newby question

[ramdino]

I am brand new to reloading. Just started my bench and got a dumb question. I am looking through my Lyman book at the powder amounts. I am going to be loading 223. The larger the grain bullet the longer correct? The longer the bullet , the more contact with the case correct? If those are correct i would assume that the heavier the bullet and the more contact with the case the more powder would be required to propel it. But when I look at 55 grain using Varget it uses 25 grain ( min load ) and the 69 grain uses 23.4 grains. Why less for a heavier bullet that contacts the casing more?
Another question is does it matter as far as powder loading what brand bullet you use or do you go solely by then weight of the bullet. I understand that different bullets perform different but my main concern is blowing something up in the rifle.

[AL MOUNT]

I've only reloaded 45/70, but I can't answer your question.

Hang in there,

some of these good folks will have an answer for ya. :)

[TheGunClinger]

The larger the grain the heavier the bullet, not longer. Most manuals explain your questions. Just read read and then read.

[BobMcG]

Welcome to readloading.

The larger the grain bullet the longer correct?

Often, but not always. It depends upon the bullet type/style.



The longer the bullet , the more contact with the case correct?

Well.... often, the longer the bullet, the deeper it has to be seated into the case to keep the OAL correct for use in magazine fed firearms. (As well as being able to chamber the round correctly.) Single shot rifles give a bit more room to work with.

If those are correct i would assume that the heavier the bullet and the more contact with the case the more powder would be required to propel it.

That's a nice thought, but along with deeper seating depth comes reduced case capacity. (The amount of room you have to put powder in.)


But when I look at 55 grain using Varget it uses 25 grain ( min load ) and the 69 grain uses 23.4 grains. Why less for a heavier bullet that contacts the casing more?

Because of the above stated reason. ;)


Another question is does it matter as far as powder loading what brand bullet you use or do you go solely by then weight of the bullet. I understand that different bullets perform different but my main concern is blowing something up in the rifle.

The main reason to own the manuals for the bullets you intend to use, or at least the loadbook manual for the round you are using.
Buy plenty of books and read, read, read. :)

[BobMcG]

Oh yeah, welcome not only to reloading but to TFF as well!

[Alpo]

If you're speaking about the same diameter and shape of bullet (.224 Spitzer, .308 Spitzer, .429 SWC, etc) then normally the heavier bullet would be longer. Not always, though, as a slightly lighter bullet with a hollowpoint might be just as long or even longer than the heavier bullet. A 308 110 spitzer is longer than a 308 110 RN, and longer than a 308 125 HP.

With a bottlenecked rifle bullet, many times it will have the same amount of bullet inside the neck, and the lighter bullet will just be loaded to a shorter overall length. There will be less of the bullet outside the case. Other times, with a very heavy bullet, the entire neck would be full of bullet, and some would be extending down into the case-proper, to keep overall length of the cartridge within limits.

The 223 has 1.87cc volume in its case. Let's assume that the 40 grain bullet, when seated correctly, takes up .05cc of space. That leaves 1.82cc capacity. 25.0 amount of 2200 powder, when burned in that much volume, produces 50,600 psi, and pushes that bullet at 3800 fps. Now you go to the 76 grain hollow point, and it takes up .10cc. You now have 1.77cc space left, and 20.1 grains of the same powder produces 51,000 psi, and pushes that heavier bullet at 2700 fps. Less powder capacity means less powder is needed to get the same pressures.

I, pretty much, go by bullet weight alone. I don't think there's a big difference between a Speer 55 grain Spitzer and a Winchester 55 grain Spitzer. I will also look at the type of bullet. Back to the 30 caliber - there might not be a charge difference between a 110 grain RN (that's intended for the M1 Carbine) and a 110 grain Spitzer HPBT in my .308 Winchester, but the seating depth will most likely be different.

But brand doesn't make a huge difference, as far as I can see.

[Orin]

Also, think about how long it takes to budge the bullet into motion & accelerate. Match that to thoughts re a compressed explosion... a light bullet will budge faster & as it accelerates will give room for the explosion, thereby lessening compression.
Hey, guys... I'm a newby here too. Am I doing OK? Don't wanna act like I know anything cuz most of you amaze me. But maybe I can help a few other newbs. Slap me if I say wrong. No probs.

[mncarpenter]

Also, think about how long it takes to budge the bullet into motion & accelerate. Match that to thoughts re a compressed explosion... a light bullet will budge faster & as it accelerates will give room for the explosion, thereby lessening compression.
Hey, guys... I'm a newby here too. Am I doing OK? Don't wanna act like I know anything cuz most of you amaze me. But maybe I can help a few other newbs. Slap me if I say wrong. No probs.

Welcome to both of you, don't worry, if ya get outa hand someone will surely let ya know..:D

Work up your loads from minimum..especially if you're still asking for basic info. Don't deviate from the load books and make sure you're using up-to-date books as some powders have changed in composition over the years and old data make present you with unsafe conditions. Learn how to determine correct OAL's for your gun. Some powders show compressed loads at or near max loads, and are perfectly safe that way, as long as you stay with-in specs! Varget is one of them(look for a little"c": behind the grain data-ie: 27.5c.

Be safe. Check your weights. Use more than one book to cross reference loads. I use Hodgon powder, and use their data center frequently to cross reference loads.

[LDBennett]

ramdino:

Reloading cartridges is about pressures in the tens of thousands of PSI (15,000 PSI to over 60,000PSI). The cartridge case, which is a gasket that seals the chamber, and the gun have limits that must not be exceeded. Excessive pressures will burst the brass case and in the process damage the gun (and maybe you!). So it is most important to keep the pressure in limits.

Things that can affect the pressure is the mass of the bullet (heavier bullets are harder to start moving and allow the pressures to increase quickly compared to lighter bullets that are easier to start moving), the size of the cavity in the cartridge case where the powder resides (too small and the pressure can increase too fast), the surface friction of the bullet moving in the barrel. There are others too but those are the biggies.


Reloading data is determined by testing in pressure barrels that will not blow up under excessive pressures and include pressure measuring devices. All the various load levels are tested for each bullet (usually for each manufacture's bullet, not just the bullet weight) with the bottom line of keeping the pressure within industry standards.

So heavier bullets typically have reduced amounts of powder to keep the pressure under the max allowable. The safe thing is to use the OAL recommended in the reloading data so as to keep the case capacity normal and the pressures harnessed. Reloading is NOT a science lab project because a failure of the test could destroy the gun and/or you. Follow the reloading manual data. No experiments! BE SAFE!!

LDBennett

[Waldog]

Ditto LD! He is spot on.