01-18-2020, 06:47 PM
Hi folks, I need some help with developing a subsonic cast bullet load for the grendel. I'm on a budget, so i'd like to avoid the hornady 160 RN, and preferably cast my own. I recently bought a lee 170gn gas checked "cruise missile" mold from midsouth shooter's supply. I'll be shooting these through a 24" 1:8 twist barrel that's cut with a grendel II parallel throat chamber and a .264 groove diameter from BCA. As is, this is a 1.5MOA gun with 123gn hornady commercial loads and my goofy ass pulling the trigger. I have a good supply of pure lead, wheel weights, tin, and hard magnum bird shot, so getting a sufficiently hard alloy should be no problem. I'll probably be using hornady brass, and the powders I currently have available are IMR3031, trail boss, and LILgun. I'd happily buy another powder if need be.
so far from a few weeks of deep diving the forums here, on the cast boolits site and a few others, my plans include casting the bullets in a 15-20 bhn alloy, annealing, sizing to .265, powder coating up a thou or two, and then size again while seating a gas check. Then I plan to heat-treat, and water quench to get my hardness back, as well as to further bond the Gas check to the shank by re-melting the powder coat under the gas check during the heat-treat. I intend to seat the bullets out to just touch the lands, which I realize may involve quite a bit of bullet shank intruding past the case neck into the powder space...hence the extra step to bond the gas check with re-melted powder coat.
My first load attempts will likely be a calculated 95% fill of trail boss, and then working down a few tenths at a time if I'm still supersonic, not to drop below 70% fill, per Hodgdon's dire warnings. I know there are probably much better powders for this application, but published load data for this bullet in the grendel case is non-existant. I've heard that some shotgun powders like unique, red dot, etc. are useful in this type of application, but I don't have Quick-load software, so it's all speculation to me.
Hopefully some of you guys can shed some light on any stupid mistakes in my plans. I'm not looking for pinpoint accuracy, 2MOA would do nicely out to 100 yards. These will be plinking and short range varmint loads, so reliable expansion isn't really high on my list. Furthermore, cycling the action isn't a huge priority to me. This is not a rifle intended for hunting or serious defensive use...just for funsies.
I also have found through my research on the cast boolits site that in a 1:8 twist swedish mauser barrel, this bullet seems to have a 1700fps velocity limit, but guys are using a ton of filler with fast rifle powders in a 6.5X55 case to get those speeds...however, any questions about those loads return a veritable raft of $hitposting and bickering. Seems to me that the smaller case capacity of the grendel would be a tidy solution to that problem, so as a secondary objective an action cycling moderate velocity supersonic load would be cool too, but that's not really why I got this mold.
Thanks in advance for any light you can shed on the situation!
so far from a few weeks of deep diving the forums here, on the cast boolits site and a few others, my plans include casting the bullets in a 15-20 bhn alloy, annealing, sizing to .265, powder coating up a thou or two, and then size again while seating a gas check. Then I plan to heat-treat, and water quench to get my hardness back, as well as to further bond the Gas check to the shank by re-melting the powder coat under the gas check during the heat-treat. I intend to seat the bullets out to just touch the lands, which I realize may involve quite a bit of bullet shank intruding past the case neck into the powder space...hence the extra step to bond the gas check with re-melted powder coat.
My first load attempts will likely be a calculated 95% fill of trail boss, and then working down a few tenths at a time if I'm still supersonic, not to drop below 70% fill, per Hodgdon's dire warnings. I know there are probably much better powders for this application, but published load data for this bullet in the grendel case is non-existant. I've heard that some shotgun powders like unique, red dot, etc. are useful in this type of application, but I don't have Quick-load software, so it's all speculation to me.
Hopefully some of you guys can shed some light on any stupid mistakes in my plans. I'm not looking for pinpoint accuracy, 2MOA would do nicely out to 100 yards. These will be plinking and short range varmint loads, so reliable expansion isn't really high on my list. Furthermore, cycling the action isn't a huge priority to me. This is not a rifle intended for hunting or serious defensive use...just for funsies.
I also have found through my research on the cast boolits site that in a 1:8 twist swedish mauser barrel, this bullet seems to have a 1700fps velocity limit, but guys are using a ton of filler with fast rifle powders in a 6.5X55 case to get those speeds...however, any questions about those loads return a veritable raft of $hitposting and bickering. Seems to me that the smaller case capacity of the grendel would be a tidy solution to that problem, so as a secondary objective an action cycling moderate velocity supersonic load would be cool too, but that's not really why I got this mold.
Thanks in advance for any light you can shed on the situation!