Sierra 125 SPT
 

Sierra Reloading manual shows Maximum load with AA#5 for a 125 gr. SPT to be 12.6gr. This produces 1800 fps out of a 10" Contender. Is this Maximum load based on pressure capacity of 221 Fireball brass or the contender frame? I ask because I have some #5 and I wanted to load up some hot rounds but I'd like to get at least 2200fps. 12.6gr is not a lot of powder. Bad idea?

I would not think the limit is the contender frame when you think of some of the loads that people stuff through them.....I would think it was based on pressure curve for the powder and case cap.:smile:

AA#5 is a bit too fast for the 300-221 Fireball*. A better choice of powder would be AA#9, H110, LilGun or W296. I have had the best results with W296.


I have posted some of the loads that I have worked up for the 300-221 Fireball here:

http://www.reloadersnest.com/frontpa...?CaliberID=135

Here are some results for H110

http://www.reloadersnest.com/unverif...ID=135&ID=3213


*Note: the 300-221 Fireball, 300 Whisper and 300 Blackout are all pretty much the same cartridge, with only slight variations in the neck dimension.

320pf

I found it.
52,000 for 221 Fireball brass
55,000 for 223 Rem Brass

So yeah AA#5 would be too fast with the 125s. But it does work beautifully in contender with 6grs under a 240 SMK.