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HSMITH · February 28, 2007, 12:07 AM

Crazy4nitro, Blue Dot will spike pressure much higher than you would expect for a given change and do it with very slight changes in the load, that is what I mean by "nasty" in the upper ranges. It will provide little or no warning prior to this either. You will be working up, a tenth at a time and go from everything just fine to stuck cases with a single tenth of a grain increase. Each gun is an individual, so there is no way to predict where this will happen with your gun. In some guns it will be within printed data by a couple tenths of a grain, in other guns you might be able to go a tenth or two over max before it spikes.

A chronograph is almost essential when working up Blue Dot full magnum loads, the speeds it will make are surprising and need to be watched so you don't just keep on working up. It is pretty easy to challenge the construction of the bullet with Blue Dot, and only a chronograph will tell you that.

Mike Irwin, that load makes a little over 1400 FPS in a 4" M19 for me with a Speer JHP, and the powder will make almost 1600 before pressures get high. I won't post what I run, but with a bullet that will seat and crimp in the cannelure at 1.590" it is a good bit higher. Blue Dot is a little faster, but caution is the better way to go here.

February 28, 2007, 12:07 AM	#15
HSMITH Senior Member Join Date: June 21, 2002 Posts: 2,019	Crazy4nitro, Blue Dot will spike pressure much higher than you would expect for a given change and do it with very slight changes in the load, that is what I mean by "nasty" in the upper ranges. It will provide little or no warning prior to this either. You will be working up, a tenth at a time and go from everything just fine to stuck cases with a single tenth of a grain increase. Each gun is an individual, so there is no way to predict where this will happen with your gun. In some guns it will be within printed data by a couple tenths of a grain, in other guns you might be able to go a tenth or two over max before it spikes. A chronograph is almost essential when working up Blue Dot full magnum loads, the speeds it will make are surprising and need to be watched so you don't just keep on working up. It is pretty easy to challenge the construction of the bullet with Blue Dot, and only a chronograph will tell you that. Mike Irwin, that load makes a little over 1400 FPS in a 4" M19 for me with a Speer JHP, and the powder will make almost 1600 before pressures get high. I won't post what I run, but with a bullet that will seat and crimp in the cannelure at 1.590" it is a good bit higher. Blue Dot is a little faster, but caution is the better way to go here.