Reloading 300 AAC Blackout
By Major Rob Robinette
QuickLOAD Propellant Table for 300BLK & 130gr Barnes TSX
The 130gr TSX is an excellent 300BLK hunting bullet. Winchester 296, Hodgdon Lil'Gun and Hodgdon H110 work best with the 130gr TSX from a 16" barrel using the standard cartridge overall length (COL) of 2.26". You'll need to drop down a few grains since these are Dangerous Loads right at SAAMI max pressure of 55,000psi.
300BLK 130gr Barnes TSX Range Table
The bullet begins to go transonic just after 600 yards and the wind drift is 2.7mil at 600 yards. This range table was created using the best data from the propellant table above for a 16" 1:8 twist barrel.
QuickLOAD Propellant Table for 300BLK & 150gr Sierra MatchKing
QuickLOAD Propellant Table for 300BLK & 168gr Sierra MatchKing
Hodgdon H110 works best with the 168gr SMK from a 16" barrel.
300BLK 168gr SMK Range Table
The bullet begins to go transonic just after 500 yards and the wind drift is 3.0mil at 600 yards.
QuickLOAD Propellant Table for 300BLK & 175gr Sierra MatchKing
QuickLOAD Propellant Table for 300BLK & 190gr Sierra MatchKing
The 190gr Sierra MatchKing is the "sweet spot" of 300BLK bullet weight for long range shooting with the best combination of velocity at 600 yards (where the bullet begins to go transonic) and a wind drift of 2.4mil. For 300BLK long range shooting you can't beat the 190gr SMK.
QuickLOAD Propellant Table for 300BLK & 210gr Sierra MatchKing
The 210gr SMK slightly underperforms the 190gr SMK with the same wind drift but lower velocity at 600 yards.
QuickLOAD Propellant Table for 300BLK & 220gr Sierra MatchKing
Hodgdon Lil'Gun works best with the 220gr SMK from a 16" barrel for full speed, supersonic loads.
300BLK 220gr SMK Range Table
This is a case where the heavier bullet underperforms for long range shooting because the 210 and 220gr SMK takes up too much case capacity which cuts powder capacity and muzzle velocity too much. The 190gr SMK outperforms the 210 and 220gr SMK for short and long range shooting. Of course for subsonic shooting the 220gr SMK is king.
QuickLOAD Propellant Table for 300BLK & 220gr SMK SUBSONIC
Vihtavuori N133 works well with 92.7% case fill and 79% powder burn for 1100fps. Sochem S335 also looks good with 92.4% case fill and 76% powder burn.
300BLK 220gr SMK Subsonic Range Table
Using the Dillon RL550B Auto Casefeeder With Rifle Cartridges
Dillon states the RL550B auto casefeeder is for pistol calibers only. They want you to move up the the more complex and expensive XL650 to use an auto casefeeder on rifle calibers. Caliber conversions for the XL650 are much more expensive and difficult to swap out so the ability to reload rifle calibers on the RL550B with a casefeeder is a win-win. The big drawback of installing the auto casefeeder on the RL550B press is it makes it very difficult to load cases individually which means all rifle calibers become a real pain to reload. I was able to use an unmodified 32 H&R Mag Casefeed Adapter to auto feed 300 Blackout brass on my RL550B.
For .223 brass I milled a 3/8 inch x .9 inch long notch in the 9mm Casefeed Adapter to fit the taller brass. Warning: The modified 9mm Casefeed Adapter will no longer work with 9mm brass. I used the 9mm caliber conversion because I had it on hand but the 32 H&R Mag casefeed caliber conversion is a better fit and the feed ramp is better for both .223 & 300 BLK.
This method can be used for other rifle calibers. 308 Win uses the .45 Auto casefeed caliber conversion. The .308 case is tall and right at the clearance limit. The case may strike the die's decapping pin. I was able to shorten my decapping pin to get enough clearance to reload .308 with the casefeeder.
Left - 9mm Casefeed Adapter Modified to Work With .223 Brass
Right - 32 H&R Mag Unmodified Casefeed Adapter for 300 BLK
32 H&R Mag Feed Ramp with Filed Upper Edges
Before modifying the 32 H&R Mag feed ramp the bottom of the brass would float above the feed ramp floor. I beveled the upper edges of the feed ramp (Station 1 Locator) using the round face of a 6 inch file. I placed the file in a vise and slid the feed ramp back and forth to get the right shape to allow the .223 and 300 BLK brass to ride lower and slide along the bottom of the ramp.
I used a Dillon XL650 Small Rifle Casefeed Plate to drop the .223 and 300 BLK brass into the feed tube. You can also use the RL550B Small Pistol Casefeed Plate with the included spacer washer under it to drop .223 and 300 BLK brass. The Large Pistol Casefeed Plate with 2 washers installed works better than the small pistol plate. For .308 brass the XL650 Large Rifle Casefeed Plate is needed. You also have the option of simply hand filling the casefeed drop tube with brass.
Auto Casefeed Supplying 300 BLK Brass to the RL550B Progressive Press
The above picture shows the RL550B Small Pistol Casefeed Plate but the best solution is to purchase and install an XL650 Small Rifle Casefeed Plate.
I shot a short video showing how well the RL550B works with 300 BLK brass: youtube video showing the casefeeder in action with 300 BLK brass
It's very easy to change out the casefeeder caliber conversions. You simply slide the lower feed tube up an inch, pull out the Casefeed Adapter, pull out the Station 1 Locator (feed ramp) then swap in the new parts. If you need to swap the casefeed plates in the upper bin they simply lift out.
45 ACP Casefeed Adapter Modified to Work With 308 Winchester
308 Winchester is a tall case and the case may make contact with the decapping pin when loaded with the RL550B auto casefeeder. If you raise your decapping pin as high as possible while still reliably removing the primer the 308 case will usually clear the pin. You can also shorten the pin to help with clearance. When the case does make contact I simply give it a nudge with the eraser end of a pencil to push it in place for the resizing die. Keep the loading lever movement nice and smooth and even a tall .308 case can be auto fed.
300 BLK, 308 Win and .223 are my high volume rife cartridges, everything else I can load using a turret press.
I used the standard, Dillon recommended setup for loading 300 BLK on the RL550B: .223 shell plate and locator pins and the 7.62x39 AK powder funnel.
Although the XL650 Small Rifle Casefeed Plate works best with .223 and 300 BLK I tested the RL550B pistol casefeed plates and this is what I found:
14 Pieces of 300 BLK Brass
Small Pistol Casefeed Plate with No Washer = 0 cases dropped into the feed tube (brass fell out of plate holes)
Small Pistol with 1 Spacer Washer = 10 cases fed in 1 minute 30 seconds
Small Pistol with 2 Spacer Washers = 13 cases in 1:30 (bought extra washer at Lowes)
Large Pistol with No Washer = 0 case in 1:30
Large Pistol with 1 Washer = 6 cases in 36 seconds then no more for over 1 minute
Large Pistol with 2 Washers = 12 cases in 28 seconds then last 2 cases would not drop
47 Pieces of .223 Brass
Small Pistol Casefeed Plate didn't do well with .223
Large Pistol with No Washer = 0 cases (brass fell out of plate holes)
Large Pistol with 1 Washer = 19 cases in 3 minutes
Large Pistol with 2 Washers = 38 cases in 3 minutes
The Large Pistol Casefeed Plate with two spacer washers attached to the bottom of the plate works pretty well for 300 BLK and .223, at least with the small batches of brass I tested.
Enjoy your now more flexible RL550B now take a look at my online Recoil Calculator.
By Major Rob Robinette
US Army and Air Force (Retired)
Major Robinette was a Battalion Marksmanship Champion, Squadron Rifle Team Captain and Range Officer. Rob also spent 10 years as a federal law enforcement officer. He holds a Federal Firearms License and is the CEO of Nolichucky Guns. He enjoys all forms of rifle and pistol use.
The author shooting his suppressed Ruger Precision Rimfire with Gemtech Subsonic 2