one more question for C.O.L

Pressure could rise. If length is shorter, the bullet is further inside the case leaving less space. But unless you are at max charge with 10x fired full-length sized brass in an undersized chamber, I doubt it would be too worrisome.
 
The "recipe" - assuming it came from a loading manual, also told you what brand of brass, brand and size of primer, and so on that the reloading company used to pressure test in their outfit - so all a "guide" for you in using your stuff - for certain your chamber and bore will not be precisely the same as theirs, so their results may or may not have much to do with what works in your outfit. In the manuals, is repeated multiple times to start at the Start level of powder charges, especially if you change a component - and then work your way up to see what happens in your rifle - sometimes yours will need less, sometimes the same, sometimes more. Bullet seating depth is one of the things that can influence your load's pressure. So can changing the brand of primers, or the brass, or using from a different production lot. Or sometimes, it makes no difference. You are the only one loading for your rifle - so start low and tell us what difference it made, changing COL in your outfit.
 
From what I understand is that COL(COAL) is “unique” to each rifle, for rifle with magasins, the COAL is dictated by that cause it is useless to have your bullet out at let say 0.10” from the land if at that length your ammo doesn’t fit the mag!
 
Yep - was a thing, for example, with early Weatherby chambers - deliberately cut with extra "free bore" by the factory - if the cartridge fit the factory magazine, early ones were 3/8" or more to get to the lands. Was a way, back then, to help manage "peak pressure". Led to reports of "custom" chambered rifles, which omitted that free bore - "to be more accurate" - would freeze bolt or get sticky bolt with factory ammo. But DGY above is generally correct - reloaded ammo has to fit magazine in a hunting rifle, first - then, want to verify that you are not jammed into the lands at that length - might or might not be able to play with COAL within those parameters. If you are single loading, like for a target rifle, not the same concern - at that point, some hold out that bullet "jump" becomes very important, others rely on concentricity, and so on ...
 
There are two very important measurements to have when it comes to reloading. One is COAL - or the total length from the base of the case to the tip of the bullet. This is important to ensure ammunition fits inside the magazine of the firearm.

The second measurement is CBTO - or Cartridge base to Ogive. The ogive is the part on the bullet that actually contacts the lands. This measurement varies so much depending on the individual bullet you use and your firearms chamber. It even changes as you shoot your gun because the throat is worn away with every shot. This is the measurement to use when someone is discussing the distance off the lands.

Have a read through these articles and it will enlighten you and make you a much safer and better reloader:

https://bergerbullets.com/effects-o...coal-and-cartridge-base-to-ogive-cbto-part-1/
https://bergerbullets.com/effects-o...coal-and-cartridge-base-to-ogive-cbto-part-2/
 
dean5820 said:
the recipe of C.O.L is 2.800”，so I have to make it to 2.8”？ could be lower？like 2.735”
Click to expand...

Yes. Unless your ammo is loaded at book max (which might be way over max for your particular rifle) that seating depth won't make any difference.

I have seen new rifles with short throats that require the bullet to be seated deep.

This is why the books asks you to start at the Start load and work up. That way you can set whatever COAL suits your magazine and chamber.
 
You must log in or register to reply here.
Back
Top Bottom