Thanks Muffer, It certanly does the business, any more info on the Motty barrel ?
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Thanks Muffer, It certanly does the business, any more info on the Motty barrel ?
Just a heavy Motty barrel fitted, dated 1950, I picked this and one other Range Rifle up together from an old target shooter, the barrel looks pristine and was coppering up, so I told myself 'new barrel' and ran it in as per target rifle.
I love it, when I've got time, it gets a run along side my target rifle. I'ts happy at any range, although the new centre sizes are making it hard to get possibles.
Not all Mk.VII was cordite loaded, hence the Z suffix on those that were not.Quote:
Originally Posted by muffett.2008
You're right Beerhunter, but that's really where the similarities begin to seperate.
The cordite load for the standard Mk.VII was 36.5 sticks of cordite, +/- 1.5 sticks.
The loads for the 7Z and 8Z range from 40-41 grains of N.C or 36 grains of Neonite.
Lets put that into context, cordite at a known velocity of aprox. 2450-2550 fps, or 40-41 grains of N.C powder, the same load I am using today with modern powders at 2700 fps.
We will not get into the Neonite, other than to say it is a very fast and dangerous powder.
Now to the projectiles, The flat base we are all aware of, the boattail was introduced from
8Z on, it was so extreme, it even looks like a boat, compared to the very small boattail on modern projectiles, allowing for a long bearing surface, as opposed to the very small one of the military BT.
That brings us to the match cartridges of the day that were so sought after by Marksmen and Snipers alike, it's projectile also having a long bearing surface and small BT.
It's load was the standard load but tolerances were more controlled, an example of it's accuracy of load is a test fire of five rounds of Kynoch 303S.L.
1. 2496fps lo. 2496
2. 2512 " hi. 2512
3. 2507 av. 2502
4. 2499 ES 16.59
5. 2496 SD 07.14
Attachment 38714
These are magic figures for something made back in the 30's, that's the sort of consistancy we are chasing at a slightly higher velocity, the less air time the less wind variation.
IMR 3031 is (I'm told) usually used as a cordite replacement due to it's similar pressure and burn characteristics.Quote:
Originally Posted by muffett.2008
One question, using 43 grains of RX15 are you showing any signs of over-pressure? I ask as your load is a full 3 grains over the max in the Hornady book and 1 grain using the Lyman book.Quote:
Originally Posted by waco16
I know the difference in Hornady is the fact they test with their own bullets so know exactly from what materials they use what they believe should be the Max. load. I also know most reloading manuals error on the side of caution as we live in a sue somebody to retire atmoshphere.
The aim when I started was to try and match service velocity (the Sierra bullet being the same weight as the MkVII).
I began with the starting load in the Sierra manual and went up in half grain increments using a Chronograph to check velocity.
All they way up to this load there were no over pressure signs.
Normal caveats apply - safe in my firearm etc etc........
Like I said before, you cannot duplicate the original cordite load...........in safety.
muffett.2008,
Well, maybe you are right and then, maybe not.
The mere fact that the odds are against me makes me think that it's worth trying. A good challenge here - for some years to come. ;)
Snowy Owl
I admit I am a Hornady fan and just had my son point out they are now making .303 British Vintage Match ammo in 174 grain BTHP. Ballistics are muzzle 2430 FPS, 0 at 200 yards give you +2.6 inches at 100 yards, -10.5 inches at 300 yards, -30.1 inches at 400 and -60.4 inches at 500 yards. At 500 yards it is still 1669 FPS.
muffet.2008 how does this compare to original cordite MKVII?