Why such a difference?

[wisconsinteacher]

I looked at 3 different sources for 338WM loads with 225 grain bullets and RL19 and got max list loads at 74.0, 75.3 and 78 grains. To me 4 grains difference at max list is a lot. The 3 list maxes come from Nosler #7, Lee Reloading and the Alliant webpage.

I am going to try 73-74.5 grains to start out and work up if I have to. I would think that a 225gr bullet going around 2800fps would hurt a black bear or deer!!!!

 

[DrMike]

Differences in chamber dimensions, lot-to-lot variations in powders, difference in brisance in the various primers, all contribute to the differences reported in hand loading guides. This is the reason we always begin load work-up at a safe minimum and work up to a safe maximum. For this reason, it is an extremely poor practise simply to select a load and use it; the assumption that it is safe in your rifle may lead to a nasty surprise.

 

[OU812]

Mikes information is spot on as usual. Another factor to consider in the different max powder charge listings is bullets. A 225 bullet weight in copper, bonded, or cup and core will not have the same bearing surface or resistance to conform to the lands and grooves resulting in different pressure levels.

 

[wisconsinteacher]

Well I think I am starting safe with 73.5 grains of RL19 and a 225 Hornady bullet. Tomorrow should tell the story.

 

[OU812]

Well I think I am starting safe with 73.5 grains of RL19 and a 225 Hornady bullet. Tomorrow should tell the story.

You will probably be just fine but if it were me I would load up 1 round each, 1/2 grain increments starting at 72 grains. Use them to foul the barrel while working up safely to your starting 73.5. I see it as an extra 3 bullets for safety, because you never know.


Bill

 

[DrMike]

Hornady lists 73.3 grains of RL19 as the maximum charge for their 225 grains bullets.

 

[wisconsinteacher]

I will do that with 72 grains and then creep to the 73.5gr load.

 

[RiverRider]

When I'm working up with a new combination I like to shoot pairs of each charge. When a pair shows a spread of an inch and a half I know not to go back there and if I reach max before I expected it I won't have too many rounds to disassemble.