Good afternoon gentle folk,
I am in the process of collecting bits and pieces to begin reloading .303 brit and possibly 7.62×39
Looking at the load charts I see many different choices of powders for any given bullet weight. How does one choose a specific powder?
Any help is greatly appreciated.
Is a good question - most powder and bullet makers publish books or recipes with loads that they tested to be at safe pressure levels - does not mean that all of their recipes are going to work equally in your rifle - your chamber and bore are different than the one they used, the lot of bullets, the lot of powder , the primers and probably the brass cases that you use are probably different to what they used. There is at least as many reasons why your results might be different than theirs, rather than the same - that leads to what works really well for one guy, may not work well for you.
These days, is almost about what can you find to use - powder, primers, etc. So far as I know, most brass and most bullets relatively easy (still) to find some - in some areas, not so for powder or primers - so it might occur that you have no choice about what you use?
Some years ago, I received a 22-250 - was not sure what powder to try with 53 grain bullets that I had on hand - a correspondent advised he had very good results in his 22-250 using IMR 3031 powder, and same bullet weight - so I got some. Turned out to also be the powder recommendation from another person to try to reproduce 30-06 loads from 1906 - not nearly the same as used today. Is really up to you to "work up" what particular amount works best (and safely) in your rifle, using your components - what someone else uses might give you a clue where to start - but I do not like to use any one else's recipe, without "working up" to that level. What I found is that many "Start" loads function just fine for me. If performance from 30-06 not adequate, then get a 300 Wby or whatever - but, sooner or later you will find a combination that suits your needs.
I notice that some reloading manuals like Lyman, Nosler or from Sierra will indicate what they consider the "best" or "most accurate" powder that they tested, but numerous other manuals do not indicate that. And their results may not apply to you or your stuff. Is a place to start, though.
Correctly or not - it has been my past practice to start with selecting the bullet weight that the thing was designed for originally. Your 303 British probably used 174 grain in service, at 2440 fps plus or minus 40 fps - although the very originals used 215 grain. But I notice most commercially loaded ammo for 303 British is 150 grain or 180 grain - it likely all will "work". Your 7.62x39 probably used 123 grain in service, at circa 2,300 or 2,400 fps - my latest batch is 150 grain bullets to try - to be seen if they will "fit" into my chamber and what kind of groups that I get when I try that - whatever was "original" is likely a "good enough" place to start, although there will be some variation.
Then, velocity - in an extreme - seems to be a desire among some to "push limits" - for example, to "load up" a 45-70 to be like a 458 Win Mag, or a 30-06 to be like a 300 Win Mag. I have done so myself. But, also I probably got that "back asswards" - I got a 458 Win Mag rifle and load it DOWN to 45-70 levels. The price of the rifles is not much different. As I have got older (I am 68), I see less and less need to "push limits" - if your 7.62x39 is not enough, get a 308 Win. Or a 30-06. Or a 300 Win Mag. Or a 300 Weatherby Mag. And so on.
Velocity - is a typical North American thing to think "faster" is "better" - I would guess with premium bullets, etc. that might have some truth to it. However, I notice European and Africa old-school guys always mention "too fast" - is likely they were using NOT PREMIUM (read: cheapest) bullets when hunting game. Typically those guys were concerned about the bullet's penetration - its performance AFTER impact - where as most target shooters are concerned about performance between the muzzle and the paper target - in other words, BEFORE impact. And, there was a quote that I read from old school bench rest shooter Speedy Gonzales - he apparently said or wrote that he did not care how fast the bullet was going, as it went through the same hole as the last bullet did. Sort of up to you what is most important to you - I have not had much luck to get maximum velocity and smallest groups from the same load/rifle - other's experience will vary from that.
