My 9mm doesn't like .356 boolets

[Coconino]

My problem is finding a good 125-147 gr cast bullet that works without tumbling. I have found commercial bullets like Precision and Acme that work fine and are accurate but these have no lube groove. But Bear Creek 147 gr with than large (and unneeded groove) tumble. When I used the Lee 125 RN mold sized .356 I would get tumbling when shooting them from a Browning HP, SIG, or M&P. I may get a NOE 135 gr mold when I get funds up to try. I taper crimp and use mixed brass.

[mdi]

FWIW, and remember what you paid for it

Just a thought; many times one will bring up a subject and many times there will be a lot of negative responses (just mention you like to trim revolver ammo and stand back for the "you're wasting your time" replies). But the important thing is it's your ammo, your gun, your time, and as long as a particular practice won't blow your gun up, do it! I may do some things most don't but I'm reloading for myself and not to please forum experts. There is no Reloading Police to kick down your door and confiscate your handloads because you did it wrong (or different). If you don't want to cast yer own, fine. If you can only use .355" bullets, OK, you researched and tried.

Remember, this is an open forum where anybody is welcome to drop any suggestions about any part of reloading, whether they know tons about the particular subject or just read something yesterday. All I can really say is read them all, use yer brain and common sense and you'll be able to pick the good info outta all the "stuff'...

[lightload]

I've read the thread an learned a lot. One idea is to talk to the nice man at Penn Bullets and ask for a sample pack of unsized(& unlubed)9mm boolits. This sample pack would have a range of boolits from light weight to heavy and may have a few from the .38 section as well. In essence, the op would then have a big bag of gauges for research.

[dudel]

Sort 9mm by headstamp? Are you shooting at 100m out of a 9mm rifle? Yes, I read your reasoning, I just suspect you're in the vast minority when it comes to that particular behavior.

I must be in the minority as well. I sort by headstamp to get a consistent primer feel and seating. When I ran mixed brass, you couldn't tell if the pocket was loose or tight of if the primer had gotten cocked. For example my S&B cases have much, much tighter primer pockets than most any other brass I use (Fed, Win, RP, Starline and LC). Much easier for me if I sort brass. As a side benefit, I get more consistent bullet tension. It also culls out those cases I don't want (steel, Americ, etc). Can't hurt, and I find it relaxing. If it's more accurate, that's not a bad thing.

[MtGun44]

Wow, paying to modify the throat rather than use a good boolit design seems
strange to me.

Try Lee 120 TC normal lube, sized to .357 or .358 for any 9mm. Works for many
different guns, feeds perfectly, only a tiny bit of full diam outside the case means
not a problem like most of the RN 9mm designs. Folks see RN FMJs as standard,
so assume that they need the same or similar shape in cast.

Save yourself some trouble and try the Lee 356 120 TC sized .357 or .358.

[SSGOldfart]

This doesn't sound like an issue where the boolit is stopping on the throat. It sounds like the chamber itself is on the tight side. If the OP can seat a boolit upside down flush with the case mouth and it won't chamber, here is where to start looking, because that eliminates the OAL question and also the throat/freebore diameter interference question.

It may be that this barrel likes a certain crimp or certain size boolit and that's all it's gonna be happy with.

BEFORE I would consign the problem being the chamber, I would consult a GOOD precision micrometer that reads in .0001" increments, and look to see if the boolit itself is oval shaped. You would be surprised the number of dummy boolits that people send along with their barrels or cylinders, that are egged and the customer who sent them was unaware of this runout. Some of the issues have been from not running the boolits through a sizer at all, to a worn out sizer, not enough crimp, not pushing the boolit far enough into the sizer, I would make SURE you got a round boolit to start with and for this you need a GOOD mic, calipers won't be precise enough to give correct readings in tenths of a thousandth of an inch. Just a couple tenths runout is enough to cause the entire problem the OP is dealing with.

Very well put DougGuy

[Lloyd Smale]

I shoot 358s in all my 9s. Ive owned a pastle of them through the years and the only one I had that wouldn't run 358s was a fancy smith 956. It needed 356s to run right. It wasn't the tack driver I was led up to believe anyway. I traded it off and got a sti Trojan in 9. it ran everything and was hands down the most accurate semi auto pistol I ever owned.

[rsrocket1]

Farmerjim, there is no need to modify the M&P barrels.
I shoot the Lee 356-120-TC and TL356-124-2R just fine in my M&P9 and Shield 9 with stock barrels. The M&P is actually an M&P40 with the stock 9mm S&W barrel. My barrels slugged at 0.3545" and yes the throats and chambers are tight. The throats slugged at just under 0.3565" and a 0.356" bullet feeds into it right up to the rifling. My bullets drop at 0.358" and after ASBB PC, they are 0.360". I size them in the Lee 0.356" push through sizer and they measure out to 0.356". I use the Lee 38 S&W expander plug in the 9mm PTX die which expands the case the full length of the bullet:

The bullets are very snugly seated with plenty of neck tension from the case and I can expose as little or as much bullet above the case rim and have no trouble avoiding the rifling. I can seat the 25-120-TC out to the bottom of the lube groove and the TL356-124-2R out to beyond the second TL groove. I use the Lee taper crimp die (not the Factory crimp die) to close the flare and put a very mild taper crimp (much less dramatic than the photo below appears). Here's a picture of various seat depths anywhere from flush to 2nd TL groove. All rounds passed the plunk test in both the M&P and Shield barrels. You can see where the case is still slightly expanded, but the cartridge still fits easily within the chamber of the field stripped barrels.