Alliant Reloader powders

[rogn]

I noticed a long time ago that Reloader powders at least the slower ones as in 300 mag would really heat the barrel up. Shooting some R22 in a 300 Win Mag recently the barrel( heavy barrel) got rather toasty after only one shot. I let it cool about 5 min minimum between shots. The ambients here have been undesireable with temps and humidity matching on some days. As a result it was a long time cooling. After 3 spaced out shots the barrel was probably over 125*. Most of the other powders, probably with little or no NG content seemed not to cause the same amount of heating, even when producing similar velocities.
Im wondering whether this heating shows any accelerated throat damage compared to single base or lower NG content powders. Has any one done any investigation or kept rounds fired data in association with throat damage/deterioration. I may use this things for some hunting but will mostly damage paper targets or rattle some little steel plates. I could easily fire 4 or 500 rounds before fall hopefully gets here and just wondering what the cost will be in terms of barrel life with the R-series powders.

 

[msinc]

I believe that throat erosion is definitely accelerated by elevated heat and high velocity. I also believe that barrel steel, even though it is advertised as or reported to be some certain alloy, can contribute to accelerated throat erosion. I have not purposely destroyed barrels in some experiment to see what it took to cook the throats, but I have burned several out. I was unable to trace it to any particular powder, I found it was either sustained shooting in hot weather or again, possible poor barrel steel.
As to the original question regarding Alliant powders...I have used them quite a bit and have not noticed my barrels getting hotter than any other powder. In the last two years I have spent considerable time testing various different loads for some of my rifles. What I did notice was that N-140 and N-160 as well as Reloder 26 seemed to not shoot as hot as the others. I tested quite a few maximum charge loads. Reloder 26 seemed to me that it heated the entire barrel pretty evenly. That is to say that when it warmed up, the barrels felt almost exactly as hot at the muzzle area as they did at the breech or chamber area. I do have a nice digital surface thermometer I can test this with. Seems like my rifles got hotter at the chamber area with other powders. I got interested in barrel heat after seeing the beginning of some throat erosion in a custom barrel on one of my personal rifles that didn't have enough rounds down it to cause this, as it was also positively never over heated. The rifle is a 223, which is not noted as a barrel burner, and was fired less than 200 rounds.
I believe this barrel may be poor steel. I am going to set it back and re-chamber and then carefully record the rounds and the barrel temps to see how fast it burns out again. I have a new barrel {different brand} I will chamber up on a different 700 to use as a control barrel for testing.