Subsonic .223

[gunner1stclass]

OK here's my situation, I'm trying to run a subsonic 223 bullet. The bullet I'm using is 55g cast lead with a gas check. Right now, I'm using trail boss powder 2.8 grains if I shoot a 10 shot string I end up with one or two shots that are 50 ft per second high or low. I'm weighing each charge, my average velocity is running about 985 this is perfect as it gives me a fairly good and super quiet load, but the accuracy sucks. Does anybody have any thoughts on another direction that I could go with this or another powder to use I know trail boss is widely used in cowboy shooting and I have a lot of it, but I also have red dot, unique and a few others. Just for looking for something that I can shoot that's extremely quiet.

 

[SDPlinker]

With lead your neck tensions will have to be consistent, do you size all your bullets and your necks?

 

[marksman1941]

If you can run a heavier bullet that could help. Trailboss is a good powder to stick with, as it removes any chance of a double charge. Pistol powders are pretty easy to make a mistake and blow yourself up. Neck tension will also be a big thing to check on.

Some bullets don't stabilize well at subsonic velocities. Usually high bc bullets aren't ideal. Round nose, or more blunt bullets, tend to work better for subsonic applications. I haven't loaded 223 subs, but in 308 that's been my experience.

 

[Oak_Leaf]

Post up some numbers or target pics. "Sucks" means different things to different people.
Here's some suggestions on things to check though:
1) Barrel twist rate - you don't want it too fast with cast; use a twist rate calculator to see what it spits out.
2) Case Fill - that is a very low case fill and inconsistent combustion is to be expected; If you choose to go this route, there are some cast bullet forums where they talk about adding some additional inert materials to case to take up the extra volume.
3) You may be in a horrible spot for the barrel harmonics.

 

[Lee7588]

What is the gun you are using? Just curious if you are using an AR and it is cycling correctly

 

[gunner1stclass]

With lead your neck tensions will have to be consistent, do you size all your bullets and your necks?

All bullets were sized to .224 and al cases are full length sized.

 

[gunner1stclass]

What is the gun you are using? Just curious if you are using an AR and it is cycling correctly

Remington 700 R5 with a 223 banish can

 

[marksman1941]

Post up some numbers or target pics. "Sucks" means different things to different people.
Here's some suggestions on things to check though:
1) Barrel twist rate - you don't want it too fast with cast; use a twist rate calculator to see what it spits out.
2) Case Fill - that is a very low case fill and inconsistent combustion is to be expected; If you choose to go this route, there are some cast bullet forums where they talk about adding some additional inert materials to case to take up the extra volume.
3) You may be in a horrible spot for the barrel harmonics.

2.8 grains of trailboss is probably 60-70% case fill. It's a high volume powder. For comparison, I use 10.5gr of trailboss in a 308 for 85-90% case fill.

 

[SDPlinker]

All bullets were sized to .224 and al cases are full length sized.

Case necks, all same brass, case necks tension are consistent, not crimping??

 

[gunner1stclass]

Post up some numbers or target pics. "Sucks" means different things to different people.
Here's some suggestions on things to check though:
1) Barrel twist rate - you don't want it too fast with cast; use a twist rate calculator to see what it spits out.
2) Case Fill - that is a very low case fill and inconsistent combustion is to be expected; If you choose to go this route, there are some cast bullet forums where they talk about adding some additional inert materials to case to take up the extra volume.
3) You may be in a horrible spot for the barrel harmonics.

You are absolutely correct sucks was a bad term to use. Two inches at 25 yards was about the best I could get there are a number of shots that are closer together than this probably within an inch but for someone who's used to an inch or less at 100 yards this was downright disturbing.

Case file is an absolute concern and I know I'm running on the low end. I've got a couple of loads for my 308 with red dot that are 7 or 8 grains that shoot pretty darn good.

 

[gunner1stclass]

Case necks, all same brass, case necks tension are consistent, not crimping??

I just ordered at lee 223 crimp die, I'm going to try that this weekend if it gets here in time

 

[SDPlinker]

May help, personally I wouldn't but may bring consistency? Case length is critical when crimping.

 

[gunner1stclass]

May help, personally I wouldn't but may bring consistency? Case length is critical when crimping.

I understand, I normally don't crimp my lead bullets. But I thought I would give it a try hoping to make it more consistent.

 

[Oak_Leaf]

2.8 grains of trailboss is probably 60-70% case fill. It's a high volume powder. For comparison, I use 10.5gr of trailboss in a 308 for 85-90% case fill.

I think it would be more like 35-40% fill in his 223 at 2.8 gr.