300AAC Subsonic load data sources

[DShortt]

I recently started shooting 300AAC in a bolt action rifle which is a completely new to me cartridge. I'm having trouble finding much load data for a bolt action with a 20" barrel. Can anyone point out a good source for me? I'd prefer a fairly wide selection of powders, bullets and primer combinations so hopefully I'll have at least a few components on hand.
Thanks for looking.

Before someone asks I have several reloading manuals but none are recent enough to contain 300AAC data.

 

[6Creed73]

I use the Hornady app. You can buy the whole thing or pay like 99 cents for individual calibers. Like with every other caliber the load data isn't absolute, I just use it as a starting point.

Here is an example for a 225gr bullet.

 

[Walt Krafft]

What twist is your barrel? If not 8 or faster you are probably wasting your time.

 

[Mike6158]

I'm new to .300 BLK too. I've got a load that I like so far. I want to shoot a hog with it to see how well the bullet works. I'm a fan of the Barnes TTSX bullets. Hopefully the Hornady SUB-X's work as well as the TTSX does. I'm trying the 190gr Hornady SUB-X's. Data came from the Hodgdon site 11.4 gr of Hodgdon H4198. I've got some CFE BLK. I may try that too. The rifle is a Ruger American. 7 twist. No LabRadar data yet. Once I get the can problem sorted out I'll spend some time on that.

The load I'm using now shoots great until I mount my can (Sandman-L). Something is out of whack. I've used a good quality alignment rod. I've watched Mike's video on concentricity. I'm pretty sure it's the suppressor because it does the same thing on an AR that is chambered in .300 BLK. But that's a different topic for a different time.

 

[DShortt]

What twist is your barrel? If not 8 or faster you are probably wasting your time.

It is a 1 in 8.

 

[Walt Krafft]

I suggest you buy some factory subsonic ammo to establish a baseline to reload too. SigSauer makes excellent 300BO ammo.

 

[dellet]

Welcome to no-mans land.

If you’re looking for Published 300 Blackout data for a 20” bolt action, I’ll save you some time, it doesn’t exist.

If you scour the european powders for 300 whisper, you will find some, but you’re not likely to have the powder. Maybe I’m wrong, but no too many people keep any Vectan/Noble sport around.

Hornady, Sierra, Vihtavouri and some of the old Accurate powder data is available online. Data that is not separated into sub/super is best. Data like Hodgdon, is problematic because the “subsonic data” is not related to pressure, Max load is capped at 1050 fps.

Most 300 Blackout data is geared toward AR’s and powder that will cycle the action. This leaves about 20 good powders used in something hand fed off the table. Look for 300 whisper data. It was geared more toward Contenders.

The current Sierra manual has both, the Whisper data is in the SSP load section, Single Shot Pistol. The SSP data is in many older manuals.

Note the 10” barrel and 1-10 twist.

Sierra .300 Whisper Loading Data | PDF | Cartridge (Firearms) | Rifle

The 300 Whisper cartridge was developed by J.D. Jones for subsonic use in military firearms like the M16 rifle. It is based on the 221 Remington case necked up to accept .30 caliber bullets. Load data is provided for 110, 125, 135, 150, 165, and 180 grain bullets using powders like AA9, H110...

www.scribd.com

Here’s Accurate number two in PDF.

Accurate Reloading Guide | PDF | Cartridge (Firearms) | Pistol And Rifle Cartridges

Accurate Arms Reloading Guide, Smokeless Powders L O A Number Two ® iii DISCLAIMER Accurate Arms Company, Inc. disclaims all possible liability for damages, including actual, incidental and consequential, resulting from reader usage of information or advice contained in this book. Use data and...

www.scribd.com

Now the problem you’ve got yourself into.

Subs and a 20” barrel will have some unique challenges. Almost all data out there will be for a 16” or shorter barrel. Depending on the bullet/powder combination the predicted velocity could be fast, could be slow. With supers you can pretty well depend on it getting faster with a longe barrel. You can’t count on that with subs. Fast burning powders with a heavy bullet and long bearing surface may start slowing down. You may actually need to increase charge weight over data.

Good news is that you can shoot any bullet from 85-265 grains subsonic. If you single feed there is no magazine length restriction and 308 Mauser bullets loaded around 1.700” OAL feed just as well as 250 grain Atips at 2.400”+. An AI magazine is your friend.

I shoot a 24” 1/10 twist, my only limitation for bullet length is about 1.5” with a plastic tip and 1.4” without. 208 AMax, 220 SMK both are stable to 300 yards. You 1/8 won’t leave many bullets on the table.

Quickload will be your friend in this project.

Lots to consider, “I need load data for a 22” 300 Blackout” is a really broad question. Consider the range of powders for a 220 grain sub will include AA#2, Bullsye and a couple Dot powders on the high end, LT 30, 4198 on the low end, you probably have something on the shelf that works well.

It’s a pretty deep rabbit hole if you like to tinker with loads. I found it very interesting and changed my thinking about some of the accepted norms of hand loading.

Don’t ignore supers, a 20” bolt action will bet a 150 grain bullet over 2300 and a 110 pushing 2800.

Hope that helps some. Narrow down your goals, can probably have more specific help.

 

[Walt Krafft]

Dellet listed many of the issues you may have. The SAAMI spec barrel length is 16". If you do not have a can, subs are kind of a waste of effort, they will still be loud from the muzzle blast. Your bolt action takes all the AR issues off the table. Depending on how much you plan on shooting and your desire to figure it out, factory ammo may be your best bet. The factories spend a lot of time and effort getting the Blackout to shoot reliably.

 

[Mike6158]

I can not recommend Gorilla ammo's subs ot supers (reason below). They shoot fine in a bolt gun, with or without a can (but why bother if you don't have a can as touched on above.

Failure to cycle in the AR happens too often with subs and not at all with supers, with or without a can. I haven't attempted to make any changes to the AR for the cycling issue. I can put a .223 upper back on it and it works fine.

The Gorilla ammo I bought uses Lake City brass. It's "once fired" "government" brass and most of the cases I recovered had crimped primers. I have a way to cut the crimp out but no swager. I don't need anything else added to case prep so I choose not to mess with it.

 

[DShortt]

Well, that's the conundrum I'm in. I have a bolt action with a 20" barrel I want to shoot subs in with a suppressor. I guess I might have to start with AR data because apparently I'm one of the few to see a use for a combination like this.

I appreciate the responses. At least I know I'm not missing an obvious answer.

 

[Steel Mover]

My, my....Just go to the source, the spring, where all this originated, look on the net for the data by J D Jones of SSK Industries on the 300 Whisper. 296 is H110 by it other name.

 

[dellet]

Well, that's the conundrum I'm in. I have a bolt action with a 20" barrel I want to shoot subs in with a suppressor. I guess I might have to start with AR data because apparently I'm one of the few to see a use for a combination like this.

I appreciate the responses. At least I know I'm not missing an obvious answer.

There’s a few out there, so you’re not alone. It just gets complex.
Do you want to safely shoot shoot tins cans and chipmunks in the backyard?
An 85 grain Mauser bullet and about 4 grains of trail boss. The neighbors will
Think the cat farted.

Maker bullets designed a 110 subsonic bullet that expands to about 3/4”

You want to poke holes in “bullet proof glass”?
A 240 SMK will do that at 1000 fps.

Target shoot at 200 yards, tough to beat a 175 SMK.

The other problem is you can have quiet, accurate or clean. Tough to get all three, but it can be done. 2/3 is easy.

Bullets known to work well through the trans-sonic range are good choices. You will be shooting right in the middle of it. Magnum primers for ball powders and off to the loading bench.

Honestly, the more you start thinking about the cartridge as having a multiple personality the better off you will be.

Here’s some SSK contender data that shows the powder spectrum a bit better.

https://www.sskfirearms.com/media/pdf/default/LoadDataCatalog.pdf

This is mostly light bullets but you will get the idea.

Light Weight subsonic Single Shot Loads » 300BlkTalk

N120 is a good powder to use. Hard to get in trouble with it. In a pinch use 1680 data and expect it to be slow. Add about 1/2 grain to get the same velocity.

Adjust for barrel length as needed.

Same for 4227 well with low density loads.

Just take your time.

 

[Konocti's Wigwam]

Keep in mind that most people on the edge with 300 blackout have moved to 1:5 twist. This creates the same stabilizing effect that 1:3 twist has on 8.6 blackout.

My opinion is that 300 blackout doesn't have enough powder to take anything larger than small game. I'm just working up a ladder using a 150 grain CX and 150 grain Barnes TSX, both for supersonic using a 7.5" 1:5 twist barrel. I have several usable powders, but sticking to Accurate 1680 and CFE BLK (close to same burn rate). I could actually find CFE BLK at Bass Pro in my area (California).

EDIT: Question for you guys, have any of you used the nickel plated Starline 300 blackout brass? They sell both brass and nickel plated brass. I'm thinking to try it as it is rumored to last longer and be tougher. To date I have only used resized blackhills match 5.56 brass. Anyone with experience on the nickel plated?

 

[DShortt]

That's an interesting thought. I should look at down range energy before I spend too much time on this.

Thanks for your observations.

 

[Mike6158]

EDIT: Question for you guys, have any of you used the nickel plated Starline 300 blackout brass? They sell both brass and nickel plated brass. I'm thinking to try it as it is rumored to last longer and be tougher. To date I have only used resized blackhills match 5.56 brass. Anyone with experience on the nickel plated?

I just loaded some this afternoon. I haven't shot it yet. I got irritated with the Lake City brass that I salvaged from my Gorilla ammo and decided that unloaded brass was pretty look at but doesn't shoot very well.

I've loaded a lot of 7mag rounds with nickle plated brass. I'm not sure how many firings but I know it's about 10 years old and I've load tested with that rifle a lot. I have a test loaded for it right now but I need the rain to slack off a bit before I can shoot it.

 

[dantiff2]

Post in thread 'What did you load today?'
https://forum.accurateshooter.com/threads/what-did-you-load-today.4032303/post-38651892

 

[6Creed73]

Well, that's the conundrum I'm in. I have a bolt action with a 20" barrel I want to shoot subs in with a suppressor. I guess I might have to start with AR data because apparently I'm one of the few to see a use for a combination like this.

I appreciate the responses. At least I know I'm not missing an obvious answer.

I know a few people who have 300BLK bolt guns...I would not worry about finding load data for your specific application, and honestly, the 4" difference isn't going to be drastic.

I use my 300blk exclusively suppressed from a 8.5" barrel and use the 16" data as starting points. Even with an 8" difference, the differences between my velocity and published velocity isn't huge. Do some simple ladder testing and be done with it.

For what it's worth, I hate CFE-BLK, H110 is ok, but better suited fir supers imo. By far, my favorite powder for subs is A1680. But with the bigger bullets you will need a drop tube and will still be slightly compressed, depending on your brass. I like a compressed load, but with a bolt gun, seating depth may not be as big of a deal for you.

 

[dantiff2]

Unique powder is the key. No worries with being under 50% load density just whatever charge gets the velocity you want, works! Enjoy!

 

[DShortt]

Unique powder is the key. No worries with being under 50% load density just whatever charge gets the velocity you want, works! Enjoy!

There's an interesting idea. I've used Unique in reduced cast bullet loads a lot. Never thought about it in this application. I'll investigate that. Thanks!

 

[dellet]

That's an interesting thought. I should look at down range energy before I spend too much time on this.

Thanks for your observations.

Down range energy with subs is a problem, not for lack of effectiveness, but game laws. If there is a minimum energy requirement, for rifles 1000# at 100 yards is normal. Can’t get there with a sub.

For pistol 500# at 50. It’s doable with a 220 grain bullet and 1050 fps.

It’s not bullet effectiveness, that’s the problem, it’s the drop.

The 194 Lehigh is a good example, high BC, low expansion velocity, it would be effective to Around 800 yards, double caliber expansion about 300 pounds of energy on impact and drops 3 feet in the last 10 yards.

Going supers 150 grain Speer Gold dot 2200 MV will still have 1000# at 275 yards and near double expansion down to about 1550 fps.

Trick is getting bullets designed for the cartridge.
Deer at 3-400 yards with subs is doable. You’ll get more flack than guys shooting deer at 1000 plus yards tho, for good reason.

There is so much misinformation out there by fans and critics that it’s tough to sort it out. Study the numbers, they don’t lie.

A bullet that barely bends the tip shooting into dirt is useless hunting.

A sub load with a double digit SD, won’t be worth shooting past 50 yards. Too much vertical stringing.