whats a load of 40 grains of cordite equal to in modern powders??

Using the Ross Seyfried conversion factor of 1.19 it would equate to 47.60 grains of RL-15. The conversion factor is just for RL-15.

The earlier conversion for cordite in nitro express rifles was based on grain for grain Cordite/Dupont IMR3031. This was a safe starting point and the loading for IMR3031 could usually be increased until the Cordite point of impact was attained.

Most, including myself in the .404, have found that the slower powders e.g. 4831 produced better accuracy, velocity and correct point of impact. Elmer Keith, while advocating 3031 and 4895 as replacement for Cordite in many of the old British cartridges, also promoted 4831 (probably H4831 back then) as a good powder for loading the British stuff e.g for the .404 I have used 60-65grs IMR3031 or 85grs IMR4831 to duplicate the original Cordite load of 60grs with a 400gr bullet.
The slower powders fill cases and with a magnum primer give good ignition and usually a clean burn.

Or, take the original cordite load and multiply it by 1.333 to get the correct load of IMR 4831. Thus, your 40 grains of cordite would equal 53.3 grains of IMR 4831 (40 x 1.333 = 53.3).

quote:

Originally posted by MJines:
Using the Ross Seyfried conversion factor of 1.19 it would equate to 47.60 grains of RL-15. The conversion factor is just for RL-15.

I agree with Mike, but I would begin with original cordite load x 1.15 and work up. I am a big fan of RL 15 . Good luck!

quote:

Originally posted by DoubleDon:

quote:

Originally posted by MJines:
Using the Ross Seyfried conversion factor of 1.19 it would equate to 47.60 grains of RL-15. The conversion factor is just for RL-15.

I agree with Mike, but I would begin with original cordite load x 1.15 and work up. I am a big fan of RL 15 . Good luck!

Me three!

One thing to remember is that Cordite was a long stick powder, long like spagetti.

So if you use IMR 3031 or Rl 15 it might be necessary to use some sort of filler, such as dacron polyester or a foam plug.

Some cases, like the 450 No2 or the 475 No2 must use filler even with IMR 4831, or hang fires will result.

The filler must be compressed between the powder and the bullet.

quote:

Originally posted by N E 450 No2:
One thing to remember is that Cordite was a long stick powder, long like spagetti.

So if you use IMR 3031 or Rl 15 it might be necessary to use some sort of filler, such as dacron polyester or a foam plug.

Some cases, like the 450 No2 or the 475 No2 must use filler even with IMR 4831, or hang fires will result.

The filler must be compressed between the powder and the bullet.

Agreed! I prefer backer rod (3/8", 1/2", 5/8") purchassed at Lowe's or Home Depot, cut to length. Approx. 1/8" greater than base of bullet to powder.

I agree completely with NE 450 No2 above! The conversions for the smaller cordite cartridges is OK with the 3031 and 4895 powders because of the smaller capacity of the cases. Most of those were chambered in strong bolt and single shot rifles, and required no filler.
With the large NE cases for double rifles a lot of rifles were damaged in the early days of experimenting with powders to substitute for the cordite. The causes were not well understood for some time after cordite was no longer available. This was caused because of very low volume loads in the large cases. The accuracy suffered becase every way the rifle was held the powder was spread in different places inside the case. Then there was the flash-overs the raised pressures too suddenly. The 3031 and 4895 were very popular powders in those days so were the first to be tried. The war surplus 4831 was available back then but some shyed away from it because they knew nothing about it, and considered it cannon powder. Once a few started experimenting with 4831 it was found that it worked very well in those large NE cases, and needed no filler in most cases.

Another thing that came about once the need for filler with the 3031, and 4895 powders the experimenting started with finding the best fillers. This again caused problem at first, as people used things like crème- of- wheat for filler because it had been used to fire form cases with light loads of pistol powder. However, when used with enough powder and heavy bullets this spiked the chamber pressures ringing chambers if they were lucky, and burst barrels if they were not.

Then along came RE-15 which was slower burning and requires far less filler, and shortly the filler was sorted out with this powder, and it became quite popular then and still is today, but still requires filler, the types of which Tony posted above. With the three 4831 powders available today none require filler in cases up to 500NE, except the cases Tony mentioned 450#2NE, and the 475#2NE being the most likely candidates need some filler even with the 4831 powders . Those powders are IMR-4831, H-4831, and H-4831sc. The IMR-4831 being the fasted burn, and the two H powers slower with the “sc” meaning short cut. Both H powers are the same burn rate but the sc allows more powder in the same case, and flows through a powder measure better. The fillers have about boiled down to Dacron fiber fill, or the Kynoc foam fillers. Just enough to fill the airspace between the powder, and the base of the bullet, slightly compressed. This serves two purposes, #1 it improves accuracy because you get consistent powder burn with no chance of flash-over, and # it holds the powers against the primer for best ignition.

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quote:

Originally posted by DoubleDon:
Agreed! I prefer backer rod (3/8", 1/2", 5/8") purchassed at Lowe's or Home Depot, cut to length. Approx. 1/8" greater than base of bullet to powder.

I have a quick, little bit OT, and sure to be dumb question but bear with me a I don't reload. At least not rifle stuff like this.

What prevents the foam backer rod from melting and fouling the bore with residue?

I have used dacron polyester and 3 different densities of foam in my 450 No2.

I have recovered all 4 and none show any signs of burn, char or melting.

The Kynoch foam wads are hard to beat. You will pay $15 for a package of 100 and you can usually cut them in half and use half to extend the pack to 200.

quote:

Originally posted by butchloc:
whats a load of 40 grains of cordite equal to in modern powders??

What caliber is this for?

I have my foam cut at Houston Foam and Plastic. I bought a cutter to match the Kynoch plugs and just order more when I run low.

There look to be a number of accepted conversions with varying powders.
I don't fret about it since there are good modern powder loads out there for every cartridge you can think of.
I too prefer to use backer rod as a filler. Just so easy and cheap to boot.
I have not noticed any residue or fouling in the bore which is any different than loads with no filler.

quote:

Originally posted by Rusty:
I have my foam cut at Houston Foam and Plastic. I bought a cutter to match the Kynoch plugs and just order more when I run low.

Rusty,
Where did you buy your cutter or get your cutter made?

Lane,
I had them make it for me. It stays there and they use it when I order.

Rusty,
Do they have a .510 cutter?