Category Archives: cartridge recipes

300 AAC Blackout Subsonic Load Recipe: 190gr SMK using IMR 4198

Count IMR 4198 (as you can see in the photo it’s an extruded powder) among the options for powders that can be used for loading subsonic rounds that cycle in AR platform rifles. Recipe was created and tuned using a Lee Precision 4-hole Turret Press with double-disc powder throw and load both factory BLK brass and 5.56 brass trimmed to 300BLK specs.

Performance: This recipe successfully cycles both a carbine length upper (and gas system) with a 16″ barrel and also a 9″ pistol length upper, w/o suppressor. No bolt hold-open on either upper in my testing. No signs of overpressure or instability. The test cartridges sounded quieter than the LilGun loads I fired afterward. Chrony readings coming soon. 

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.Com neither assumes nor authorizes any person to assume for it any liability in connection with the use of any data.

Caliber: 300 AAC Blackout (300 BLK)

Projectile: 190gr Sierra Match King HPBT

Primer: Winchester Small Rifle Primers

Powder: IMR 4198

Measure: 11.0gr

Lee Auto-Disc setting(double disc): Top Disc 0.43 | Bottom Disc 0.47

Min OAL: 2.222

Max OAL: see discussion below

Regarding OAL I had to experiment to find a length that fed well. Here is my thought process to arrive at the OAL I set my dies to:

  • The standard AR-15 mag accepts cartridges up to 2.260 OAL
  • The SAAMI Specs show an acceptable range of 1.78-2.260 OAL for the 300 BLK (although 190gr SMK is a long projectile and as such will require a longer min OAL than the range defined in the SAAMI spec)
  • My personal Min OAL: 2.140 to accommodate projectile length

This seems like a pretty big tolerance but remember that the BLK supports a wide range of projectiles that are different lengths. Since the 190gr SMK is one of the longer BLK projectiles I set my seating die to give me the longest possible cartridge-about 2.220 and ranging up to 2.240. 

300 AAC Blackout Load Recipe: 220gr SMK using LilGun

When I started researching recipes for 300 BLK subsonic loads the recommended powder was Accurate 1680. The Interweb phenomenon took hold and now there is a false impression that 1680 is the only powder that works for subsonic AAC Blackout loads.

Slowly the truth is getting out there- and I can now personally confirm success with LilGun as an alternative to 1680 for subsonic BLK loading. Also LilGun requires less charge per round than 1680– so it’s even more efficient– it’s my new preferred powder. More alternatives here– I plan to work on IMR options next.

Recipe created and tuned using a Lee Precision 4-hole Turret Press with double-disc powder throw and load both factory BLK brass and 5.56 brass trimmed to 300BLK specs. I recommend using LC brass when possible as I find its the most consistent. I still use CCI #400 primers, although you should note that these primers are a little soft so CCI #41 primers are best.

Performance:This recipe successfully cycles both a carbine length upper (and gas system) with a 16″ barrel and also a 9″ pistol length upper, no suppressor. No bolt hold-open on either upper, but that could be the PMAGs I used. No signs of overpressure or instability. Chrony readings coming soon are here and I had no problems dinging a 100yd target with these without hold-over.

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.Com neither assumes nor authorizes any person to assume for it any liability in connection with the use of any data.

Caliber: 300 AAC Blackout (300 BLK)

Projectile: 220gr Sierra Match HPBT

Primer: CCI Small Rifle Primers (no. 400)

Powder: Hodgdon LilGun

Measure: 8.8gr

Lee Auto-Disc setting(double disc): Top Disc 0.30 | Bottom Disc 0.30

Min OAL: 2.140

Max OAL: see discussion below

 

Regarding OAL I had to experiment to find a length that fed well. Here is my thought process to arrive at the OAL I set my dies to:

This seems like a pretty big tolerance. I set my seating die to give me the longest possible cartridge-about 2.220 and ranging up to 2.240. Some factory ammo I purchased didn’t feed well due to FTC (Failure to Chamber). It turned out that they were the short end of the SAAMI OAL specs. Some scouring on forums and experimentation proved that longer OAL fed better : no FTCs on any of my BLK cartridges since this change.

 

The beauty of using these high mass projectiles in a modern sporting cartridge is that they pack a serious punch and don’t use much powder– a nice bonus when supplies are scarce or you’re on a budget.

 

235 gr softpoint 300 BLK Subsonic load recipe

Performance

11 test rounds were fired at a local range using a friendly neighborhood SDN-6 suppressor. No signs of excess pressure on any cases. The cartridges fed out of a Gen3 PMAG30 with no problems.

The bolt cycles but does not lock open (no BHO) after the last round clears in a 16″ Model 1 upper with a 1:8 barrel twist (if you somehow ended up with a twist slower than 1:8 or 1:10 it will be frustrating if not impossible to stabilize a subsonic projectile).

There was one potential keyhole but I cant tell for sure. This range is really splashy and I regularly get splash rips in targets– UPDATE: I tried another 15 rounds today – heavier crimp this time but no keyholes and decent accuracy (T1 turned out to be pointed a few clicks left – I figured that out after this group and the can shifts impact about 1″ downward).


As always with load recipes YMMV so consider this a starting point, be cautious and be safe. Chrony results can be found here.

Components

A word on powder: Accurate 1680 is tough to find sometimes but the powder density matches the case capacity very nicely in the BLK. More on alternative powder options here. I use CCI primers because they are a bit faster burning than Winchester and that’s handy for subsonic loads to help ensure you maximize ignition to help cycle the action.

These projectiles came from Hunters Supply and as mentioned below are 235 gr soft point cast boolits. No gas check on these. They cost about the same as 220 gr SMKs but expand much more nicely:

 

KB ALERT: Winchester or a similar, harder primer (iow avoid Federal primers for more reasons than the name) are the only safe ones to use in a Lee Progressive loader-be sure you use the correct type of primers with a Lee Progressive system. Make sure you read up on what sort of primers are safe for your loader.

Reloading Press

I run this load recipe on my Lee Precision 4-hole Turret Press and am using a mixture of RP factory BLK brass and Reformed 5.56 brass (LC and PMC- note that not all PMC brass has the proper casewall thickness to work for BLK) trimmed to 300BLK specs.

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.com neither assumes nor authorizes any person to assume for it any liability in connection with the use of any data on this site.

Load Data

Caliber: 300 AAC Blackout (300 BLK)

Projectile: 235gr cast soft point, no gas check

Primer: CCI Small Rifle Primers (no. 400)

Powder: AA1680

Measure: 10.8 gr

Lee Auto-Disc setting: .71

Min OAL: 2.220 in.

Max OAL: see discussion below

my optimal OAL: 2.223-2.227in.

Crimp: I am experimenting with crimp to help secure the projectiles so they chamber as expected. I will update this when I have results

 

Here is my thought process to arrive at the OAL settings I use:

 

Joe Biden Projectile Test

Joe Biden wishes all bullets were made of chocolate.

[

 

What difference does THAT make?

.40 S&W target load recipe

Unless this is your first visit to this site you likely have a sense that I believe in the phrase Train to Maintain. That equates to some level of live fire practice and live fire requires live ammo. This is the recipe I use for my training ammo. It's based on efficiency- don't get wild with your powder, don't get wild with a heavy practice projectile. The most reasonably priced projectiles I like to work with for my .40 are 135gr FMJs from Berry's Mfg. Cheaper projectiles can be found- for example lead wadcutters can be had for half the price- but I just like the glimmer of the copper jackets.

Reloading Press

I run this load recipe on my Lee Precision Pro 1000 Press and load once-fired brass (both factory and re-mans) along with a bunch of range brass I foraged from various ranges. If you're starting out with a caliber range brass can be a really useful way to build up your brass on the cheap- just be sure to scrutinize those empties for damage and compliance with spec.

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.com and its contributors neither assume nor authorize any person to assume for it any liability in connection with the use of any data on this site.

Load Data

Caliber: .40 S&W

Projectile: 135gr FMJ

Primer: Winchester Small Pistol Primers

Powder: Winchester 231 or HP-38

Measure: 6.3gr

Lee Auto-Disc setting: 0.57

Min OAL: 1.125 in.

Max OAL: 1.135 in.

KR-15 optimal OAL: 1.130 in.

I calibrate my bullet seating to hit the middle of the tolerance- theoretically that will result in more usable rounds because the variance in either direction is the most forgiving.

 

178gr A-Max Subsonic 300 AAC Blackout Load Recipe

Hornaday makes some really interesting projectiles. While the gel block above is a supersonic impact from a .308 you still get the idea that this could be a sweet BLK projectile as a sub or a super. A really thin casing and excellent expansion are the hallmarks of this projectile and should pack a punch. As if the gel block wasn’t compelling enough the loaded cartridges have a red tip that looks positively evil. Do me a favor and don’t let the Antis or Common-Sense Gun Violence Prevention Groups (sic) learn about these- they look so damn scary we may have to fight another gun control law over them.

Many of the newer Hornaday projectiles have polymer tips and come in heavier weights that can be loaded for subsonic use in the 300 Blackout. The tip helps when loading a cartridge like the 300BLK because it helps the cartridge navigate the feed ramps and chamber (see OAL notes at the end of this post). The tip also resists deformation if it has a rough ride to the chamber.

Performance

Seating projectiles to a longer (but safe) length in my own Blackout ammo has resulted in reliable feeding- please be sure to stay within the safe range of COAL (lower limit= minOAL…for upper limit stay under max OAL in SAAMI specs) when tuning your own load recipes.

The bolt cycles and locks open after the last round clears in both my 16″ rifle and a 9″ AAC pistol (after seeing how nice those AAC uppers are I need to start saving my pennies for one of my own). The test rounds fired a sub-MOA group at 50 yds.

Chrony results can be found here

Components

A word on powder: Accurate 1680 is tough to find sometimes but the powder density matches the case capacity very nicely in the BLK. More on alternative powder options here. I use CCI primers because they are a bit faster burning than Winchester and that’s handy for subsonic loads to help ensure you maximize ignition to help cycle the action. KB ALERT: Winchester or a similar, harder primer are the only safe ones to use in a Lee Progressive loader-be sure you use the correct type of primers with a Lee Progressive system.

Reloading Press

I run this load recipe on my Lee Precision 4-hole Turret Press and load both factory BLK brass and 5.56 brass trimmed to 300BLK specs.

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.Com neither assumes nor authorizes any person to assume for it any liability in connection with the use of any data on this site.

Load Data

Caliber: 300 AAC Blackout (300 BLK)

Projectile: 178gr Hornaday A-Max

Primer: CCI Small Rifle Primers (no. 400)

Powder: AA1680

Measure: 10.8gr

Lee Auto-Disc setting: 0.71

Min OAL: 2.210 in.

Max OAL: see discussion below

my optimal OAL: 2.223-2.227in.

 

Regarding OAL I had to experiment to find a length that fed well. Here is my thought process to arrive at the OAL settings I use:

This seems like a pretty big tolerance vs any handgun OAL range. Some factory ammo I purchased didn’t feed well due to FTC (Failure to Chamber). It turned out that they were the short end of the SAAMI OAL specs. Some scouring on forums and experimentation proved that longer OAL fed better : no FTCs on any of my BLK cartridges since this change.

 

Internet reloading recipes- a cautionary tale

Wildcatting, the practice of making interesting and unconventional cartridges together, is one of the attractive qualities of the 300AAC Blackout offers. That magnificent achievement (insignifia of the day: 300 WTF was its nickname before AAC finished the BLK project) is capable of sending a diverse range of projectiles downrange- 110gr to 225gr is typical. Compared to .243 Winchester, which typically ranges from 55gr-117gr, it's a big difference.

Another reality of owning and feeding a 300 BLK is that while manufacturers are continuing to add 300BLK product lines it's hard to find much besides 220gr HPBT or 110gr FMJBT rounds. That commercial stuff is pretty expensive too- limited availability pushed ammo into the $1-2 per round price range last time I checked. So why not load your own 300 AAC ammo and embrace the diversity of options and lower prices?

Well, handloading is an inherently dangerous activity if you arent really careful. Your ammo is only as trustworthy as the data (aka recipe) you use to determine whether or not a cartridge is safe. Fortunately it's typically not difficult to find reliable data- that's why there are multiple books published, Quickload software, and for the really brave/lazy people, the interwebs.

The BLK is still pretty new by firearm standards… My Lee Precision Loading Manual doesn't have any BLK data. The dies I got from Lee (they make a great product for the hobbyist and sell at a very fair price compared to their competitors) came with some data but it doesn't cover all the different projectiles you can find in 7.62 NATO/.308 – not even close. Now what? Google is my pal. I search for everything and crowd-source info. The limits for your recipe should be constrained by either published data or from a reliable piece of software like quickload. Here is a scary example of why I look for a credible source to add confidence to load data…

Recently I switched my loader from subsonic to supersonic settings to pound out some rounds. One small problem- I didn't adjust the bullet seating die as far as I should have, and the subsonic projectiles seat a lot lower and logically use a lot less powder. I didn't notice until a few cartridges seemed notably short… and I googled a recipe and according to it I was at a safe COAL (Cartridge Over All Length). It must be confusion because Its been a few months since I ran this load, right?

I was unconvinced…being cynical is a good trait for this sort of work. So I took a second look at my notes and measured a few rounds (3)left over from a range trip as check measurements. The internet load had a way shorter OAL(Over All Length- same as COAL) than a recently published load by Accurate Arms (links to the bad data and good data are below) and I trust them since they manufacture the powder and therefore have a lot to lose by publishing recipes that aren't checked for safety.

Under Pressure

Thank goodness I followed my instincts. Check out the pressure graph I found from a quickload user on blktalk:

In case this is the first time you have seen one of these graphs, note how the red line makes that lovely crest above the dotted horizontal line labeled 'Max Pressure'? See how that dotted line is preceeded by a reddish zone under it? That's very bad- as in KB (ka-boom!). Also red bars and the word DANGER in all caps in the upper right corner indicates that you don't want to put these rounds anywhere near a chamber.

This powder and measure really fills the case, so I wanted to be sure that nothing measured up short. I was happy to remove and dismantle the 4 or 5 that were below Min OAL of 2.140nafter remeasuring. I actually have had the best feeding performance using longer COAL. I gradually increased the OAL until I found a setting that fed more easily.

COAL Constraints

Longer OAL doesn't increase the pressure so as long as the round is shorter than max oal fits in the mag and cycles the action you're good to go as long as you don't seat the bullet too short on the powder and create excess pressure – aka anything under Min OAL.

The other limit for length is max OAL to ensure your projectile or bullet doesn't get lodged past the chamber- that is also unsafe and can cause dangerous chamber pressure. Use the SAAMI specs and the pressure limit/published min OAL checks as your safety constraints.

Brain break while that last part soaks in…FUN BLK FACT OF THE DAY: the reason subsonic 300 BLK loads cycle the bolt is because the projectile is heavy. For this reason most 5.56 subsonics won't cycle with a standard gas system.

The Reliable 1680 Load Recipes

The data I trust and have used successfully in the past is published by Accurate Arms– they make the powder so I trust their recipes. Also it worked safely in the past.

The Unsafe Load Data that should NEVER be used

This file came up high in search results for 150gr OAL data – IT IS UNSAFE AND SHOULD NOT BE USED. The min OAL listed for 150 gr FMJBT is way too short for 1680 powder here. It's a nice looking document but if the 1680 data is that wrong it's not trustworthy. Also the parent domain has nothing to do with firearms or reloading – further making the doc suspect.

Be careful with your recipes- safety should always be the first priority.

 

Alternative powders to AA1680 for 300 Blackout

According to the metrics this site gets more than a couple visits from people looking for load recipes and info on components for 300 AAC Blackout cartridges. It seems that 1680 is even more scarce in the wake of the biggest gun and ammo buy in history – so I will do my best to assist.

DISCLAIMER: Use this information at your own risk. Just because these settings work for me (or in some cases below someone claimed they worked in an internet post) and my rifles it does not guarantee that they are safe for you to use—in no way can I guarantee that these recipes won't injure or kill you. I strongly advise reducing your starting load and working your way up.

I also strongly advise using Quickload or something similar to ensure safety when experimenting with load recipes. Ammoguide.com is a pretty nice subscription-based site I recently joined that has vast resources, tools, load data and info. Handloading is a dangerous activity and mistakes can have serious consequences- picking little shards of aluminum out of your face, losing fingers, even death. Please be extremely safe and extra cautious while reloading and proving out recipes.

Accurate Arms 1680 is nice for the BLK because the powder charge matches case volume nicely- not a ton of space inside a cartridge…. 1680 is a popular wildcat and 5.56 powder also though– a few years ago 5.56 subsonic loads were a popular home recipe (and still are although it's tough to get a standard gas system to cycle the action and still stay below 1100 fps velocity in a 5.56). 1680 is a decent powder for supersonic 5.56 handloads also– it's typically not easy to find, especially in the current market climate of constrained ammo and components.

Fast burning low volume rifle powders are a must for the BLK and even some pistol powders can work- while this is traditionally viewed as dangerous since pistol powders burn too fast for rifle loads the AAC Blackout is an exception. Not only is the case small to begin with but once you add a .308 projectile the room for powder gets scarce.

Another thing to consider is the projectile you are loading. The two I stick with most of the time are 220gr HPBT (Sierra) and 150gr FMJBT- if you need to know that projectiles should be .308 caliber you probably should refer to the disclaimer above, stop reading this and learn about the 300 AAC Blackout cartridge and maybe about basic handloading.

110gr is supposed to be the ideal projectile for performance and range in The BLK. I am a subsonic fan though so I prefer the 205gr and higher weight projectiles since they are easier to keep under the 1100fps threshold. The 150gr FMJs are more economical for range loads- at least for copper jackets from Barrys. Projectiles can make a big difference though when it comes to powder.

Powders that cover most 300 BLK projectiles

Hogdon H110 works well for 110-220gr projectiles. Note: H110 loads should never be reduced by more than 3%. Tuning any lower can result in inconsistent burn- aka squib loads- aka projectile in the barrel just waiting to become a KB.

Hogdon H110 isn't bad according to Foghorn (who graciously loaned the header photo you see on this site).

Hogdon Lil Gun and IMR 4227 also have good coverage across the realm of projectiles for the Blackout.

Powders for specific 300 BLK projectiles

IMR Trail Boss is an interesting critter. It was designed for Cowboy Action pistols but is one of those pistol powders that performs well at high density and voila! Is a handy charge for the BLK. My data suggests that Trail Boss is better for the smaller projectiles (110-115gr). Bonus: Trail Boss is the proverbial cat's ass if you're looking for subsonic 110-115gr loads.

For 220gr loads check out VithaVouri N130- look at post by civilian75 here for details. Also the AA5744 looks like a good match according to Accurate Arms

Reloader 7 (R7) also has a good reputation for subsonic 208gr and heavier projectiles.

Unique is another powder that is popular with the Wildcat crowd. Some people tell me it's ultra frustrating to work with and others rave at the versatility of the stuff. I have no experience with this one so you will have to scour the forums for load data. Try 300blktalk.com to get started.

 

subsonic 300 AAC BLK (Blackout) load recipe

The BLK was designed to accommodate both supersonic and subsonic ammo without any tuning or performance headaches. The subsonic loads are intriguing: who wouldn’t want to send a 220gr Sierra HPBT for a big, heavy projectile to create high performance at subsonic fps. That’s a mere 3.4 times heavier than common 62gr 5.56 ammo. 5.56 ‘heavy’ projectiles weigh in at 75-80gr. The BLK was designed to run suppressed too- so if real quiet os your bag and you I enjoy some closer range shooting (effective hunting range is about 100m). 

This is the recipe I use for supersonic loads for my Model 1 300 Blackout Carbine. About 50 rounds of this recipe fired through my 16″ rifle at distances up to 200 yards to punch paper and plink. I’m using 220gr Sierra Match HPBT for the projectiles and AA1680 for powder. The bolt locks open after the last round clears.

Accurate 1680 is tough to find sometimes but the powder density matches the case capacity very nicely in the BLK. rI use CCI primers because they are a bit faster burning than Winchester and that’s handy for subsonic loads to help ensure you maximize ignition to help cycle the action. KB ALERT: Winchester or a similar, harder primer are the only safe ones to use in a Lee Progressive loader-be sure you use the correct type of primers with a Lee Progressive system.

I run this load recipe on my Lee Precision 4-hole Turret Press and load both factory BLK brass and 5.56 brass trimmed to 300BLK specs. 

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.Com neither assumes nor authorizes any person to assume for it any liability in connection with the use of any data.

Caliber: 300 AAC Blackout (300 BLK) 
Projectile: 220gr Sierra Match HPBT
Primer: CCI Small Rifle Primers (no. 400)
Powder: AA1680
Measure: 11.2gr 
Lee Auto-Disc setting: 0.71
Min OAL: 2.140
Max OAL: see discussion below
 
Regarding OAL I had to experiment to find a length that fed well. Here is my thought process to arrive at the OAL I set my dies to:
This seems like a pretty big tolerance. I set my seating die to give me the longest possible cartridge-about 2.160-2.200. Some factory ammo I purchased didn’t feed well due to FTC (Failure to Chamber). It turned out that they were the short end of the SAAMI OAL specs. Some scouring on forums and experimentation proved that longer OAL fed better : no FTCs on any of my BLK cartridges since this change
 
The beauty of using these high mass projectiles in a modern sporting cartridge is that they pack a serious punch and don’t use much powder– a nice bonus when supplies are scarce or you’re on a budget. Did I mention that the BLK delivers the same amount of muzzle energy from a 10.5″ barrel as a 5.56 does out of a 16″ barrel? 
 
 

supersonic 300 BLK recipe: 150gr FMJBT

This is the recipe I use for supersonic loads for my Model 1 300 Blackout Carbine. Over 500 rounds of this recipe fired through my 16″ rifle at distances up to 200 yards to punch paper and plink. I use Berrys 155gr jacketed .308 FMJBT for the projectiles and AA1680 for powder. The bolt locks open after the last round clears.

The reason I didn’t go with a 110 or 135gr projectile is pretty much convenience: I like using Berrys plated pistol bullets for my handgun training ammo and this was the lightest (therefore cheapest) .308 boat-tail they carry. At about $0.22 each (although who knows what price they will come back at after they clear the 6-8 month order backlog) it makes plinking rather affordable with the BLK compared to the luxury factory ammo prices as production ramps up. Based on recent news this wont happen until a few months  after the current logjam on ammo production is cleared

Accurate 1680 is tough to find sometimes but the powder density matches the case capacity very nicely in the BLK. I use CCI primers because they are a bit faster burning than Winchester and that’s handy for subsonic loads. KB ALERT: Winchester or a similar, harder primer are the only safe ones to use in a Lee Progressive loader.

I run this load recipe on my Lee Precision 4-hole Turret Press and load both factory BLK brass and 5.56 brass trimmed to 300BLK specs.

Update: I notices some pressure signs on my brass and have adjusted the starting load to lower the charge. Please update your records accordingly.

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.Com neither assumes nor authorizes any person to assume for it any liability in connection with the use of any data.

Caliber: 300 AAC Blackout (300 BLK) 
Projectile: 150gr jacketed FMJBT
Primer: CCI Small Rifle Primers (no. 400)
Powder: AA1680
Measure: 18.0 gr starting load
Lee Auto-Disc setting: 1.18
Min OAL: 2.140
Max OAL: see discussion below

Regarding OAL I had to experiment to find a length that fed well. Here is my thought process to arrive at the OAL I set my dies to:
This seems like a pretty big tolerance. I set my seating die to give me the longest possible cartridge-about 2.200. Some factory ammo I purchased didn’t feed well due to FTC (Failure to Chamber). It turned out that they were the short end of the SAAMI OAL specs. Some scouring on forums and experimentation proved that longer OAL fed better : no FTCs on any of my BLK cartridges since this change

Be safe and have fun out there. As you can see I had one flyer at 100m but I’m pretty sure that was just me getting settled. Sorry but its just that fun to use this short range tackdriver and it’s still a group you can be proud of.