difference between 300 BO and 300 Ham'r

Ian

Notorious member
That reminds me of my quest for thick-necked '06 brass back before the XCB project. I had contacted Hawk on the phone and asked about necking down the basic brass. After determining that it wouldn't gain what I was after, we talked about making a run of '06 wildcat brass with thick necks, but I'd have to pay a setup fee and it would have to be marked as some kind of wildcat for liability reasons. It wasn't outrageous, as I recall the minimum was 5K cases and something like a grand to do the run. Still, it was cheaper to build a rifle.
 

popper

Well-Known Member
CFEBLK works fine, cast or jax. Lower pressure curve but most say it has to be a full case to work well. I did 18gr (almost full) under a 185 GC RD style from my 10" 1:8 pistol AR. Worked good (figure 1550 fps) but haven't tried it in carbine or at any longer range. Claimed to be dirty when loaded light but IMHO it doesn't generate enough pressure to expand case neck but makes lots of gas. Meters like 1680, 4 shot groups had 3 in one hole, other 1/2" away, second has 2 touching, doubled - shot at 7 yrs. Eyes are keeping me from seeing POA very well at any distance. IMHO it's like LeverE, when it works, really good. And low flash.
 
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fiver

Well-Known Member
it took star-line over a year to complete a run of 45-70 cases for the boolits site a couple of years back.
they were already making 45-70 cases at the time and all they had to do was run off a bunch more.
 

waco

Springfield, Oregon
I'm shooting the 7.62x40 and very happy with it. Shoots 125 Gr. Sierra Pro Hunters or the 110 Barnes TTSX that Wilson sells into 3/4", 100 yard groups with several loads.
Only loaded AA1680 and a little 296. Waiting on a report regarding CFEBLK before I buy any.
Having a little trouble with the neck wall thickness on some PPU cases I converted. Didn't realize PPU brass was that thick.
The LC cases I used worked fine.
For hogs out of an AR15, Its a great rig.
Rifle Twist is too slow for any subsonic, suppressed work.
I've seen where people are shooting 125 Nosler Ballistic Tips, but I've been told by the Nosler people the 125 gr. Accubond ogive is too long for this cartridge. Too bad, that would be a sweet shooting bullet!
My results with CFE BLK
 

Bruce Drake

Active Member
I got tired of my 300BLK upper after I realized that after 100 yards it just didn't keep the velocity up for ethical shots with lightweight 125gr bullets. But yes, I know it was originally designed for close range shots with heavy bullets but I like to shoot rifle matches that start at 200 yards also.

That said, a Rimless .30 Herrett (7.62x41) is my replacement cartridge. I recut my 300BLK upper and its been fun working up the wildcat. .30 Herret is originally a wildcat based off the old rimmed 30-30 cartridge but some folks discovered it makes a neat cartridge when a 6.8 SPC case is trimmed down and reformed.

It can also be made with 22 Nosler Brass if you don't want to convert the AR15 bolt over from the standard 223 Remington case head size, but 6.8SPC is a more readily available brass and the bolt is one of the easiest things to replace on an AR15. I first built the wildcat that way which these photo show the rebated rim on the brass on the first picture. I've since got the 6.8SPC bolt and converted 6.8 SPC brass for use in the same rifle. The 2nd and 3rd photos show how the 6.8 SPC cases are trimmed and reformed. The increase in cartridge size definitely helped with the terminal velocity. The PC coated bullets are 125gr Lyman 311315s and the jacketed bullet is a Sierra 130gr softpoint but I've also fired it with 150 and 180gr lead bullets also.
 

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Hawk

North Central Texas
Thanks for the video Waco.
I was hoping someone had tried the CFEBLK with light hypersonic bullets. It might be a little slow for the 7.62x40 WT.
Just wondering how it compares to AA1680 in a head to head matchup.
 

Bruce Drake

Active Member
Date Quantity Primer Powder Weight (gr) Powder Bullet Weight (gr) Bullet Type Bullet diameter Mold # Case target size @50yards target size @100yards Expected Velocity (fps) Comments
9/1/2012 200 CCI SR 18.0 H110 110 hornady spitzer 0.308 mix 2300 Sub MOA!
18 Tula SR 18.0 H110 123 hornady spitzer 0.308 mix
20 Tula SR 17.0 H110 123 Hornady FMJ 0.308 mix
46 Tula SR 18.0 AA1680 125 Ideal 311359 0.308 mix 1900 Giving it a shot!
9/24/2011 20 Surplus SR 6.0 Red Dot 130 Lyman 311410 0.311 Lyman 311410 mix plinker, no ejection
12/15/2011 100 CCI SR 17.0 H110 147 Hornady FMJ 0.308 mix 1900 pops primers at 90+ degrees
2/11/2012 60 CCI SR 17.2 H110 147 Hornady FMJ 0.308 mix 1900 pops primers at 90+ degrees
2/11/2012 40 Surplus SR 17.2 H110 147 Hornady FMJ 0.308 mix 1900 pops primers at 90+ degrees
2/11/2012 30 CCI SR 17.2 H110 147 Hornady FMJ 0.308 mix 1900 pops primers at 90+ degrees
3/8/2014 100 mix 16.4 H110 147 FMJ 0.308 mix 1900 This should be the best load for 147gr
9/24/2011 40 Surplus SR 14.0 H110 150 FMJ M2 0.308 mix fired and ejected but no feeding 2nd round for semi-auto fire
10/26/2011 17 Surplus SR 17.0 H110 150 FMJ M2 mix
25 Tula SR 18.0 AA1680 150 hornady spitzer 0.308 mix 1950 2nd Loads with AA1680
9/24/2011 20 Surplus SR 14.0 H110 160 Lee .311 0.311 LEE TL155gr mix fired and ejected but no feeding 2nd round for semi-auto fire
10/26/2013 6 Surplus SR 15.2 H110 165 hornady spitzer 0.308 mix light - need more powder for proper feed of 2nd round
75 Tula SR 18.0 AA1680 175 Lead spitzer GC 0.312 Lyman 311413 mix 1900 First loads with AA1680 - Too long at 1st lube ring. Must shorten to feed properly.
9/24/2013 20 Surplus SR 10.0 H4895 200 Lee .311 LEE RN 200gr mix fired but short-stroked bolt - need to increase powder
6/29/2014 30 Surplus SR 17.0 H110 130 Sierra HP 0.308 mix tesr
6/29/2014 1 Surplus SR 17.0 H110 123 Hornady FMJ 0.308 mix test
6/28/2014 5 Surplus SR 16.0 IMR SR4759 123 hornady spitzer 0.308 mix ladder test
6/28/2014 5 Surplus SR 15.0 IMR SR4759 123 hornady spitzer 0.308 mix ladder test
6/28/2014 5 Surplus SR 14.0 IMR SR4759 123 hornady spitzer 0.308 mix ladder test
6/28/2014 5 Surplus SR 16.0 IMR SR4759 147 FMJ 0.308 mix ladder test
6/28/2014 6 Surplus SR 15.0 IMR SR4759 147 FMJ 0.308 mix ladder test
6/28/2014 5 Surplus SR 14.0 IMR SR4759 147 FMJ 0.308 mix ladder test
11/20/2017 50 Remington SR 15.0 H110 178gr Spirepoint - Gas Check 0.309 Lyman 311413 mix ~1700fps test of old bullet design and new load


This help you Hawk?
 
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Hawk

North Central Texas
Thanks for the post and the info Bruce.
Right now, my best load with the 7.62x40WT is 26.6 gr. AA1680 (max Load) behind a 125 Sierra pro hunter, in fire formed cases.
Wilson is loading CFEBLK powder in their new 300 HAM'R, which is basically a 7.62x41. Just wondering how CFEBLK powder would work in this cartridge. I think it's a touch slower than AA1680, but I know powders don't always follow the rules with each cartridge.
Guess I'll need to buy a pound and try it.
 

Bruce Drake

Active Member
Wilson's 300 Hamr is built off the 223 Rem if I remember right. The 30 Herrett Rimless is built off a bigger volume case but the performance would probably be close to identical. I'm planning to develop loads from 7.62x39 load data to start with that cartridge as their internal volumes are close to matching.

Thanks for the post and the info Bruce.
Right now, my best load with the 7.62x40WT is 26.6 gr. AA1680 (max Load) behind a 125 Sierra pro hunter, in fire formed cases.
Wilson is loading CFEBLK powder in their new 300 HAM'R, which is basically a 7.62x41. Just wondering how CFEBLK powder would work in this cartridge. I think it's a touch slower than AA1680, but I know powders don't always follow the rules with each cartridge.
Guess I'll need to buy a pound and try it.
 

sundog

Active Member
300 BO is kinda a modern day version of 30 Carbine other than the suppressed heavy weights. I got a bunch of brass from CastingMachine over on cast bullet board and it's doing just fine. It's reformed once fired LC 5.56.

Aside from comparing ballistics to other stuff, it's just a fun round to play with in the AR with cast bullets. I've been using powder coat RCBS 7.62-130-SPL. It also does very well with Nosler 125 BTs, too.