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Reloading Techniques For Reloading


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Measure this and measure that.

 
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  #1  
Old 04-08-2005, 09:38 AM
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Measure this and measure that.

A bunch of you guys are measuring bearing surface and base to caliber for boat tails and base to ogive. All of which are length measurements. Are any of you measuring bullet diameter (maybe to +/- .0001") to see if there is a corelation to the length measurements? Would a longer BS corespond to a bullet with a larger diameter? By my thinking it should and if so I might be able to sort bullets based on diameter since I have a micrometer but I don't have a bunch of money for the other fancy gauges. At the very least this measurement should increase or decrease drag on the bore within a given BS length. Yes? No?
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Old 04-08-2005, 10:18 AM
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Re: Measure this and measure that.

4Ked horn: There is a cheap way to check for varying bullets with the ogive checker sold by Sinclare under the name of Davidson's ogive checker, these attach to your calipers and are a poor mans way of having better control of spotting different lengths. I have seven of them for the various dia. bullets. You might want to look at these as they are about eight bucks a pop.
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Old 04-08-2005, 10:21 AM
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Re: Measure this and measure that.

[ QUOTE ]
Are any of you measuring bullet diameter (maybe to +/- .0001") to see if there is a corelation to the length measurements

[/ QUOTE ]

Yes. On a few of those longer ones, there are high sides that make the diameter slightly larger but that has only been the case with the 300 grain .338 MK. All other bullets seem to be better.


[ QUOTE ]
At the very least this measurement should increase or decrease drag on the bore within a given BS length. Yes? No?




[/ QUOTE ]

Yes it does. On our 2000 yard shooting, bullets that were segregated according to bearing surface length made the standard deviations get reduced by half and the vertical stringing at 2000 yards was reduced more than just trimming meplats alone. In fact, the last time we tested the MOAG at 2k on our hunting trip, NONE of those bullets had been trimmed, but all were segregated by bearing surface. In the grand scheme of things, I would say that bs segregating makes 98% of the vertical stringing disappear, and meplat trimming makes up the remaining 2%!

One thing I would also like to mention is that most of this extra technical stuff really means nothing if you are just shooting out to 1000 yards or less. Maybe even 1500 yards or less. I never do any of this crap to my other guns, and they shoot great at and up to 1500. Of course, they are using smaller bullets that are easier to make consistent than that big 300 grainer. I have 600 140 grain 6.5mm Berger vld's for "old blue" right now, and they have meplats that are perfectly flat right from Berger, and the bs and ogives on them vary less than .001"!

In other words, on a .308 that goes subsonic at 900 yards or maybe 1000, and is just being used for varmints and gongs and not comp, I would just forget about all this tech crap. Just load them up with <font color="blue">normal </font> match techniques and go shoot. It is kindof like trying to super tune a toyota camry to run the quarter mile in 11 seconds by just changing the air filter. It ain't gonna do you much good. Better off just getting a tricked out muscle car. [img]/ubbthreads/images/graemlins/wink.gif[/img]
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Old 04-08-2005, 11:02 AM
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Re: Measure this and measure that.

[ QUOTE ]
Would a longer BS corespond to a bullet with a larger diameter? By my thinking it should and if so I might be able to sort bullets based on diameter since I have a micrometer but I don't have a bunch of money for the other fancy gauges.

[/ QUOTE ]

I'll say that it most likely would not effect bearing surface length, and here's why. To measure BS length a basic tool is used in order to engauge the bullet at a specific diameter on both ends. For a 30 caliber a hole with an ID of .300" is used and will engauge the bullet at approximately the same location on the ogive as the rifling would, the same ID hole is used to slip over the boattail as well. So, the two inserts with these .300" ID holes in them basically tell you how close the "near top" of the boattail is in relation to the "near bottom" of the ogive and thus the approximate bearing length that will be "engraved" by the rifling upon firing.

If you have the capability to bore the .300" holes (or whatever ID you need) in these inserts you can think of many ways to creatively use a caliper of dial indicator to read the bearing length. You'll just need to keep things lined up and consistant, and remember these measurments are just relative to one another.

In a nutshell though, the OD of the bullet will not tell you the length that will be engraved. It may tell you by your own experience if a bullet will foul excessively if it is too large or some other thing you attribute to its larger diameter, and possibly help weed out some bad eggs if you do sort this way. One thing to remember though is that most bullets are not uniform in diameter along the bearing length and you'd have to decide where to measure them for comparison, then if they varied (or did not vary) in the other area you did not measure, the question what to do arises.
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Old 04-08-2005, 11:15 AM
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Location: Central PA
Posts: 1,310
Re: Measure this and measure that.

[ QUOTE ]
A bunch of you guys are measuring bearing surface and base to caliber for boat tails and base to ogive. All of which are length measurements. Are any of you measuring bullet diameter (maybe to +/- .0001") to see if there is a corelation to the length measurements? Would a longer BS corespond to a bullet with a larger diameter? By my thinking it should and if so I might be able to sort bullets based on diameter since I have a micrometer but I don't have a bunch of money for the other fancy gauges. At the very least this measurement should increase or decrease drag on the bore within a given BS length. Yes? No?

[/ QUOTE ]


The manufacturing process really cant let the diameter be off -- unless different dies are used. I have a 50millionths mic, maybe i'll check a few 142's when i get a chance.

JB
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  #6  
Old 04-08-2005, 11:41 AM
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Re: Measure this and measure that.

I hope that I am not the only one feeling this way. When I buy 'match' bullets, I want match bullets. Having to dick around and sort and separate and modify and toss is not what I feel deserves the match bullet cost premium.

I here some shooters complain about the cost of custom bullets. I say, pay it. how much is your time worth? What happens when you have 50% of useable bullets? how much confidence do you have that the last shot to make a winning group doesn't have a wonky bullet and blow the match?

I think QC from the big match bullet makers should improve. I discussed some new bullets with one main company and they were so excited because it met their 1/2 MOA goal for accuracy. YIKES!!!!!!

I think Partitions do better...

Jerry
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  #7  
Old 04-08-2005, 12:04 PM
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Re: Measure this and measure that.

I've made several ogive "comparators".

Last one was from a large metric nut found at a hardware store in those fancy yellow parts cases, drilled a 19/64 (.297) hole through one facet. Deburred and polished it a littel bit and it works like a champ. Looks a lot like the Sinclair comparator but less holes.
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