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O.K., I'm sorta new to the casting my own bullet realm and I came up with an interesting question. Now I know that it seems the conventional wisdom has said to size your bullets .001" larger then the bore. The question I have is, with fast moving 2000+ fps rifle bullets that are linotype or heat treated WW and GC does this still apply? I have not seen or read anything about it explicitly and have read through Veral Smith's book at least once cover to cover. The reason I bring this up is that aren't the linotype or heat treated bullets as hard as condom bullets? And if so, why size them larger then one? I'm getting ready to order a die for my Star and at $40 or so dollars a pop I'd like to have a better chance at being right with the first one, instead of the second or third. I've got a Lachmiller 311 169 PT that I'm going to start with. Pure lead slugs are running B/T 168.+ gr and 170.0 gr, bare. One of the rifles I am going to try them in has a Palma Match chamber. I'd like to hit 2500 fps or more if possible. The die and lube are two of my last shopping items. What are your thoughts and experiences here? Thanks, (corrected spelling in Veral's name) [ 12-09-2003, 05:19: Message edited by: Byron ] | ||
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quote:I'm not familar with the design, are you talking a pointed spitzer or pointed bore ride design? Depends on the barrel per the speed and bullet design. Palma barrels can be had well under normal groove dia and I think Krieger offers them with what amounts to 5 thou for land depth. That's to your advantage if that's the case and a minimal neck dia helps alignment. What I did was buy the inexpensive Lee push thru dies and size then heat treat-- always lubing in an oversized die as to not deform the bullet or soften the bearing surface. Adding the check at lubing makes the seal and lube won't come forward that way. I put thousands of rds thru a Hart in 06. Groups were the best at 1/2 thou over groove heat treated very hard @ 100. [311644 @ 200 grs treated hard, 54 grs #19 210M @ 2450 fps] My best groups @ 600 were unsized heat treated about 2-3 thou over groove. I think finding the amount of engagement into the rifling for the load is more critical than actual dia.....for most common designs seen. The BR guys run anywhere's from 1.5-3 thou over groove, some of their tapered bullets fitting the throat like a glove. But if the bullet doesn't fit it won't shooten no matter the other de-tales. 2500 with accuracy using a common design and not fitting the throat precisely might be tough. But a good tube & machining makes a big difference in your favor. Find your actual groove dia BTW. What's stamped and what it measures often differ. [ 12-09-2003, 05:10: Message edited by: aladin ] | |||
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Byron, Good question, thanks for asking. Actually, conventional wisdom is shifting from "groove diameter" to "throat diameter". If the bullet is a sloppy fit in the throat, it is less likely to be delivered straight into the rifling, and may also experience some gas cutting while it is in the throat. In a perfect world, the throat diameter is the same as the groove diameter or maybe 0.001" larger. If the throat is a few thou larger than groove diameter, size to fit the throat, allowing a little clearance for easy chambering. If the throat is more than a few thou larger than the groove diameter, as many mass produced guns are, I am not sure what is best -- perhaps a new barrel. | |||
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Some old military Mauser rifle throats were intended to chamber a round literally coated in mud (trench warfare). They were cut large for this reason. The throats are big. Very big. Much bigger than +.001" over bore diameter. We have made up special bullets to fit some of these mil-surps that filled up their throats completely and have had good success shooting bullets that get swaged down .004"-.006" by the weapon's own throat during intitial or first movement of the bullets. They do get good initial alignment and they have lube grooves that are deep enough to do the job. The technically best answer is "measure and fit your bullet to the throat itself for a rifle, fit your bullet to your cylinder throats areas on your revolvers" when shooting lead bullets. Oldfeller | |||
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On a slight tangent, to get 2500 fps, lube choice is gonna be REAL important. The now obsolete Bullet Master would do it, but I've been out of the game for a few years and don't know which of the current crop will. | |||
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I guess it's a good thing I like to tinker because there is diffinetly more to cast bullets then meets the eye. O.K., here is some info on the bullet (all measurement are approx. - bare): Spitzer nose Overall Length 1.050" Nose Dia. .297" - .299", length .525" Crimp/Lube groove .050", depth .018" Drive band .140" wide, dia. .311" another lube grove another drive band Gas Check Shank dia. .280", length .160" These measurement were taken with digital caliper, so take them for what they are. I will update with chamber/throat dimensions when I get to work because that is where my drawing is at. Of the lubes that came with the sizer, Lyman IDEAL - ?, RCBS - Rifle Bullet Lubricant, and Javelina - The Alox 2138F - Beeswax, I guess I could start with the RCBS. But based on what I have read on this site maybe I should see about getting some of Felix's or LBT lube. Later, [ 12-09-2003, 20:12: Message edited by: Byron ] | |||
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quote:Sounds like Lyman's version of 311413. Found this bullet very accurate at traditional speeds but not consistent at high velocity. My mold had a small dia gascheck shank which didn't give a rock solid hold by the check-- which I thought detracted from high speed grouping. Your mileage may well vary.. If your goal is high velocity you'll need Tom Gray's lube, Thompson Blue Angel used by many BR guys or I believe Felix lube would handle those speeds and PSI. I wish you the best in your effort Byron. Very interesting project IMO. | |||
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Aladin, This group was fired with the Lyman 314299 sized .310 in my CZ 550 30-06 with WRA brass over 30 grs of 844 surplus powder with kapok tuff filler. It's ten shots. There was no care taken in casting, I didn't cull out by weight, I didn't orient in the sizing process, and they were water quenched at casting. I sized them after they were hardness treated and lubed with Javelina. The only experimentation I tried with it so far was to shoot the bullets unsized as the dropped from the mould and accuracy was down alittle bit. I was surprised my CZ shot like this as I have mentioned before SO FAR it hasn't shot condoms like thise YET. I wish I had someplace to try them at 600 yds like you have. Joe | |||
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