5.56 NATO / 223 Remington Pull-Downs

[The_Shadow]

Cartridge is from Ammo Manufacture: Black Hills 5.56 NATO 77gr Sierra Match King OTM  2009 (provided by Shadow)
Ballistics Information: 5.56 NATO / 223
Muzzle Velocity: 2750 fps
Muzzle Energy: 1293 ft. lbs
Brass Make/Headstamp: Winchester  WCC – Brass
Bullet Make/Weight/Construction/Info; Length 1.0025"/Dia. 0.2245": Sierra 77gr. OTM
HP Depth 0.2320" / Boat Tail Hollow Tip
Actual weight 77.0 grains  / crimp cannelure  0.2230"
C.O.A.L.: 2.2430"/2.2445"/2.2465"/2.2475"/2.2475"2.2480"/2.2490"/2.2505"/2.2550"
Primer: Small Rifle Brass color (crimped)
Case: Diameter 0.3730" Crimp Diameter 0.2465"/0.2475" Length 1.7565"
Powder Description/Positive ID/Type/Charge Weight:  ?BL-C 2?  25.0 grains 









There are several powders that come close to this loading but BL-C2 seems to be the best fit for this 2009 BHA contract;
Hodgdon    BL-C2
Hodgdon   H-335
Hodgdon   H-414
Winchester    W-748
Winchester    W-844 = H-335
Winchester    W-846 = BL-C2

[sqlbullet]

Given the qty of Wc846 I have on hand, this is great news for me!

[The_Shadow]

Mitch can you post a picture of the WC846 powder for me, enough to cover the bottom of a scale pan.  The pics I have of 846 I have a re 10X magnification...I also emailed you a link to some more info.

[sqlbullet]

Not greatest quality, but here you go:



Lot # 406359

[The_Shadow]

Thanks for the picture of WC846

Here is the newer CFE223 powder...





There are small disk that like a flake type powder in the mix...see those inside the green circles

[Pctechdude]

Shadow, I never played with Ramshot Tac but supposedly this is what black hills uses, but somewhat modified I hear for flash. I was able to find a picture that looks almost identical. And the 25 grain load fits. In Australia the loading is 23.8gr IMR 8208 XBR.

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[The_Shadow]

Shadow, I never played with Ramshot Tac but supposedly this is what black hills uses, but somewhat modified I hear for flash. I was able to find a picture that looks almost identical. And the 25 grain load fits. In Australia the loading is 23.8gr IMR 8208 XBR.

Many guys have tried to duplicate the Black Hills 5.56 mm 77-gr. OTM, Mk262 Mod 1, but all of the commercial powders tested didn't get to the accuracy and performance of the BH ammo.
Many were very close, but temperatures played into the loads tested and as the velocities got up to the same level pressure signs showed on primers, ejector dings and marks.
There is a whole series of the testing here: 

[Alaska]

Given the qty of Wc846 I have on hand, this is great news for me!

I know the Austrila down under version is IMR 8208 @ 23.8 with 77 MK

[RDub01]

Don't know if you all caught this, but Johnny's Reloading Bench's UTube channel did an exhaustive study on duplicating this round, the 77gr Black Hills. Quite interesting, if you have to time to watch them all. Comes in several parts. Part 1 is here;

https://www.youtube.com/watch?v=4iirWnaWjhc&t=1126s

[The_Shadow]

Yes, I have watched them all!

[Alaska]

Black hills was known to use TAC in their MK 262 ammo
ADF uses IMR 8208
23.8 of IMR 8208 @ 2750 fps in 18?
77 MK @ 1.901?
I have found best  accuracy at 23.3 of IMR 8208 in my MK 12 Mod 0

Most of the comparators on the market don’t give you a true base to ogive measurement. As an example, the base to ogive measurement for a round of MK262 Mod 1 when using a Forster Datum Dial is 1.865”. However, that same round of MK262 has a base to ogive measurement of 1.822” when using an S.A.C comparator.