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Sizing, Alignment. Groove dia and Bearing Surface
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I'm continually amazed at how hard some myths in cast shooten die-- if they ever do.

Lets set the parameters.. We're talking factory production guns, not no BR stuff-- ya know the country.. were the average pocketbook can purchase a mid-lund shooten iron. But we [now at least] have to live with intolerances, call it runout- whatever. Barrels that vary inside by a thou or more at times. Much more. Chambers that aren't straight... bolt lugs not matching up.. you get the picture. As technology advances the basics are buried in the fatass bonus's of some 'magagement' team. Ok-- enough rant.

One of my interests is tuning the off the rack shooten iron. Bedding, bore lapping and polishing, trigger etc. Then comes the ammo. Over a decade ago I got bored with jacketed shooten... find the 'load' and the chase ends. Maybe some tweaking as to fps but ho.. hum. Then along comes a Lee mold at a rumage sale... I was hooked. Shooten cast has taught me MORE about shooten irons and what makes them REALLY tick than a carload of orange bullet shooten. So what has been learned?

Well I set out to increase the gripping strength of the bullet. One of my first speriments was inserting a punched out check in a mold to increase the bearing surface strength of that Lee 170. Made for some interastin' shooten but how to duplicate that increase sans all the fool'n around...

HARDER AND BIGGER. I quit sizing them. H with it. All sizing can do is screw the bullet up-- how can it IMPROVE it? Can't. Qualifier is safe chambering, loaded neck dia must clear... and of course in most all shooten irons a few more thou isn't gonna hurt a thing... it only HELPS. Why? Less rudder side to side.. fill that neck up and it helps alignment IF,... IF your ammon/bullet is loaed STRAIGHT. Moral.. find your groove dia and if your bullet is 2-4 OVER groove.. LOAD THAT SUCKER. The H with the lawyer talk.. Set that bullet into the lands for engravement and alignment and let 'er rip. ES's come down, groups get tighter. Sometimes NO- but often yes.

I look at some DE-signs and really wonder how the heck they shooten a-tall, I mean-- think of the bullet area just engraving the lands. On a typical 30 cal your lucky to get to .20". And you wonder why the thing wonders when the fps goes up or the psi is something more than cold Wis winter day...? I'm just amazed some of them hit anything--even the backstop. But the kicker is sizing to groove dia.. you reduce the bearing surface strength yet again to FIT the bore. This is almost mindless-- it is like trying to go forward with the thing stuck in R. Now if your rainbowing them at a target and it works-- more power to ya. I've done some rainbow shooten too, 1200's and suchlike. Interesting to take a good loading in a good barrel and play at that level. You learn the atmoshere's are in control mostly. But you loose rds..."three were right there but the other two musta been bad bullets". Nope. You'd be surprised at how bad they can be and still group.. for wt that is. Again talking the factory view.

One of my most humorous things ever read about cast shooten is weighing the gaschecks. No-- the dude was serious. He segregated everything into neat little piles. Fine-- works for him, that's his personality-- who am I to rain on it? BUT... it's a waste of time. Yes weight does matter.. just ask my scale.. But again.. dimensional uniformity and uniformity as to hardness is where the GAINS are made. Cast me some nice frosted bullets, heat treat them and take me shooten.. And then I get something to measure.. My scale has a nice life, does a check now and then against my measure... and gathers DUST. Heck-- I don't wanna wear it out..! I had it over 30 some yrs..

THOU shalt mount thy check STRAIGHT. Accuracy is about perpendicular and parallel. Take some accuracy iron and load it with that good load and just before seating the bullet file a small angle on one side of the base. Small is fine. What happens? Well you need a bigger piece of target paper...If you have runout/variation in how your checks seat as to bottoming out.. your not gettng the accuracy your capable of. Simple as that.

Bed that gun decent. Mouthful there.. when's the last time you checked the action screws? and you getting vertical? Mmmm.

It's the whole package to find good accuracy. Do the major things first. Refine later. Enjoy. And remember-- a gunwriter is just a lazy guy who has a wife with a good paying career....or they wouldn't write such drivel.

End of rant.
 
Posts: 1529 | Location: Central Wisconsin | Registered: 01 March 2001Reply With Quote
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Good thoughts. I'm in the process of stocking my .358, and was going through my copies of Gunsmith Kinks, from Brownell's. I had forgot about masking the bottom of the recoil lug before seating the barrel in the AccraGel, so had to go back and scrape a few thousandths out of the bottom. There are small things we forget about for best accuracy, and assume everything will remain the same with a rifle, once we have it shooting sweet. And when things go sour, we start looking for problems with bullet fit, lube, scope mounting, on and on. And it may just be simple maintainence that is required.
 
Posts: 922 | Location: Somers, Montana | Registered: 23 May 2002Reply With Quote
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