Not quite the same meat but I 'adjusted' a 7.62mm No4 barrel muzzle that needed to be breeched in a but further to get anything like CHS. when the foresight block threads overturned by some way.
Just machined the lugs off plus .030" or so down to the end of the overturned lugs. Then machined a knackered .303" No4 muzzle to suit. Put 2x flats on the barrel, sweated the new 'sleeve' in place, aligned on the glass flat plate and nobody could tell the difference after it'd been through the phosphate and paint plant. Even had the bayonet lugs this time.
Still shot like a pig but 7.62 was cheaper than .303!
09-01-2013 08:38 AM
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So, did we end up with a definitive answer as to who made these "A W" barrels - Lithgow or CAL?
Really Senior Member
Just wondering - do you know what the groove diameter in the 7.62 mm No 4 barrel is? How much under-size from a standard No 4 barrel is this?
reason I ask, is: I note in the UK that No 4 barrels in .303 cal are very scarce, but those chambered to 7.62mm Nato are available.
My question is this: Could the 7.62 barrel be reamed out to take the.303 case, and could the bore cope with a standard .311" ( = .303) bullet?
And, if not, would the neck or full length resizer in a standard reloading die allow a .308 bullet to be seated into a reloaded .303 case, making a rimmed .308?
And, if this conversion was done, would it pass Proof? And would the calibre still be .303?
Originally Posted by RobD
Rob, some good questions and was asked similar last year, the case neck can be resized using a .308 die, so that's not a problem, regarding proof house think something like this you can provide them with the cases etc, as its a wildcat round probably proofed as a .303/.308.
As regards to re chamber its a no go as the 7.62mm/.308 chamber is to fat for a .303 reamer, the solution would be to bore out the 7.62mm chamber and then make an insert in .303 I,m not sure if anyone has done this and if it would be any good?
As regards to the reamer you would need to get a .303 reamer reground on the neck to the same as .308
To be honest the easiest solution is to use the 7.62mm barrel as it is.
I took in a No4 Mk2 barrelled action some time back in 7.62mm (its one of the Belgian barrels that was in a recent thread) I had the woodwork but shelved the idea. Its only due to recent post from thunderbox that I,ve looked at rebuilding it plus I use a lot of downloaded ammo now, and with x amounts of unique powder and a 110 grn round nose .30 bullet produce excellent results.
Last edited by bigduke6; 09-01-2013 at 06:16 PM.
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Really Senior Member
If you are starting from scratch, it is no big deal to do a ".303" barrel on a ".30" blank. The .003" difference is only a minor quibble, especially as it is a three thou TIGHTNESS, not LOOSENESS.
I have done a couple using slightly "tired" heavy 7.62 target rifle barrels. You know the ones: the driver can't get eight of ten "centres" / "V" bulls two weeks in a row and decides to get a new barrel! The biggest problem is getting one long enough as you have to chop off almost the entire 7.62 chamber to get to fresh meat to support the .303 chamber. If you are building a Carbine or "bush" rifle, no worries, but that 25" plus No. 4 barrel is a squeeze.
If your gun-plumber has a .303 reamer with a removable pilot, all he needs to do is swap in a .299" pilot. Going the whole hog, he can also grind the leade-cutter section of the reamer a little more steeply. That way, The chamber will still accept Mk7 ball, if you can find any, as well as a lot of other projectiles. It might make the bench-resters cringe, but this rifle was never intended to be a bench queen, but a functional "service" rifle. I nailed a very nice red deer with the old girl using the 155 Palma bullet. Mind you the range was VERY short: the silly hat-rack was almost about to walk over me as I hid behind a two-inch diameter sapling. I had been using the Palmas for a training shoot with my son and that was the only ammo to hand as we wandered back down the dry creek bed that afternoon. Heart, lungs and liver were "wrecked" by that bullet. Delete endless wild goat recipes; insert endless venison recipes!
The "creative" tooling was used to cut the chamber in my "rough" No4. It works very well with any decent .308" diameter bullet, especially Sierra Palma 155s and a couple of brands of 168gn beasties. It means I can use the same range of bullets in that ".303" as my .308 and 7.5 Swiss.
I whacked a bunch of Yugo ball with .311" diameter bullets through that hybrid chamber as soon as possible after getting it together. Pressure problems? None noticed then or any time in the last decade or more.
Despite being 1:12" twist, it is seems to just stabilise the relatively long Mk7 / 8 bullets, but won't stabilise any of the long, extra slinky "VLD" bullets, especially at safe ".303" velocities, but that was never the intention.
Last edited by Bruce_in_Oz; 09-02-2013 at 12:06 AM.
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Also very good for the .30 M1 Carbine round.
Originally Posted by Bruce_in_Oz
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new at this site
Very interested in converting a No4 MK1 into a 7.62x51. I have 3 No4 and one SMLE. I was looking for some time for 7.62x51 barrels for the no4 but nothing... I checked the website you posted but it seems to have nothing there regarding the "kit" Could you post the actual address?
Really Senior Member
I was told some years ago they are Lithgow. I really have to call Brain Dick this winter.
MJ, don't take this personally, but that's crap.
Originally Posted by MJ1
Really Senior Member
That grey phosphated lower barrel in the pic is not the same as the Lithgow ones I have.
A similar profile to a .303 barrel, the front sight seating lugs set back as per a standard No4 barrel and there are no bayonet lugs forward of the sight.
That barrel looks seriously fatter than standard and seems to have the front sight base further forward.