Pistol primers & powder questions

[Flashover16]

Typically the ball, slow burning powders like W-296, H-110 are used with magnum primers, is it a must do?? you decide.
these powders also perform best with a strong crimp.
as for 700-x/800-X, I believe that if you check with the company they will tell you they are made as a competitive powder for other manufactures powders.
so they should not be the same, only similar.
Remember when most of these powders were developed these were independent companies and so had powders that were developed for use against other companies powders.
its never a great idea to substitute one powder for another, follow manual guide lines. w-231 is a very wide use powder in many calibers of pistols.

 

[Flashover16]

I never really thought about it that way but you are exactly right. With the powder settled against the bullet it would take longer to ignite and vice versa against the primer.

The biggest determination of burn rate is , grain size, grain shape,(both of which determines how much of the surface area of the powder is in contact with the flame), chemical make up and any deterent added to the powder itself.
some powders become unstable with to low of a powder load, some it doesn't make a bit of difference, slow powders typically have a heavier burn deterent added to them.
hope this helps.

 

[SpeedyR]

most things have been covered here but to re-iterate one point- some powders, specifically H110 the manufacturer usually recommends a magnum primer. Not to say that you can't substitute a non mag primer, but especially if you are just getting into reloading, I would recommend following the manufacturers recommendations.

I know most of my H110 loads (357 and 44) I use magnum primers. Don't know why but if they say I should I start from that and if I have problems that I look at solutions and see if I can change something.

another example (not related to your specific questions) is using small rifle vs small pistol primers in a cartridge such as 22 hornet. Most of the manuals say small rifle but some have found a bit better accuracy using small pistol primers.

but other than that the recommendations are good. dont' assume anything (IMR vs. Hodgden being the same). Also when in doubt, call the company in question and ask. they have technical folks on staff that can answer your question, but more importantly can probably tell you why you should/shouldn't do something.