Why Better as cast

[megasupermagnum]

H110 is not a powder I would use for this. It does one job, it is a full power magnum handgun powder, and it does it well. Outside of that, I would move on. Something like Blue dot or 2400 work well with reduced loads, and may be slow enough to keep the port pressure up. I can't help with 300 blackout specifically, I've never mess with one.

[sutherpride59]

H110 is not a powder I would use for this. It does one job, it is a full power magnum handgun powder, and it does it well. Outside of that, I would move on. Something like Blue dot or 2400 work well with reduced loads, and may be slow enough to keep the port pressure up. I can't help with 300 blackout specifically, I've never mess with one.

Well for 300 blackout in an AR people use little gun, CFE BLK, accurate 1680, H110, H4198, and a slim few others that will produce enough gas but stay at a low enough pressure. In a bolt gun they use whatever the heck they feel like just about lol. H110 was giving me better accuracy but both were having velocity issues. I could try H4198 but I don’t remember anyone having great luck with it and my initial super sonic tests didn’t show it to be a good fit for this rifle in the accuracy or cycling department.

[charlie b]

Glad you tracked the velocity vs impact point. At these low velocities a 100fps difference (10%) can result in the differences. I noticed similar when using subsonic loads in my .308 (I am not worried about cycling a gas gun so I use Blue Dot). When shooting at higher velocities the drop difference is much less (5% or less).

Which boats were you on? Son was on the Acushnet and Boutwell back in the 90's.

[sutherpride59]

Oh cool so he was over in ba-ha-rain lol. I was on the decisive out of Pascagoula MS, the Middget out of Seattle, and the Blackpowder in Kingsbay GA (MFPU blocking vessel). I’ve made some trail boss loads but don’t want to mess with the pistol powders too much. The velocity drop might just be something I have to live with. I know playing around with it a couple of weeks ago holding the gun up then aiming down on target resulted in more consistent velocities so I think these powders due to full amount are a bit position sensitive. I’ll shoot with filler tomorrow and that would confirm it. If I have to add filler for hunting rounds I can be ok with that. Range pews just won’t have any.

[MaxJon]

Fillers are unnecessary, to me it's all about the right powder choice...

[charlie b]

Oh cool so he was over in ba-ha-rain lol. I was on the decisive out of Pascagoula MS, the Middget out of Seattle, and the Blackpowder in Kingsbay GA (MFPU blocking vessel).

No, he was on the Acushnet at that time in Eureka, CA. Got out when they sent it to Alaska.

He was warned by the Chief of Boat that if they every painted the Boutwell grey it was time to punch out

I agree with above about finding the right powder. Does anyone know what the original BO powder was? After all it was designed as a subsonic cartridge.

[sutherpride59]

Well that’s just it for subs everyone is using those choices that I listed, the most prevalent is 1680 but that and CFE BLK are almost identical but I just realized today that I missed a big step in referencing reloading data, the load data calls for magnum primers. As I read many folks getting erratic velocities with subs weren’t using magnum primers so I’ll try to pick up a box today after shooting if nothing I did fixed my problem.

[MT Chambers]

southern pride beat me to it, nose down on a Star and your worries are over.

[MaxJon]

Less is more.....minimal bumping/sizing/distorting, betweeen the mold and chamber the better, regardless of sizing method I believe.

[1hole]

By the time any bullet fully enters the bore it's precisely sized to fit that bore.

-----------------------------------------------
Southern Pride: Ah, Kings Bay and Camden County, GA ... and memories.

I lived in Kingsland from 1953-1956. There was no Kings Bay then; St. Marys, Kingsland and Woodbine were the "population centers" of sparsely inhabited Camden County, GA, and even combined they didn't amount to much.

Woodbine had both of the black/white consolidated high schools for the whole county. The black high school was near new, very nice brick buildings, while the white school was a ramshackled old frame and clapboard siding structure. Our's was grades 8-12 and it still only had a total of about 500 students. Then came the U.S. Navy @ Kings Bay, a wad of nuke submarines, a bigger wad of people and the population exploded.

I still pass through Kingsland on I-95/U.S. 17 once or twice a year. The old towns and schools are gone. Much of the old "woods" is now filled with modern yankees with all their lust for more goobbermint controls and higher taxes, clumps of people with odd accents mostly living in HOA rule controlled swarms.

I remember that a few of us boys had access to .22 rifles in those days. For about $.35 we could pool our nickles and dimes to buy a box or two of ammo from the Western Auto store (without raised eyebrows or questions). Everyone had a balloon tired American bike and we would pedal down some dirt side road far into the woods and shoot it.

There's nothing left that I can recognise now but Camden County, GA, was once a very good place for southern boys to grow up .... while it lasted.

[sutherpride59]

That’s pretty neat I always wondered about the history of that old town and how it used to be. I loved living in Kingsland but I’m glad I’m back in Texas, gods country.

DISCLAIMER: These are my results I don’t wish to argue about my findings or my methods. Advice is welcome.

I just wanted to make a post wrapping this whole ordeal up because I hate reading threads that never have a conclusion added and wondering what the results were. For my gun unsized ended up working just as well as the boolits sized to .312 even though my bore is indeed .3081. I believe it has more to do with needing to build good pressure in these subsonics rounds more than barrel fitment, also doesn’t help that they are 9bhn so very soft. My final load ended being .312 gaschecked NOE 311299 205 grain projectiles, .311 Noe expander to open the cases, seated with the drive bands just below the case mouth and max crimp, all over 9.1 grains of H110(w296) with CCI small rifle primers.

Things that didn’t work Or made no difference: Dacron filler opened up the groups to 3 times the size and should not be used in a gas gun as it was DIRTY AS HELL, minimum crimp lead to bigger groups and increased velocity spread(Soft lead and little case fill you need more pressure), sorting brass between factory and converted brass didn’t make a noticeable difference, magnum primers didn’t remedy velocity Inconsistency issues But shrunk the groups a tiny amount(probably more of luck than an actual gain, not enough to buy more of them), Gas check prevents leading of the suppressor completely but at these speeds didn’t make the accuracy any better, H110 vs CFE blk both performed about the same with H110 making tighter groups and I didn’t need the extra gas from CFE to cycle the gun so H110 will be the choice powder.

Still getting inconsistent velocity but I’ll play around more with that in time and it doesn’t pertain to the original post. If I find anything that really helps I’ll make a new thread and post it. Might even take the time and do a write up on it.