I was reading on my #1 of WW748 that is has a lower burning temperature to prevent barrel erosion. I always understood that ball powders are the hardest on barrels. Another guy told me to always use VV extruded powders as they help to extend barrel life. Does anyone really know??
Please tell me if you have any knowledge on this topic.
Posts: 391 | Location: Kansas | Registered: 12 March 2002
quote:Originally posted by B_Koes: I was reading on my #1 of WW748 that is has a lower burning temperature to prevent barrel erosion. I always understood that ball powders are the hardest on barrels. Another guy told me to always use VV extruded powders as they help to extend barrel life. Does anyone really know??
Please tell me if you have any knowledge on this topic.
B, I always heard the opposite about powders....that ball powders gave the longest barrel life. In fact, the reason the military changed from stick to ball propellents in small arms was for this very reason. Or that's the way I heard the story.
Posts: 19677 | Location: New Mexico | Registered: 23 May 2002
I doubt that there is any real difference in powders as far as barrel life is concerned. Early ball powders made for military use, like many in the original Hodgdon surplus line, had a heavy deterrent coating which was designed to extend barrel life (it also made a cruddy mess in the bore, to the bane of sporting rifle users). I suppose in an machine gun barrel, it might have helped extend barrel life.
As sporting rifle shooters complained about the residue from ball powders, the manufacturers responded by modifying the deterrent coating. While it made them cleaner burning, the change also probably negated any advantage they had in extending barrel life.
Most shooters of game calibers will never, ever have a chance to burn out a barrel in their lifetimes or that of their grandchildren. If you're a really high-volume target or varmint shooter who does get the opportunity to burn out a barrel, then rejoice at your good fortune and have fun screwing on a new tube every decade or so.
Posts: 13248 | Location: Henly, TX, USA | Registered: 04 April 2001
Years and years ago the myth was that double bases powders were hard on barrels because of the nitroglycerine content. The ball powders and then Hercules propellants (mostly double based,) now Alliant, suffered as a result. I saw a number of tests in the Rifleman in the 50's which disproved the myth. What does wear out barrels is hot, hot loads and over bore cartridges. I've had to replace several barrels which weren't overbores just because I was into a velocity kick for a while and loading very hot loads.
748 IS a double based powder and the story you heard may be a carryover.
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001
My gunsmith, an old-time gun crank with knowledge that I respect immensely, has always recommended Win 748 in 308 Win loads, based partly on the barrel life theory (also on accuracy, which is his main concern). Since he does my work, and awfully good work at that, I've tended to listen to him...
quote:Originally posted by Stonecreek: Most shooters of game calibers will never, ever have a chance to burn out a barrel in their lifetimes or that of their grandchildren. If you're a really high-volume target or varmint shooter who does get the opportunity to burn out a barrel, then rejoice at your good fortune and have fun screwing on a new tube every decade or so.
Stonecreek-
On big game rifles, I agree with you. Most of us will be doing good to wear out a barrel in a lifetime of big game hunting.
However, on my varmint & high power competition guns, it's a planned part of the project that the barrels *will* need replacing. (A competitive HP shooter usually budgets a barrel per year). I have a few right now that I cringe at the thought of replacing, as they shoot so well. I tend to "baby" them to some extent because of it, but I know their day will come.
For this reason, I do try to take advantage of any barrel-life-extending tricks that I can use. Ball powders, NEVER overheat them, usually less than full-house max loads (if the accuracy level is there), clean carefully, etc.
Double base powders contain nitroglycerine and nitrocellulose. HINT: they use nitroglycerine to extinguish oil well head fires. Single base powders are primarily nitric and sulfuric acid and cotton. They rely on a heat wave (or flame front) to ignite. Double base powders rely more on pressure wave than heat to provide ignition. They burn cooler at the same pressure levels as single base powders. They also provide more velocity due to the longer pressure / time curve which can accelerate throat erosion due to high velocity contaminants pushed behind the bullet at similar velocities. If the weapon is kept clean double based powders are easier on barrels than single based powders.
