EXTREME COPPER COATED BULLETS IN 9mm ?

[lonewolf5347]

I have a total of maybe 2 thousands round down the sr9 pistol seem by two best loads are
135 gr. R.N.F.P. 3.5 gr. Bulleye and 5.0 power Pistol powder @ 1.145
The 135 gr. dia: are at .356
I also did a few mods to the gun cut 2 1/4" coils off the striker spring added a new trigger bar @ polished all the internals it has become my favorite steel plate match gun and also a few IDPA courses.
The gun is a range gun trigger breaks a little under 3 1/2lbs and I have yet to encounter and problems with light primer hits.
I seem to have the gun down were she will hold a 3" group now two hand hold at 35 yards for distance shooting two hand hold unsupported.
I am always trying to improve the gun on the range seem I been playing with a few rounds at 357 dia. again extreme copper coated at 147 gr. R.N. using 3.5 gr. B.E> powder at 1.155 the gun chambers the round no problem ,pressure may be up a little but no signs at far as a hot load. The brass will eject about 5 ft. compared to 2 Ft. using the 135 gr. bullet @ .356
I do find the large diameter bullet has no black soot on fired cases accuracy has gotten better but would like to ask are entreme bullet as hard as FMJ will I do any damage to the barrel. going to the .357 dia. bullet in the ruger sr9

 

[Schwing]

The short answer is no. Plated bullets are very similar to cast. That thin coating of copper doesn't make it measurable harder.

If they chamber and cycle properly, I would bet they are far more accurate than the .356 as well.

 

[Captaingyro]

Have you slugged the barrel? That would provide an important bit of info.

 

[rsrocket1]

Extreme plated bullets have a thicker coat of plating than a lot of other bullets. Yes they will wear out a barrel faster than lead bullets, but you are talking about maybe 100,000 rounds versus 200,000 rounds. I have around 40,000 rounds through my M&P 40 barrel (almost all lead) and you couldn't tell the difference between it and a new barrel.

As caaptaingyro said, slug your barrel. I'll bet it's close to 0.355"-0.356" so the .356" bullet is sealing up the bore nicely. That prevents gas cutting of the bullet which leads to copper fouling and it also prevents the much smaller but still harmful barrel erosion.

Now, if you go to 0.357" on your Ruger, you want to make sure the throat of your barrel (the part in front of the chamber but before the rifling) is at least 0.357" otherwise your cartridges will not pass the plunk test if you seat any part of the 0.357" bullet above the rim of the case.

You must also realize that your pressures will be higher, particularly the peak pressure so be sure you are not loading to max published loads. It would be a good idea to chronograph your loads. My M&P 9mm with a 4.25" barrel shoots the same loads about 80 fps faster than my Beretta 92FS with a 4.9" barrel. The difference is that the M&P throat is 0.356" and the bore is 0.3545" while the Beretta throat is 0.358" and the bore is 0.357"

 

[Dudedog]

I have had excellent results with the RMR 124gr 9mm Flat nose and the RMR 147gr "Target HP" Both have much thicker plating than some other plated bullets, very close to jacketed.
RMR offers THR members 5% discount with a code. (code at the start of BDS PIF thread)
The RMR 124gr FNs a run .3565 dia.
Should be no problem with the Xtremes but as noted above if you use .357 dia ones you need to do a load work up as pressures will be higher.