Powder charge for 300-BLK

[rustyinbend]

I'm scratchin' my head a little on this one. Here's the story ... I've always reloaded 300-BLK subsonic, and decided to build a standard velocity cartridge just because ... well ... because I can.

I have two bullet candidates sitting on the shelf ... Sierra MK 125's, and Hornady VMax 110's. Figured I'd work up a load on both. Since I'm using IMR 4227 (also a bunch on the shelf), I used the Hodgdon Reloading site and did what I usually do, start with an average mid-way between the Start and the Max. Started with the SMK-125 and got a charge of 16.6 and COAL of 2.060 ... loaded 50 with no issues, but the case is definitely full to the neck, maybe even compressing a teensy bit during seating.

Now as I look at the reloading data for the Hornady VMax 110's, it's saying a Start of 19.0 and a Max of 20.0 ... which gives me 19.5 and literally fills the entire case ... also saying the COAL should be 2.050 resulting in an even more deeply seated bullet (in an already totally full case).

So my questions are:
(1) Should I just use the SMK-125's that fit nicely and forget about the HVM-110's?
... or ...
(2) Should I load up the HVM's as directed and compress the crap out of them (or increase the COAL) (or both)?
... or ...
(3) Should I decrease the SMK's below the Start level and try shooting a reasonable charge that fits the case?

Anybody hit this situation before, and what did you do about it. Right now, I've got 50 cartridges of SMK-125's and plan to go shoot those tomorrow and see how they perform.

BTW ... my subsonic load is great ... I use Hodgdon L'il Gun (8.4gn) and SMK 220's. Good groups, nice and quiet. Only down-side is that the L'il Gun is really a "sticky" powder and it's a pain in the ass to empty and clean out my ChargeMaster. Probably need to work up a good subsonic load with the IMR 4227 someday soon.

 

[spife7980]

I’m assuming this is for an ar? What brass?

I use the 125 pro hunters in federal brass with cfe blk (I know not applicable) but I realized I was hitting max compression driving seating depth beyond book spec with cfeblk before the book said I should be.

At all depths it shot best when just compressed not not effecting seating depth. Worked out to 19 something grains of cfeblk when the book max was like 21 (it’s been awhile).

If an ar I would go book max length or as little in the case neck as you are comfy and still feed and just let the speed be what it is, don’t chase it. It will never be a 30-30 so don’t try. 1900 vs 2100 won’t make a lick of difference in real world application. It’s a blackout so make it how we you need for best accuracy and have a ball. It’s a lawn mower cartridge, not a Ferrari.

If a bolt have fun making your lawn mower a dragster.

 

[rustyinbend]

Yup ... it's an AR ... Adams Arms (adjustable/piston) ... a very nice rifle. Brass is StarLine once-fired.
Thanks for the advice. I also have some CFE-BLK ... might try that too.

 

[Bobby Ball]

Just wanted to throw a learning experience in since I just recently added 300bo to the reloading list. The max length can vary greatly depending on the bullet profile. I had some eld's laying around, and I had picked up a box of some Hornady sub-x (175). And I had started loading everything, like a full run, maybe a hundred pressed ready to shoot. And everything was right in the middle of all the spec that I could find. (That's me assuming the credibility and guilt, lol). So in the most amateur way possible, before I put everything up for the night to take to the range first thing in the morning, I just wanted to verify that they fed through the mag and chambered properly etc...

Of course, they didn't. Not even close. (Like 40 thousandths). Of course I'm sitting there dumbfounded with a stupid wtf look on my face as I'm looking over the cartridge drawings and load info for what must have been 45 minutes...
Like an idiot...
Until I finally realized how much different the shape of the subsonic's compared to some super high bc bullets really was, and how much of a difference in the CTBO between them actually was.

I guess point being the lesson I learned right out of the gate with 300 BO is that the bullet can make a major difference in the seating depth, which in turn GREATLY changes the case volume for powder. I'll attach a quick picture to illustrate what I'm trying to say. Hope this saves someone else some time and frustration.

 

[r.tenorio671]

...why not just use the Lil`Gun for your supersonic loads? LilGun is one of the powders that give the most velocity for given bullet weights and complete burns in short tubes. Considering the limited (practical) distance of the 300BLK cartridge, I prefer the flat-based bullets, less chance of compressing loads with some of the bulkier powders one can use in 300BLK.

 

[rustyinbend]

Just wanted to throw a learning experience in since I just recently added 300bo to the reloading list. The max length can vary greatly depending on the bullet profile. I had some eld's laying around, and I had picked up a box of some Hornady sub-x (175). And I had started loading everything, like a full run, maybe a hundred pressed ready to shoot. And everything was right in the middle of all the spec that I could find. (That's me assuming the credibility and guilt, lol). So in the most amateur way possible, before I put everything up for the night to take to the range first thing in the morning, I just wanted to verify that they fed through the mag and chambered properly etc...

Of course, they didn't. Not even close. (Like 40 thousandths). Of course I'm sitting there dumbfounded with a stupid wtf look on my face as I'm looking over the cartridge drawings and load info for what must have been 45 minutes...
Like an idiot...
Until I finally realized how much different the shape of the subsonic's compared to some super high bc bullets really was, and how much of a difference in the CTBO between them actually was.

I guess point being the lesson I learned right out of the gate with 300 BO is that the bullet can make a major difference in the seating depth, which in turn GREATLY changes the case volume for powder. I'll attach a quick picture to illustrate what I'm trying to say. Hope this saves someone else some time and frustration.

No doubt ... the left is my Supersonic cartridge with 16.6g of IMR 4227 and a Sierra MK 125 with a COAL of 2.060 ... the right is my Subsonic cartridge with 10.1g of IMR 4227 and a Sierra HPBT 220 with a COAL of 2.260. The size difference is obvious.

 

[rustyinbend]

...why not just use the Lil`Gun for your supersonic loads? LilGun is one of the powders that give the most velocity for given bullet weights and complete burns in short tubes. Considering the limited (practical) distance of the 300BLK cartridge, I prefer the flat-based bullets, less chance of compressing loads with some of the bulkier powders one can use in 300BLK.

Yeah ... still experimenting with that. I just don't like the "stickiness" of the L'il Gun, and what a pain in the ass it is to get all of it out of my Chargemaster when I'm done loading powder. I've also got a couple of canisters of CFE-BLK that I want to try, and see how that performs. I've been spending the last few years perfecting my long-range cartridges, and only recently decided it was time to "show the love" to a couple of 300-BLK rifles I've been ignoring. Lots to test ... but the weather sucks. I have plenty of "time" ... what I need is "warmth" at the range.

 

[Bobby Ball]

I've been happy with the BLK. I've tried the cfe223 and the BL-C2 also. It's a bit of a mental adjustment switching from 80 grains of N565 or N570 coming out like Lincoln logs to this stuff that's like 11 grains of baking flour. I've never made such a mess of my reloading area until my first run in with 300 blackout.

 

[rustyinbend]

I've been happy with the BLK. I've tried the cfe223 and the BL-C2 also. It's a bit of a mental adjustment switching from 80 grains of N565 or N570 coming out like Lincoln logs to this stuff that's like 11 grains of baking flour. I've never made such a mess of my reloading area until my first run in with 300 blackout.

What's the charge weight, COAL, and projectile that works for you and your CFE-BLK?

 

[Old Man with Gun]

my go to load, shoots well in all 4 of my suppressed SBRs.

 

[Bobby Ball]

 

[Ape_Factory]

I've used CFE BLK for subs and supers. I found for supers, better numbers/accuracy with H110. For subs, CFE BLK cycles everything! Very gassy and dirty though and I'd look at Vihta Vouri N120 as it's much much cleaner burning.

I load the V-Max and Speer 125 TNT's for bonded bullets, I'll have to dig my numbers out. I use LC brass exclusively. Converted or otherwise. Wanna say I'm at around 19 grains with H110 and don't remember them being overly filled.

Just nabbed two pounds of RamShot Enforcer to use with Barnes 110 grain solids, hoping to eek out a bit more velocity safely over H110.

 

[r.tenorio671]

...just a FYI on powders and bullets I've used for supers:
Powders : Lil`Gun, H110, W296, AA5774, IMR4227, 300MP
Bullets : Speer 110 HotCor, Nosler 110 VGdn, Berger 115gn, Hdy 125SST, Hdy AK 123 (pushed thru a .308 bullet sizer), Sierra 125 SMK, Speer 125 TNT, Speer 130 HP and pulled M80 FMJ 147gn

 

[Ape_Factory]

Ramshot Enforcer is like dust...same consistency! Meters really well and obviously fills the case well. With that said, I popped two primers at 19grains with the Barnes 110 grain flat base TAC-TX bullets. Which is a shame as my SD dropped to 5 and I had about a 50fps jump over my normal H110 load. The cartridge overall length was 2.250. At 18.5, my SD's were in the 20's. I may try working up in .2 grain intervals and maybe try seating the bullet at 2.255. Not sure what else I can do to reduce the pressure other than less powder or a different powder. I use a very light crimp with a Lee factory crimp die. Cases were all trimmed and primer pockets unified/reamed.

My H110 load is 2175fps out of a 9" barrel and the Enforcer 19 grain load was 2238 fps. First time I've ever blown a primer.

I've tried the Hornady CX 110 grains which have a boat tail and I could not get the same velocity out of them as I could the Barnes. I was about 25fps slower with the Hornady and H110.

 

[Ape_Factory]

Forgot to mention, my Hornday V-Max load is 19.7 grains of H110. It does not fill the case (Lake City).

 

[powerspc]

I just tried some 150gn FMJBT using VIHT-N110 out of a gas gun.

Barrel: 10.5" LMT
Powder: VIHT-N110
Primer: WSR
Brass: Starline (new)
Bullet: Hornady 150gn FMJBT
COl: 2.090"

All 5 shot groups, all grouped good enough for me (2.0-2.5 MOA at 100 yds). I was shooting off a bag/bench with an ACOG. All measurements taken with a Garmin Xero C1 Pro. 37 degrees, light rain. That powder burns so clean, I was so pleased I just ordered another 8 lbs and 2,000 more bullets. I'll probably just stick with 13.9-14.0 grains, that's shooting plenty fast for me and good enough for a 200-300 yard round.

Charge: 13.3gn
FPS (avg): 1698
SD: 3.1
ES: 7.9

Charge: 13.6gn
FPS (avg): 1720
SD: 5.4
ES: 15.5

Charge: 13.9gn
FPS (avg): 1746
SD: 0.8
ES: 2.2

Charge: 14.2gn
FPS (avg): 1765
SD: 2.1
ES: 6.2

Charge: 14.5gn
FPS (avg): 1785
SD: 4.6
ES: 13.2

 

[Ape_Factory]

Vihtavouri really does burn clean. I use N120 for 300 blackout subs and it's night and day compared to something like CFE Black.

 

[waspocrew]

Vihtavouri really does burn clean. I use N120 for 300 blackout subs and it's night and day compared to something like CFE Black.

Agreed - I use N110 and it’s way cleaner than CFE. Just bought an 8lb jug to last me a while.