Project Omark

Suppressed Omark .308

My  plan for some time was to build up a rifle that would solely be dedicated to lead cast projectiles. It had to be accurate at standard velocity as well as sub-sonic loads. I also wanted It cheap to run and reasonably accurate in both modes. Accuracy at 100 meters had to be around an inch or so with normal cast loads, however with subs, being uncharted grounds, I had to be realistic. But this was a project that was meant to be fun and a learning curve.

The first aspect I had to consider was that of the calibre. It had to be able to deliver enough energy as to be a humane kill. Allowing an animal to suffer needlessly was just plain unacceptable. I had a ball park idea of the cal I was after.  But occasionally I would visit Gary from Talon Arms and would bounce ideas off him, everything from the 7.62 Tokarov through to the 7.62×39.  I was after a calibre that I could tailored to suit any animal, from small game right through to the bigger four legged variety. Gary has a vast knowledge in firearms and was good to chat to.

On one occasion, Gary spoke of a rifle that he was working on, a suppressed single shot Baikal in .308 . Gary told me of some of the results that he was achieving from this .308 and being a honest upfront type of guy  started to convince me on the ubiquitous 308.

We discussed for a while the pros and cons of this calibre, the potential projectile weights through to the styles of suppressors.  I noted that the suppressor  on Gary’s project was a custom built suppressor made by Robbie Tiffen at Gunworks.

Now whilst I am always open to acquiring  yet another calibre rifle, the idea of working with the .308 cal had many positives, I had all the dies, the brass , a bit of lead, all this in turn meant there was more money to spend on other parts of the build. It made sence to stick with something that I was already set up for.

So with the calibre sorted I started to give thought to the type of rifle to base it on. One of the requirements of the rifle was to be quiet. This immediately discounted semi autos which saved me a lot of grief with actions failing to cycle subsonic loads. This left me with realistically only one option.

You see, I have a couple of Omark Sportco model 44’s and they are extremely accurate, one is an NRA rifle and the other one a TR F in the making. But what was even better still is, I had a third that was a little tatty! But was still able to obtain a cloverleaf with a trusty 155gr load at 100m! I had the contender!

The Omark has an incredibly strong action and a very proud history. It’s a single shot that was at one stage trialled as a sniper rifle for the Australian Army,  however reverse engineering an internal magazine proved too costly both in dollars and accuracy.

So rifle sorted, cal picked, it was can time.

I already have a suppressor from from Gunworks on a Ruger MkII  25/06 that I own.  It has proven to be a well-built and designed suppressor. Robbie’s suppressors’ also incorporate a muzzle break, which in itself is an invaluable tool. The first time My ex wife used the  rifle suppressed with normal jacketed loads she achieved a one ragged hole at 50 meters. When she took the suppressor off, well that was the end of that game!

about now i should introduce my nephew aged 10 who was to group the rifle at 100!

My test pilot Bench testing a No8 .22 at 50m

I would need a supressor that had a far larger internal volume than my 25cal, with extra baffles, it was going to have to extend further forward as well as back, it was going to be big!

I met up with Robbie and we chatted about what I was trying to achieve. He suggested a couple of additional ideas and I left my rifle with him.

Now the fun bit began.

Whilst all this was going on I had started to learn how to cast lead projectiles from Jeff, (also known as the Cast Bullet Kid and for good reason), Jeff has been tinkering with lead for a very long time and has a great knowledge of all things cast bullet related.

Well, with a bit of coaching and patience I was able to make some half decent projectiles. I settled on a couple of projectiles.

I used wheel weight when making these projectiles and they were then left to cool on their own. A hardness test showed that these came to about 8.5BHN. The projectiles were then weighed and visually sorted as to ensure  that there was no visible flaws. These were then sized down to .310 and .309(sizing was done in two stages, the projectile that was larger than .314 when first cast).

As this was a rifle that was a project I wanted all things to be as consistent as possible. I full length resized the brass, weighed it and settled on a specific weight range for the brass, tumbled, uniformed the primer pockets, debured the flash hole and chamfered.

I made a few rounds up and waited. Soon enough the phone went, it was ready. Off I went and picked up the suppressor. As a size comparison, 25/06 on top, the 30 cal custom below!

What a beauty! The rifle balanced perfectly and it soon got the name “fat boy”, or that may have been a reference from Amanda (Robbie’s beloved) in my general direction. Robbie tested the rifle with a couple of rounds that I had made up and the noise signature was remarkable. Robbie relieved the barrel of a few inches and cut the stock back to allow for the extra size fatboy had!  This also had the benefit of bring back the centre of gravity and balance to a natural hold for me. Robbie also came up with an interesting sling adaptation, but I will leave that for him to discuss with his clients.

I was straight off to the range.

UPDATE on the Omark 4th July 2011

Well, what an adventure, where to catch up too….. Jeff and I travelled down to Dunedin and picked up about 300 KG (that’s roughly 660 pounds) of lead ingots. So now  I have a bit of lead to test with…..I’ve also weee stack also of some other “reclaimed weapons grade lead” I’ve ferreted away! So I should be good for a wee while!

From there I made a series of test projectiles in different sizes with a combination of powders.  Initially playing in and around the 9Gr of Trail Boss behind a 208gr projectile sized .312 with filler and flaring the case mouth. The sound reduction is stunning and all tested exceedingly well with the suppressor on, it IS a joy to shoot and use, it is however it is a bipod set up this girl! But my hearing is thanking me for it too!

So far the winner in the normal velocity search has been a Loverin design projectile, I think it’s a 180 gr but it is sub 1/2 inch groups at 100, it’s sitting on 30 grains of 2206H with a filler. I will need to go back to this round as we are now trying differing gas checks and with varying success. The gas check maker is the Freechex 3 (see links in resources) and man does it make some great GC’s. I will do a cost break down but its such a cheap and accurate round! this again tested well with the suppressor, noise marginally more than a 22 but very muffled, if that makes sence? and it takes most of the crack away.

The subs on the other hand I really need to go back to. But would like to find something as equally accurate in subs as the loverin design. Have a couple of designs im looking at, just need some time to test! was in parts inch at 50 meters but experienced some inconsistencies, i would prefer this not to expand over 3 inches at 100, but its only a goal!

I did however find an accurate bunny buster, and have a set of molds again coming in from NOE in the states, a 118gr mold HP…..the potential for destruction….biblical! Watch this space for that update!!! whilst in Dunedin we stayed with some very lovely people place with bunnies. Managed some head shots at over 100 meters…….brutal!

Next step ;  I’m now looking at tweaking the sizing at .310 and .311, i will also test fill verse no fill on the 2206H in the loverin design. (I always use filler on subs or any low volume of powder in any case). I am testing trail boss for the subs but have some Alliant 2400 on order. I am using WW lead and then water quench , but i will test the  hardness later and post those results. The filler at the moment is a product sold by TCBK (see links in resources) and is a wool designed disk. I’m even tempted to try a polenta fill ive used in a Carcano 6.5….. recycled lead and organic polenta…….the greenys will love me for that!!!


a small back injury has thwarted me slightly! However………

I have another mold coming in from the states and plan to trial several varying powders and weights to see what best suits.

The powders that i am trialing are the alliant 2400, ADI2206 and 2208 as well as the Trail Boss. What intend to look at is the 118HP and the 180 Lovern, these will be at both sub and normal velocity and then i will find a bigger round to try later.

I intend to vary the lead hardness as well to see what results they give. I have made what is commonly refered to as lyman No2 lead and depending on the manner i cool the lead will again further harden it if i want or need to!

Ive even purchased a 25 cal mold……..87gr, 120 and 120 HP…….

The group to the left is a “Group” photo with the famous Moose or Angle projectile……..

Have a closer look at the cavity on the projectile to the left, that’s the new 30cal mold!!! The projectile to the top right is a 120 Gr 25 cal mold for my 25/06, then the version with out the cavity just under that. I will be testing those round as soon as i get mobile again but I am rather confidant that they will be just fine, ive also an 87 gr 25cal to test.

These were the first of the cast projectiles I made and trialed. Of all, the flat nose Loverin design was the greatest success. That thing from the word go just grouped a one ragged hole group. unfortunately now after improving the alloy recipe i will be going back to the drawing board, but at least i have a bench mark to work from. The other issue is now after using the molds from NOE……… well I don’t think i will bother with others, these molds are just the ducks nuts!

So the 30cal load continues……

Well today the powder arrived, so in the next few days I will start to make some .308 ammunition and fully document the process and outcomes.

4 Responses to Project Omark

  1. Stephen Coote says:

    Great site. I’ve fired many rounds through old Lee Enfields.

    Thanks for the info on cast bullets for the .308. This is something I’m keen to try.

    Best wishes from Nelson. Stephen Coote.

  2. Mark says:

    Stephen, Thanks for the comments, much appreciated, unfortunately I am in a state of limbo at the moment, lack of powder ! , But trust me, as soon as I can, I will post some new info and range results . What will also be of interest are the Gas Checks that we are making and what difference they make.

  3. Paul Francis says:

    Mark, just scored an Omark myself now, may have to get you to give it the once over!, I’ll need to score some projectiles off you to get up and running, are you back at work yet?

  4. Mark says:

    Well Done, every man needs two or three, Trust me this wont be the last, bring her around this weekend, i dont think we will be shooting 5-600 tomorrow if this rain keeps up so it will be a good day to cast some lead and look at new toys! I might start a post on Omarks and reloading? or we can post here, would be a good exercise, im sure we can draw some current and other future Omark owners out of the woodwork!

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