500 SW Compressed Powder?

[Revolver]

I recently cast the boolits shown below, NOE 375 gr Spire Point. I am wanting to use 1680 powder. Accurate lists 43 grain as a starting load (47.5 gr max) for a 370 GR flat nose lead boolit. I realize that a spire point will have more boolit in the case than out, reducing the internal capacity, which I need advice on. As it stands 43 grains of 1680 would be a tight fit with this boolit, possibly even compressed.

Any advice on this spire point boolit and 1680 would welcome. Thank you.

http://www.doaks.net/projects/guns/sw500/NOE-501-375-SP.jpg

[Revolver]

No responses so I googled the heck out of it. I read on numerous forums that it is actually suggested to compress 1680, which makes me feel a little better since I know ever everything on the internet is true. I would however appreciate some input from the local experts here if possible. Or maybe i can get ahold of Accurate?

[Wayne Smith]

Absolutely get ahold of Accurate and query them. However, compressed loads are common and even listed as such in my Sierra manual and, I think, in my Lyman manual. The slower the powder the less to fear it.

[Revolver]

Thanks for replying, I sent an email to Accurate this morning.

[Revolver]

Just reporting back in case anyone else is interested. I have been emailing with a fellow named Scott from Accurate. Basically the 43 grains that was the starting load for the 370 gr Flat Nose is above max load for my boolit.

After giving him my spire point boolit specifications this is what said...

"I have calculated some loads using your bullet. 1680 is going to be very low on pressure due to usable case capacity; if you are after performance then you will want to use Accurate 4100."

Caliber: .500 S&W.
Barrel length: 8.37”

Powder: Accurate – 1680®.
Bullet weight: 375 grain Lead spire point. COL: 2.126”
Start Load: 38.5 grains (ca 1386 Fps) ca 23824 Psi
Maximum load: 42.8 grains (ca 1570 Fps) ca 32,731 Psi LD ca 116%

Powder: Accurate – 4100®.
Bullet weight: 375 grain Lead spire point. COL: 2.126”
Start Load: 35.2 grains (ca 1552 Fps) ca 34,251 Psi
Maximum load: 41.5 grains (ca 1838 Fps) ca 54,940 Psi LD ca 105%

[Revolver]

Ok, did some testing. First, here is what the guy from accurate calculated for this boolit based on the weight and dimensions of it (For 1680 powder)...

Start Load: 38.5 grains (ca 1386 Fps) ca 23824 Psi
Maximum load: 42.8 grains (ca 1570 Fps) ca 32,731 Psi LD ca 116%

I chrono'd 38.5 grains at 1236 fps. (150 fps slower than Accurate's calculation).
I chrono'd 40.0 grains at 1337 fps

So where do I go from here? How do I know how far to take it since my numbers don't match up to theirs?

Thank you.

[captain-03]

Man - I like that boolit -- wicked looking!! Got to find me one of those moulds ....

What exactly are you trying to achieve with that powder/boolit combination -- speed - accuracy, etc ... ?

1337fps w/375gr boolit ain't too shabby!!

[runfiverun]

you are getting 75 fps from 3/4 gr powder right now,or about 50 from a half grain that's pretty dang good.
you might be looking at a bbl length difference is all.
i'd just look for accuracy in the next grain or so and call it good.
unless i started seeing diminishing returns [like 20 fps from a half grain] then i'd stop.

[Revolver]

I guess I don't know what my goal is with this load. Just want something that goes boom for now. The 40 grains had some kick to it! I'll test the accuracy on it at 40 grains and go from there. I feel bad for all the pumpkins around here currently.