I am fairly new to reloading, so I wanted to ask the more experienced rloaders this:

Lyman 3rd edition pistol and revolver shows using unique powder with a 150gr JHP max load as 6.6gr, 1132fps and pressure @ 23,300. Starting load is 5.5gr.

Alliant website for same projectile using unique powder shows max load @ 8gr, 1245fps and pressure @ 34,000. If I reduce this load by 10% (7.2gr) as suggested by alliant, then this starting load will still be higher than max load as suggested by Lyman.

Does Lyman use the lower pressures due to some firearms do not fully support the cartridge in the chamber? I fully agree that 23,300 is much safer than 34,000, but I also want an efficient load.

Any words as wisdom?

And my Sierra manual shows it at a maximum charge of 7.5 grains of Unique...With a starting powder charge of 5.6. What a variation in maximum loads. Not that uncommon. Why do you want a maximum load? Were it me I'd start from the bottom of the charge listing and work up watching for high pressure signs. Start at Lyman's 5.5 listing and work up. Don't start at the top powder charge and work down. You may never make it to the next lower level.

I have the Alliant Load manual and the Lyman 48th Edition besides the Sierra Edition V and they confirm your listings. Though they be the highest listings.

after a year into the world of reloading, I found if you start with the lowest possable and work upwards, the first thing you find is where all things come TOGETHER, recoil is balanced with report, thats balanced with accuracy, just like that "ahhhhhhhh angels singing".
If ya go the other way (max first) things come APART, and yes you still hear angels singing but not in a good way!
I have a .41AE that i reload for, and stated loads say like 4.7 up to 6.5 or something like that, i went in .2gr increments from 4.7 and i stopped at an even 5.0 cause the "pop" went to a "crack" the gun seemed to jerk a hair less than factory loads, and the spread on the paper went from a shotgun blast to key holed 2 of 5 in a 2 inch circle at approx 10 foot, so i stopped....

Thanks for the info. To clarify things, I didn't want to start with a max load, but I also didn't want to have a load which is posibally under the minimum load to start.

Alliants min load is higher than Lymans max load so I became concerned on a possible misprint in the manual. I hear an undercharged load can be just as dangerous as a max load due to possible barrel obstructions.

I will for sure start with the 5.5 and work up from there, just didn't understand the huge gap between the two. Thanks again for the advice.

Lawyers....

Thanks again for the info. Is there a decent powder you can suggest? When I go shopping, I'm like a kid in the candy store and just can't decide which to choose. So far by suggestion, I picked up a pound of Unique and a pound of Clays. Only reloading .40 and .45 ACP currently.

You might get a pound of W-231. Not sure how it will do in the .40, but you will like it in the .45 ACP. My favorite load for my Colt 1911 is 185 grain JHP over 5.7 grains of W-231 and WLP primers. That will give you about 865 fps from a 5" barrel.

By The Way...If I want to get starting loads and reasonable top loads. My "go To" manual is the Lyman 48th Edition (Tends to be a bit conservitive in its load data). And I have around 5 or 6 manuals to play with.

Just got back from Cabellas, with new goodies in hand. New Sierra fifth edition, a pound of 231, and an assortment of bullets. Lymans 48th edition was sold out, but I've got a copy on order. Hopefully with 3 different manuals I'll be able to produce something that will work for me.

Thanks again for the advice.

Another thing to keep in mind is that all manuals DO NOT USE THE SAME PRESSURE RATING SYSTEM. Some use Copper Units of Pressure (CUP). Some use Pounds per Square Inch (PSI) and others may use other types of measure. The systems to the best of my knowledge are not inter-changable. So whatever is in the manual you use; stay with what it says. Auto-loaders are a bit picky in feeding and cycling. And after working on a loading for my dad's AR. I am of the opinion that you should only load one or two rounds with a given charge at the listed OAL and if the bullet is not listed call the bullet maker and ask for it, and see how the firearm likes it. If it goes boom but does not cycle the next round into the chamber then you know it is too light for the action. When you get to the load that will work the action then you can drop the lesser charges and start working up your load for accuracy and reliability. If it is not an auto-loader then it really will not matter and you can shoot whatever will come out the muzzle; or you do not care if you have to manually work the slide for the next round as in a perfect load for target work and time per round of fire is not a problem. And I will second what has all ready been said about pressure. Just pay attention to what you are doing and have fun with it and you will like it alot. The pursuit of "the" load is very addictive.

Bushmaster,
Back when I was chasing brass I used the exact same load in my Combat Commander! I then switched to 250 grain cast lead round nose bullets and dropped the charge to the point that the action would just function reliably. That load (4.5 grains of 231) gave mr 1 1/2" groups at 25 yards shooting left handed (my weak hand). I didn't want to scew up my pistol hold on my revolver because I was competing so I shot the 45 left handed. I bought the gun for $175 because it wouldn't function. there were more burrs and scoring in that action than I had ever seen before. After two days of polishing, porting and staking it shot pretty good. I never could get it to be 100% reliable but it was accurate for a play around plinker. I sold it after removing the Colt bluing in favor of a good parkerized finish for $600 which paid for my progressive press and a host of used equipment for reloading. I got a good deal and the guy who bought it got a gun that he watched me shoot - he knew the gun could shoot and that was what he wanted. I don't know if he ever was accurate with it but I got my money and enjoyment out of it.