I'm new to loading cast bullets and need some advice on how far off the lands I should be seating the bullets.

The rifle is a Rem 700 bolt-action chambered in 450 Marlin and I'd like to optimize accuracy --- my normal routine for jacketed bullets is to start a certain distance (close) from the lands and move away as I test...the question is...how close to I start testing with cast bullets?

Seating depth, especially for cast because of the low static resistance of starting the boolit, should start with a fairly strong intact with the lands. The slower the powder, the harder the contact; the faster the powder, the lighter the contact. The better the boolit fits exactly the throat, which is defined as the lead-in plus any preceeding freebore, there is less need, if any, to have the boolit "jammed" into the lands. Placed gently into the lands, yes, but not "forced". Usually this action depends on the length of the boolit's nose, i.e., designated as a "bore" or "land" rider design. ... felix

start with minimal engraving..just where you get kiss marks on the bullet. If it weren't for possibly pulling the bullets, you'd probably get best results with firm engraving. Use your own thermometer and see what works best.

Bill,



With cast bullets you do NOT have to avoid high case pressures by backing off from the rifling (high pressures generally don't exist in the relatively milder loadings that work best with cast bullets anyway).



With cast, your goal is to achieve perfect alignment of bullet axis down the center of the rifled barrel. Any off-center at all is detrimental to accuracy and is NOT recoverable. "With cast, the battle over accuracy is fought and either won or lost before the bullet has moved its first inch down the barrel."



I cram my bullets just as deeply into the rifling as I can and still be able to unload them. I design bullet noses and first driver bands to pick up the absolute maximum of perfect centrality and bore-axis alignment off the throat as I possibly can.



Cram it in, Cram it in.



Force the case itself to follow the alignment of the bullet in the throat, never let the case/chamber have any say at all in the initial firing alignment of the bullet or your accuracy will be degraded -- especially in straight-sided cases such as your 450 Marlin.



Good luck, it really is a different sort of world with cast compared to jacketed bullets when you start going after accuracy.



Oldfeller

Do this first from Aladen:Making an Impact Slug of a Rifle Chamber/Throating
#500752 - 12/10/03 06:08 PM Edit Reply Quote



Rec'd a request to insert this posting over here. Done.


Take a well fireformed case NOT resized and fill it with ww alloy or harder to just below the shoulder/neck junction.

Your need a pure LEAD bullet with some length. This is what's being compressed to form your impression. [Gianni suggested using a lead wire. You can also readily make a slug by drilling a hole in wood, filling with pure lead and knocking it out]

Insert lead bullet litely lubed on the outside into the case and chamber the rd.

You need a rod just under groove dia.. the hardward store sells steel rods pretty cheap. Something a few inches longer that the barrel with faced off/square ends.

Wrap one end with a couple wraps of electrical tape or similar to make a nice fit to the grooves. This prevents the rod from going to the side or galling.

Take a piece of tissue paper or Kleenex and put a wad of around 1/2" comressed into the muzzle end. This compresses and cushions the action and prevents the rod from seizng on the end of the lead bullet.

Insert the wrapped end into the muzzle down to the lead slug-- now tap that rod with measured stokes with the buttstock on the floor--not hard... just even swings with little wrist action. Just enough to fully compress that lead slug. It'll bounce the same when the slug is compressed fully.

Open the action with care as NOT to deform the now impressed slug of your throat. That dab of lube will help.. I often leave the rod in the bore and as I open the action I litely poke the rod end on the wall to give it a boost. Easy does it as not to deform your impression.

The lead slug/bullet should neatly form to the dimensions of your throat and chamber origin and some of the rifling IF it's long enough. Reverse seating a bullet could give you can idea of how long a lead bullet to use IF the throat is very long. Most often their one caliber of length or less. "End"
The rest of this thread is on pg 3 of cast bullets this sight, if you want to read it.
Now get you a Lyman M die in 45 rifle cal. it has a 2 stage expander with flair for cast boolets.
Load a dumby round with your CB seated long with light neck tension, insert in rifle, close bolt pushing boolet in to case, open bolt, remove dumby hoping that boolet stayes in case, if it does, that is your max OAL.
Load 10 at that length, 10 .005 shorter and 10 .005 shorter than that, go shoot them and see what they do. Spearment from there to get what you want.

Calamity Jake