.223 subsonic 69g smk

[husbandofaromanian]

Has any body been successful stabilizing this bullet subsonically? My research has shown that is has a stability factor of almost exactly 2.0 in a 1-7 twist at 1050fps.

btw, I own a TC contender with 22lr and .223 barrels and suppressors for both calibers. I regulary shoot 22lr suppressed out to 300 yards. So please, no snob remarks as to why I should shoot 22lr instead of .223 subsonic. I am moving to .223 subonic for a better b.c. and so I will stop leading up my suppressor.

 

[Jeeping]

This is probably the area where not many have gone. Try using pistol powders, works well for me in 35 rem and 308. I haven’t tried with 223 though.

 

[husbandofaromanian]

As for powders, loaders have recommended both Trail boss and titegroup. I am leaning toward Trail boss so I won't have to worry about a magnum primer.

 

[Jeeping]

Also keep in mind that whatever powder you use will only take 1/5th or so of the case capacity. For example, my 35 rem loads take 6.5gr of unique, and in order for that little amount of powder to get good consistent ignition, I use toilet paper (little bit so as to keep powder down) as some sort of wad. Works good for me, chrono shows tolerable velocity spread. Without the wad though, velocity was all over the place.

P.S. I get all kinds of *** looks at the range, but don’t really care. had a guy tell me that something was wrong with my rifle, hehe.

 

[Jeeping]

Just reread your post, I dont know how TP would work with your can. Probably can find some other material to use for wading, or maybe you can get away without one. I'd imagine that shooting subsonic anything out to 300 yards, will need to have good SD to get decent accuracy.

 

[redbullitt]

Just use the trailboss, then you will not need any filler or anything like that. I would not want to have any of it (filler) near my suppressor anyway. I bet you will have around 2/3 case fill, maybe even more. From what I have seen it is not position sensitive like many pistol powders.

I have had very good results with trailboss in 308. Large rifle match primer, No filler ever, fairly consistent velocity. Plenty good enough for 1.5 inches at 100. Targets at LR are no problem if you have a good MOA base and lots of adjustment on your glass.

Not sure about that bullet. Shorter stubbier bullets are easy to stabilize, but in 223 finding one like that might be tough. The flat nose 30 30 bullets have done well for me in 308, as have the round nosed ones. Again, not sure of any in 223 like that. Casting something could be done I bet if all else fails.

If that bullet does stabilize for you, go for it.
You may want to try loading it backwards. Sometimes that will get you better results since subsonic flight and supersonic flight prefer very different shapes. That is not to say the smk wont shoot well. My 300 blk shoots a 240 smk sub VERY well.

The heavier bullet should get you much better results than the typical 40 grain 22lr. Assuming you have a 1-7 twist by OP, I would think it would be fine. You should also note that the typical stability formula (ie the one we usually think of) is not optimized for subsonic projectiles.

I have always just done the "try and see" approach (WITHOUT THE CAN) anyway lol. Just remember to test stability at close range and further out. i like to shoot through a piece of cardboard into white regular paper. Helps to do it in different conditions as well.

 

[kingmt]

I use a slower twist barrel but it seems the lighter the bullet the better they shoot. I have also read that the backwards bullet is even better but I have only done it in 30-06 which did improve groups at every speed. I use a powder that is in the same burn rate as Blue Dot that works well.

 

[husbandofaromanian]

Engel uses Sierras 63smp bullet. So if the 69smk doesn't stabilize I can always use the 63.