Bump up.

[Alan de Enfield]

Throats on the lee's were generous to say the least but another malady that can present itself is cord wear unless a person knows what they are looking for at the muzzle end they may miss the fact the rifle is afflicted with such a thing and keyholing.
.

Armourers notes dated 9/43 suggest that No1 & No5 causes of wear are :

[muffett.2008]

We have been lucky here in OZ, Mulwex Powders serve us well and there never has been a shortage of other brands.

Using AR2206, 2206H, 2208 AND 2209. we get an average 125fps variation using the same load (NOTE some of these loads are at the high end of the scale) so a rifle giving 1900fps with 2208 will give a good result with a faster powder.....the load difference though between 2206 and 2206H to achieve the same velocity is 1.5grn.

By careful monitoring of pressure signs we can tailor the load to give good results.
My powder cupboard is full of various powders, my bookcase full of loading manuals dating from the 60's, marvellous how the loads varied over the years from book to book, finding and keeping records of equivalent burn rates has always been a challenge, but then we wouldn't do it if it was not.

As to cordwear In all my time Inspecting these old clangers, I have never seen chamber wear caused by a pullthru, muzzle wear yes, my service days saw a fair smattering of chamber wear in L1A1's, no muzzle wear as the flash eliminator prevents the cord being pulled against the crown.

On the whole, Lithgow barrels and chambers are a lot tighter than their counterparts....stories of oval chambers were usually just that .....stories.

[Bindi2]

Muff at what distance from the muzzle were you placing your chronny It appears to me you are keeping the velocity down as well or is 1900 the start base then watch for pressure. What is your upper speed level when looking for accuracy. You are correct about the manuals. I shudder every time 3031 is mentioned.

[22SqnRAE]

Bindi,

The common optical Chrony brand with the wire and domed plastic shades is placed at 10' from the muzzle. While not D = 0, it's a fair indication of Vo, without the majority of gas effects from the shot.

Strap on types measure with electromagentic fields closer to muzzle, but are not really suitable for service rifles that don't have clean muzzles.

[CINDERS]

My inference to cord wear was only referencing the muzzle not the chamber as the chamber will guide the pull thru and flannalete through into the bore it is as stated pretty well known the throats in the lee are generous I mentioned it as a fact all of mine show various stages of fire cracking and pitting in the bore from corrosive ammo my 1916 with a '37 barrel being the worst of the offenders.
I was pointing it out unless the person was savy with these things or the gunsmith then the issue of having a cord worn muzzle may go unoticed and have the new to the rifle scratching their heads as to a 20 moa group or keyholing.

Labradar is the best we have used no chance of putting a round through the chrony or the magnetic foot.......

I had a bad experience with Win ball powder 760 in the 303 using a light load instead of it burning from the rear it flashed right along the top and was virtually a detonation thankfully it was in my No.4 I now load exclusively with 2209 46Gns capacity according to quickload for *2440fps so there is no chance of a flash over.

[muffett.2008]

Yep, that's about the distance. funny that Bruce, I have a fair bit of 3031 left....I can send you some just for nostalgia.
1900fps was just an example , we basically tried to achieve a minimum of 2150fps, but if we could not achieve that safely then a minimum of 1900fps would do before we would mark it for a change of barrel, lower than that keyholing and accuracy became a significant problem.

It took three of us, one chronographing the rifle with milsurp spec ammo and a set boattail load(Sierra 174gr) recording the velocities of both loads, the second inspecting the fired cases for pressure signs and rifles for safety and sight alignment, the other reloading/FLS cases with different loads to achieve our base figures.

A great way to spend a weekend, each rifle then firing a 5 round group that went into the rifle butt as a record for the future.
At night we would rebarell the odd one or two.......those were the days.

We did rotate the jobs a bit.....the shoulder can only take so much.

[Bindi2]

22... I have had a chronny since the early 70s in fact I have two of them pre wire and dome tops and a Lab radar. I also know that Chronnys need to be in light shade to work properly not direct sun. I use the Chronnys for pistol work now days and the Lab for my rifles. Muzzle blast can affect Chonnys like mine at 10 feet particularly in direct sun.

[22SqnRAE]

22... I have had a chronny since the early 70s in fact I have two of them pre wire and dome tops and a Lab radar. I also know that Chronnys need to be in light shade to work properly not direct sun. I use the Chronnys for pistol work now days and the Lab for my rifles. Muzzle blast can affect Chonnys like mine at 10 feet particularly in direct sun.

Bindi, I'll follow Ron's footsteps and make it clear to all, like Ron has done in a very thoughtful manner - in no way are my responses intended to be pedantic or posturing as a know-it-all. These threads serve as a world wide education platform and its great that less experienced folks can lean much form fellows like you, Muffett and Cinders. So thanks for the continued discussion, it's greatly appreciated.

I've found similar with the Chrony Beta model in different light. Direct sun buggers up the shadow that's supposed to show on the plastic arches, meaning the reading is generally faulty and useless. In overcast days, it's generally pretty good. As you stated, a little shade over the arches makes a difference in getting good readings. I've not yet had any muzzle blast problems with my measurements. Mind you, I'm only measuring .303 and a few .308 rounds from my TR.

Bit envious with your Lab Radar. When properly set up and the user has read (an understood) the instructions, they're a treat to use and repeat info. Bets bit is that they can be used alongside anyone's rifle on the mound. A real bonus. Using technology to improve knowledge is a good thing. Pity it's still out of my budget...

Kev's exercise in trying to establish what works and what's the limits would be an excellent weekend of time well spent.

[Alan de Enfield]

Muzzle/ crown protector for use when trying to 'hammer' out blockages (either squibs or snapped off 4x2 pull thru)

Only issued to the armourers so not intended for use with pull thru's or to stop cord wear.

Fitted over the muzzle until it hit the 'internal stop', the smaller diameter hole was inboard of the muzzle so when the rod was hammered down there was no impact or damage on the crown

[CINDERS]

Yep got one of those thingies sitting on the shelf Alan never used it trial fitted bit of a mission with a No 1 MkIII not to bad with the No.4 though thanks for the share.