My 300 AAC Blackout Pistol Plinking Load Development

[nksmfamjp]

I thought I would make a thread to share my load development progress and gather tips along the way.

GUN: First, I'm shooting these loads from an 8.3" Ballistic Advantage barrel with a Hanson profile and a KAW comp. The bolt is an Aero MPI/HPT Nitride bolt. Passed the GO gage and would not pass on GO +0.002" shim.

TARGET: Trying to make a reasonably cheap 300 load for plinking and SD rifle training. I have some characteristics that make pistol AR a good choice.

LOAD DESIGN:
Case - bought 1000 processed from Coug91
Primer- CCI #41
Powder - starting with Ramshot Enforcer, but will try H110 also.
I think Ramshot Enforcer has a bit better burn rate and good case fill....maybe slightly better than H110 in an 8" barrel, but it is close enough to try both....Enforcer first
Bullet- Hornady 110 Vmax or Speer 125 gr TNT
Starting with the Hornady because they are on sale and available. Bought 400. Have 1000 Speer on backorder.

EQ:
Hornady LNL
Hornady Die Set
Hornady Powder Dispenser
Lee FCD

STEP 1: Set OAL. Hornady say 2.05". I checked with my OAL Gauge and the throats is super long....any OAL that fits in the mag will be a mile from lands! So, 2.05" for now.

STEP 2: Sort brass for fit to case gage. Of 515, had to cull 14...not bad.

STEP 3: Make test loads at charges of:
DATA
So, 15.5, 16.0, 16.5, 17, 17.5 Let's make them up

Advice?

[tallburnedmidget]

I thought I would make a thread to share my load development progress and gather tips along the way.

GUN: First, I'm shooting these loads from an 8.3" Ballistic Advantage barrel with a Hanson profile and a KAW comp. The bolt is an Aero MPI/HPT Nitride bolt. Passed the GO gage and would not pass on GO +0.002" shim.

TARGET: Trying to make a reasonably cheap 300 load for plinking and SD rifle training. I have some characteristics that make pistol AR a good choice.

LOAD DESIGN:
Case - bought 1000 processed from Coug91
Primer- CCI #41
Powder - starting with Ramshot Enforcer, but will try H110 also.
I think Ramshot Enforcer has a bit better burn rate and good case fill....maybe slightly better than H110 in an 8" barrel, but it is close enough to try both....Enforcer first
Bullet- Hornady 110 Vmax or Speer 125 gr TNT
Starting with the Hornady because they are on sale and available. Bought 400. Have 1000 Speer on backorder.

EQ:
Hornady LNL
Hornady Die Set
Hornady Powder Dispenser
Lee FCD

STEP 1: Set OAL. Hornady say 2.05". I checked with my OAL Gauge and the throats is super long....any OAL that fits in the mag will be a mile from lands! So, 2.05" for now.

STEP 2: Sort brass for fit to case gage. Of 515, had to cull 14...not bad.

STEP 3: Make test loads at charges of:
DATA
So, 15.5, 16.0, 16.5, 17, 17.5 Let's make them up

Advice?

So far everything seems sound. I would add that you probably want to get a Sheridan gauge to ensure your rounds will chamber. The 300BLK can easily be knocked out of spec during various stages of the reloading process. I know from personal experience. The gauge will help you catch the issue and help identify why/where you may be knocking the round out of spec.

That is about it for advice from me

[nksmfamjp]

Well, I chamfered and deburred the cases slightly. That went ok. Some mouths were slightly out of round. Ended up kinking 1 case seating bullets. Seating flat base bullets sucks. I might flare them up a bit when I switch to the powder measure.

At the end of the day, I have 25 rounds ready to test that all fit in the case gauge.

Also, I got a ring dent in the bullet seating....Hornady seater, Hornady bullets, what give?

First things first, I need to do some barrel break in with factory ammo.

[Smurky]

Well, I chamfered and deburred the cases slightly. That went ok. Some mouths were slightly out of round. Ended up kinking 1 case seating bullets. Seating flat base bullets sucks. I might flare them up a bit when I switch to the powder measure.

Also, I got a ring dent in the bullet seating....Hornady seater, Hornady bullets, what give?

Loading Flat Base and Lead/lead coated bullets I use a Lyman M die for 30 Carbine and I learned here that a NOE expander plug in a Lee universal expander may be better and finish up with the Lee FCD. Better than a flare IMO.

I am not familiar with your combo of bullet and powder, are you loading compressed loads? That may be the reason for the ring dent in the bullet. The dent is usually caused excessive force to seat the bullet in my experience.

[Mike7.62]

IMO the problem isn't with the flat based bullets, but with the out of round case mouths. I routinely load flat based bullets into many calibers, even those with rather thin necks and case mouths such as .30-30, and .32-20, and never have a problem. I noticed that in your list of components you bought cases that were "processed" from another party. By processed do you mean sized? Sizing should eliminate any out of round case necks, assuming an undamaged sizing die, and with a decent chamfer should seat a jacketed flat based bullet with no issues.

By "ring dent" do you mean a circular indentation near the point of the bullet? If so you need to more closely match the bullet seating stem to the point type of the bullet. Some die sets come with a couple of styles, but others do not, and you may have to contact the manufacturer for another style. Here are the Hornady options:

https://www.hornady.com/reloading/dies/ ... cessories/#!/

[tallburnedmidget]

Well, I chamfered and deburred the cases slightly. That went ok. Some mouths were slightly out of round. Ended up kinking 1 case seating bullets. Seating flat base bullets sucks. I might flare them up a bit when I switch to the powder measure.

At the end of the day, I have 25 rounds ready to test that all fit in the case gauge.

Also, I got a ring dent in the bullet seating....Hornady seater, Hornady bullets, what give?

First things first, I need to do some barrel break in with factory ammo.

If you are loading lead bullets you will need to expand/bell the case mouths. The Lee Universal Expanding die does the job very well. This would help with flat based bullets as well though my flat based bullets really don't need it. My powder coated lead bullets do need it though

[nksmfamjp]

I called Hornady. They said the seater should work. Their biggest concern was neck tension. I tried a couple of ways to measure the ID of case necks with little success.

Therefore, my next step is to run brass through the Hornady FL die. Afterwards, it should be ok. I will also switch to belling the mouth slightly with my powder measure as required.

If not, I will be back here in full panic!

[Mike7.62]

I'd try the FL resizing and then chamfer with a 30 degree VLD chamfering tool. It should allow for an easier passage of the flat base bullet. Remember that if you bell the case mouth, you will be work hardening the brass and will likely need to anneal the cases more often, or you will suffer case mouth splits.

As for measuring inside diameters of case necks, you can use either vernier calipers for a fairly close idea, or an inside micrometer for the most accurate one. The mike can be expensive though, but if you want accuracy...

[dellet]

Asking for advice on an open forum is risky. There’s always some jackass that comes along tells you to stop because you’re clearly not up for the task.

Today i’m that jackass. A couple things stand out as really basic errors that reading one good book could have avoided.

Trying to load cases with deformed necks, is a huge mistake. Sizing new brass is rarely a step you can skip. At very least using a mandrel to round the necks is required. It’s also quite possible, your culls could be saved. What case gauge are you using.

You mentioned using the Hornady OAL gauge, then said that it is impossible to load a 110 VMax long enough to hit the lands and fit in the magazine. Either your barrel is junk, or you don’t quite have a good grasp on using the tool. That bullet will hit the lands at about 2.200”

You said you had no way to measure the inside of the neck. This can be done with any caliper. If you're going to load, you’re going to need one. I am interested in knowing how you measured the OAL of 2.05” without one.

Take it for what it’s worth, you have made some pretty basic mistakes that aren’t terrible, but show a lack of understanding. There have been some good suggestions and if you follow them you’ll be on the right path. The worry is there are some other real basic things that over looked can make for a bad day.

Just a few things that stand out as needing a second look.

[nksmfamjp]

Dellet,
Appreciate the feedback. I have reloaded for about 20 years with more calibers than I care to count, including some wildcats, but no real case forming.

At the end of the day, the neck diameter was too small...probably by about 0.0005. Do your calipers measure I'd of a small cylinder well? Look up the word "chord" in an image search. My Mitutoyo calipers form a chord on the ID causing some accuracy error.

Cases with deformed necks is an issue. This was a little more mild than that, but I do need to fl size them.

The culls were from being too big in the case gauge....Lyman, if it matters. Culls that don't fit at the base are from being fired in oversized chambers or some other work hardening that causes fl sizing not to work. So, culled....others are rim damage.

Yep, I know how to measure OAL. That bullet hit the throats way out in the neck. Ballistic Advantage makes fine barrels and I know how to use the tools.

What book should I read? I was thinking more about writing one, but no time for that.


So, results...
17.5 gr gave best accuracy, but with ringed bullets and other minor issues, I'm basically starting over....still thinking I'll load 17.5, 17.2, 16.9, 16.6. Have other stuff to do before I get this done.