atl5029
04-11-2022, 02:49 PM
Hi All,
I've been MIA for quite a while, but back with a new potential cast application and questions.
I've been following the development of the new 8.6 Blackout round coming out this year and am very excited for it and am planning a build. If you have no idea what I am talking about, 8.6 is to 308 what 300 Blk is to 223. Like 300 Blk, it is built for both supersonic and subsonic loads. Supersonic bullet weights are in the 160-225 range for this cartridge, and while there are plenty of great hunting bullets out there, there are virtually no 338 target bullets out there in this weight range, just 250 and 300, which are used in subsonic loadings. This brings me to the possibility of making up some cast boolits for affordable practice rounds.
The problem comes in the standard twist for this round, which is 1:3. Yes, you read that correctly. Yes, that is faster than just about anything out there. Yes, it is required for what the cartridge is designed to do - sub MOA with 300 grain subsonic loads out to range, extreme terminal performance on game with supersonic loads from short barrels.
My obvious concern and question is whether a cast boolit is even capable of being shot out of such a fast twist barrel without coming apart or extreme leading. One thing the cartridge does have going for it, like the 300 Blk, is that in supersonic it is not extremely fast. 2000-2500 FPS depending on bullet weight.
My thoughts are since this is a target boolit, to cast something very hard, powder coat, and gas check it in order to (hopefully) properly engrave on the rifling without just shearing the bearing surface of the boolit off. Once it leaves he muzzle, it'll be doing extreme RPMs. I would think a well made CB, being all one material, would hold together under even extreme RPMs.
I may also run this same CB in my 338 RCM with a 1:6.5 twist. The twist is not as extreme, but it'll be going significantly faster.
To those who may have any insight into this, what are your thoughts? I know some people run 1:5 300 Blk barrels. Any advice on creating a CB up to my requirements for 8.6?
I've been MIA for quite a while, but back with a new potential cast application and questions.
I've been following the development of the new 8.6 Blackout round coming out this year and am very excited for it and am planning a build. If you have no idea what I am talking about, 8.6 is to 308 what 300 Blk is to 223. Like 300 Blk, it is built for both supersonic and subsonic loads. Supersonic bullet weights are in the 160-225 range for this cartridge, and while there are plenty of great hunting bullets out there, there are virtually no 338 target bullets out there in this weight range, just 250 and 300, which are used in subsonic loadings. This brings me to the possibility of making up some cast boolits for affordable practice rounds.
The problem comes in the standard twist for this round, which is 1:3. Yes, you read that correctly. Yes, that is faster than just about anything out there. Yes, it is required for what the cartridge is designed to do - sub MOA with 300 grain subsonic loads out to range, extreme terminal performance on game with supersonic loads from short barrels.
My obvious concern and question is whether a cast boolit is even capable of being shot out of such a fast twist barrel without coming apart or extreme leading. One thing the cartridge does have going for it, like the 300 Blk, is that in supersonic it is not extremely fast. 2000-2500 FPS depending on bullet weight.
My thoughts are since this is a target boolit, to cast something very hard, powder coat, and gas check it in order to (hopefully) properly engrave on the rifling without just shearing the bearing surface of the boolit off. Once it leaves he muzzle, it'll be doing extreme RPMs. I would think a well made CB, being all one material, would hold together under even extreme RPMs.
I may also run this same CB in my 338 RCM with a 1:6.5 twist. The twist is not as extreme, but it'll be going significantly faster.
To those who may have any insight into this, what are your thoughts? I know some people run 1:5 300 Blk barrels. Any advice on creating a CB up to my requirements for 8.6?