Throat question....

[fatelvis]

I just cast my No.4 Mk1 chamber/throat using Cerrosafe, and found that the throat measured .314". Being the first time ever doing this, I'm trying to figure what to do next! I casted a bunch of Lyman 314299s and sized them to .314". (nose measures .303") Do I just load them normally, concealing the grease grooves in the neck, and hope for the best? Wouldnt that mean the nose would be in the chamber, and it only being .303" be "rattling around" in a .314" throat? Do I need to seat the bullet out further, or what? Thanks!

[MBTcustom]

I would seat the boolit out further until it touches the lands and back off .001-.005.
It doesn't hurt anything to have exposed GGs. Of course, you can't get too carried away with that, otherwise you wont have any strength to your cartridges, and the boolits will come out too easily when you have them in your pocket etc.
If this works, you might look into getting Tom at Accurate Molds to cut you one with an extra driving band or something in order to get into the lands a little sooner.

[cbrick]

I would seat them out myself. Doesn't hurt anything with boolits to even have them engrave the rifling, many of my rifle rounds do. I'm not fond of exposed lube grooves carried in the pocket, they pick up too much lint & stuff but the vast majority of my ammo is for use at the range & carried in an MTM ammo box so it hurts nothing. Don't seat them into the rifling so tight though that if you need to unchamber a loaded round that you pull the boolit leaving it in the bore & dumping all the powder.

Rick

[Larry Gibson]

Seat them so the GC is at the base of the case neck. A bit of lubed groove out front most often won't hurt a thing. The bullet nose will fit past the "throat" up into the "bore" which will be much less than .314 and closer to the .303 of the nose. The front driving band seated out as mentioned will enter the throat at the front of the chamber neck and center up the bullet for transition from the case into the throat/bore.

Larry Gibson

[kbstenberg]

The only other consideration is if the case will fit and function in the magazine.