Hello,
I have been doing some loading for my m&p 9 and 40 and its time to get more bullets. I used SnS hard cast bullets and have been please with them. 125 grain 9's and 180 grain 40's. There are other weights to choose from. How does the weight affect the bullet etc. And how do you choose?
Thanks

For 9mm I like 125 gr. The 115gr work okay too, but the loads I have worked up with the 125s are very accurate and I see no need to change or experiment with others. I don't reload .40, but I do reload 10mm, and generally like the 180gr. Again, the 150s work, but my 180 loads are very satisfactory. If you have target shooting in mind I think your bullet choices are fine. Heavier bullets can be useful for hunting, but neither caliber is a hunting cartridge so it's a moot point.

I've come to the conclusion that each bullet weight in each caliber is happiest with a certain burning rate range of powder. (For example, for most effecient "balance" if you're loading a 90gr bullet in the 9mm, you want a medium-fast to fast powder, like Red Dot, W231, etc. However, if you're loading a heavy bullet, like a 147gr in the 9mm, you want a medium-slow powder, like Herco, HS-6, AA#7, and WSF. Using a fast powder with a heavy bullet or a slow powder with a fast bullet may work, but it won't work as well.)

Likewise, I've come to the conclusion that certain calibers have "ideal balanced" weights for bullets. In the 9mm, I really like 135s. Now, you can't find 135s very frequently, but if you look you can. Berry's sells plated ones and Zero bullets makes an FMJ. Now, I designed and cast my own LPRN bullets in that weight, and there are bullet moulds available from other suppliers and from some cast bullet companies, but I don't know if your company you mentioned has that weight. In that case, my second-favorite weight in 9mm is 124-125gr. Again, this is a middle-of-the road bullet weight for this caliber. Best load balance with 124-135grs in 9mm is provided by a powder between W231 and Herco. AA#5, W231, and Unique are excellent choices.

In the 40, I really like 165s. They give ideal load balance. If you find 170s, 175s or 180s, those are good too, though I think they get less-balanced as you get heavier. Again, a middle of the road powder is best, something from Unique to WSF.

As you can see, for general-service ammo, middle-of-the-road bullet weights are the best, and match them up with middle-of-the-road powders for that bullet weight in that caliber. I also find I like single-base powders more and more, as well as ball powders. (Unfortunately, I don't know of any single-based ball powders, so sometimes you don't always get what you want...)

These are what weights I use for competition, and are very popular with many competitors; others use heavier in the 9mm and some use lighter in the .40.

Depends a lot on your shooting style, the intended purpose, and what your gun likes. OK OHP chose 180gr in .40 to better break windshields in cars when needed, for example.

You pays your money and you makes your choices.

I usually load 115s in the 9mm & 165 in the 40 S&W. Others would work too of course.

I've always used different bullet weights to help dial in my fixed sighted pistols. Light/fast bullets usually shoot low, heavy/slow bullets shoot high. I try different weights/styles of bullets until I find one that shoots to the point of aim that I'm looking for for that pistol/distance combo. Then I fine tune that weight/type of bullet by using different powders & charge weights until I get tight groups that are at my point of aim.

There has been a lot of work on heavy bullets for almost every caliber lately. Some real heavy 44Mag and such. The reason I bring all of that up is to qualify my next statement; I like heavy for caliber bullets. Heavy for the cartridge when designed that is.

147gr for 9mm, makes my Sig P226 more like 5 38spl M60's loaded with "THE LOAD" than just a spray and pray run of the mill 9mm. For the 40S&W I like the 180gr bullet.

Like OKFC says, yous chose!