Category Archives: Handloading

Impressive Energy Transfer

Lehigh Defense is one of a small number of manufacturers producing specialty projectiles that can do some amazing things- such as expand at subsonic velocities. One of their more intriguing products is the controlled chaos projectile.

Check out the video for a slick animation showing the 3 components of the bullet with some awesome field testing footage, guest starring auto windshields and watermelons!

And yes, they make projectiles specifically for the 300 BLK.

Initial Impressions of my Chrony F1

Recently I decided to quit borrowing other people's chronographs and instead purchase my own.

A basic Chrony model F1 with a tripod costs about $100 from Amazon. With the optional pushbutton remote the F1 is capable of displaying the stats for several strings of 10 shots (either 6 or 10 if I recall correctly). You can either buy the remote from a retailer for $20 or make a simple remote with <$10 of supplies from radio shack.

I found that it was easy to use, worked great with my homemade remote and helped me capture solid data on my LilGun recipe for 220gr 300 BLK Subsonic handloads.

One note to other buyers: although the directions claim you don't need the sunshades over the top of the cameras on a cloudy day it's worth leaving them on all the time- on this particular cloudy day I had to aim really low to get readings from the 9″ barrel and ended up aiming more closely than intended…


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.


Where I get my BLK Brass

While you can make your own BLK brass I don't have a bunch of .223 or 5.56 brass just laying around. It's not difficult to make your brass but right now I'd rather focus on other things. The problem with ordering brass online is that you don't always know what the quality will be like (for example all my FTCs from and prices vary widely.

Recently I found a place that delivers the best brass I have seen to date at a fair price: . I bought a sample 100 pieces of LC brass and am very impressed. Outstanding responsiveness too- never waited more than 24 hrs to hear back from them.

  • Mirror shine on the cases- you can see into them while loading
  • Every piece ran through my Lee dies like butter
  • Test firing went as expected- no problems feeding, chambering, ejecting. Fired cases look good.


Chronograph results- at long last

I finally got to borrow a chrony and made the most of it- here are the results of testing the recipes listed here on an 85 degree summer day. Test results are the average of 3 shots and were fired out of a 16″ barrel- so velocities are higher than what you could expect from a shorter barrel.

I also noticed something interesting while testing: the PMAG30 doesn't hold open when empty but the USGI and Promag mags do- even with subsonic loads.


If you’re new to reloading – know your squib

This is a good overview of squib loads. If you want to load your own ammo take note- squibs most often happen on reloads. This has nothing to do with remanufactured ammo- it typically has to do with paying attention to what you're doing when you run the press. I only had this happen once and I can guarantee you I lost track of what I was doing at that moment and didn't have a good process for walking away from my press and resuming- it resulted in me seating a projectile in a cartridge that didn't have a charge. Anyhow here are a few salient points I want to reinforce about detecting and dealing with squib loads.

  • Pay attention to the sound- when only the primer goes off it sounds different. If something sounds different while you're shooting, stop and check it out (DGU may be a different story but you shouldn't be using handloads in a defensive firearm).
  • The unburnt powder depicted in the video may or may not be present. If something seems wrong check the barrel- it's not worth a KB in your hand, especially if you stop because something seemed peculiar.
  • If this does happen to you, how to get the bullet out? It's typically best to back the bullet out the way it entered the gun. Normally that's also the shortest path too. Note that it may take a vise and you may trash a pushrod doing this…or you can always ask your friendly neighborhood armorer to take a look, but what fun would that be?

Avoid for BLK brass

About one year ago I needed more brass for my 300 AAC Blackout (BLK). A quick interweb search led me to a promising site at . It looked to me like this place knew what they were doing and seemed to be turning inventory quickly. Prices were not awful but I wanted something I could quickly load without investing any time into making my own BLK brass.

Getting the brass delivered was the challenge. My experience resulted in 5 phone calls beginning 4 weeks after ordering – each ended with a pledge from to ship 'by the end of the week'. Apparently my experience was one of the better ones…

As if that isn't irritating enough I recently started using my brass from these jokers and guess what? Out of the first 130 pieces I have had about 10 FTCs (failure to chamber). That is likely because the. Brass is PMC and as noted here PMC can be a headache because the case wall thickness is not consistent. It's been increasingly frustrating as I go through more of the brass- for example I had a FTC rate of 1 per every 10 at my last outing.

The company is focused on reprocessing once-fired brass. However their primary customer base is large manufacturers of ammunition- companies who order 10k or more pieces at a time. This helps explain why orders in the 1-2k piece range aren't a high priority for them. Also the unprecedented demand for ammunition means that turning 5.56 brass into BLK brass means more overhead (labor and handling) for them…I know this from talking with someone in their shop who answered the phone on one of my 6 calls to see when my order would ship.

If you are looking for BLK brass my suggestion is to either:

  • Get your hands on some high-quality brass like LC, Federal, Winchester, Remington (R-P) and make your own- its not exceedingly difficult as long as you start with consistent cases.
  • Buy preformed BLK brass from a different vendor- a little Internet searching can yield good results- Midway sells pre-primed brass for example. Also take a look at 300blk forums to see what others report as good experiences.


Barrel Twist: why does it matter?

A lot of people at ranges across America are probably couldn't tell you what the barrel twist rate is or their rifle without looking. As noted above, barrel twist is the number of inches spanned in one complete rifling rotation- iow how fast is your projectile spinning by the time it exits the muzzle? Twist rate is commonly noted as a ratio- for example 1:8 (the preferred 300 BLK twist rate- especially if you want to shoot subsonic ammo). Barrel Twist also has an effect on the projectile weight you use:

Common barrel twists for 5.56 AR-15 rifles:

1:9 – does not stabilize heavier projectiles well (55gr and up- you will see 'keyhole' hits on your targets); stabilizes lighter projectiles extremely well (like varmint bullets)

1:7 – stabilizes heavier projectiles well ; stabilizes light projectiles well enough. You can't go wrong with a 1:7- that's what the US Military uses.

Common barrel twists for .308 Bolt Action rifles

When shopping for bolt actions twist becomes an important consideration if you want to be able to use and experiment with subsonic loads. Bolt actions can have different twist rates (and barrel lengths – which also factors into stability with heavy projectiles) than the ones listed here so it's worth some investigation before you make a decision.

1:16 – will not stabilize a heavy subsonic projectile (200gr and higher) in .308

1:10- will nicely stabilize a heavy subsonic projectile and also stabilize lighter projectiles well enough

Common barrel twists for 300 BLK (AR-15 platform) rifles

1:8 – this does the trick and supports whatever you send downrange regardless of the muzzle velocity

1:10 might stabilize a 200gr projectile at subsonic speeds but you are severely limited in projectiles with a 1:10 BLK barrel

The bottom line here is that you should be certain that your 300 Blackout kit has a 1:8 barrel- there isn't a good reason not to.

How to analyze your brass for signs of Overpressure

Some people say that you should only reload brass certain number of times before you should throw away. While no one wants to blow up their gun with a bad cartridge it is up to each individual to work within safety contraints they are comfortable with. A more rational and economical method exists, IMHO: Inspect each piece of brass around the second use and discard them once you start sending text signs of overpressure. You also should closely inspect spent cases when testing a new load recipe- regardless of whether or not you saw it published somewhere.

Pro tip: Heavily scrutinize R-P brass stamped with “AAC 300 Blackout”. It is the thinnest brass I have ever seen- as in .22 thin. After 3-4 tours of the supersonic circle of life (they were factory cartridges) I am seeing some wear on some of them- imprints and case head separations. While having your bolt stick or seem 'heavy' is a strong indicator that something is wrong with the ammo there are some subtle (and not so subtle) things you can watch for that indicate overpressure…

A progression of flattened primers under increasing pressures

  • Flattened primers
  • This is commonly cited as the thing to look for but it is not an absolute. Some primers will flatten at safe pressures, some won't flatten at all and some primers can even blow out of the cartridge. Definitely check for additional indicators if you see this though- I view oddball primers as the clue that closer investigation is required.
  • Ejector imprints
  • These are another sign that merits closer investigation. Note how the case on the right shows that dark ring- this is also an ejector imprint. While there are some reasons that you may get these without overpressure being involved the way I see it is that 2 possible indicators deserve a close look at the case and double-checking the cartridges.

  • Greatly enlarged primer pockets :
  • Easily identifed by misshaped primers- during ignition the primer flows into the new bloblike shape of the primer pocket. You can also see dark rings around the primer- an indication that the primer pocket is no longer sealing off ignition (read: throw that case away). Note that you may not always see such dramatic rings like the ones above

If you see any of the three overpressure signs listed above you can test the primer pocket:

  • Decap suspect brass and try to press the case head over a primer by hand. If the primer doesn't hang up a little the case is no longer safe to use.

Dangerous and Certain Signs of Overpressure or Excessive Case Wear

If you encounter anything that resembles the two indicators listed below JUST DISCARD THE CASE. Also double check you load data and for your own safety pull the bullets and recycle your components from that batch of ammo. It can be really frustrating but safety and precaution should be guiding principles when reloading.

  • Case Head Separations
  • When the case fires the head of the cartridge wears and reloading dies cannot replace that material. The case stretches too- if you are trimming your rifle cases excessively start watching for lines like the ones above on your cases. Even if you are not yet trimming the brass don't reuse cases like this because you surely do not want the head to shear off during ignition.
  • Case Ruptures
  • Case ruptures are a definite warning sign. If you see anything like the cases above while testing a handload or any other ammo please stop firing it immediately. Follow up by disassembling any remaining loads from that batch and back your load recipe down a grain.

For a handy review or future reference this video has great examples and explanations:


235 gr softpoint 300 BLK Subsonic load recipe


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.


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. 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: