265gr For .300 Blackout

LoonWulf said:

In my loads with 231 i used cotton as a case filler, and that helped with my velocity spread a bit, but yours are already better than i was getting.
I think bore fit may have more to do with accuracy since these are cast bullets. I got decent accuracy even with what seemed like inconsistent velocity.
The 245s were pretty tight in my gun, i managed to get one stuck about 4" from the muzzle so i tapped it out with a brass rod. Measured at the first band it was .308 and change according to my caliper, base bullet dia was .310ish, if i remeber correctly, again measured with the caliper.

Missed the 1.5@50, thats about what i was getting.

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That's a bit depressing that you stuck one. I'm not judging as I have stuck plenty of bullets - on purpose no less! But I will have to approach this with a fair degree of caution.

I sent off an email to Acme and they apparently forwarded my message on to a man named Gordon who it turns out is the designer of this particular bullet. We ended up talking on the phone for a good 15 minutes or better and he is quite the guy!

The 265gr bullet sold by Acme is designed around the .300 Blackout and IMR 4227 powder, although he did say others could be used. He gave me a starting charge of 10.0gr (4227) with the OAL at 2.10" (2.12" is apparently max for an AR mag). Apparently some experimentation DOWN as well as up from that charge may be required, but this is primarily to tighten groups up. With the 10.0gr charge, the bullet is likely to be supersonic from a 16" barrel, but I'm sure it can't be by much. At 2.13 to 2.16 OAL the groups tighten dramatically, but this would only apply for single-shot or single-loading.

He said he and his testers have put around 80,000 of these bullets downrange over 2 years of testing and they generally perform well and stabilize in 1:8 twist barrels best. Furthermore, shooters have reported getting 2 MOA using this bullet with no load development, which is encouraging.

All in all, it was a great conversation and I wish we could have talked all day! He is obviously very knowledgeable and friendly.

I went ahead and ordered 250 of these bullets to try out. I am pretty far behind on all my loading projects, but I'll try and get to these ASAP and post back here with results.

These came to $56 for 250 shipped by the way. That works put to 22.5 cents per bullet, which isn't terrible. If they work as planned, I'll be ordering a ton which will be better on overall shipping.

My order arrived today in the classic Acme (big) wooden box. The bullets are ridiculously long (pictured with a 9mm for comparision). Testing to follow.

I think Lee makes a 230gr mold, but I may be mistaken.

I freed up some time - by breaking some other reloading equipment - so I jumped on this project. I managed to load a total of 3 cases before I had to run out the door.

I had trouble with the coating and even some lead shaving off with all 3 bullets. I used two Lake City brass and one CBC/Magtech. You can't actually overseat the bullet with a proper load (10.0gr IMR 4227) because it compresses the powder and bottoms out.

I did have trouble getting my powder measure to drop the right charge, but I think I have a good fix for that. Unfortunately the limited time I had prevented me from swapping all the parts, so I was trying to hand charge the cases. This resulted in one case that had a low charge. I caught this when I went to measure the OAL - one case measured 2.07 instead of 2.10. Since the bullet can only seat deeper if less powder is in the case, this was an easy catch.

The good news: I contacted Gordon, the bullet designer. He told me he recommends RCBS dies for this bullet (I use Lee). He even offered to send his own die set to me!
He also said he has ordered a new set of molds slightly smaller and wanted to send me some to try.

So, minor hiccups but I think I will be able to get through them. For what it's worth, I intend to shoot the two bullets. I'll report back on how they do. With the length of the bullet I'm not that worried about some coating being missing.

Some hilarious pics for everyone below. Cartridges are .357, .30 Carbine, the 265gr monster, two loaded rounds and a .30-06.

And another with a 9mm case, .45 case, 150gr .308, and of course the loaded rounds and the big bullet.

Ok, update on the assembly disaster. Just for clarity, I use a Dillon 550 which flares pistol cases using the powder funnel. On a whim I put my .32 ACP powder funnel on the .300 Blackout toolhead, ran the powder die WAY out and proceeded to flare the case and drop the powder. I keep dropping erratic charges, which a quick look at my reference material revealed was due to using the wrong powder bar on the powder measure. I am now in business on the 265gr and will report back as soon as I can get a day off to go test everything!

My Dillon powder measures usually drop charges within .1gr. I'm not too worried about that. At 800 fps the coating shouldn't be too much of an issue, but with the .32 funnel I think I have that fixed.

Quick update: I got a handful of these rounds loaded up (and got the proper powder bar in the press). I can't get more than 4 rounds into a 30-round PMAG Gen2. There is a small nub at the front of the magazine that I think is designed to align .223 bullets. It doesn't go all the way down the mag though, so I could (and will eventually) grind it off and these should load just fine. I have a surplus 20-round aluminum mag laying around, so I tried them in that. They all loaded just fine into the mag although I did have to tap it on my bench to get all the rounds pushed to the back, but it does work.

For the 10 seconds it will take me with a Dremel I shouldn't need to reinvest in mags, but I'll certainly keep it in mind if my skills aren't what I remember!

Got about 50 of these things loaded up and went to test the mags. As I mentioned earlier, the PMAGs gave me trouble, but the Mil-Surp 20-rounder has plenty of room. I also have a single 30-round Hex mag, but I forgot to load it up. I intended to buy some more 20-rounders for bench shooting anyway.
The only reason I even as many 30 round mags as I did (10) was because they were $8/each. I need half or less for each size really.

Another_Kelley said:

Did Gordon say you can get way with simply using the standard 300AAC sizing die?... no mention of needing an aggressive chamfer, flare or utilizing a 7.62x39 expander ball to prevent shaving?

I'd love to see a picture - Does anyone feel like pulling a bullet out of a well chamfered case sized with a standard die and no flare?

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He mentioned modifying a 7.62x39 die for the ball expander IIRC. I resize using a standard BO resizing die.