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I suspect with the much faster rifle powders, higher pressures might be produced by larger diameter bullets, however with normal powders, I doubt this is a problem, as long as the bullet fits the chamber mouth loosely, ie: with .002" to .004" or more slop.

Ackley did some fairly extensive tests on this and found in the .30/06 they were able to shoot 150gr. .323" bullets with 'normal' pressures, after enlarging the necks to allow these oversized bullets, and adding:

"this experiment has been carried to a greater extreme several times by altering the chamber in a .30/06 rifle to accept .35 caliber bullets. It has been found that 180gr., .35 caliber Barnes bullets seated in a GI .30/06 cartridge using the original powder charges will pass through the .30 calibre barrel with no signs of undue pressure. It must be remembered that the bullet has t travel only a very short distance before it is sized to fit the bore through which it will pass."
That is rather extreme test, but shows oversized bullets themselves do not create excessively high pressures.
(page 31 - volume 11)

Now, if the chamber's neck will not allow the oversized bullet and release that bullet easily, excessive pressures will of course, result, just as an overly long ctg. neck crimping into the bullet by the front of the chamber will cause excessive pressures.

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Daryl

"a gun without hammers is like a Spaniel without ears" King George V

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