Omark Model 44 - Ammunition

[La Capitain]

Hi everyone,

I'm looking for some advice and input as to what people use for ammo in their 7.62x51 Omark Model 44. I have read so many varying threads and articles about to use or not to use .308 winchester. I have tried both in my rifle. The .308 (brass cartridge) chambered, fired, and ejected fine. The 7.62x51 Nato (copper cartridge) round chambered, fired and stuck. It was so stuck that we had to use tools to eject the cartridge. Some theories are that the version of Model 44 is chambered to a .308, or that the copper casing on the 7.62 Nato round expanded after being fired.

What do you use?

I've attached some photos, one also shows the serial number. I don't know much about the time frame or origin of this particular rifle, it was given to me as a gift.

Thanks in advance for any info!

[Jim Watson]

I know of no "copper cartridge" in a modern smokeless caliber.
I suspect you loaded it with a copper plated steel military round or even the sort of cheaply made stuff I call "imitation army surplus."

Markings notwithstanding, I would not shoot ammunition that had to be forced out of the chamber. I would not be shooting surplus or cheap imports in a nice target rifle like that in any case.

I would give it .308 Win if I could not find any 7.62 Match for it.

It was made sometime in the late 1960s or 1970s.
It has either been restocked or is of a different production series than the one I have illustrated by deHaas. An improvement for the shooter, I think.

[Jimro]

An Omark 44? You shooting in Australia?

Stay away from copper washed steel cased ammo, it has a poor reputation in bolt action rifles.

I'd contact one of the shooting clubs in your area that shoots fullbore rifle, and see what ammo most fullbore shooters are using in there Omark 44s.

Jimro

[La Capitain]

Thanks for the replies.

No I'm not in Australia, I'm in BC, Canada.

I tried talking to a few of the guys from the club in town, but most haven't seen an Omark before. There's a couple more senior fellows I'm trying to get a hold of.

And yes, I'm not using the NATO rounds anymore, once and it stuck was enough. I am going to look at some match ammo.


Cheers.

[Jimro]

Well, if I recall correctly those Omark 44s shot excellent with good lots of 7.62 Nato ammunition for fullbore matches. Some weird idea that everyone needs to shoot the same ammo in competition to even the playing field or something. Stay away form cheap steel cased ammo.

I think the Omark 44 came with two twist rates, 1:12 or 1:14. Use a cleaning jag and rod to measure your twist rate.

If you have a 1:14 try Winchester white box 147gr FMJ and Black Hills 155gr Amax load.

If you have a 1:12 try Fed GMM 168 gr match load, or Black Hills 168gr match load. You might try the 175gr match load from both as well if you plan on shooting past 800 yards.

Good luck finding a load your rifle likes!
Jimro

[La Capitain]

Thanks very much for the info, its nice to get some direction!

[La Capitain]

I am looking to enter Target Rifle competitions. I found this quote in the rule book:

"The following ammunition / rifle combination is FORBIDDEN; Use of .308 Winchester / 7.62x51 commercial metrification equivalent ammunition, in a rifle chambered for use with the 7.62 x 51mm NATO cartridge. NOTICE: The .308 Wonchester / 7.62x 51 pressure as permitted for CIP / SAAMI are higher than those permitted in the 7.62x51 NATO cartridge."

That being said - my rifle is stamped 7.62mm. However all ammo I am able to find is .308 / 7.62. What do others use?

[Jimro]

Wow, that's utter BS.

I guarantee you all the other competitors are ignoring that rule.

Once upon a time the 7.62x51 was spec'd to 50,000 cup. In a manual it was listed as 50,000 psi copper. During a revision someone dropped off the "copper" and it became 50,000 psi.

The 308 Winchester, having been accepted by SAAMI and CIP used the more modern piezo resistance method to determine pressure, and measured chamber pressure up to 62,000 psi piezo.

Now, a milspec 7.62x51 M80 round launches a 147gr projectile around 2,750 fps (depending on barrel length) meausred 78 feet from the muzzle. A 308 Win launches a 150 gr projectile around 2,800 fps measured 15 feet from the muzzle.

Obviously if the charge weights are the same, and muzzle velocity is the same, then pressure should be about the same too.

Anyways, you see the same "mistake" with 30-06, which is SAAMI spec to 60,000 psi, and the 7.62x63 (metric equivalent) is spec'd to 50,000 psi copper. In a bolt rifle none of this makes a difference, it is only in M1 Garands where port pressure becomes an issue which dictates using a powder with the correct burn rate and a projectil between 150 and 175 grains.

Jimro

[La Capitain]

I thought it was crazy with all the research out there. Thanks for the info.

[mapsjanhere]

The only time where I would heed that warning is with small ring mausers rebored to 7.62 Nato in the 50s by Spain and some south american countries. And even that is hotly debated every time it comes up.