I know there are a lot of 450 guys around here.  Anyone have an subsonic load data?  I've been googling and struggling to find it.  Just bought a Ruger American, handy little gun so far!

Between the sub 350.00 uppers in the email I got from Bear Creek and the CVA singleshot in.450 now available at walmart for 224.00 I have grown an interest in the caliber too.

I built mine with a stripped lower receiver.  Used it for deer hunting 2017 and hog hunting this spring 2018.  It did the job quite well.
I would be concerned that dropping roughly 1100 fps to get subsonic would drastically reduce it's effective range and knock down power.
I have a 450 bush suppressor sitting in ATF jail and hope to have it by this hunting season, but wasn't planning on downloading the cartridges.
Let us know how subsonic works out for you.

I'm thinking mostly for fun.  I might figure out the impact shift and carry a few rounds with me hunting for an opportune shot.

FWIW, subsonic would still have more energy than 10mm that I shot deer with at 100 yards last year, but agree, almost defeats the purpose.

I'd be in the why boat as well, might as well go for 45 acp pcc, a lot more economical to shoot than the 450. I'm waiting for my suppressor to come out of NFA jail as well. I wasn't supper impressed with hornady black as I was getting variation of 150 fps shot to shot and accuracy was only ok. I honestly like the ergonomics on my 870 better than the AR when shooting the big bore but slugs are way more expensive for an accurate load on my 870. Running a break also helps a lot over a flash hider on the 450.

Right now I'm waiting for temperatures to cool and my tax stamp to start developing a load and tuning my rifle for deer season. I have some 200 grain 460 S&W Barnes bullets that should scream and easily give me 1000 more fps than the 1 oz slugs I had to shoot out of my 870.

I am running a 450BM that I built last year using Hornady Black 250gr. (2200FPS).  Its incredibly effective as is, I got 4 deer with it last year, all but one dropped where it stood, So i dont see a need to make it more fancy as it really is quite effective out the box.  I will say the ASC 9Rd mags dont work with more than 7rds and their 7 rounders are great.  I am running an AimPoint CompM4 and a SilencerCo Hybrid.  Its easily a 3/4" MOA at 100 rifle so its minute of deer for sure.

Here are my specs

APF 16" SS Barrel w/SilencerCo ASR Muzzle Brake  
Controlled Chaos Billet Lower
CMC Flat 4.5LB Flat trigger
APF 450 Bolt
LMT Carrier
H3 Buffer
AimPoint COMPM4
Troy Alpha 15" Rail.

I shot a few deer with it. I did have an issue with my scope shifting. One deer I shot right through the top of the heart and it still ran 100 yards right at me. I like bullets that don't fragment lead everywhere so that's why I'm moving to the Barnes as well as better consistence between rounds.

Followup here.

12.5 gr Trailboss and a 300xtp netted 1000fps.  I didn't get an opportunity to shoot a deer with it.  It drops about 12" from my 100 yard zero.

I did shoot some deer with the factory Hornady 250sst.  Performance was pretty poor IMO.  One was shot right above the heart and took off on a 100 yard run before toppling.  I'll be looking for a better terminal and higher BC bullet over the summer.

Til next year

275 TSX?

Man that .16 G1 BC though....

A couple of the smokeless muzzleloader guys are working on a bullet for centerfire.  I might hold out for that.  The 300gr bullets I shoot out of my muzzleloader are .400 G1.