OT, but related, sort-of. Omark 44

[Bruce_in_Oz]

Just scored a couple of barrels for the Omark 44. Old-style, integral locking lugs and all.

Both came out of waxed paper wrappers and appear to unused.Interestingly, the Lithgow-made, hammer-forged Black Mountain tube is about an inch shorter than the "Sportco / Omark one

Does anyone have any record of the twist rates and how, if at all, that might be marked on these barrel.

I know early barrels were 1:14 inch, RH, but that changed to 1:12" at some time.

A couple of "revival projects" await. One of these is intended for FTR competition ("Poverty-Pack division) and thus may end up being fed longer, "VLD" style bullets which may not like a 1:14" twist, even from a 27" barrel.

Any thoughts?

[muffett.2008]

Bruce, Early barrels were 1.14 twist designed to stabilise the 144gr. military round on issue.
When the L2A2 round was disallowed in competition and replaced by the F4 round at slightly lower velocity the 1.13 twist began appearing.
By the time reloading became the norm and the 155gr. projectile appeared a 1.12 twist was needed to accommodate the increases in barrel length and heavier projectiles.

The twist was usually stamped on the R/H side on Sportco/Omark barrels and varied from side to side on Black Mountain,
I would need to check, but I think Shultz and Larrsens were on the left.
The three twist rates all proved suitable for competition.

[tiriaq]

My first fullbore target rifle was a Nielsen MN300. I think the original barrel was 1:14. Shot the Sierra 155MK very well. A Lapua Scenar or Berger might be a different story, these being VLD style, longer than the Sierra.
Tucked away I have a Sportco barrel and a couple of bolt heads. I've thought it would be an interesting project to use these to make a rifle with a receiver and bolt body like the Nielsen.

[muffett.2008]

Bumm drumed you Bruce, played on my mind all night so had a look at my seven remaining Omarks and a read of my Armourer notes.

No twist on new barrels, to be stamped if requested......in line with serial number for both right and left handed actions.
This was due to final lockup position determined by recoil plate thickness on assembly setting up both headspace and primary extraction.
I even recall one twist stamp being at six o'clock when screwing a used barrel.

I was in the habit or changing barrels at 5000 rounds, as was the practice with hard jacket projectiles.......then came reloading and suddenly the softer jackets with longer bearing surface gave these old girls a new lease on life......so now I have 15 or more spare barrels with low round count plus the stainless ones, I adapted a few to fit mausers, bought my new barrels as blanks, machined a long reinforce when profiling and kept rechambering when accuracy was lost.

One barrel in a target rifle has had two rechambers and about 20,000 rounds and is just showing slight crazing in the throat, a rechamber and recrown would get more use out of it as it is just under 29 inches, starting at 32inch long.

[Bruce_in_Oz]

Was the 144gn Ball ammo "disallowed" or was this an intended result of Jackboot Johnny nullifying the defence Act (1910?), eliminating the legislated role of the "rifle clubs” as a official "arm" of the "reserve" services?

The "rifle clubs” brought this on themselves when back in 1959 / 60, they got their noses out of joint and declared the L1A1 "unsuitable and not adaptable to target shooting”.

They had previously got all bitter and twisted over the adoption of the Rifle No1 (SMLE) as the "service" rifle, bemoaning its alleged "Unsuitability" due o lower muzzle velocities from a shorter barrel.. There were all manner of strange experiments going on to inctreased muzzle velocity; like progressively lapping the lands to reduce "resistance”, and so on. NONE of them could perform as consistently as the mass-produced MF Mk 7 ball ammo, however.

As someone who turned several L1A1s into "race-guns” by applying mechanical principals, selective fitting and quality barrels (standard profile, but made using Schultz and Larsen or other high-quality blanks.

It was a bit like backing up the work of the US Army Marksmanship Unit, who turned the "sow's ear" of the "rattly old" M-14 into a fabulous "match rifle" and into the XM-21 and M-25 sniper rigs, still floating around "interesting places”, nearly fifty years later. I did several here in Oz, before the sky fell in; 6 inches groups at 500 yds. was "acceptance"; using "issue" (often "Hythe")sights.

Add to that, things like Incredibly high-quality bullets like Lapua Scenars and "Palma" brass that uses Small Rifle Magnum primers and some seriously "magic" propellants, and it is a whole different game. Precision flash-hole reaming and chamfering? Check. Consistent neck-reaming / sizing. MINIMIZE the feral "variables";ONE at a TIME..

One microscopic "burr" on the lands at the muzzle can "ruin" a barrel, relatively speaking.

It is al a LONG way from the sort of performances that wowed the world of rifle shooting 125 years ago.. So; Less "Voodoo" and more actual "Engineering" seems to be the way to go.

Oddly, enough, good engineering and attention to detain trump "Fudd-Lore" EVERY TIME.

[muffett.2008]

The restrictions on use of the battle round L2A2 was the late '70's, it solved two problems.
Firstly it reduced wear on the L1A1 especially those actions that were of softer metal, it was also easier on the shoulder of young recruits post VN, and secondly improved the safety factor on Enfield Rifles converted to 7.62mm that was beginning to create problems within the Rifle Clubs.

The F4 round proved so popular with both the Military and target shooters, both scores and accuracy improved causing a reduction in aiming marks.
I still have a stack of the full blood round, all berdan primed. This was well before jackboot johnny put his bulletproof vest on.