9mm bore

[Slinger]

Any of you fellas casting for a S&W M&P 9mm???? What's your bore diameter? I slugged my M&P @ .355". I've shot commercial slugs thru it sized @ .356" and they're o.k., but the gun isn't real accurate. I wasn't going to cast for accuracy so much as cost to buy the commercial stuff, but if my cast slugs are more accurate, all the better. Do you think they'd shoot better sized @ .357" being that my bore is .355"? I don't want to buy an extra sizer I'll never use.

[chris in va]

My CZ slugs at .355 and I fire a .358 boolit through it with good effect, decent accuracy and pretty high scores in IDPA. I would say a minimum would be .002 over with lead in a 9mm.

I originally tried shooting an unsized Lee 356 down the pipe, got really bad keyholing due to instability.

[noylj]

If your groove diameter is 0.355", then the minimum cast bullet diameter that will perform decently is 0.356". My guns like 0.358" bullets.

[lwknight]

I have found that hardcast bullets need not be more than .001 over. Softer bullets can be more.
If you got a true .355 bore then you are lucky. The 9mm is so mass produced that nearly every one is a pop shot as to what you will get.

[918v]

You should size for the throat, not the bore. You should go with the largest bullet your chamber accepts.

[Slinger]

I have found that hardcast bullets need not be more than .001 over. Softer bullets can be more.
If you got a true .355 bore then you are lucky. The 9mm is so mass produced that nearly every one is a pop shot as to what you will get.

Actually I get a reading of .355"- .3555" So, if it is .355-1/2", I guess I should go with .357" sizer. I'll probably just shoot straight WW. I have the Lee .358" 125 gr. RF coming so I'll try some of those sized to .358 & see what they do as opposed to those sized .357"

Any idea of the diameter of bullets "as cast" coming out of the Lee moulds? .002" over maybe or .0015"?

[A J]

I've had several S&W M&P's. 1 4" 9mm, 1 5" 9mm, 1 4" 40 S&W, 1 compact 40 S&W. The styling of the gun is exceptional, but the accuracy is only acceptable out to 15 yards. Excellent for close up shooting like IDPA or IPSC. Also a good carry gun. Accuracy is OK for defense use but they are not target pistols. Having tried every conceivable bullet/powder combination, all the M&P's got sold off eventually.

Best accuracy was achieved with the Lyman 147gr RNFP over 2.8gr of TiteGroup with a COL of 1.150". Good luck with your quest, hope you have better results than me.

[bobthenailer]

I would go with 0.357 dia cast bullets and the tc nose profile or a heaver 145 gr bullet .
Also use the same brand case and if you want sort them by length after sizeing , as they will grow.
and use the ones for target that are closest to but not over max case length .

[9.3X62AL]

You should size for the throat, not the bore. You should go with the largest bullet your chamber accepts.

Ditto.

[Slinger]

I've had several S&W M&P's. 1 4" 9mm, 1 5" 9mm, 1 4" 40 S&W, 1 compact 40 S&W. The styling of the gun is exceptional, but the accuracy is only acceptable out to 15 yards. Excellent for close up shooting like IDPA or IPSC. Also a good carry gun. Accuracy is OK for defense use but they are not target pistols. Having tried every conceivable bullet/powder combination, all the M&P's got sold off eventually.

Best accuracy was achieved with the Lyman 147gr RNFP over 2.8gr of TiteGroup with a COL of 1.150". Good luck with your quest, hope you have better results than me.

I've got two M&Ps: 45 in 5" & the 4-1/4" 9mm in question. With the tailored load the 45 will do 1-3/4" to 2 " for 5 shots @ 25 yds. 5.6 grs. -231 & the 200 gr. or 230 gr. cast. That's using commercial cast bullets. The 9mm with the 125 gr. TC sized to .356" will do 1-3/4" for 5 @ 25 yds. These groups are off of sandbags and on a good day when I'm shooting fairly well. The other loads in the 9mm range from 2-1/2" to 4". It took 5.6 grs. of HS-6 @ 1054 fps to shoot halfway accurately. I like both M&Ps and you're right, they're not target guns, but one of the best "fit in the hand" guns I've ever shot. Excellent for self-defense, plinking, etc. All in all, I'm a 1911 guy, but I like to play with the DA only guns sometimes.

[Shiloh]

Found this thread in the search feature.

Just cast some LEE 124 gr. TLTC boolits. They drop about .3572 x .3565 with 3:1 range scrap/WW and a bit of tin added. Running through a LEE .357 sizing die just grazes the boolits.
I'm hoping they will suffice for 9mm sized at .357.

If not, I also have a LEE 105 SWC and LEE 140 SWC that drop around .3584 with the same melt. These larger boolits may work for the 9mm as well as the .38/357.

I'll post result when I try the 9mm TLTC this weekend.

Shiloh