| 86thecat |
| (.224 member) |
| 10/03/10 05:18 PM |
Re: cast loads in 458WM
|
The 458 WM has a long throat, but also a wide funnel shaped throat. Primer pressure could be slipping around the bullet as it leaves the case, stopping ignition. There was a thread over on AR quite a while back discussing the difference between the WM and Lott throats, and IIRC the throat started about 10 thou larger diameter than the bullet. A throat cut with a fresh reamer could be looser than one cut with a reamer worn to minimum dimension. A good crimp and hot primers, as suggested, might help.
In reference to the WM and Lott CIP spec throats-
Quote:
Only two dimensions are needed to describe the throat fully, (edited for clarity)
1. 0.4693" (11.91 mm) wide just above the case mouth, right where the 45-degree taper down from neck diameter ends. BTW, end of neck chamber diameter is 0.4831" (12.27 mm).
2. 0-degree 29' 30" leade angle.
Wide and long, leade-only, sloppy funnel throat.
and-
Quote:
The reason for the question relates to using reduced loads with lighter bullets such as 300-350 grains. The very long free bore in the 458 Winchester frequently causes hang fires. No problem with shotgun flake type powders but with normal rifle type powders.
From this thread-
http://forums.accuratereloading.com/eve/forums/a/tpc/f/4711043/m/9201027511?r=9201027511#9201027511