450/400 load data differences

[Russ16]

Starting to load for my 450/400. Shooting The British Double suggests loads of 75-76 grains of H4350. This is significantly higher than what Hornady lists in their manual capping out at 70.9 grains.

I’m used to seeing some variation between manuals but this seems quite large. Any thoughts or experience that you’ve had success with?

 

[Mark A Ouellette]

@Russ16 You didn't list the projectile...
For what it's worth, here is Quick Load for a .410 400 Gr Hornady DGX at 70.9 gr H4350

These charts use the Quick Load default settings for this cartridge

This chart uses a powder charge of 76 gr

Perhaps the 70.9 gr charge was meant for the oldest rifles. This load may have matched the Cordite loads. That's only a guess...

 

[Russ16]

Sorry 400 grain bullets. Hornady is obviously for their DGX and DGS. Graham doesn’t specify the bullet only the weight.