Under pressure.... or over pressure

[interlock]

Guys,
I am used to working with jacketted bullets.

i am just coming to the world of casting my own. I intend to shoot 7mm08 with 130 gr gas checked bullets. they will be lee soup cans, they have lots of rings and grooves up the shaft for lube and obturation.

I use mainly Viht N140 and would hope to continue with this. It has a similar burn rate to h4895.

I would like an expalnation of pressure signs when using lead and also if the gas can get past the bullet how will i know that.

Thanks for your patience with a new caster.

steve

[btroj]

Pressure signs are the same. I can tell you this, get to max pressure in a 7-08 with cast and you will have poor results in almost every case.

If gas is getting past the bullet you will get poor accuracy and leading. Lead in the barrel will be lumps that won't just push outwith a dry patch. I like to run a dry patch down the barrel and I can generally feel leading. I then hold the muzzle to a light and look from the breech. Leading is pretty obvious.

[Plinkster]

Pressure signs will be the same as what you see with jacketed although a cast boolit will run at a lower pressure using the same charge with all else being equal. The only indicator of blow by or gas cutting that I know of is leading in the bore. I've never had an issue with leading using gas checks but I certainly won't say it can't happen. To make sure you don't have to deal with getting the lead out slug your bore, plenty of info on that here. Then measure your boolit as cast, if it's .001-.002 over your groove diameter you are golden just slap on some lube and a check and load away. If you have other than that options are available. If too small you can beagle your mold (again info to be found here) I prefer to bump my small dia boolits up but I have a custom die for this. If too large use a sizer to bring the dia down, I prefer the Lee push thru type others like the lubrisizer route. A bit off topic now and windy to boot but that's the basic new caster run down lol. Welcome to the addiction!