So I see data for 200 gr jacketed, but not hard cast. I have access to Longshot and would like to use it. Can I use the data for the jacketed? Any data specifically for 200 gr hard cast and Longshot?
Thanks!
You should be fine using the jacketed data. Reduce by 10% and work up.
My experience has not been the same.
I'd reduce by 20% to start and go slowly. Lots of variables with hard-cast bullets that simply don't come into play with jacketed bullets.
Quote from: Muskrat on August 14 2020 09:07:15 PM MDT
My experience has not been the same.
I'd reduce by 20% to start and go slowly. Lots of variables with hard-cast bullets that simply don't come into play with jacketed bullets.
Thanks for the replies and advice.
Would that be mainly due to additional drag in the barrel? Any other variables you could describe? Any idea how much of that drag is countered by the Molly coating?
Cast bullets generally have less drag that jacketed bullets. But they have the potential to seal the bore more tightly, thus increasing pressure. If the barrel/bullet combination causes excessive leading, pressure can increase as more bullets are fired. The true diameter of the barrel and the bullet and the powder charge has a much greater influence on pressure with cast bullets than with jacketed bullets, and every barrel and bullet combination is unique.
It probably doesn't make a huge difference until you get to the top 10% of a load, but at that point things can change rapidly, and the built-in safety margin of published jacketed data is no longer working for you.
On the plus side, Longshot is a good powder for heavy cast bullets, and cast bullets are usually slightly shorter than jacketed bullets of the same weight, so at a standard COAL the cast bullet will fill less of the cartridge volume than a jacketed bullet, which reduces pressure.
I guess the whole point here is that you cannot use jacked load data for cast bullets and still have the same safety margin. Pressures might be about the same, or a bit higher, or quite a bit higher, depending on several factors...bullet and barrel diameter, bullet hardness, powder load, primer, crimping technique, etc..
So start low, use a chronograph, label and save your brass so you can compare the brass from load number one to the brass of loads two and three and four and five, and you'll figure out when to stop before anything blows up.
The loads might end up mirroring published data for jacketed bullets, or they might be quite a bit different. You won't know till you get there.
Muskrat's explanation is a spot on. Cast bullets obturate, expand into the rifling, better than jacketed bullets, typically. The use of a chronograph and checking your brass for pressure signs is paramount for a safe load workup. I haven't loaded LongShot with cast bullets, but with jacketed bullets I haven't seen any surprise pressure spikes at or near the top end. It should work very well.
Quote from: Muskrat on August 15 2020 10:37:53 PM MDT
Cast bullets generally have less drag that jacketed bullets. But they have the potential to seal the bore more tightly, thus increasing pressure. If the barrel/bullet combination causes excessive leading, pressure can increase as more bullets are fired. The true diameter of the barrel and the bullet and the powder charge has a much greater influence on pressure with cast bullets than with jacketed bullets, and every barrel and bullet combination is unique.
It probably doesn't make a huge difference until you get to the top 10% of a load, but at that point things can change rapidly, and the built-in safety margin of published jacketed data is no longer working for you.
On the plus side, Longshot is a good powder for heavy cast bullets, and cast bullets are usually slightly shorter than jacketed bullets of the same weight, so at a standard COAL the cast bullet will fill less of the cartridge volume than a jacketed bullet, which reduces pressure.
I guess the whole point here is that you cannot use jacked load data for cast bullets and still have the same safety margin. Pressures might be about the same, or a bit higher, or quite a bit higher, depending on several factors...bullet and barrel diameter, bullet hardness, powder load, primer, crimping technique, etc..
So start low, use a chronograph, label and save your brass so you can compare the brass from load number one to the brass of loads two and three and four and five, and you'll figure out when to stop before anything blows up.
The loads might end up mirroring published data for jacketed bullets, or they might be quite a bit different. You won't know till you get there.
Thank you for your time explaining. Thats good info.