30 BR Sub-Sonic Loads

[ChrisNam]

I've just chambered a 30 BR in a shortened 22" Palma 1:13 barrel. I want to shoot the 118 or 125 gr bullets out to 300m, but also want to use a heavier bullet sub-sonic for culling purposes. What will be the heaviest bullet I will be able to stabilise with reasonable accuracy out to 75m and possible loads?

 

[6Dasher]

I think 150-155gr will be the max. Use N133 or N135.

 

[Kodiak99317]

Looked up some old old match reports from the 90's, when 308, short 30's and 30BR's with 1 in 14 twist barrels and heavy bullets,150 to 168) were the norm in some areas of the vast country I call Canada

34g of N200 with 135g FB approx 2600-2700 fps
30g of H322 with 168g SMK approx 2400 fps

Reduce these by 1g for saftey and good luck. They should group pretty good.

I'd say the faster powders like 4198, H322 and N133 or even approx. 18-20g of SR4759 would be the way to go as well for the sub-sonic with the heavy bullets. Slower powders will get you into big trouble with reduced loads. You may end up with sucked in cases so be careful and reduce slowly!

I'd say put a muffler aka can aka silencer on it and just shoot your 118 to 125's with your 33g of 4198

Here some data from Sierra on the 150-155's

Powder /Velocity 2200 2300 2400 2500 2600 2650
Viht N133...........27.7 29.2 30.7 32.2 33.7
IMR-4198...........24.9 26.3 27.7 29.1 30.5
Benchmark.........28.1 29.6 31.1 32.6 34.1
H322................. 28.1 29.5 30.9 32.3 33.7
H335.................30.7 32.3 33.9 35.5 36.3
H4895............... 30.7 32.2 33.7 35.2 35.9
IMR-4895.......... 30.6 31.8 33.0 34.2 35.4
AA-2520........... 31.4 32.8 34.2 35.6 36.3
Energy/ft.lbs. 1666 1821 1982 2151 2327 2417
Powder Grains Velocity Ft. lbs.
Accuracy Load AA-2520 35.6 2600 2327
Hunting Load AA-2520 36.3 2650 2417

 

[6Dasher]

Will a 168 stabilize in a 1:13 when it comes out sub-sonic?

 

[Kodiak99317]

Probably not but if your only tossing it 75 to 100 yds at a gopher or a crow, who cares eh!

 

[LRCampos]

ChrisNam, please tell us how it worked, when you test fire.

I am thinking on building a 30BR Silhouette Rifle to use with heavier bullets,168 to 150gr. jacketed, and 165 to 180gr. cast bullets) at 220 yards matches.

I thought about a 1-12 or even a 1-10 twist barrel. So, your 30BR with heavier bullets will give us a good preview.

 

[ChrisNam]

I've started with the preparation of the cases and will first try the 110 and 125 Bergers,can't lay my hands on 118 BIBs) and as soon as I get my siencer the 155 and 168's. I will keep you posted on the results. Thank you very much for the advise.

 

[6Dasher]

@kodiak; you want to hit the crow don't you

 

[LRCampos]

ChrisNam, how your 30BR subsonic rifle project is going? Any news about the heavier bullets,150-155gr.)?

 

[ChrisNam]

LR, I've done very little developing so far. I first attempted to import a silencer, but that prooved quite an exercise. I then spent a lot of time researhing the type of silencer I want and eventually decided on the Jackson type blow-back.

I instructed an enginering firm to turn the silencer, but have not yet received it.

I will post my results here in due course.

LR, are you planning a similar project?

 

[LRCampos]

Chris, actually I am planing a 30BR rifle for heavier bullets, but for Silhouette and eventually Position Shooting. In my country Silhouette is shot at 200 meters range, and Position Shooting at 300 meters. So, I need a little more momentum to knock down the rams at 200 meters,with jacketed bullets and cast bullets, that only travel up to 2.000 fps). At 300 meters, I think the 155gr. bullets is better on wind than the lighter bullets normally associated with 30BR.
That's why I am looking with interest on your project, to see how the medium weight bullets,150-156gr.) perform on low velocities,around 2.000 to 2.500 fps) on a 30BR.