S&W M&P 300 Whisper/Blackout

[Mike Hughes]

Do any of you own one of these guns? If so, Please let me know what you think about it. I have heard a lot of good things about the 300 blackout cartridge. I am looking at trimming and forming the brass from the 223 and loading with cast boolits. Also would like to eventually buy a suppressor and load at subsonic velocity. All input would be appreciated, and thanks in advance!
49031

[Moonie]

I built a 300 BO upper for my 6.8SPC hunting AR. I really like the cartridge, shoots well and handles cast beautifully. Trimming and forming brass is a pain but Grumpa (forum member) has converted brass available if you are interested, I've not used his brass but have heard good things about it.

I cut, form, trim and anneal my own, it is a chore.

[L1A1Rocker]

I've got a M1S and a PSA rifle in 300BLK. Really like the cartridge a lot. The M1S is internally suppressed and its a real hoot to shoot. The NOE 247 is a good sub sonic bullet and there is currently an active GB for a Miha 130HP boolit that I'm very axsious to try as a super-sonic load.

I recommend the Redding dies along with a Lee FC die and of course an M die to expand the mouth. It's been my experience that the 300BLK is very sensitive to powder fluctuations so weigh every charge and make sure it'd dead on.

Oh, be sure to annel the brass that you convert. Converted 223/556 brass has a very thick neck and the annelling really helps accuracy.

[W.R.Buchanan]

Kel-Tec is about to bring out their SU16 rifle in 300 BLK. It could be an alternative to an AR in that caliber, and a helluva lot less expensive.

Randy

[27judge]

I have a cmmg 16 inch upper in 300 blackout.I bought it for cast bullet plinking , i use a rcbs 180 sil bullet and 1680 powder it shoots into one ragged hole at 50 yards.IM real pleased, working with noe 311299 202 now and its almost as good .Great plinker for the grandkids nice boom and no recoil. Grumpa is great to work with for brass he did a real nice job on 1200 cases for me tks KEN