What burns a throat/barrel out quicker.....

[farmer7]

Using a load with a single-base propellant at higher pressure or a load running at lower pressures with a double-based propellant???

 

E.g. .260, 123gr Scenar 44.5gr H4350 @ 59k psi at 2920 fps vs 123gr Scenar 44gr RS60 @ 51k psi at 2930fps.

 

Does it come down to the pressures you're running at? Or is it the actual nitroglycerine content in the double base powder doing the damage?

 

Or is the Heat of Explosion/Potential of the powder in kj/kg the deciding factor?

[DaveT]

Not sure that anyone will be able to answer that definitively and evidence based.

 

For example Viht claim that the N5 series powders contain some sort of additive that mitigate the torching effect of the nitro content to avoid barrel wear.....some authoritative users will say that it does not work!

 

I use N5 and accept that barrels will be a wear item.

 

I also understand that it depends on the user.....lots of successive shots and hot barrel = greater wear rate.

[gbal]

Dave is right-there are several factors involved,and difficult to separate,and very difficult to quantify individually.

They include pressure,but especially temperature.

 

Hotter is worser.

 

As Dave says,some (dual base) powders have additives to reduce burn temperature-though probably not to single base temperatures.So generalisations about powder type need to be modified.

 

Rate of fire cumulates temperature-fast strings of shots wear barrels more-alarmingly more with hot loads.

 

There is some evidence that case design can reduce heat effects-usually in wildcat designs.

 

Put all that -and more,barrel steel/coatings-in the mix,and it's complex,though heat is the main factor (as in 'fire cracking' in throats).

 

No free lunch,especially if you like hot meals. :-)

 

gbal

[farmer7]

Thanks for that chaps. I've always stuck with single-based powders but was just curious as to how big a difference there really was between them.

 

Anyway as I'm struggling to get a hold of H4350 now I'm going to give RS62 a go in the .260, looking at Quickload it appears to be showing pretty decent velocities, especially for a single-base, not far short of some of the highest performers and a good bit quicker than H4350.

[dannywayoflife]

Some double base powders burn cooler than single base. Ramshot magnum burns at almost the same temp as N165 which is always touted as a very cool powder.