300 bar Steel Cylinders

Midland Diving Equipment DIN Gun Charging Adapter

We have available 300 bar (4,350 psi) Faber steel scuba cylinders with 300 bar DIN valves in 3 litre, 5 litre, 7 litre and 12 litre capacity for charging air rifles. Most people use the 12 litre capacity 300 bar scuba cylinder. The 3, 5 and 7 litre cylinders are typically only used as a more portable solution where mobility counts. It's extremely rare to find 300 bar cylinders for sale second-hand.

The 300 bar scuba cylinders are usually connected to your air rifle using an adapter with a 300 bar male DIN fitting at one end and the fitting required for your air rifle cylinder at the other end. We do not supply these DIN 300 bar adapters. (We suggest you try Hermanns Sporting Guns.) These adapters can be used with scuba cylinders using a 300 bar DIN, 200 bar DIN, or DIN/K valve.

How many fills will you get from a 300 bar cylinder? Well, there are so many variables that we're not prepared to say. Other owners of the setup you're using should be able to answer this much better than we could.

232 bar Steel Cylinders

Midland Diving Equipment A-clamp Gun Charging Adapter

We have available 232 bar (3,365 psi) Faber steel tanks with DIN/K valves (232 bar DIN connection with the insert removed, and Yoke connection with the insert in place) in 3 litre, 5 litre, 7 litre, 9 litre, 10.5 litre, 12.2 litre, 15 litre and 18 litre capacity for charging air guns. If you're buying a 232 bar cylinder, we suggest the 12.2 litre capacity cylinder.

The 232 bar scuba cylinders are usually connected to your air gun/rifle cylinder using a Scuba Filling Yoke/A-Clamp/K-Valve Adapter for PCP Rifles with either a 1/8" BSPP thread or a Female Foster Connection. We do not supply these adapters. (We suggest you try Hermanns Sporting Guns.) These adapters can't be used safely with 300 bar scuba cylinders.

Tech Tips

Refilling the scuba cylinder is best done at a dive shop where the compressed air provided should be completely free of moisture and other contaminants. The compressed air that you pump your car tyres up with is not clean or dry enough for a PCP air rifle, and the pressure wouldn't be high enough anyway, e.g. 150 psi (10 bar) when you need 3,000+ psi (200+ bar).

When charging the rifle, open the scuba cylinder valve very slowly. This will allow the air to pass along the filling hose, open the inlet valve and fill the reservoir. Only partially opening the cylinder valve will let you control the air flow. A slow fill is a good fill. Opening and closing the scuba cylinder valve quickly will give a false reading of how much air is in the gun, it can also damage the rifle.

WARNING: Never use anything other than divers' quality compressed air to recharge your PCP air rifle/gun. Using gasses other than clean, dry, breathing quality compressed air can be highly dangerous and will usually invalidate air rifle warranties.

Air rifles must never be filled to more than the manufacturers stated pressure, which is likely to be much lower than the pressure in the scuba cylinder. By exceeding the recommended pressure two things will happen. The first is that the power of the gun will drop significantly. It's a myth that the higher the pressure in the gun, the more power it produces. In fact, you normally find that maximum power is produced about 10 bar below the maximum recommended pressure on non regulated rifles, and a 20 bar overfill can reduce the power by 40%.

In order for scuba tanks to be refilled in an Australian dive shop they are required to be tested every year if they are used for diving. As a dive shop has no way to tell that you're using the cylinder exclusively out of the water, they will require the scuba cylinder to be in test before filling it.

We suggest you avoid aluminium scuba cylinders as most are only rated to 207 bar. Do not buy second-hand old aluminium cylinders (made of 6351 aluminium alloy, or pre 1995) as some have been known to explode and kill people. Plus you probably won't be able to get these old aluminium tanks tested, or filled at a dive shop.

A full scuba cylinder contains an enormous amount of energy. They are quite robust, however, you should treat them with great care.

We recommend you put a For Paintball Use Only cylinder sticker on scuba cylinders used to fill air gun and paintball cylinders.

Castle Rock

Bommie Dive | Boat access

Castle Rock | © Phil Watson

Depth: 12 m (39 ft) to 20 m (66 ft)

Level: Open Water and beyond.

Castle Rock is located outside Port Phillip Heads on the south-west, Point Lonsdale side in approximately 20 m (66 ft) of water. It rises majestically out of a limestone and sandy bottom to around 12 m (39 ft) on top.

The walls of this bommie have many undercuts, splits and ledges and with jagged rock turrets on top it's easy to see how this site got its name! The rock is around 200 m (656 ft) in circumference and can be circled once or twice in a dive. The fixed depth, lack of current and easy navigation makes this the perfect boat dive for newer Open Water divers.

But don't spend all of your dive time just exploring the base of Castle Rock. There is a lot of very interesting marine life to be found on the top.

Weedy Seadragon at Castle Rock
© Ian Scholey

Old Wives at Castle Rock
© Ian Scholey

Castle Rock is a wonderful dive with a wide variety of creatures including Nudibranchs to Seastars, typically on the top. You'll find Yellow Zoanthids plus numerous fish life including Southern Blue Devil, Old Wives, Boarfish, Dusky Morwong, Sixspine Leatherjacket, Scalyfin, Zebrafish, Bluethroat Wrasse, Senator Wrasse and Sweep hiding under the ledges. You can sometimes spot Weedy Seadragons under and around the rock. There is even a slim chance of a Southern Rock Lobster (aka Crayfish) or two under ledges at the bottom, or in the nearby reef.

Bass Strait Warning: Always keep an eye on sea conditions throughout any shore or boat dive in Bass Strait on Victoria's coastline. Please read the warnings on the web page diving-in-bass-strait before diving or snorkelling this site.

Divers have the opportunity to catch Southern Rock Lobster (aka Crayfish) at this dive site. Remember your catch bag, current Victorian Recreational Fishing Licence, rock lobster measure, and cray tags. Once you get back to the dive boat, or shore, make sure you clip the tail and tag your Crayfish as per Fisheries requirements. Please abide by all current fishing regulations if you intend to catch crays. See article-catching-crayfish for practical cray hunting advice from The Scuba Doctor, plus melbourne-cray-dives for a list of other crayfish dive sites near Melbourne. For tips on cooking your Crays, please see article-cooking-crayfish.

Finding Castle Rock

Over the years we've been provided with different GPS marks for Castle Rock. The GPS marks we know of in circulation for Castle Rock are:

GPS (verified)
Latitude: 38° 17.887′ S (38.298117° S / 38° 17′ 53.22″ S)
Longitude: 144° 35.863′ E (144.597717° E / 144° 35′ 51.78″ E)
Geoff Rodda:
Latitude: 38° 17.888′ S (38.298133333333° S / 38° 17′ 53.28″ S)
Longitude: 144° 35.873′ E (144.59788333333° E / 144° 35′ 52.38″ E)
15 m, bearing 97°, E
Dive Victoria:
Latitude: 38° 17.882′ S (38.29803333° S / 38° 17′ 52.92″ S)
Longitude: 144° 35.868′ E (144.5978° E / 144° 35′ 52.08″ E)
12 m, bearing 37°, NE
John Lawler:
Latitude: 38° 17.893′ S (38.29821655° S / 38° 17′ 53.58″ S)
Longitude: 144° 35.858′ E (144.59763588° E / 144° 35′ 51.49″ E)
13 m, bearing 212°, SSW

Wathaurong (Wadda-Warrung) country

Traditional Owners — This dive site is in the traditional Country of the Wathaurong (Wadda-Warrung) people of the Kulin Nation. This truly ancient Country includes the coastline of Port Phillip, from the Werribee River in the north-east, the Bellarine Peninsula, and down to Cape Otway in the south-west. We wish to acknowledge the Wathaurong as Traditional Owners. We pay respect to their Ancestors and their Elders, past, present and emerging. We acknowledge Bunjil the Creator Spirit of this beautiful land, who travels as an eagle, and Waarn, who protects the waterways and travels as a crow, and thank them for continuing to watch over this Country today and beyond.

Castle Rock Location Map

Latitude: 38° 17.887′ S (38.298117° S / 38° 17′ 53.22″ S)
Longitude: 144° 35.863′ E (144.597717° E / 144° 35′ 51.78″ E)
Datum: WGS84 | Google Map
Added: 2012-07-22 09:00:00 GMT, Last updated: 2022-05-07 23:32:54 GMT
Source: GPS (verified)
Nearest Neighbour: Deep Pinnacles, 250 m, bearing 287°, WNW
Depth: 12 to 20 m.
Dive only on: Ebb.

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DISCLAIMER: No claim is made by The Scuba Doctor as to the accuracy of the dive site coordinates listed here. Should anyone decide to use these GPS marks to locate and dive on a site, they do so entirely at their own risk. Always verify against other sources.

The marks come from numerous sources including commercial operators, independent dive clubs, reference works, and active divers. Some are known to be accurate, while others may not be. Some GPS marks may even have come from maps using the AGD66 datum, and thus may need be converted to the WGS84 datum. To distinguish between the possible accuracy of the dive site marks, we've tried to give each mark a source of GPS, Google Earth, or unknown.