H50 Bmg powder??
- Thread starter flyguy4
- Start date
Read my reply over on LRH.
You cannot use data for H50BMG with 20N29.
Cheers.
You cannot use data for H50BMG with 20N29.
Cheers.
I shoot 140gr H50bmg in a 338 Big Baer with a 300gr OTM at 4.250" and I needed 151gr of Vihtavuori 20N29 to reach the same velocity. Based on that, I'd start at 140gr of Vihtavuori 20N29 and work up if I were you.
A fully formed 338 Big Baer case from my chambers (I have two separate guns cut with the same reamer) holds 169.4gr H20 to the top of the case mouth. I believe that the capacity on the SnipeTac is slightly less, so take that into consideration.
A fully formed 338 Big Baer case from my chambers (I have two separate guns cut with the same reamer) holds 169.4gr H20 to the top of the case mouth. I believe that the capacity on the SnipeTac is slightly less, so take that into consideration.
rmr
Gold $$ Contributor
be careful with this substitution. 20n29 historically has varied quite a bit in burn rate from import lot to lot.
I've shot quite a bit of this powder over the years, (200lbs +) and the biggest lot difference was 13gns with a 50bmg. (825gn solid, 254gns N29, and the next import lot that I bought, the charge was 241gns!) the velocity was the same! (2710fps)
a chronograph is your friend here. Also be aware that N29 can be quite temperature sensitive.
I've shot quite a bit of this powder over the years, (200lbs +) and the biggest lot difference was 13gns with a 50bmg. (825gn solid, 254gns N29, and the next import lot that I bought, the charge was 241gns!) the velocity was the same! (2710fps)
a chronograph is your friend here. Also be aware that N29 can be quite temperature sensitive.
I did not understand? H50bmg you were using the same grns per load, but a different lot was 13 grn different? If that was what I understood, then when you start a new lot, do you back down some and test fire the first few rounds you load out of that lot? I use 141grn H50bmg on each round in my 338Snipetac. I sure thank you for your info, as I am not real experienced in reloading. Thank you.
LA50SHOOTER
Sworn To Protect The Constitution.
Another powder to consider is Allianz Reloder 50.
Start off at the Same charge weight as you were running or TWO percent below as was ran with H50 and work up. - Tune the powder charge for best accuracy working up in 0.3 grain increments.
Again this is not a substitute for the same burning rate. Reloder 50 is slightly slower in burn rate in the 50 bmg cartridge. - As was stated, the chronograph is your friend as is checking for signs of pressure.
In a very similar wildcat, based on the ChetTac case, I have ran equal amounts of both powders and Reloder 50 yielded slightly slower velocities.
Quick Load is another tool that is Very useful if you have access to it.
Start off at the Same charge weight as you were running or TWO percent below as was ran with H50 and work up. - Tune the powder charge for best accuracy working up in 0.3 grain increments.
Again this is not a substitute for the same burning rate. Reloder 50 is slightly slower in burn rate in the 50 bmg cartridge. - As was stated, the chronograph is your friend as is checking for signs of pressure.
In a very similar wildcat, based on the ChetTac case, I have ran equal amounts of both powders and Reloder 50 yielded slightly slower velocities.
Quick Load is another tool that is Very useful if you have access to it.
rmr
Gold $$ Contributor
H50 has been pretty consistent year to year. but I have to qualify that I have not shot a huge amount of it.
I have not used 20n29, or H50bmg in anything other than a 50bmg cartridge.
what I was trying to communicate is that 20n29 has significant burn rate differences from lot to lot. you must test each lot (chronograph) to see where it lands. things might be different with recent imports...but I would be careful with it.
with that, I will say that I much prefer 20n29 as a propellant for heavy projectiles in 50bmg.
I have not used 20n29, or H50bmg in anything other than a 50bmg cartridge.
what I was trying to communicate is that 20n29 has significant burn rate differences from lot to lot. you must test each lot (chronograph) to see where it lands. things might be different with recent imports...but I would be careful with it.
with that, I will say that I much prefer 20n29 as a propellant for heavy projectiles in 50bmg.
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