.358" cast bullets for accuracy?

[Sieger]

Hi Dan:

Your Luger's groove is in factory spec. at .357 to .358, per the original DWM drawings.

I tried this same little project, about one year ago, with .356, .357 and .358 cast lead bullets.

As the diameters of my test bullets got bigger, groups got tighter!!! At .3565, the action of my byf 41 closed totally (first time, every time) and I got really fantastic groups (7 or 8 touching at 25 yards!!!!). These were cast moly coated bullets.

At .357, groups continued to improve, but reliability got "iffy", as the outside of the case was just out enough to "catch" on the inside of the forward chamber.

Well, how do we solve this little problem (how to keep the outsides of the necks within spec)? That's simple, I purchased two custom neck reamers and ream the inside of the necks the few thousands necessary to clear.

Call Forrester and have them make some up for you. Order exact diameters .356 and .357. This will give you a .001 grip on your lead bullets and should do the trick.

Regarding your accuracy, your loads are not well matched to the Luger.

You will need to concentrate on your powder selection, your OAL and, perhaps, the design of the bullets you are using.

I'll be happy to give you some advice here, as I have been handloading for the Luger since 1978.

Sieger