.355 or .356 for 9mm lugar, which one?

.355 for 9mm ,.356 for 38 super, we are talking FMJ here.
For cast .356 for both.
Floydster

That should be fine in a 9 depending on your barrel. If you have a pure lead slug or piece of buckshot slightly oversized you can push it through your barrel then mic it and know your barrel diameter. That will give you a better idea of what you have to work with.

Both Rainier and Berry's are plated bullets and are fairly soft compared to true jacketed versions. Rainier uses .355 for their 9MM fodder and Berry's uses .356...both shoot just fine.

I've shot thousands of Berry's bullets in 9mm at .356 with no issue. You will be fine if you choose to go that route.

"...going to cause any problems?..." 1 thou won't matter.
"...wanted to try Berry's Bullets to see if my pistol liked them..." You'll have to work up a load for them. Plated bullets are loaded using cast bullet data.

The Lyman Cast Bullet Handbook states sizing to .358 but then in the comments section they state their most popular cast buttet is 356402 which casts smaller than .358. Go figger

Moptop,

I size my cast bullets .358", and even use some at .359" in my 9mm pistols. My Beretta has a groove diameter of .3572", so for me the defacto .356" diameter std for cast/plated is not what works for me, results in leading and not so good accuracy. For cast bullets, if the round will chamber OK and not hang up because of being too "fat", the bullet diameter is OK. In the jacketed arena, I'd give the .356" bullets a try and even .357" "38 bullets" depending out what you find out after barrel slugging.

Although the typical 9mm's twist rate is too fast (1:9/1:10) IMO, it sure does not help the situation that most ammo is made with bullets that are not the proper size for a lot of the barrels used.

Do you know what your groove diameter is? If you have a .358" groove diameter, a .356" bullet (plated or not) will Lead like mad.

It would be good to get bullets sized to .357" and .358" and seat them in examples of your brass to make sure cartridges with those bullets will chamber in your pistol.

I keep my 9mm bullets as large as I can get to chamber in everything (.357"), and everything with a groove diameter larger than that gets jacketed bullets only.

Oops!