Question for Fiftydriver (or anyone else who might know)

[JKO]

I'm curious about something:

I've just looked at VihtaVuoriOy's website, and I noticed that their 20N29 is slower-burning than Hodgdon's H-870 (which I use in my .30 Cody Express), H-1000, and H50BMG.

Would anyone know how it compares to WC-872 (i.e., faster- or slower-burning), but more importantly, regarding pressures and sensitivity to changes in external temperatures?

Thanks.
--JKO

 

[Fiftydriver]

JKO,

You are combining two Vhita Vouri powders in your question. There is 24N21 which is ranked on most burn rate charges as about equal in burn rate as H-50BMG and then there is 20N29 which is the slowest canister powder we can get at this time.

Just to give you an example comparing 20N29 and WC872. I have tested both in my 338 Allen Mag with the 300 gr SMK. With 149.0 gr WC-872 I get right at 3475 fps but noticable primer cratering.

With 20N29 I use 152.0 gr to get the exact same velocity but pressure is significantly less as there is hardly a hint of primer cratering with this powder.

So it takes three grains more powder to reach the same velocity but pressure is much lower with 20N29. To get similiar pressure indications on the primer I would have to drop my WC872 load down to around 145 gr which would be in the 3400 fps range.

I would say that the VV powders are much better at handling temp changes compared to WC872 which is known for some pretty wide velocity shifts.

The main difference is cost, runs around $160+Haz shipping for 20N29 which is about 4 times what WC872 costs.

With all that said, I also want to say that I personally feel that 20N29 would be to slow burning for your 30 Cody unless you were using some extremely heavy bullets. The 240 gr SMK may work well but I would suspect it would still be on the slow side. Generally accuracy and velocity consistancy are very good but peak velocity will be lower.

From what I have seen in the 30-378 Wby which is nearly identical in performance to your Cody is that H-50BMG is very hard to beat with a +200 gr bullet.

I think you need to split the difference between H-50BMG and 20N29 and try something like US869 from Hodgdon. If your looking for better stability in temp changes compared to WC872 this would be the one to look at. Slightly faster burning but would still work very well in your Cody. Very dense powder as well so you can get alot of grains in the case!!

Just my opinion.

Kirby Allen(50)

 

[JKO]

Kirby:

Thanks.

I guess I should've rechecked my data before posting. /ubbthreads/images/graemlins/smile.gif

My original post has now been corrected.

--JKO