.300 blackout boolit

[Krh1326]

Hi All…

My son has recently acquired a .300 BO , in AR platform.
I am gearing up to reload cast, for him. We have no “need” to run subsonic loads, as we are not allowed suppressors. So I believe I’m looking at supersonic only, unless I’m missing another aspect of it.

I have the dies, I have H335 and I do have H110. I have the brass and primers. I even have some of the molds, that I see are popular here. I have Lee C312-155-2R that I plan to use, as I see many here love it. I also happen to have Lee C309-170-F & C309-180-R , and I see some like them , as well. I also have the Lee TL309-230-5R.
Are the heavier Lee 230 and, say , something like MP’s 311-235’s for subsonic? Or do you guys load them and let’em rip?

Thanks for helping me get started. I plan on going with the 155’s first, but am real curious about the big heavies.

[ShooterAZ]

The Lee C312-155 is a winner in my Bushmaster 300BLK upper with supersonic loads. The C309-170F shot really well too, but it didn't feed very reliably for me. I've not seen any 300BLK data using H335? I'm thinking it's probably going to be too slow of a powder. The heavies are most commonly used for the subsonic loads. I hope this helps...

[imashooter2]

The Lee C309-150-F fed in my AR, but the lugs really tore up the boolit noses. I stick with the C312-155-2R. H335 is too slow. Stick with powders between Alliant 2400 (I’ve only seen data for lightweights) and H4198. I like IMR 4227 for the Lee 155s.

[Krh1326]

I found this data, in Lyman’s AR Reloading Handbook 2nd Edition.
Do you guys think it’s incorrect, or even a misprint?
I planned on using the 160 data ( on left ) for the 155, and the 180 data ( on right ) for both the 170F and 180R. I was counting on the H335, as I use it for my .223 and .35 Rem, as well as brother’s .308 Win. I bought an 8 lb jug, direct from Hodgdon.

[Krh1326]

[Krh1326]

[Krh1326]

[Krh1326]

May I ask, with the 312-155…. What your AR col came out to? I will tune my col, to work his specific rifle, but just looking for a starting point.

Sorry about using multiple posts, for those pics… I’m not computer friendly, and my relic is running wonky, only way I could get pics to go.

[imashooter2]

My C312-155-2R weighs 157 grains lubed and checked, cast from a hard 92-6-2 alloy. They drop at .314 and I size them to .310 and load to an overall length of 2.020 inch which is right to the edge of the driving bands.

In my 16 inch AR, 14.5 grains of IMR 4227 gets 1,733 fps average.

I won’t say the published data is wrong. I’ll just say that this is the first time I’ve ever seen an H335 published load and I’ve never seen anyone anywhere recommend powders as slow as H335. It’s also a lot of powder for not much velocity. I wonder if it will make the gas to reliably function the bolt?

Regardless, I doubt you can get enough H335 into the case to blow up your rifle. Blaze the trail!

[imashooter2]

Here’s some data from Sierra…
https://sierrabullets.files.wordpres...t-03052018.pdf

[Krh1326]

I thank you sir. I just had my doubts, too, when you mentioned cycling the bolt. I thought , maybe I just found data for a bolt gun, and panicked… but then remembered it’s AR Reloading Handbook, lol.
Still doesn’t mean they are right…

[imashooter2]

Please report back with your results. Inquiring minds want to know!

[Krh1326]

Son had a good day with his .300 blackout
The Lee 155 grs loaded with 15.3 H110 worked flawlessly.
But now for the reason for follow up:
Lee 155 gr over 18 grs H335 worked flawlessly, as well. He DID NOT have a chrono available, so cannot give that data, but performed on target the same as the H110 loads.

This rifle is new to him ( Ruger AR 556 in 300 Blk ) and he was trying to install and zero a new red dot…. First time firing it…. 50 yards and less.

But still no FTF , cycles normally , locks bolt back . The data in Lyman’s AR Book that I listed up there ^ still has lots of room to increase his H335 load, when he has access to chrono.

[WinchesterM1]

I just got back from the range with my Ruger ranch rifle in 300blk with the Nikon 2-7 blackout scope at 75 yards I shot a 5 round group in the same hole with the NOE-130rn sized to .309 PC/GC over 12.8 of H110

[imashooter2]

Son had a good day with his .300 blackout
The Lee 155 grs loaded with 15.3 H110 worked flawlessly.
But now for the reason for follow up:
Lee 155 gr over 18 grs H335 worked flawlessly, as well. He DID NOT have a chrono available, so cannot give that data, but performed on target the same as the H110 loads.

This rifle is new to him ( Ruger AR 556 in 300 Blk ) and he was trying to install and zero a new red dot…. First time firing it…. 50 yards and less.

But still no FTF , cycles normally , locks bolt back . The data in Lyman’s AR Book that I listed up there ^ still has lots of room to increase his H335 load, when he has access to chrono.

Nice! Glad to hear it. Another arrow in the quiver!

[Krh1326]

Nice! Glad to hear it. Another arrow in the quiver!

Absolutely ! Not even my rifle… sons. He’s now using my .223 brass, my wsr primers…. I stocked up 8 lbs of H335 for .223/ .308 win / .35 Rem ….. but I only haz 3/4 lb H110 for my .357 mag. For him to be able to run H335 saves my H110.

[Krh1326]

I just got back from the range with my Ruger ranch rifle in 300blk with the Nikon 2-7 blackout scope at 75 yards I shot a 5 round group in the same hole with the NOE-130rn sized to .309 PC/GC over 12.8 of H110

Is that the same as my Mini 14 - 5.56 NATO, just chambered in .300 Blk ? That sounds awesome… love love love my Mini 14. It’s never on anyones radar.

[imashooter2]

The Mini 14 was excluded by name from the latest ban try.

[P Flados]

I tried WC 844 (the Milsurp version of H335) in a 300 BO AR and found it ran very dirty.

At first it was ok, but pretty quick it was fouling up the bolt pretty bad. Also, sometimes residue in the chamber would not let the action fully go into battery.

[WinchesterM1]

Is that the same as my Mini 14 - 5.56 NATO, just chambered in .300 Blk ? That sounds awesome… love love love my Mini 14. It’s never on anyones radar.

No it is not, I have one of those though! Fun rifle!!

No this is the little 16” bolt action that takes AR mags