Need help with specific .300 Blackout loading

[de-evoproject]

Ok so I've scoured the reloading section here, run around the other forums and checked a lot of manuals but my answer mostly eludes me.

I have a .300 blackout takedown pistol, 8.5" 1/7 twist barrel that I've built and am waiting on my SiCo Omega 300 suppressor stamp.

What i would like to do is put together a sub 200 gr subsonic round that is as cost effective as possible using a copper round (no lead cast) for suppressed plinking and possible home defense/cqc.

I know it can be done as Gemtech has their 180 gr sub round and i have seen examples of 175gr subs. I did get a recommendation for a 165-168 gr from a facebook group:
"Using Quickload, I put in the following:
8.5" barrel, Alliance 1680 powder, 168g bullet, 1050fps projectile speed, OAL 2.215

Output: 12.5 grains of powder.

Loaded this up, and my standard deviation is about 12.7fps.

Using a 165gr bullet, load was changed to 12.3gr of powder, with 11.5fps standard deviation."

Has anyone else got a good load that is subsonic in pistol barrels 9.5" or less, stabalizes well, is consistent and cost effective? Must cycle action, BHO is a bonus.

Pics uploaded for reference and maybe to show off a bit.

 

[NikatKimber]

Much below 200gr and it will be difficult to keep enough pressure to cycle. I intend on running the coated lead 220grn projectiles to keep power/pressure as high as possible so it can run as reliably and smoothly as possible with both subs and supers. My research has lead me to believe that the coated lead rounds are plenty clean to run in a can; so I haven't shopped for budget jacketed bullets for subsonic loads much.

Side note, I have the same Spike's Spartan lower on my 8.5" .300blk pistol.

 

[amcardon]

Have you looked through the reloading section on 300blktalk?

 

[beastep]

Hornady does not show any loads that will be sub with anything under a 200gr bullet. But thats the only book I have right now. Just curious, why under 200gr?

As for the coated bullets, Ive shot a ton of those out of a .40 this year and they are really clean. I found an affordable source for coated blackout slugs that Im going to try after the holidays. Their shipping is a flat $5 I think.

https://www.egglestonmunitions.com/shop.html#!/Rifle-Bullets/c/10873432/offset=0&sort=normal

 

[harley128]

nice weapon

 

[de-evoproject]

Have you looked through the reloading section on 300blktalk?

I have, i think I'm looking for something too oddball or specific and haven't found much useful info.

Hornady does not show any loads that will be sub with anything under a 200gr bullet. But thats the only book I have right now. Just curious, why under 200gr?

The drop in price per round goes down pretty significantly, especially considering i can source unwanted or 2nd hand bullets easier as well.

Just looking at midway prices dropping from 200gr range to 180gr goes from $33-$35/100rds to $22-$25/100rds. Definitely starts adding up after loading a few hundred rounds for range days and filling "ready" mags.

nice weapon

Thank you. I spent a lot of time planning and building and am very proud of the build.

 

[beastep]

That is a nice pistol. I would like to build one similar if certain parts come down in price enough for me to afford it.

 

[NikatKimber]

Oh! I didn't catch it had the folding stock also! Very nice!

 

[de-evoproject]

That is a nice pistol. I would like to build one similar if certain parts come down in price enough for me to afford it.

I can understand. I've got over $3000 in this one with all accessories minus the suppressor. It wasn't a "budget build" by any means though, so that's definitely not a good indicator of how cheap you could build it. Lot's of expensive "go faster" parts like the Phase 5 EBR, Radian Raptor SD charging handle and RailScale G10 panels.

Oh! I didn't catch it had the folding stock also! Very nice!

Thanks. It fits under the seat in my Jetta and deploys quick so im happy with it.

 

[swampratt]

Have you tried the Sierra game king HPBT 165 gr bullet #2140.
Yes it is a tough bullet. It is the least finicky bullet I have ever loaded in .308 diameter.
Only problem i see is expansion during self defense with low speed.. but a hole in anyone .308 diameter will put some stop into them
Not often do you need to shoot humans.
If it was my gun I would try them. they have a long bearing surface to keep pressures up more than some short bearing surface ones.. and not to mention stability with more bearing surface length.
I would try those or look for a flat base bullet like the sierra pro hunter to try out.