps. My best load is a 55gr. Nosler BT @4060fps. All the bullets that have been fired in this gun have been MOLLY coated I feel this is a great factor in especially this caliber. My 220 is a very consistant P-Dog gun. It is truly the king of the .224's, my only complaint is case life. Granted these are hot loads but in coparison to other calibers case life is very short. I will trade that for the exceptional performance.
Chuck
PO Ackley talks about "bore capacity" in relation to caliber. True, he's writing in 1966, but he's talking physics. Laws of physics haven't been changed since 1966 as far as I know.
In sum, there is a fixed amount of intertia in the bullet, and only so much acceleration that the load charge can produce. Larger bore capacities provide diminishing returns. Once you reach maximum bore capacity the charge mostly blows hot, abrasive powder down the bore.
"Improved" calibers reach higher velocities through greater case capacity, but also through straight wall and steep neck design -- both of which are difficult to manufacture commercially.
According to Ackley, max bore capacity for .224" is about 40 gr. powder.
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