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Minimum and Maximum Loads
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steve4102
one of us
posted
I am new to reloading and I could use some help. When I am working up a load for the first time I start at minimum and work my way up till I see pressure signs or I hit Max. I am loading for 300WSM, 7MM-08 30/06 and 7.62X39. The 7.62X39 is were I am getting confused. The difference in load data from one manual to the next is were I need help.
Here is the data for 7.62X39 125gr IMR 4227:
IMR 18.5gr Max
Speer 19.0 Min 21.0 Max
Sierra 19.7 Min 23.0 Max
Why is the Max for IMR less than the Min for the other 2? I know that every rifle is different etc. but, this seems really odd that the powder manufacturer has a Max less than the others Min.
 
Posts: 1205 | Location: Minnesota | Registered: 07 February 2004Reply With Quote
Val
one of us
posted Hide Post
Interesting! I've noted the same thing as you did. The web site for the IMR powder does indeed state not to exceed 18.5 grains.
http://www.imrpowder.com/data/rifle/762x39.php

I'd suggest that you send them an e-mail and ask them that question. I commend you as a new reloader about your researching of more than one manual when developing loads. A good approach for the sake of safety.

Maybe someone who reloads for the 7.62X39 can add some insight into this. If it were me I would start at the minimum 18.5 and work up incrementaly while looking for signs of pressure. It doesn't seem likely that both Speer and Sierra would be wrong.

By the way my Lyman manual doesn't call out a load for 125 grains but does call out a load for 123 grains. For 123 grains bullets it says that the minimum is 20 grains and the max is 22 grains of IMR 4227.
 
Posts: 257 | Location: Torrance, Ca | Registered: 02 July 2002Reply With Quote
fredj338
one of us
Picture of fredj338
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Thee are so many variables to reloading, tight & loose barrels, tight & loose chambers, brass thickness, powder & primer lots, remperatures, etc. Use the loading manuals as a guide & work up a load for your rifle. You may hit maximum before a given manuals or surpass it by a bit.
 
Posts: 7752 | Location: kalif.,usa | Registered: 08 March 2001Reply With Quote
tom holland
one of us
posted Hide Post
Alot has to do with bore dia some have .310 others have .308 IMR has a .311 and .308 listed. And as you have found out not all manuals have the same start and max loads. I'm glad they came out with some data for the 308 dia 7.6x39. Good luck!
 
Posts: 1098 | Location: usa | Registered: 16 March 2001Reply With Quote
<eldeguello>
posted
Quote:

I am new to reloading and I could use some help. When I am working up a load for the first time I start at minimum and work my way up till I see pressure signs or I hit Max. I am loading for 300WSM, 7MM-08 30/06 and 7.62X39. The 7.62X39 is were I am getting confused. The difference in load data from one manual to the next is were I need help.

Here is the data for 7.62X39 125gr IMR 4227:

IMR 18.5gr Max

Speer 19.0 Min 21.0 Max

Sierra 19.7 Min 23.0 Max

Why is the Max for IMR less than the Min for the other 2? I know that every rifle is different etc. but, this seems really odd that the powder manufacturer has a Max less than the others Min.





Your answer is..... It seems very difficult to impress most reloaders with the fact that every rifle is an individual, and what proves to be a maximum load in one may be quite mild in another, and vice versa." Bob Hagel, GAME LOADS AND PRACTICAL BALLISTICS FOR THE AMERICAN HUNTER, 1977



See, what one does is work up the powder charge incrementally until you get to the most accurate load for your rifle, OR you get to the MAXIMUM FOR YOUR RIFLE, WHICHEVER HAPPENS FIRST! To do this, you MUST be able to tell when your rifle thinks the load is all it can handle! This ONLY comes with experience. That's why people tell beginners to "NEVER EXCEED PUBLISHED MAXIMUM LOADS"!! However, what none of these sooth-sayers can tell you is, "WHICH PUBLISHED MAXIMUM LOAD???", as you are discovering here!! What I do is work up to a load for EACH DIFFERENT RIFLE to the point where a definite pressure sign appears, like difficulty opening the bolt, very flat primers, marks on the cartridge head, or some such, then I drop back 5% from that point. That load becomes what I consider maximum for THAT GUN! I work up in increments of 0.5 of a grain of powder at a time in standard cases of 7X57, .30/'06, etc., size, .025 of a grain with .223-size cases, or 1.0 grain at a time in Magnums. IF I OBTAIN GOOD ACCURACY AT A POINT BEFORE PRESSURE SIGNS APPEAR, AND VELOCITIES ARE AT AN ACCEPTABLE LEVEL, (I USE A CHRONOGRAPH FOR ALL LOAD DEVELOPMENT THESE DAYS) I STOP INCREASING POWDER CHARGES BEFORE PRESSURE SIGNS APPEAR.



Now some "experts" will say that my menthods canbe dangerous, because I don't have pressure gun, and really don't know what my pressures are. I agree that I don't know what my pressures are. But I try to keep my loads at a level where I can reload a case at least 10 times. If I load at this level, I don't really care what the pressures are! All I know for sure is that I have been loading ammo this way since about 1955, and have never damaged a gun. And the great majority of my ammo is just as accurate, if not more so, and gives just as good a velocity level, as any factory stuff. In other words, my approach works, at least for me!



Good luck!!
 
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