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44man
02-12-2008, 11:37 AM
I have had this in my mind for years and why I never posted it slips my mind.
I have always figured that when case tension is needed and brass is tight, that you can size a boolit when seating, if it is too soft.
The gas check leads the boolit when seating and opens the brass just enough to help protect the lead as long as the lead is not dead soft.
Could this be one of the most important reasons for using them?

felix
02-12-2008, 12:17 PM
No doubt about it! Use anything that helps keep the boolit straight and firm. However, we have to make sure the boolit does not bend/scrape when seating/crimping the gas check in the first place. Best chance of that is sizing only when the boolits are at their maximum hardness, but we never do. Some of us cast and place the produce into storage until years later because those boolits shoot the best. Well, the real reason is that many of us don't have the energy to cast, size, load, and shoot in the same year. ... felix

mroliver77
02-12-2008, 01:32 PM
Felix do I understan correctly that you are talking sizing base first?
J

SWIAFB
02-12-2008, 02:05 PM
I believe that there would be to much variance in neck tension to warrant having the casing try to size the checked boolit.

felix
02-12-2008, 02:22 PM
Yes, base first to crimp the gas check on. Base first would not be needed if the shank and check are perfectly square to one another before and during any real force is applied to make the "crimp". ... felix

runfiverun
02-12-2008, 10:14 PM
i think that you would re-size somewhat w/o the g-check

however i know some bp goys that actually re-size the outside of thier cases after boolit seating. this is with 20-1 mix they tell me they dont think it affects thier groups at all

and judging thier groups @ 200 yds they may be correct
i would try to avoid it myself
but if you are getting it in the case withhout shaving the boolit where is it going to go
you probably are stretching the case not squeezing the boolit

runfiverun

Bass Ackward
02-13-2008, 07:30 AM
I have had this in my mind for years and why I never posted it slips my mind.
I have always figured that when case tension is needed and brass is tight, that you can size a boolit when seating, if it is too soft.
The gas check leads the boolit when seating and opens the brass just enough to help protect the lead as long as the lead is not dead soft.
Could this be one of the most important reasons for using them?


What my testing indicates is that the GC allows straighter seating mostly because it allows less belling. Belling in most dies is not uniform. Especially if your case (singular) isn't trimmed to a uniform length all around. You don't trim straight wall cases because they are TOO long, you trim them for uniformity around a single case for a uniform bell and then a uniform crimp.

The uniform crimp only has a big effect on your powder charge if your loads are below 25,000. But a "uniform" crimp ALWAYS straightens the loaded round " IF " the bullet is hard enough to survive it. Otherwise crimping a soft bullet just deforms the bullet more. Which is why having case anneal be no harder than needed for the pressure we want to run allows better loaded ammo. Hard brass is simply harder to load well, especially without hard bullets ..... or a GC.

44man
02-13-2008, 09:20 AM
Runfiverun, I also do that with my BPCR if the flare is too large to chamber a round. BUT, the case is only run into the size die only to close the flare, not to size anything. The die is adjusted up with a spacer so it does not size.
That works a lot better then any crimp die.
Bass is right about hard brass with a good crimp and soft boolits. No better size die made then the crimp! It sure wipes out all the throat fitting for accuracy. I am sure a lot of you shooting soft boolits have seen a crimp still on your brass after shooting. Poor accuracy and bad leading can be the result.
That is why I use hard lead for hunting and depend on the meplat instead of expansion. With the recoil and heavy boolits I use, I need hard brass. ( My grandson thinks he is big and tough but flinches so bad he digs trenches way in front of the target, then he stopped the barrel with his head. No damage done, hard head!:mrgreen:)
The smaller calibers need expansion for hunting and you then need more care to keep your boolits from being ruined by the brass. A two part boolit really helps. A good case for bass's annealing too since the recoil is not as bad.