The 303/6mm

[savagetactical]

I have an old Enfield action laying around and was thinking of having it barreled for this particular wildcat. Anyone here have any experience with it ?

[frnkeore]

It sounds like it would be a excellent caliber. I think loading data would be very close to the 243 Win.

Frank

[220]

There was a family of 303 wildcats that were offered commercially here in Aus, a couple of 22 versions 6mm .25 .270.
303/25 was by far the most popular and factory ammo was available until the early 90's.
The recently released 6th edition of the ADI load manual still has data for the 25 & 270 versions, many of the ADI powders are imported into the US by Hodgdon so should be available to you.

[Stephen Cohen]

One of the conversions that were popular in this country, My copy reloading Simplified by Cyril Waterworth shows it to be only a couple hundred feet a sec slower than 243, I have know those who owned them.

[Bad Ass Wallace]

The enfield action is rather weak as military actions go and it may not be really worthwhile, I have a number of wildcats built on stronger P14 actions which are very worthwhile.

[Hardcast416taylor]

A Canadien gunsmith by the name of Elwood Epps made quite a few different chamberings on the .303 case and Lee-Enfield actions.Robert

[savagetactical]

The enfield action is rather weak as military actions go and it may not be really worthwhile, I have a number of wildcats built on stronger P14 actions which are very worthwhile.

I am aware of this, however it was my understanding that the 303 wildcats were usually good to go in Enfield actions .. Maybe I am wrong, from what I understand most were built on Enfield actions.

[groovy mike]

Don't know where you get the idea that enfield actions are weak! They are pretty darn strong!

http://www.milsurps.com/showthread.php?t=37689&page=5

[Char-Gar]

There are Lee Enfields and there are Lee Enfields. Those made in Canada (Long Branch) and the US (Savage) use a better steel than those made in Britain, India etc. When discussion the strength of these actions, who made them does matter. I should think they are all amply strong for the original chamberings, but we are talking about Wildcatting here are we not? That is an entirely different topic.

[303Guy]

The 6mm-303 has the same chamber pressure as the 303 British so it makes no difference. Another name for the cartridge is 6mm Musgrave for which load data is available. As stated the 6mm-303 is a couple of fps slower than the 243 - basically starting loads for the 243 are max loads for the 6mm-303. Now the 25-303 has the same performance as the 243 and is in my opinion, a better choice for the Lee Enfield. I have one and it's great. I have achieved sub MOA with it at 185m without even bedding the fore-end properly and it has a skinny SMLE profile barrel. Mine is built on a Lithgow action which is about as strong as an North American built No4. Performance is right between the 250 Savage and the 257 Roberts. A 100gr bullet can do 2900fps, same as a 243. The 100gr bullet has been driven higher but I'd say that's stressing the Lee Enfield a bit. 87 gr bullets are going to be proportionately faster.

[DeanWinchester]

I bet a 6.5x303 would be awesome. Bet it would be close to a 6.5x55 swede and if it is, well we all know how great that caliber is with copper condoms. Not real cast friendly but the 6,5mm is a very good shooter.

[madsenshooter]

Reamers and dies are available for the Musgrave, least they were at one time. Lee had the dies, limited production. I'm still working on something similar, 6mm/30-40AI, but if I hold the reamer short, I can keep the chamber .303 length. .303 cases are generally a bit easier to come by than 30-40. I have a couple 6mm barrels, just need money to pay someone to cut Krag threads for me.

[savagetactical]

The 6mm-303 has the same chamber pressure as the 303 British so it makes no difference. Another name for the cartridge is 6mm Musgrave for which load data is available. As stated the 6mm-303 is a couple of fps slower than the 243 - basically starting loads for the 243 are max loads for the 6mm-303. Now the 25-303 has the same performance as the 243 and is in my opinion, a better choice for the Lee Enfield. I have one and it's great. I have achieved sub MOA with it at 185m without even bedding the fore-end properly and it has a skinny SMLE profile barrel. Mine is built on a Lithgow action which is about as strong as an North American built No4. Performance is right between the 250 Savage and the 257 Roberts. A 100gr bullet can do 2900fps, same as a 243. The 100gr bullet has been driven higher but I'd say that's stressing the Lee Enfield a bit. 87 gr bullets are going to be proportionately faster.


Thanks for confirming what I had been told, it was always my understanding these cartridges came into existence because of a prohibition of owning rifles chambered in military calibers. I just think having a No. 4 with a 6-303 barrel would be a neat project , plus I have a huge amount of 303 brass and I already own a 6mm Remington so I have a large quantity of 6mm projectiles. I actually would want a military profile barrel so I could keep the original appearance of the No 4. Maybe evening making a No.4 T Sniper with replica MK 32 scope chambered in 6-303.

[savagetactical]

Reamers and dies are available for the Musgrave, least they were at one time. Lee had the dies, limited production. I'm still working on something similar, 6mm/30-40AI, but if I hold the reamer short, I can keep the chamber .303 length. .303 cases are generally a bit easier to come by than 30-40. I have a couple 6mm barrels, just need money to pay someone to cut Krag threads for me.

I will check with Lee for some dies and look into obtaining a reamer . Thanks for the information

[Reverend Al]

Although I'm sure that Mr. Epps chambered up a few Lee Enfields in his popular Canadian wildcat cartridges too, most of them were built on the stronger (and just as easy to obtain up here) P14 Enfield actions. I've seen several of his P14 Enfield sproters around my area that were re-chambered to his .303 Epps Improved cartridge, (which wasn't far off .300 H&H ballistics). He also chambered up a lot of large action Martini rifles too. The only thing that hurt his line of improved cartridges back in that era was a lack of high quality hunting bullets suitable to the enhanced performance of his cartridges ...
By the way, his original retail store out in Ontario is still in operation by a family member!
https://ellwoodepps.com

[savagetactical]

Very cool and thanks for the information and the link.. Reverend Al.

[rosst]

83313

83314

this beautiful 6/303 cam up on our version of ebay a couple of times for $2000NZ with dies, cases, scope etc.

[303Guy]

Now that is eye candy! The 6mm Musgrave used the same shoulder angle as the (non-existent) standard 303 Brit so it looks different to your 6mm/303.

You know, the Lee Enfield would work with the 6x57 Mauser. One can get x57 rimmed cases which would be even better. Then there is the 6mm/303 Epps. That should equal the 243. It's not so much the strength of the action but the flexibility. Apparently too high a pressure destroys accuracy. I've never experienced that though - I keep my loads reasonably moderate. Careful powder selection might yield higher velocity at moderate pressure.

The 6.5/303 would be pretty good I should think. It's at the 'optimum' case volume to bore area zone for velocity. Think in terms of starting loads for the 260 Remington as max for the 6.5/303. A 95gr bullet would do 3000fps with some powders - maybe up to 3100fps. The 6.5x57 rimmed or rimless comes to mind although the overall length may exceed the magazine length with a long bullet.

I should mention that the idea of a larger case volume is to lower chamber pressure. My thinking is to match modern cartridge velocities at lower pressures suitable for the Brit.

[savagetactical]

Now that is eye candy! The 6mm Musgrave used the same shoulder angle as the (non-existent) standard 303 Brit so it looks different to your 6mm/303.

You know, the Lee Enfield would work with the 6x57 Mauser. One can get x57 rimmed cases which would be even better. Then there is the 6mm/303 Epps. That should equal the 243. It's not so much the strength of the action but the flexibility. Apparently too high a pressure destroys accuracy. I've never experienced that though - I keep my loads reasonably moderate. Careful powder selection might yield higher velocity at moderate pressure.

The 6.5/303 would be pretty good I should think. It's at the 'optimum' case volume to bore area zone for velocity. Think in terms of starting loads for the 260 Remington as max for the 6.5/303. A 95gr bullet would do 3000fps with some powders - maybe up to 3100fps. The 6.5x57 rimmed or rimless comes to mind although the overall length may exceed the magazine length with a long bullet.

I should mention that the idea of a larger case volume is to lower chamber pressure. My thinking is to match modern cartridge velocities at lower pressures suitable for the Brit.


That is some good information.. I will say I have no interest in doing a 6x57 on an enfield as I already own a Herters Sporter in 6mm Remington which is what a 6x57 is essentially. I was thinking one of the Aussie wildcats would be fun and different to play with ..

[Reverend Al]

I always thought that it would be a fun project to custom build a Lee Enfield, Ross, P14 or Martini based "7x57mm Rimmed" sporter rifle. You just use an RCBS #7 shell holder with a set of standard 7x57mm dies and run some .303 British cases through the FL die and ... voila ... you now have "7x57mm Rimmed"! It would be an easy barrel blank to obtain (or you could always re-work a lightly used barrel by shortening up and re-threading a donor barrel from another rifle) and you could chamber it up with a standard 7x57 reamer and then machine the rim portion of the chamber on the lathe. Being rimmed (and formed from .303 Brit brass anyway) it would feed from the LE, Ross or P14 magazines with no problems. It's always been a very popular bore size too so there are tons of high quality "J words" and a wide selection of Boolit moulds out there, both in a wide range of weights. Hmmmm ....
Just what I need ... another project!

[303Guy]

The 7x57 rimmed would have the same shoulder head-spacing if carefully done so the rimmed or rimless case would fit. No cutting out the breach face for the rim. That space is already there. There is little danger of 'high pressure' factory rounds being fired in it because there is no such thing as a high pressure 7x57 factory cartridge (I hope). I have thought about it.

I doubt one could easily form 7x57 from Brit cases as the case body of the Brit is smaller - the x57 has the same base diameter as the 308. It will work but there will be a fat bulge at the web and the Brit is a little shorter which shouldn't be a major problem. Cases could be made from 30-06.

[madsenshooter]

rosst's cartridge looks close to what I had in mind for my Krag.

[Reverend Al]

Actually the .303 Brit cases do reform to make great 7x57R brass as it's already been done many times and worked quite successfully. There are a lot of the Czech Brno combination guns in my area and when the 7x57R ammo was tough to get it was common practice to form it from .303 Brit cases using the .303 shell holder and the regular 7x57 dies. The cases grow slightly in length when you re-form them from .31 calibre to 7mm and the finished cases generally come out at the perfect length. We didn't have any trouble with expansion at the base ahead of the rims when reloaded and fired either, but as mentioned it is a low pressure cartridge when loaded properly for break action combo guns. The rimmed cases would also work well with the existing bolt head and extractor on a Lee Enfield, Ross or P14 action rather than having to rework them to extract and eject a rimless case if regular 7x57 rimless cases were used.

[303Guy]

Interesting. Thanks for that info. There is a fellow who fired a 30-30 cartridge in a 303 chamber and it fire-formed pretty well. The web expansion looked pretty even too. So, why not expand a Brit into 7x57? I didn't think of the case elongating on sizing down.

I've heard of someone using 303 Savage cartridges in a 303 Brit chamber. He said it worked better for moose than 303 Brit ammo!

[savagetactical]

That is an interesting tidbit of info , as desirable as 303 Savage ammunition is I doubt I would be using any in my Enfield.

[303Guy]

Strangely, this fellow hadn't had any problems up until that time. Not recommended! We could duplicate the load though - if we knew what it was. I wonder what alloy and hardness was used for the 303 Savage?

[savagetactical]

Strangely, this fellow hadn't had any problems up until that time. Not recommended! We could duplicate the load though - if we knew what it was. I wonder what alloy and hardness was used for the 303 Savage?

The 303 Savage operates at lower pressure than the 303 British so that most likely had a role in it.