I just got the urge to do a 300 blackout the other day. I was at Ottomanelli's and they had everything but a barrel to do the build.

 

The rifle is done and it consists of the following parts:

Seekins T7075 lower

Seekins T7075 upper

Seekins monolithic rail

CMMG LPK but I had an RRA FCG that I liked better

DD full auto BCG

Spikes tube, spring and heavy buffer

CTR OD green stock and OD green grip

Spikes 30 cal muzzle brake

YHM lo pro gas block

YHM black gas tube

AR Stoner chrome 1:8 twist 300 barrel

 

The rifle is amazingly light and looks great, ill post pics of it when I can.

 

I ordered a Nikon P300 scope and I have PEPR mount laying around.

Sounds interesting... Looking forward to seeing it...

I build mine a couple of months ago and I love the cartridge! You can reload so many different rounds for different purposes. Is the one pictured on my avatar.

What are some of the recipes you've tried? I have a grendel and can't wait to compare the two.

What are some of the recipes you've tried? I have a grendel and can't wait to compare the two.

I load 125gr with H110 and those fly about 2240fps and 175gr with N110 clocking 1700fps. I will send you a pm tomorrow with all the details of the loads.

That would be fantastic. I have brass, various bullet weights and H110 and access to N110.

I just got the urge to do a 300 blackout the other day. I was at Ottomanelli's and they had everything but a barrel to do the build.

 

The rifle is done and it consists of the following parts:

Seekins T7075 lower

Seekins T7075 upper

Seekins monolithic rail

CMMG LPK but I had an RRA FCG that I liked better

DD full auto BCG

Spikes tube, spring and heavy buffer

CTR OD green stock and OD green grip

Spikes 30 cal muzzle brake

YHM lo pro gas block

YHM black gas tube

AR Stoner chrome 1:8 twist 300 barrel

 

The rifle is amazingly light and looks great, ill post pics of it when I can.

 

I ordered a Nikon P300 scope and I have PEPR mount laying around.

 

sounds nice. Please post pics when you can and give us a Range Report.

 

I have been tossing around the idea of building my second Umbrella receiver set as a 300BLK. All i need is a barrel.... hmmm...

sounds nice. Please post pics when you can and give us a Range Report.

 

I have been tossing around the idea of building my second Umbrella receiver set as a 300BLK. All i need is a barrel.... hmmm...

Plenty barrels available at Midway and Brownells this days...

Lol I ordered a barrel today..... Now off to get some ammo

Lol I ordered a barrel today..... Now off to get some ammo

Congrats!

If you need any help with the installation let me know.

just curious, whats the benefit of converting to 300 blackout in the real world? i'm a newb so hope this isn't a stupid question. 

30 cal projectile in an AR platform with only a barrel change.

Yeah the gun shoots amazing. The subsonic rounds make barely any noise so I would imagine suppressed they are silent. I sighted in my budget Nikon P-300 BLK scope and plugged away. The gun is was extremely accurate with both factory subsonic and my 147 gr supersonic, H110, CCI450 loads.

 

On issue is I only had a spikes heavy buffer and it isn't cycling well. I'm going to pop a standard rifle weight rifle buffer in to see if that solves the problem.

Apparently there are issues across the platform with gas blocks, gas port sizes, and buffers based on extensions used.  I think you're headed in the right direction by dropping down to a standard carbine buffer.  I have heard of some messing with the carrier also, whether it be ar-15, modded ar-15, or m-16. 

 

 

At least we don't have to worry about suppressed issues.  McGreevy handled that for us.

pics or it didn't happen...lol

I promise pics up after I change out stock me buffer. I have an OD green RRA operator coming to replace Magpul CTR/spikes heavy buffer, spring and tube.

I promise pics up after I change out stock me buffer. I have an OD green RRA operator coming to replace Magpul CTR/spikes buffer, spring and tube.

 

I'm anxious to see the pics. Most likely wont have mine built until the end of september.. Have to find time to get everything together and then build her when the wife is at work..... 

I'm using the JP silent captured spring with great results http://www.jprifles.com/1.4.7.2_os.php

And this is my 300blk rifle...

looks great.....

Very nice!

I have a heavy buffer right now, because it was laying around, but I'm changing to the RRA operator stock. If it can't cycle a standard rifle buffer ill either get the silent spring or the low mass buffer.

 

Thanks for the suggestion.

.

OK, now that the brain fart is over, for those reloading 300BLK, Sheridan Engineering http://www.sheridanengineering.com/index.htm is offering a gauge that equals the SAAMI max chamber for checking reloaded or converted brass rounds. $35 shipped. Picked one up, works great.

 

The have gauges for 50 beo, 6.5 and 6.8 also.

Finally got the kinks worked out this afternoon. I bought an RRA operator rifle stick and the gun cycles subsonic and supersonic rounds.

 

I sighted in my Nikon 300 BLK scope at WP today.

 

I absolutely love this round. Ill be loading it bulk over the next few days.

 

I'll take a pic later and post up.

Here's the rifle.

And this is my 300blk rifle...

What scope do you have on it?

What scope do you have on it?

Bushnell Elite Tactical with BTR-2 reticle

http://www.bushnell.com/hunting/rifle-scopes/elite-tactical/smrs-1-6-5x-24mm-illuminated-btr-1

beautiful scope, it costs twice as much as my rifle!  

Budget build is getting a bit pricier. I bought a Giesle SSA-E two stage trigger on sale for 189.99 shipped (that's about 40 bucks off) and a whisper spring for 130 bucks at midway. I like the gun so much I thought I'd make some strategic upgrades.