I loaded 10 only cartridges using the 135gr Lead Spire Point bullets mentioned earlier. I loaded them to approximately 2150fps using 18.5gr of H110. I used these rounds strictly for testing for proper function, signs of over pressure and ejecting issues. After the first 5 rounds passed all my tests and rang my gong at 100yds I tried shooting the last 5 at my 50yd target. I got a 2"-3" group. Considering I found lead bullets don't group as well over 2100fps as they do under that speed, I think I might see better groups by reducing the charge. So my first attempt at using supersonic lead loads in my 300 BLK looks promising. I'll update this later as I gain more data.

I loaded 10 only cartridges using the 135gr Lead Spire Point bullets mentioned earlier. I loaded them to approximately 2150fps using 18.5gr of H110. I used these rounds strictly for testing for proper function, signs of over pressure and ejecting issues. After the first 5 rounds passed all my tests and rang my gong at 100yds I tried shooting the last 5 at my 50yd target. I got a 2"-3" group. Considering I found lead bullets don't group as well over 2100fps as they do under that speed, I think I might see better groups by reducing the charge. So my first attempt at using supersonic lead loads in my 300 BLK looks promising. I'll update this later as I gain more data.

That's pretty hot. I hope you get better accuracy with lighter loads. What barrel are you using? What rate of twist?

That's pretty hot. I hope you get better accuracy with lighter loads. What barrel are you using? What rate of twist?

Yes, I was wondering that too.  Twist for heavier (longer) bullet, going at reduced speeds, would need to be pretty quick.  1:7 1:8?

That's pretty hot. I hope you get better accuracy with lighter loads. What barrel are you using? What rate of twist?

I have a CMMG 16" barrel with a 1 in 7 twist. I get excellent accuracy using 125gr - 130gr with 17.0gr to 17.5gr of H110.

I use the Missouri bullets 245's and the Palmetto 203's with no problems in my AR

I finally was able to load and shoot for accurracy some loads using the 132gr Lead Spire Point using 17.0gr of H110 netted a 2" group at 50yds. Disappointing to say the least. I got 3" at 100yds. The rifle is capable of 1" groups with jacketed bullets. I was hoping for 1" at 50 and 2" at 100. I think I am pushing the bullet too fast and H110 is not known as a good powder to use with lead.

Thanks to Old Mose as he turned me on to the Lyman AR Cartridge Reloading Manual. The manual has 2 loads for the 300 BLK using lead bullets. This is the first published Blackout loads using lead bullets that I have seen. The two bullets used weighed 160grs and 180grs. It just so happens I have a good supply of .308 (Sized .309) lead bullets in 166grs and 180grs. As far as powders are concerned it turns out I have two of the recommended powders. Those two are H4198 (I have IMR 4198 which is next to H4198 on the burn rate chart) and H335. I have a ton of H335 and it listed the most accurate load with the H335. So here is what I loaded using H335:

I will let everyone know how these shoot.

I was finally able to get to the range with some of my new reloads a few weeks ago.

I was able to shoot 166 grain LRN bullet sized to .309. I had a starting load of 15.5 grains of H335 and went up to 20.0 grains. The OAL was 2.100". I had absolutely no FTF or FTE with any of these loads. I started seeing pressure signs at 18.0 grains and stopped at 18.5 grains. At 18.5 grains I was getting nice just barely sub 1" groups. I took apart the remaining rounds as I didn't want to take the pressure signs any farther. I may get even better accuracy out of the 19.0 grain loads but I decided I was happy with what I got from 18.5 grains.

Next is 185 grain LRNFP sized to .309 using H335.