How many grains of Trail Boss can you put in 300 AAC?

[tsubaki]

I have some new Hornady brass, figured I might as well load a few with Trail Boss.
Measured the suggested minimum of 6.8gr for a 150gr bullet and it almost filled the case up.

Rechecked rezeroed everything and still came up too full to install the bullet unless I wanted to compress the the donuts.
That's supposed to be a no-no.

Just for the fun of it I filled the case up to the top, wiped it off level and measured the load.
7.7 grains

Hodgdon has a suggested maximum load of 7.8gr listed.



Just where is the rest of the powder supposed to go?


How much does your case hold?

[SafetyJoe]

What is the case capacity in terms of water? If I know that number and the specific type and length of the bullet, the length of your brass and the OAL you want to seat the bullet to I can enter all those numbers into my quickload program and it can tell me what your available case capacity will be for trailboss powder. It can even tell me approximate chamber pressure and muzzle velocity if you tell me the barrel length too. Just place an empty brass on the scale, zero that out and then fill the case with water and weigh it again. If the case has a new primer you'll have to replace it and let the brass dry out afterwards.

[tsubaki]

Thanks that would be more than interesting!
I'll get on that!

[tsubaki]

Total case capacity in water 24.5gr.
Bullet is a 150gr Remington PSPCL, this is a flat base spitzer design. Bullet length 1.040".
Case length 1.360".
COAL 2.220"
Barrel is 16".

[tsubaki]

This is what 7.8 grains looks like.
http://i175.photobucket.com/albums/w159/tsubaki3/IMG_0959_zpskey79hg8.jpg

[tsubaki]

I just eyeballed it and came up with 6.5gr.
How you recon that will turn out?

[Happyguy]

Let me know how it works. I am not sure that it will operate an AR 15.

[SafetyJoe]

Quickload says 6.56 grains of trailboss is 100% case capacity and the chamber pressure should be 25,758 psi and the velocity should be 1147 fps. Let me know if you want me to run the program using a different powder or bullet.
Here's a screen shot. 262

[tsubaki]

Thank you very much Joe, I may take you up on that!

Got another bullet type and book to show up this week.

The velocity is a little higher than I expected and surprised it should burn all the powder.
It may take a couple of weeks before testing the data and see if it will cycle.

[SafetyJoe]

Muzzle pressure is estimated at only 83 bar so it probably wont cycle. Just let me know how it turns out because I'm interested in knowing. I like using that quickload program. I've found that it has the ability to open up new possibilities which is always interesting.


Thank you very much Joe, I may take you up on that!

Got another bullet type and book to show up this week.

The velocity is a little higher than I expected and surprised it should burn all the powder.
It may take a couple of weeks before testing the data and see if it will cycle.

[tsubaki]

Again thank you very much!
That program is turning out to be as valuable as the price.
I didn't comprehend the need of reading muzzle presssure until you clarified it.

[Mbaker78]

From what I've read, trailboss won't cycle an AR. For 150gr supers you'd be better off with lil'gun or H110/win296, for subs I've heard good things about accurate 1680 but I haven't used any of it yet. I prefer much heavier bullets for subs, somewhere in the 200-240gr range, IMR4227 has worked well for me with them.

Your gas system length will also make a difference in what will cycle and what won't, you'll be best off with a pistol length gas system over a carbine length.

[DukeInFlorida]

Lil Gun is the only powder I use for 300 Blackout. The current load data books give you the proper amt for any given bullet.

I would NOT use TrailBoss.

DO NOT CRUSH THE DONUTS!!

[Pacomdiver]

i use h110 in mine. mines a 10.5 barrel pistol with a pistol length gas system

[DaveL]

I've tried 5 different powders for subs. 220gr Nosler BTHPM and 10.9grs. of 1680 turned out to be the best load by far. Consistent SDs and primers, consistent velocity, and great accuracy.

The worst was Lil'gun. Big swings in SD, some primers looking like they were just inserted (except the firing pin divot) and some looking like an overcharge (flat. I mean really flat).

All loads were individually weighed using my Ohaus M5 beam scale and LC converted brass.

Trail boss will not cycle my carbine. TB has it's nitch but not in this application.
IMR4198 and H110 worked OK but 1680 was noticeably more accurate.

For plinking loads I tried several different powders and I settled on 150gr Sierra FMJBT Gamekings with 17 grs of H110. It's a very accurate load.

For Whitetail hunting I settled on Nosler 125 gr Ballistic tip Spitzers with 21.5grs of 1680.
JMHO
Dave

[Mbaker78]

i use h110 in mine. mines a 10.5 barrel pistol with a pistol length gas system

Did you SBR it or make it a pistol? My 10.5 started life as a pistol and barely got used, as soon as I got the F1 back to put a stock on it, it became one of my favorite guns.

[Pacomdiver]

dont have the extra cash for the bribe fee yet, so its on a pistol lower

[Mbaker78]

Understandable, but the SBR is fun.

[tsubaki]

Today I got an average of 840fps with the 150gr PSPCL and 6.5gr of Trail Boss.
As expected it did not cycle the AR.