Montana Gold 230 grain .45's CMJ v. FMJ

[Bruce]

Those who have loaded both and shot both, any difference you can tell between the two?? thanks

[big_kahuna]

FMJ has exposed lead base, will smoke more. Slightly cheaper than CMJ.

CMJ has gilding-metal on the base, so little if any smoke. Cost a little bit more than FMJ.

Accuracy is good with both (but JHPs are more accurate than either in my limited experience). No other appreciable differences I can think of.

[38superman]

There shouldn't be much of a practical difference in performance.

Try them both and if your gun does better with one or the other, fine, use them.

I suspect that the CMJ might push velocities a bit higher.

This is because the base of the bullet will deform less under pressure and provide a more solid stable surface for the burning gases to push against.

That however, is only a theory on my part and I have no data to back it up.

I do prefer the CMJ for the simple reason that I expect handling them while reloading will result in less contamination and lead exposure.

Not really a major issue with me since I use latex gloves while reloading anyway.

Just my thoughts.

Tony

Edited March 7, 2008 by 38superman

[pskys2]

Used both of MG's 230 .45's. Never saw any pressure, accuracy or velocity difference. The plain base of the FMJ will smoke while the covered base of the CMJ won't.

Ended up using the CMJ to stop all smoking and they were cleaner then the FMJ in my Revolver. Then went to Ranier Plated's cause I got a bit better price, and there was little to no difference there either.

[Steve J]

I've been shooting the CMJs recently over 4.5 grains of Tite-Group. My gun is a full 50% cleaner than after shooting the same amout of Zero exposed base FMJs.

On a side note, the Zero FMJs were chron'ing at 750 fps, whereas the MG CMJs felt to be ever so slightly softer shooting, but chono'd at 805 fps. They are on the light side of 230, whereas the Zeros are on the heavy side, but I wouldn't think the difference would be that drastic. I'm cooking up some control loads to chrono to see what's really up.

[steveknapp]

Any differences in the load data between them?

[38superman]

Any differences in the load data between them?

No.

[steveknapp]

But there are differences between round and HP, as well as jacketed/plated vs lead?

[38superman]

But there are differences between round and HP, as well as jacketed/plated vs lead?

The load data will not vary due to RN vs. HP.

However, it can and will change when switching between jacketed / plated / lead.