300 blackout V-Max 110gr & 150gr sp

[f55]

First try at 300 blackout (formed from 223 brass)

110gr vmax coal 2.040, 18.8gr H110, I did try making some dummy rounds of 150gr sp but the tip keeps hitting the feedramps and denting.

3 shot group is with 110gr vmax

The second pic is the feedramps of my core 15 300 blk, not sure if this is ok or do i have a problem?

The pic of feedramp is before the rifle was shot, this is new.

 

[jmiddy]

Your feedramps are GTG nothing wrong, in a semi- sp bullets are always going to get banged up.

 

[Boomer74]

The second pic is the feedramps of my Core-15 .300 blk, not sure if this is ok or do i have a problem?

The pic of feedramp is before the rifle was shot, this is new.

Your feedramps aren't aligned to your reciever perfectly, the cut-outs dont match/line-up...

There are worse examples, but you should be able to smooth it out after a few thousand rounds.

 

[Rookie{OMC}]

How do you like the Blackout so far?

What barrel length did you go with?

What make of brass are you using to make yours?

 

[2bad4u2]

Winchester brass is likely going to be your most reliable commercial brass for making .300 BLK. I'm also using IVI with no issues, however, some individuals have claimed the neck diameter is too large after forming and gives them feeding issues. If you can use brass without having to turn the necks down, that's the way to go. Incidently, the .300 BLK was designed to accomodate most brands of converted brass such as Lake City (US).

 

[f55]

Thanks for responses.

I am using AE and Winchester brass both feed and eject fine, i trim to 1.355 and check headspace with Wilson case gauge.

The barrel is 16" (core 15 complete upper from Wantstalls, DD lower)

I will make some more brass over week end and try some 150gr.

 

[f55]

Tried 10 rounds of 150gr sp with 16gr of H110. I had a few ftf in each mag and 2 inch groups at 50 yards.

I will stick with 110gr over 19gr which gave just under inch groups at 50 yards

 

[Rookie{OMC}]

I was tinkering with 147 FMJs (IVI pulls I got from a fullbore shooter) and with 14.8 of H110
It was shooting 1 1/4" at 50 meters fairly consistently with a 11.5 " 1in8 barrel. Still haven't
settled on a load for that bullet yet.Waiting for the snow to go

 

[f55]

Found some 150gr fmjbt and 168gr amax, made some dummy rounds and both feed and extract fine with no damage to tips.

will try 16gr H110 for the 150gr and 14gr for the 168gr amax.

 

[Suputin]

I find the 110 VMAX is too short for the BLK in an AR. Seated properly in the case the OAL is too short and tends to cause stovepipe feeding issues. Getting anywhere near an OAL that allows reliable feeding means the bullets are barely in the case mouth.

I have switched to 125gr Ballistic Tips as they are long enough to fit into the case mouth and feed properly.

However most of the time I shoot 200gr subsonics as they are where this round really shines in an AR.

 

[f55]

I have shot 30 rounds of 110gr vmax with out issue, but the 150sp would ftf. I make a few dummy rounds of each and test to see how they feed.

Which 200gr do you use?

 

[Suputin]

Either 208 AMAX or 200gr Lapua subsonic.

 

[Paulinski]

Once my LMT barrel gets here I'm jumping on the .300 Blackout bandwagon...

I got few moulds to try from 150gr to 247gr...

 

[cr5]

So far my 110gr v-max and Speer 125gr TNT loads feed and cycle 100%, my 145 tracers, 155 A-max and 165 GMX are having issues. I shortened them slightly from where I started and they are feeding better now but most are short stroking and don't lock back after last round. I am going to concentrate on the 110gr v-max first and look for an accurate load then start moving up the ladder till I get them all working or give up on any that prove more troublesome than they are worth.
I bought a box of factory 208gr 300 whisper subsonic loads and they don't cycle in my gun either. I am running a PWS MK109 piston upper with 9.75" barrel and it only had a few rounds through it when I tried them so it may get better as it breaks in.
Factory Rem 115gr FMJ also feed and eject and lock back after last 100%.
I would have to check through my log book to give more details on the loads so if anyone is intersted shoot me a PM and I will be happy to share and exchange info.
Once I get some more time at the range and some better results with the chrony I am planning to start a thread and putting it all in there. My chrony didn't like the cold, I think it was actually the battery that didn't like the cold so I only got numbers for a few of the loads.

 

[Suputin]

So far my 110gr v-max and Speer 125gr TNT loads feed and cycle 100%, my 145 tracers, 155 A-max and 165 GMX are having issues. I shortened them slightly from where I started and they are feeding better now but most are short stroking and don't lock back after last round.

You are mixing up a few issues here.

OAL has three different variables associated with the magazine. 1. Too short and the lightweight bullets will cause the round to stovepipe as it pops out of the mag. 2. Too long and the tips will drag in the mag and cause feeding issues. 3. The ogive of the bullet can also determine length as the side rib of the mag will cause the bullets to toe-in as they go down the mag. This can also cause excess drag and feeding issues. Thus you need to find a seating depth that is long enough to allow the rounds to feed properly without binding up in the mag.

Short stroking is 100% a result of too light a load or too fast a powder. Both give an inadequate pressure pulse at the gas port. Either switch to a powder of a more appropriate burn rate or up the powder charge a bit.

I am going to concentrate on the 110gr v-max first and look for an accurate load then start moving up the ladder till I get them all working or give up on any that prove more troublesome than they are worth.

Personally I find the 110 VMax to be too short to work in the BLK. IMO the 125 Ballistic Tip is a better choice for supersonic. 150gr stuff is even better as it offers more hitting power and is easier to get to feed and function.

I bought a box of factory 208gr 300 whisper subsonic loads and they don't cycle in my gun either. I am running a PWS MK109 piston upper with 9.75" barrel and it only had a few rounds through it when I tried them so it may get better as it breaks in.

How long is your gas system? Reliable subsonic function requires a pistol length gas system. A carbine length system will make your life very difficult if you want to reliably cycle subsonics. The only thing you can do if you want to use factory subsonics is to open up the gas port and go to an adjustable gas block. With hand loads you can adjust powder and charge to get better subsonic cycling.