Reloading the 300 Blackout

[Deaf Smith]

Gang,

If I was to reload the .300 Blackout, would the Hornady .308 150 gr fmj slugs work well?

I'm thinking about standardizing one one weight and use 296 powder.

I also wonder if the canniur on the FMJ slugs are needed for the blackout.

Thanks,

Deaf

 

[mstreddy]

I haven't used the Hornadys, but I've used generic 147 and 150 gr FMJ bullets. What I have found is that to get the suggested lengths, the cannelure is typically above the mouth. In general you don't want the length too short as they may not feed well in AR platforms if too short.

Try them out. They should work just fine for you.

 

[Walkalong]

They will work just fine. I use a light modified roll crimp into the cannelure.

Here is a pulled (Argentine I think) 147 with the crimp groove.

I bought some blemished 150 Gr FMJ bullets from Midway and believe they were Hornady. I crimped them into the cannelure. I also bought some other unknown 147 or 150 Gr bullets and loaded them the same way. They make good plinkers if you can find them for a good price.

 

[rg1]

Haven't shot any Hornady 150 FMJ's but I shoot M80 147 FMJ's with H110/Win 296 powder. No problems with 147's and they shoot well in my AR 300 Blackout. Hornady tested in a 16" SW AR using Hornady brass and WSR primers. They tested at an oal at 2.220" but info I've read is that 2.065" is a good length for feeding from AR magazines. What I've read is to measure the bullet ogive where it's diameter is .250" and mark the bullet at that point. Align that mark with the bump on the inside of the AR mag and that will give best feeding from magazines.
Hornady in the 9th Edition lists 296 powder and the 150 FMJ to start at 12.7 grains for 1500 fps----13.8-1600----14.9-1700----and maximum at 16.0 grains for 1800 fps. Some loaders list a little higher but be careful going above 16 grains. Lake City LC .223 brass has been the best cases to convert that I've tried. Make sure the neck of the loaded 300 BLK round is .334" or less or it might be too tight in the chamber and cause pressure to spike. Have fun.

 

[CMV]

I'm getting best results for accuracy with 125gr Speer TNTs. Not real expensive compared to many popular 300 BLK bullets. They seem to work better out of my 16" 1:8 than the 110gr VMax, 125gr SST, or 125gr SMK. Haven't tried any 150gr bullets yet. Not really sure if I'm correct, but I'm thinking you want to stay on either end of the spectrum for 300 BLK - lighter .308 bullets for high velocity & the heaviest thing you can stabilize for subs.

Been playing around with MBC cast 245gr bullets for subs. Those are MUCH less expensive than 208gr AMax or 220 gr SMKs. They seem to work really well, but the last round of a magazine doesn't feed with them for some reason. Still playing with length to see if that resolves the odd behavior. A little better accuracy with 220gr SMKs, but I can afford to shoot the cast in bulk

296/H110 seems to work well. One thing I notice is mine are very sensitive to slight variations in powder charge. Maybe I'm just at a bad node, but the typical ± .1gr I get with a Lee Pro Auto Disk doesn't seem to bother my .223 loads at all & they group tight. That same variation seems to open up my 300 BLK groups & they'll tighten back up if I trickle each charge.

 

[Another_Kelley]

I also wonder if the cannelure on the FMJ slugs are needed for the blackout.

I like to crimp everything getting ran through an auto loader. A good crimp at the cannelure is going to be a nice insurance against inadvertently chambering a 300blk cartridge in one of your 5.56 rifles... the lighter-weight bullets when uncrimped can actually set back into the case - fully chamber, compressing the powder - and we all know what happens next if the trigger is pulled.

 

[Elkins45]

I like to crimp everything getting ran through an auto loader. A good crimp at the cannelure is going to be a nice insurance against inadvertently chambering a 300blk cartridge in one of your 5.56 rifles... the lighter-weight bullets when uncrimped can actually set back into the case - fully chamber, compressing the powder - and we all know what happens next if the trigger is pulled.

I love this picture! The barrel held up much better than the receiver did in this case.

I have loaded some FMJ 147 pulls that I bought from Midway ages ago and they seem to work just fine. I think mine aren't seated all the way to the cannelure but I haven't had much trouble with setback or neck tension.

 

[ssyoumans]

I load all of my 147 & 150gr 300 Blackout loads to 2.140", but I have lightly filed the ribs in my Magpul mags that I use for 300 Blackout. For me, my FDE color magpul are for 300 Blackout.

15.6gr of W296 with LC 11 brass and WSR primers gave 1753 FPS with perfect functioning in my 8.5" CMMG barrel.

 

[bangswitch]

Gang,

If I was to reload the .300 Blackout, would the Hornady .308 150 gr fmj slugs work well?

I'm thinking about standardizing one one weight and use 296 powder.

I also wonder if the canniur on the FMJ slugs are needed for the blackout.

Thanks,

Deaf

They will work great, as will the Win296. I use mainly 125 gr. Nosler and 155 gr Palma Match King and use Win 296, but more often use either H110 or LilGun, because they give better velocities with 125's near max loads for that bullet size although they're pretty close for 155's. AA1680 is the go-to powder for heavy subs, 190 grains and up. I don't crimp anything I shoot and have never had any setback issues in either my AR Blackout, or my M1A. And you can chamber an uncrimped BLK round in a .223 chamber, depending on what C.O.L. you use. I tried it in a DISASSEMBLED .223 upper, and it seated all the way.The best way to prevent cross-loading is to use different type magazines and clearly mark them, since AR magazines will hold either cartridge without modification. I load my 125's and 155's to 2.150, and the few subs I load go 2.200.

You can get MV's around 1800 fps with W296 or H110 pushing 150's, and another 100 fps with LilGun. Doesn't sound all that fast, but it's good for silhouettes out to 300 yards.

BTW, a great source for brass is www.evergladesammo.com. Cut and resized 5.56 mostly LC milbrass, once fired. About $0.16/case

 

[oldpapps]

"If I was to reload the .300 Blackout, would the Hornady .308 150 gr fmj slugs work well?

I'm thinking about standardizing one one weight and use 296 powder.

I also wonder if the canniur on the FMJ slugs are needed for the blackout.

Thanks,

Deaf"

Lots of good info above.

In my tests I have found that any bullet weight from 110 to 220 with a suitable profile will feed, strip the next round and lock back on the last round, if the loading is built correctly.

I classify bullet weights for the BlackOut in three columns, 1) fast/hunting, 2) cheap/inexpensive, 3) sub-sonic/hunting. OK, all weights can work for hunting.

The 150 grain weight spread is a good one. Light enough to get a little speed, heavy enough to have penetration of those hard targets (pigs). But the right bullet must be picked. I have two 'standard' loading in this range, the first is in the cheap/inexpensive column, 147ish grain GI pulls pushed to 1945 FPS with H110 but for a little better accuracy to 1870 with Lt'Gun. These pulls (that I have) just don't get very good accuracy and every weapon will perform differently. I also run 150 grain Interbond at 1908 FPS, H110, with excellent accuracy out of my 16 inch carbine gassed and buffered weapon.

Now turning to the canniur question (I never remember how to spell that word). I ignore them. I prefer a tight case grip and use a LEE Factory Crimp DIE as a final step in the loading process. I tried an experiment, chambering a .300 Blackout in a .223/5.56 chamber. The bolt didn't go into full battery and couldn't fire. I had the devil of a time getting that round out, it was inert for safety sake. I used a 110 grain V-Max bullet.

And to your FMJ choice. For paper targets, no problem. For 4 footed targets, I don't think this is the correct choice.

My test with heavy/er slugs. I don't shoot sub-sonics and haven't found anything I liked with 180ish to 220ish weights. With lesser slugs, I like the 110 range (when I can find them). I'm pushing 130 grain cast lead powder coated at 2144 FPS and am impressed with the preliminary accuracy I'm getting.

I don't expect the same degree of precession accuracy with my 300 Black with standard GI trigger group and I get from my .223 Wilde 20 inch HB with great trigger. But then, I didn't build it for the same uses.