Metford Rifling ?

[dromia]

Over the weekend I've been playing around slugging some bores, cast up some soft lead slugs in the .310" Cadet mould and have been banging them into muzzles with gay abandon.

I've just slugged my Metford rifled Long Lee Enfield Mk1 Volunteer by LSA.

Measurments come out at bore diameter .303/4" as its a tricky measurement and groove diameter .308".

Now this rifle shoots commercial/military jacked OK although I haven't really done any experimentation with jacketed bullets mainly trying cast and the best I was getting was 4" groups with the Lyman .314" bullet.

Having now slugged the bore I'm wondering should I be using .308" bullets?

When it comes to shooting bought .303" ammo in this rifle Its resizing a jacketed bullet from .311" to .308". Usually in Enfield barrels the measurments are more generous and the usual issue is undersize bullets not oversize, hence the effectiveness of flat based bullets.

The 8mm Mauser round was originally .319" groove and then enlarged to .323" and we are warned not to shoot the .323" bullets in the old J/I rifle. Is this just because of the diameter differences or is the JS .323" round also loaded to a higher pressure?

My thinking on this is firstly is it a good idea pressure wise to shoot manufactured .303" in this rifle even although it is BNP stamped. Secondly I think some experimentation with .308" bullets might be in order.

Has anyone any experience of this?

Views welcome. :?

[awo425]

No experience with Metfords(I am too poor to buy one) but had some similar things with one special finn Mosin M27.

I was alway under the impression, M27 do have .310" or wider grooves, so I loaded some D cartidges wit the Lapua D166 and some with 180grn .311" Sierra Prohunter.

Poor grouping, hard kick, stiff bolt, I was not ammused

Then I slugged the bore and found out, that the groove is more like .308". From that time on I used Lapua Match ammo with 185grn .308" bullet, MOA groups, easy bolt, PERFECT!!!!!!!!

Best thing is, the gun shoots not to hing, 200m seting on the sight give perfect X hits with a 6 o'clock hold.

Chris

[dromia]

The interesting thing about the Lee is that there were no pressure signs when shot with jacketed ammo.

[bradtx]

Adam, Offering nothing more than what you know, I'd use a .308" bullet if any of my L-Es slugged small.

My knowledge of the Metford is pretty limited in general, but I thought that smokeless (just cordite?) had a negative effect on the rifling...true?

Take Care, Brad

[dromia]

Hi Brad,

thats why they developed the Enfield rifling, it is more substantial than the Metford type to withstand the heat erosion of cordite.

Its not so much of a problem with cooler modern powders, Marlin's microgroove rifling looks like a Metford variation and doesn't seem to have a problem.

Obviously I'm not intending to put thousands of jacked rounds through it but a few dozen or so a year for comps and to give it an airing, the lead load development is my main aim for more regular shooting and 200yrd service rifle competitions.

[bradtx]

Adam, Thanks for the reply.

There are just so many interesting facets and variations with the Lees. I for one am guilty of just zeroing in on two or three of those facets, but I do like to have the others in my peripheral.

Take Care, Brad

[belgmart]

To be more precise, the issue that cropped up with both Martini-Metfords and Lee-Metfords was due to 3 factors:

- Soft barrel steel

- shallow Metford rifling

- erosive nature of cordite (high burning temps)

The Enfield rifling that replaced the Metford rifling eroded actually as quickly... but was quite a bit deeper, so it lasted longer before being 'shot out'. With modern powders, the problems much less. Add a modern barrel into the equation, and they become non-existent. Of course, we're talking segmental rifling here - the 1st Metford rifling was a form of gaintwist rifling...