powder for 223 subsonic 75-77gr bullets. 16" barrel

[rockwind1]

i am JUST ASKING,,,,,,so before everyone goes off the deep end on why this is NOT a good idea.

i was going to order some beck sub sonic 223 ammo but like everything else, they are out of stock for ever. so i have plenty of materials at hand,,,and yes i can figure out a powder, BUT,,,,, lots of smart folks on here have no doubt gone down this path,,,, would any one just share a good powder for this purpose, i have 77 smks and 75 hornadies and 69 rmr's. will be using processed brass 1x fired, lake city. with rem 7 1/2's.

 

[MikeinTexas]

Trail boss. Follow their recommendations about max, then back them down until they are subsonic for your altitude.

 

[roostercogburn98]

Trailboss as mentioned

 

[culater]

I've used titegroup

 

[whatsupdoc]

https://hodgdon.com/wp-content/uploads/2020/07/subsonic-data-final.pdf

https://www.ballisticstudies.com/site/ballisticstudies/files/Hodgdon%20H4895%20reduced%20load%20data.pdf

 

[db2000]

Curious, why not a heavier bullet if going subsonic?

 

[rockwind1]

Curious, why not a heavier bullet if going subsonic?

just mag length issues is all. ar-15,,,, do you know any alternatives?

 

[jet_lagged]

I have used TiteGroup. If buying powder, I would try VV Tin Star or Trail Boss instead, due better case fill and less velocity deviation. Almost any pistol powder should be workable, but like TiteGroup, casefill will be an issue and will cause large SD's.

I found that 55gn flat based varmit bullets grouped better for me than 55 FMJ boat tail bullets out of a 1:8 twist AR barrel. You may have trouble getting real stability out of the longer boat tail bullets that you mention.

 

[hino895]

I’m loading 4.4g of clays for 975fps using a 77gr smk.
16” barrel

 

[redbullitt]

As was said, tin star, trail boss probably the best.

Red dot may very likely be workable too. Fast and bulky to try and get a little case fill in there.

Never a bad idea to have a rabbit load option in any rifle. Smart.

 

[semperfireloading]

Probably like around 3.5 grains of N330 with cotton to hold it, and you can't do better. You might get SD of 2.
Messing around with Pistol Powder and AR15

 

[gigamortis]

Titegroup with its hot burn temperature works well in cases with a lot of left over case volume like .38 Special and .45 ACP, etc. The hot burn helps ignite all the powder consistently no matter how the powder lays in the case. That way, your ES and SDs will be as minimal as they can be.

 

[st1650]

Probably like around 3.5 grains of N330 with cotton to hold it, and you can't do better. You might get SD of 2.
Messing around with Pistol Powder and AR15

If you know what you’re doing, N330 is amazing. I use it for my 300BLK subs and get very good SD. Just gotta be careful with the pressure curve.