Major velocity loss

[Ultramag45]

I shoot a 338 Rum.. lately some serious velocity drop....I shoot 93 gr of Rl22 with 225 gr Accubonds... its a 1holer for sure.... close to 700 -8oo rounds down this factory tube...chronyed this load several times as I shoot ballistic turrets... It started out around 3175... years have gone by and the throat erosian has quieted it down to 3120 or so... Lately I have been getting 3050 to 3030 consistently.. shot today and was at 3000.... what is going on...same lot of powder same primers, clean barrel.... same temp outside... Is my powder bad!!!!! its still shoots very accurately 1/2inch at 100yards sometimes better.. any ensight would be much appreciated..gun)

 

[trueblue]

Your post mentioned throat erosion. Have you checked your ogive measurement lately?
Throat erosion could be giving you less pressure and therefore less velocity than what you have had in the past.
That is where I would start.

 

[Derek M.]

Your post mentioned throat erosion. Have you checked your ogive measurement lately?
Throat erosion could be giving you less pressure and therefore less velocity than what you have had in the past.
That is where I would start.

+1. My first thought as well. Wearing out a barrel usually decreases pressure due to less resistance. Additionally, regarding powder, I don't know. I have heard that blackpowder, like pyrodex and pioneer for muzzleloaders loses its "umph" over time. In fact, I've been advised to buy fresh powder annually, but I've never compared shot with the same powder year after year either.

I know that smokeless powder is said to be good for years and years, but I've never heard whether or not it also loses "umph" with time. This would be a good question for the powder manufacturers.

 

[kidcoltoutlaw]

Is it the same lot of bullets ? Is the seating OAL the same that to can change pressure,

Thanks,Keith

 

[kidcoltoutlaw]

Call Sierra 1 800 223 8799 if anybody knows they will,

Thanks,Keith

 

[Ultramag45]

Your post mentioned throat erosion. Have you checked your ogive measurement lately?
Throat erosion could be giving you less pressure and therefore less velocity than what you have had in the past.
That is where I would start.

OK.. I have alwasy shot this load seated at COAL 3.63.. easiest way to check ogive measurement?... dont think I have ever really checked it,,,,Just seen where they just go in the gun and seated differently from there.... let me know, thanks

 

[elkaholic]

If your powder is stored somewhere where the temps vary a lot, it can have quite an affect on performance over a year period. I, too, would also look at the throat erosion.....Rich