bolt action cast boolit designs

[rvpilot76]

Need some "absolutes" here. I'm pretty sure that you want to keep the base of the boolit above the neck/shoulder junction, but how much of the boolit do you want jammed into the lands? I'm playing with the MM design page, and adjusting little things to get the desired outcome. Just so you know, I'm designing a 215 grain GC for my SMLE. Having fun with it too. Thanks, fellas.

Kevin

[David R]

I find the gas check doesn't have to be in the neck. ONLY MY OPINION.

For a 215 grain, you are going to need a long boolit, so a bore rider might be the only way to go especially if you don't want the gas check in the boiler room. Slug your bore and take a chamber cast to see what your rifle is telling you about the boolit you are ordering for it. You will be happier.....So will your rifle.

David

[Buckshot]

..............Ditto what David said. A cast of the neck end of the chamber, the throat and leade would show you exactly what you have to work with. Start at the throat right there in front of the chamber mouth and mike the casting every .100" up to the full groove depth.

Don't forget you're gonna want it to feed from the magazine too!

..................Buckshot

[rvpilot76]

already know the throat and bore dimensions. Just need to know how long to make the front band to jam into the lands. I've got plenty of room out front for the nose; it can be .860" with a little to spare before it get to the front of the magazine.

Kevin

[Char-Gar]

I don't think I want the front body band to "jam" into the rifling. I want large enough (diameter) to fill the throat, but not so long as it jams into the rifling. Jam it into the rifling and most likely you will shove the bullet back into the case.

The bullet body should fill the throat, but not be more than about .0005 more. Much larger than this, and the bullet will shave lead as it passes through the throat. This tight fit should help the bullet to enter the rifling straight.

The nose of the bullet should be .001 - . 002 larger than the bore so it can ride on the lands with light engraving.

[NVcurmudgeon]

Chargar has it right, IMO. On the other question, most of my CB loads have the GC below the neck/shoulder junction, because I like long, heavy boolits. I never had any safety problems, and accuracy is very competitive.