I have been reloading for forty plus years however I have not until now reloaded any ammo that headspaces on the case mouth.
I have just reloaded a box of .450 Bushmaster to factory specs, 37 gr. Hodgdon LiL-Gun powder, W-W small rifle primer, Hornady 250gr. FTX bullet.
All the reloading data I read available for the .450 Bushmaster stated that one couldn't use a roll crimp or factory crimp die and that a taper crimp die was necessary because the case headspaces on the case mouth (like 9mm). I have and used the Hornady taper crimp die that was included in the Hornady four die set.
My question is this; I customarily use a Lyman inside/outside chamfering tool on the case mouth after sizing/depriming. The case mouth measures a nominal .480 and it was recommended to taper crimp down to .475 to hold the bullet securely. All this I have done, however I am wondering since the case headspaces on the case mouth, will the outside chamfering of the case mouth affect the head-spacing?
The Hornady guy said one should be able to run one's finger over the bullet toward the case and feel the edge of the case. I can do this although on my reloads the edge does not feel quite as sharp (probably due to the chamfering). Should I not chamfer when using a taper crimp on cases that head-space on the case mouth? Should my reloads be OK with respect to head-spacing (I am using an AR rifle)?
I plan to start loading 45 acp which I also understand headspaces on the case mouth so the same rule of taper crimping should apply, am I correct?
I have just reloaded a box of .450 Bushmaster to factory specs, 37 gr. Hodgdon LiL-Gun powder, W-W small rifle primer, Hornady 250gr. FTX bullet.
All the reloading data I read available for the .450 Bushmaster stated that one couldn't use a roll crimp or factory crimp die and that a taper crimp die was necessary because the case headspaces on the case mouth (like 9mm). I have and used the Hornady taper crimp die that was included in the Hornady four die set.
My question is this; I customarily use a Lyman inside/outside chamfering tool on the case mouth after sizing/depriming. The case mouth measures a nominal .480 and it was recommended to taper crimp down to .475 to hold the bullet securely. All this I have done, however I am wondering since the case headspaces on the case mouth, will the outside chamfering of the case mouth affect the head-spacing?
The Hornady guy said one should be able to run one's finger over the bullet toward the case and feel the edge of the case. I can do this although on my reloads the edge does not feel quite as sharp (probably due to the chamfering). Should I not chamfer when using a taper crimp on cases that head-space on the case mouth? Should my reloads be OK with respect to head-spacing (I am using an AR rifle)?
I plan to start loading 45 acp which I also understand headspaces on the case mouth so the same rule of taper crimping should apply, am I correct?
Last edited: