Originally Posted by reloader97
Eeeek! I've been shooting pure lead without gas checks out of my .308 time for a good cleaning.
Shooting PB or pure lead bullet at high velocity is not always an issue when it come to leading,it's when you mix high velocity generally anything over 1400 fps. and high pressure 35 to 40K PSI together that a gas check becomes useful. It's perfectly normal to shoot a PB bullet at 1700 fps. but in a low pressure load like the 45-70 with no leading issues at all.
Leading is a complex issues and can have many causes it can be caused by one thing or several things combine. Bullet fit is the key if the dia. is to small to begin with your going to get leading. Once you have the bullet dia. correct you can build your load based on bullet BHN and how it relates to velocity and pressure your load generates.
Gas check basically have two purposes. One is they allow you to shoot a much softer alloy bullet ie HP or soft flat nose bullets for expansion purposes at a much higher velocity and pressure than the lower BHN bullet could normally withstands. Gas checks also help seal the bore and keep any high pressure gases from taking advantage of any rifling induced defects to the bullets base that can cause gas cutting and then leading.
Aside from all the above gas checks also help with new revolvers with misaligned cylinders or with forcing cones and bores than may have rough factory tooling marks that haven't been polish out from shooting lots of jacketed bullets. They also provide better grip for cast bullets shot in micro-groove barrels that have shallow lands and grooves.
Gas check bullets don't make cast bullets inherently more accurate if that were the case the 38 Spec. wadcutter would have a gas check. There just another option that allows you to shoot cast lead bullet in certain situations that the normal plain base bullet might not preform as well of be the best option for a piratical load or firearm.
I shoot gas check bullets in both handguns and rifles in all action types,different BHN combination and velocity/pressure loads.