slow and surplus powders

[ought6plinker]

Hello Im trying to figure out burn rates and thermal stability of different current and surplus powders for over bore cartridges like 30-378 w/220+, 257stw etc. wc872 is a ball powder like very near old h870, aa8700 is a slightly faster ball powder? with us869 between those? 5010 I think is a stick powder(does that make it less heat sensitive?) and is h5010 better then imr5010? as far as i know50bmg is the only"extreme type" powder after retumbo but where does it and 5010 stand in burnrate compared to us869,872and8700??anyone have data using overbore stuff in 30"ish barrels with 5010 or 50bmg ,or comments on how they act so that my little mind can compare to my other data?? any info on wc860 or wc868?? ten question marks latter(sorry) I think kirby said he had powder bridging issues with 50bmg in the 257AM but retumbo was good in 257stw!so the question there is does a sharper shoulder 40vs25 make bridging problems worse?? whoa ok Im done Thanks

 

[brianwinzor]

I just looked up several of Kirbys old posts, and he reported powder bridging issues using Rl25 and HRetumbo in his 22/6mm AI (40) with the Wildcat 100 grain ULD.

So far (400 shots) I have used AR2225 (HRetumbo in US), AR 2218 (H50BMG in US), VihtN170, and H870, in my 224 Clark (22/257 AI with 30 degree shoulder) using the same bullet, and have never experienced powder bridging problems. I am unsure whether this actually proves that the shallower 30 degree shoulder is the reason, but it certainly appears that way.

Kirby also reported having powder bridging issues using slow burning extruded powders such as H50BMG in his 257AM. So far I have not experienced powder bridging in my 257Weatherby with the 156 grain Wildcat ULD using AR2225, AR2218, and H870, but have experienced the problem using Viht 20N29.

On burning rate I have found that AR2218 (H50BMG) is about 1 grain slower burning than H870, but unfortunately I have never had access here in Oz to aa8700, WC872, US869, IMR 5010, and H5010 so I am unable to comment based on personal experience. I hope the above is of some help. Regards, Brian.

 

[358sta]

No PM's. Guess I'll just post this in the thread.

I have some load info comparing some of the commercially available slow powders to several of the surplus ones. Its a portion of my load log done up in MS Word. I would be more than happy to email it to you if you want. Just shoot me an address. I will explain what I did if you're interested in the info. I don't want to re-type all of the info in your thread and feel you can come up with your own conclusions based on the data instead of me giving you mine.

 

[ought6plinker]

good morning PM sent-guess it worked thanks for the replies