Armory Sponsor
Posted: 1/12/2012 5:17:45 PM EDT
|
ok, this may be a dumb question, and I swear Ive read my manuals. Unless I just overlooked it.
What is the "title block" tolerance on cartridges. i.e. My Lymans book says the brass on a .223 Remington should be 1.760. is that +/-.000 anything that isn't 1.760 is grounds for rejection and needs to be hammered flat and put in the scrap bin? |
|
No.
I don't have that book within reach at the moment, but that isn't what it means. For example, the case length specification for 223 is 1.740" - 1.760" You can safely run your case lengths anywhere within that range. SAAMI Specs for rifle Here is the SAAMI spec link so you will have all the cartridge dimensions for standardized ammo at your fingertips. |
|
Quoted:
my Lyman 48th edition doesn't give a range on anything that Ive seen. I realize bullet diameter is probably held much tighter than cartridge overall length. Cartridge OAL isn't as important as the datum length to where the bullet engages the lands in the bbl, till you hit magazine restrictions. Some bullet tip designs imply that there will be large variations in the lengths of the bullets, others not so much. Regardless of the bullet length and its effect on COAL, most serious loaders worry more about the ogive datum and may even take steps to control the meplat shape and diameter on their bullet tips. If you understand the effect of "jump" on pressure, then you understand you must determine the best COAL for your application. In some circumstances, such as magazines with restrictive lengths, you have a limit to how long you can seat a bullet. If the chamber reamer creates a situation where the length is too long when the magazine is considered, that bullet will always have a gap to jump. In Service Rifle with 223, we single feed the 600 yard cartridges and use heavy bullets. In this case, we ignore the magazine length restriction and may even jam the bullet into the lands if that is what works best. Your mileage may vary. |
Armory Sponsor