The Firearms Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
91 Posts
Discussion Starter #1
Being such a newbie to reloading, I've had several questions that I've posted here and found this forum to be of great value. Very pleasant responses to my many questions. A great help to my reloading journey. So, thanks for everyones help.

Now to my question...

I've only produced about 25 finished rounds. I've found that no two cases weigh the same or are the same length. No two projectiles weigh the exact same. No two powder throws are exactly the same weight. No two overall lengths the same.

What are the tolerances for these measurements? So long as I stay longer than my "trim to" lengths and shorter than posted lengths am I OK to shoot the round? If my charge is 1 gr. under the suggested starting powder charge, is that OK (certainly provided I don't get to my max charge)? What about OAL? If I need to be at 2.235 is 2.340 or 2.30 OK?

These are examples only, but I would like to know (except for the max powder charge) just how much variance I can safely factor.

Thanks in advance for your help,

kevinh
 

·
Premium Member
Joined
·
34,532 Posts
Have you thought of doing this with a box of new factory ammo?
 

·
Registered
Joined
·
538 Posts
PERSONALLY, i will not shoot a hand loaded round that is more than 1/2% out of spec., but that is my choice. Some factory loads are out more than that. Your gear should be repetitive in dispensing powder and seating bullets, otherwise you should get it repaired of replace it. I like to have my seated OAL to be +/- .003 or so. This tells me the press and die are tight. When reloading, I check every 5th round for accuracy by weighing the powder charge and measuring the OAL after seating. Bullets are going to vary ever so slightly, but they should all weigh almost the same. You should be inspecting your bullets for damage, but I wouldn't be so meticulous as to start weighing each bullet. There is a safety factor built into each reloading formula to compensate for these minor deviations. If you want to drive yourself crazy, weigh and measure some of the cheaper ball ammo out there. Some of it is crazy out of spec.
 

·
Registered
Joined
·
10,066 Posts
kevinh:

Many here preach absolute consistency in reloading but here are the facts:

Empty cartridge cases vary all over the place for weight even with the same head stamp and absolutely from different manufactures.

When seating bullets the seating punch must touch the bullet sides (called OGIVE) rather than just the end of the bullet, as bullet length from tip to tip varies because of the way bullets are made.

The trim-to length is for the cartridge case (unloaded). There is a tolerance of 0.010 inches. You are suppose to trim it back to that trim-to length to within a thousands or two, shoot the loaded case, re-size the case, and check for case growth (AFTER SIZING!!). When the trim length grows to 0.010 inches more than the trim-to length then it is time to trim again.

Checking overall length of the complete cartridge should not be done end to end. You need to use a comparator and calipers. The comparator is a device that has various holes in it for the different cartridges and bullet sizes that you slip onto the bullet and then measure the cartridge OAL for comparison between reloaded cartridges. The number you get is NOT the manual OAL. You do one cartridge setup for that manual OAL and you compare it to all the others you loaded using the comparator. Errors in seating depth of 10 thousands is no problem unless they push the OAL such that the cartridge will not chamber or fit in the magazine. Use the manual dimensions for setting up the OAL.

http://www.midwayusa.com/product/746974/ptg-bullet-comparator-22-24-25-26-28-30-calibers

http://www.midwayusa.com/product/365474/ptg-bullet-comparator-17-20-22-27-30-33-calibers

Most powder measure will throw powder to a couple of tenth of a grain or better. If yours does not then first check your technique, then consider using a ball powder or short cut powder (Hodgdon and Winchester make several). If the measure is still inaccurate get a better powder measure. The cheap plastic ones as sold by some are notorious for inaccuracy. A good RCBS, Lyman, or Redding powder measure usually give excellent results. Be NOT concerned by differences in powder charges in the plus and minus range of up to 0.2 grains. All other uncorrectable systematic errors swamp out powder charge tolerances if less that that. Weighing every charge is a waste of time (not my opinion but that of experts and verified by testing) if the measure is throwing to plus or minus 0.2 grains every time.

For a better understanding of how cartridges work, and how reloading in general works, the Hornady reloading manual is the best. It has drawings that help you to better understand, unlike most other manuals.

LDBennett
 

·
Registered
Joined
·
5,631 Posts
LD is right about new #8 Hornady load book-I'm going over this weekend to help a newbie set-up and lent him my manual to read-called me last night and said after reading just a couple of chapters,he understood the whole process a lot better.
 

·
Registered
Joined
·
10,066 Posts
The Hornady manual has pictures to demonstrate both how the cartridge works and errors of reloading and the effects of such errors, all in color pictures. This explanation has been in the Hornady manuals for at least 15+ years that I know about as it is in my manuals from over 15 years ago.

I have always been an advocate of knowing how things work to better be able to use them effectively. But how things work have been a goal of mine from childhood and guided me into engineering with a 30+ year career before retiring. But the quest for How-it-Works has never left me, even in my 7th decade.

LDBennett
 

·
Registered
Joined
·
91 Posts
Discussion Starter #7
Thanks for all the above advice. Trust me, I'll take it to heart.

I, too, enjoy the information in the Hornady manual. I've read it several times. Mine is a much older version. I have a few other manuals that are more current but I would like to buy the most up-to-date Hornady manual.

I'll have to wrap my head around using a comparator. I don't have one...

Thanks again,
kevinh
 

·
Registered
Joined
·
91 Posts
Discussion Starter #9
kevinh:

Be NOT concerned by differences in powder charges in the plus and minus range of up to 0.2 grains. All other uncorrectable systematic errors swamp out powder charge tolerances if less that that. Weighing every charge is a waste of time (not my opinion but that of experts and verified by testing) if the measure is throwing to plus or minus 0.2 grains every time.

LDBennett
That answers a lot of questions...my powder measure is throwing +/- 0.2 grains. I just didn't know if that was within the tolerance level or not. When trying to load 25.4 grains and some throws were 25.2, 25.1, 25.7, etc. (but close within that range) I didn't know how close to EXACT weights I needed. But understanding that a different load data manuals will give different weights of powder with the exact same bullet and case I was just a little unnerved about it. Again, I'm staying pretty far away from the max loads.

Another issue I think I'm having is with the powder. I'm using the Hogdon Varget powder. You know, the extruded one. I know it's getting some pellets caught in my powder drum thingy (I don't know what it's called) and shearing off some of the pellets. I can't imagine that enough are shearing in half to make 0.3 grains difference, but maybe so. As soon as I can I'm going to switch over to ball powder and I'm thinking that may give me more accurate powder throws.

Interesting though, I started this journey not really worrying about extreme accuracy but the more I tweek things the more I tweek things. I guess it's the tinkerer in me.

Anyway, thanks again

kevinh
 

·
Registered
Joined
·
10,066 Posts
kevinh:

When you start using ball powders you will find that the measure will do a better job. Some measures handle extruded powders better than others but most of the name brand metal measures do kind of OK. Still, going to ball powders is the way to go if you can.

The ball powders I use are H335, H380, H414. They cover most cartridges. If you have to reload a Magnum cartridge then H4831SC, a short cut extruded powder, meters pretty good. For most pistol rounds I use Winchester 231 or the EXACT equivalent (same powder with a different label) HP38. Other ball powders for magnum pistols could be Accurate #7 and #9 or H110 (or its exact equivalent Winchester 296). IMR4227 is also a shorter cut extruded powder. There are other but you get the idea.

All these powder meter well.

To use extruded powders you have to develop a consistent technique with the powder measure handle. Usually the instruction that come with the measure give you guidance as to what that technique should be. Extruded powder grains get all tangled up as they are delivered and some might stay in the delivery tube and add to the next cartridge. That is why some measures have a small hammer on the side to vibrate all the powder in the delivery tube out of it.


LDBennett
 

·
Registered
Joined
·
751 Posts
personally i prefer to stay with ball powders or flake powders or at least small size extruded powders as they throw (measure) more accurately.
be very careful of going below the stated minmum load as some powders are very unstable in lower amounts in certain case sizes and can quickly and without warning develope overpressure values,,, watch for over presure signs carefully,, shot sounding diff,, primer backing out,,back of case and primer showing signes of bolt marks,,hard extraction,,, reloading manuals usually have pics of these signs. as long as you stay with the basic stated loads you should have no problems,,
if u check older manuals and manuals from diff powder and bullet manufacturers you will see diff load info,, as long as u stay within the variances you should be safe and have no problems just be careful small changes only no large changes between diff loadings ..
be safe and have fun
 
1 - 11 of 11 Posts
Top