Another 300 black out question

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Jonny2guns

Jonny2guns

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So I ordered some cast bullets from Brazo 215gr. fn because I want to load some sub sonic without spending $1.80/rnd like with jacketed. But I have not been able to find any load data for cast bullets in the 300BO.
I would like to use CFE BLK powder.
Where do you find reload data for cast bullets in newer cartridges? Screenshot_20210528-060805.png
 
Jonny2guns said:
So I ordered some cast bullets from Brazo 215gr. fn because I want to load some sub sonic without spending $1.80/rnd like with jacketed. But I have not been able to find any load data for cast bullets in the 300BO.
I would like to use CFE BLK powder.
Where do you find reload data for cast bullets in newer cartridges?View attachment 1001152
Click to expand...
I would use data in a like weight of jacketed. Maybe back off 1/2 a grain. Good thing about subs are that they usually run no more than 25k psi. So there's forgiveness.
 
Fwiw, my cousin and I both tried those bullets in our sbr's, and we could not get them to feed. Loaded the long, short, hot, mild, gas block wide open, gas block restricted, nothing ran. The brazos guys sent me 10 loaded rounds that work in their guns, and they wouldn't run either. I gave them to a buddy who loads them in a 308 bolt gun, and they work great for him.

Hopefully you have better luck. I run a 150 grn lee round nose 30-30 bullet in mine now at about 1450 fps.
 
greyling22 said:
Fwiw, my cousin and I both tried those bullets in our sbr's, and we could not get them to feed. Loaded the long, short, hot, mild, gas block wide open, gas block restricted, nothing ran. The brazos guys sent me 10 loaded rounds that work in their guns, and they wouldn't run either. I gave them to a buddy who loads them in a 308 bolt gun, and they work great for him.

Hopefully you have better luck. I run a 150 grn lee round nose 30-30 bullet in mine now at about 1450 fps.
Click to expand...
The OPs uploaded picture shows a profile that looks similar to MBCs 245 gr. BLK bullet. The 245 gr. I seat to an OAL of 2.100". They feed reliably in the 2 AR pistols I have.
But maybe the nose is more blunt with the 215 gr.
 
Try Berry's 220gr plated spire point. You can get them for less that $.30 a bullet in quantity. The are clean and feed well.
 
I have never had any luck with the MBC or Acme profiles in 3 different ARs. They feed and function perfectly in my bolt action though...

I was having a separate but similar issue with a couple of the AR barrels feeding coated or lead bullets. I switched to plated and they now feed just fine.
 
Havok7416 said:
I have never had any luck with the MBC or Acme profiles in 3 different ARs. They feed and function perfectly in my bolt action though...

I was having a separate but similar issue with a couple of the AR barrels feeding coated or lead bullets. I switched to plated and they now feed just fine.
Click to expand...
I know you said 3 different ARs, but could it be a feed ramp issue will all 3?
 
kcofohio said:
I know you said 3 different ARs, but could it be a feed ramp issue will all 3?
Click to expand...
It could indeed be a feed ramp and in fact that is the most likely explanation. The trouble is the ramp is part of the barrel and the only practical way to address that is to replace the barrel or the bullets. At one point I looked into having the hump in the feed ramp ground off, but once I got plated (and jacketed) bullets to work I dropped that idea like a hot rock.

The only downside to plated bullets is that they cost a bit more than coated. Once I crunched the numbers I realized I don't shoot enough Blackout for that to be a serious issue.
 
I run quite a few hi-tek coated cast bullets from Gallant/Miss Bullet Company, and a couple of other places. I load the Gallant 217 BTs at 2.12, with between 10 and 12 grains of RL7 depending on which of my ARs I'm loading for (I have from 7.5 to 10 inch barrels). ~ 11 grains will function 100% with a can on any of them......but without the can it's hard to get 100% cycling in the 7.5 and staying under 1100 fps in the 10 inch with the same load. I'd suggest for your gun, start at ~ 9 grains of RL7 and ~ 2.12 OAL, shoot ladders in .5 increments over a chrony until you get full function, including lock back on last round. So far, RL7 is hands down my favorite sub 300BLK powder, and as a positive note, it's one that isn't hard to find these days.
 
EricBu said:
I run quite a few hi-tek coated cast bullets from Gallant/Miss Bullet Company, and a couple of other places. I load the Gallant 217 BTs at 2.12, with between 10 and 12 grains of RL7 depending on which of my ARs I'm loading for (I have from 7.5 to 10 inch barrels). ~ 11 grains will function 100% with a can on any of them......but without the can it's hard to get 100% cycling in the 7.5 and staying under 1100 fps in the 10 inch with the same load. I'd suggest for your gun, start at ~ 9 grains of RL7 and ~ 2.12 OAL, shoot ladders in .5 increments over a chrony until you get full function, including lock back on last round. So far, RL7 is hands down my favorite sub 300BLK powder, and as a positive note, it's one that isn't hard to find these days.
Click to expand...


RL7 I have about 1/3 lb left and I haven't seen it available for over a year. However I did score 8lb of the CFE BLK the other day and it is specifically designed for the 300BO sub sonic.
 
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