AR-15 Pistols: 1st Shots with the .300 BLK and .458 SOCOM

This is a function check and the first shots fired from my new AR-15 pistols.

Several months ago I bought a 10.5″ fast twist 1:10 .458 SOCOM pistol upper from Tromix and an 8.5″ .300 BLK pistol upper with lower build kit, plus a lower, from Palmetto State Armory. I am using the same lower with both uppers.

I found this kit on sale from PSA: PSA 8.5″ .300 AAC BLACKOUT 1:7 NITRIDE 7″ LIGHTWEIGHT M-LOK MOE EPT SBA3 PISTOL KIT – 5165449761

And bought this lower from them as well: PSA AR-15 LOWER SAFE/FIRE – 1728

Many thanks to Starline Brass for providing the brass for both pistols!
Starline Brass website
Starline Brass at Brownells

I bought my Hexmags from GunMag Warehouse: Hexmags

The bullets in this video were cast from these two NOE molds:
HTC310-225-RN
HTC459-500-SP
(Use code “LOB001” to get 10% off your order at NOE.)

Here are the sights I used in this video:
Feyachi Flip Up Iron Backup Sights
Field Sport Red and Green Micro Dot Sight
Monstrum Lockdown Series Adjustable Height Picatinny Riser Mount with Quick Release

And here is the video where the lower was assembled: Building an AR-15 Lower – Loads of Bacon and Full.Lead.Taco Assemble Together! (w/ OzarkSpirit)

   

Disclosure of Material Connection: Some of the links in the post above are “affiliate links.” This means if you click on the link and purchase the item, The Reloaders Network will receive an affiliate commission. This is being disclosed in accordance with the Federal Trade Commission’s 16 CFR, Part 255: “Guides Concerning the Use of Endorsements and Testimonials in Advertising.”

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JCM45
JCM45

Nice guns, and great shooting, Bacon. More coming?

GunFun ZS
GunFun ZS

I’m enjoying the new videos James and I’ve always been kind of interested in 458 socom. The main thing that scares me away from it is proprietary brass. I will enjoy seeing your work up of the 300 blackout loads.

NickJ
NickJ

Those are two great calibers :-))

The Social Regressive
The Social Regressive

Hahahahaha!!! I love the target at the end!

mr.revolverguy
mr.revolverguy

Bacon — I have been waiting for this video, AWESOME thank you. I am in love with the 300blackout as it is a reloaders dream. I am conducting a test right now with subsonic loads to see when a 300blackout piece of brass needs to be trimmed. Right now I am on my 8th loading of the same brass. My wife says every time I take out 300blkout it is the only time I have cheated on her 🙂 I take tons of data of all factory and reloads and put them in a spreadsheet here http://www.dayattherange.com/?page_id=3817 self proclaimed largest… Read more »

Cranky Cleatus
Cranky Cleatus

Glad to see success with both pistols on 1st time out. Both calibers will provide loads of fun going forward. 🙂 Bet those 500g bullets drain a cast pot in no time 🙂

Bigger behind the trigger
Bigger behind the trigger

I m going to have to try the 458 SOCOM. My dad was and I still am a huge fan of the 45-70. This is a more modern version. Happy shooting

IWatchedWhat
IWatchedWhat

Looks good, how did your socom group with the cast? Mine has been a real bear to get it to shoot anything but patterns.

Keane
Keane

Great video, man. You may want to double check, but I think I saw a TGC Legal Brief video that says that using something like the Magpul afg is verboten on an AR pistol.

John Fazer
John Fazer

You can use the .458 for a ninja smoke escape in an emergency lol.

Pony47
Pony47

Hey Bacon , Love the video ! that SOCOM 458 looks like a flinch monster !! Thanks for the video !!

243 Outdoors
243 Outdoors

You better think about a bullet trap with that much lead going down range. That is quite the blast coming out of the 458. Wow.

Mike Treen
Mike Treen

That was totally wicked!!!!!

MCK
MCK

I’ve got a Bear Creek Arsenal 7.5 upper 1:7, don’t if ya watch my vids on it but after lil work and research they have “match” Chambers (tight tolerances) and since I’m a caster I had trouble with feeding issues, even after all the work I did to the bolt and feed ramps running factory ammo fine, so, the fatter bullets I have to seat deep and limited to certain styles for reliability, and after all that I’m good…I wanted ask you about the dimensions of that ‘as cast’ size of the NOE and I’d like to see if they… Read more »

Ghost Rider
Ghost Rider

Nice builds LOB! Does that 458 use standard 5.56 mags or do they need to be modified?

KFW
KFW

Great video. 300 Blackout is a great cartridge to reload for and perfect for short barrels. That 458 is a beast and looked like there was quite a bit of muzzle blast from that comp. I am looking forward to see what you cook up for these.

aaron
aaron

I do believe you are correct again. I have a few different are pistols with different twist rates and barrel lengths and a couple riffles in 300 blackout. That caliber is a reloaders dream. I never get tired of trying new things. My oldest son hade me help him build a 50 Beowulf. That’s a lot of fun to. I get a real kick out of it. 😂😂 thanks for another great video. I have been thinking about building a 458 but if I do I think I might need to add on to the reloading room. I load for… Read more »

Jesse B Outdoors
Jesse B Outdoors

Ar builds are so much fun. I’ve got a few 223 loaded to start doing testing with. Great video brother 👍🇺🇸