Sht. LE III won't chamber .303 Brit - UPDATE

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yidava25

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This is a little outside my wheelhouse so please bear with my ignorance.
Bought a Sht. Lee III* sporter, and it won't chamber .303 British factory ammo. Cartridge comes to a sudden and sharp stop about 3mm from where it needs to for the bolt to go into battery. There are no visible obstructions, I've tried it with no magazine in the rifle and with an empty cartridge, as well as an empty cartridge that I trimmed back about 2mm - same story. It chambers a loaded .308 Win round easily, but I have not attempted to fire that :)

Google has told me that people have rechambered some of these to something called ".303 Sporting" for legal reasons (not allowed to own a military-cartridge-firing firearm?)which basically involved bumping the shoulder down and trimming off 2mm or so. That would, I think, jive with what I'm seeing here but I can find no barrel markings that translate to a rechambering job... but I'm no expert on Lee Enfield stamps/markings. Also I know that there is such a thing as a .308 Win conversion that has been done in the past, but it should include a modified or maybe a completely different magazine - my rifle has a standard SMLE mag as far as I can tell. .308 definitely doesn't feed out of it.

Any thoughts, ideas, ways to tell what it's chambered in or whether there's something else wrong? I can provide photos of all it's markings and even borescope images if that would help.
Thanks
 
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Isn't a .303 Epps just an improved .303 British? If that were the case I would think there shouldn't be anything stopping a brit round from chambering.
 
Do a chamber cast or find a smith who can.

It would be best to know exactly what you are dealing with and after a hundred years (give or take) any number of modifications or incidents could have changed what is safe to fire in a particular gun.
 
vagrantviking - yes I should do that, any alternatives to Cerrosafe that you know of or would I just have to order that?

JP - negative although that's a good idea that hadn't occurred to me
 
OP, now it's time to become a bit more creative.

Go to the dollar store and purchase a can of Play Dough.

Jam the Play Dough into the chamber until you know it's full. You don't want it to be pushed too far into the rifling leade.

I would suggest you coat the chamber with some wax or oil first, but Play Dough is pretty slippery stuff and designed not to stick to the sides of molds.

It's quite cold outside right now so after you fill the chamber to just past the leade, set the rifle out in the cold for a few hours, if possible, or put it in the freezer if you have one.

This will give you a very nice "chamber cast" that will be easily compared to your cartridges.

I was given a couple of "Lithgow" rifles that had been sporterized in Australia. The fellow owned a farm there and, in the area, where he lived, rifles that chambered the 303 Brit were banned.

Both rifles had been chambered by the same smith and were fitted with after-market barrels. I shot both of them for many years. They both had identical chambers and .308 bores. The case looked like the smith had a standard 303 Brit reamer reground to shorten the OAL appx 3mm, with a 40-degree shoulder, etc. The case dimensions to the shoulder were identical.

The Play Dough will need to be tapped out with a bit of wooden dowel or a cleaning rod. It will pop out easily unless you've pushed too much into the bore.

The frozen dough plug will give you a duplicate in reverse of what your chamber looks like and it will show any obstructions if there are any.

The last can of dough I purchased cost a toonie.
 
bearhunter said:
OP, now it's time to become a bit more creative.

Go to the dollar store and purchase a can of Play Dough.

Jam the Play Dough into the chamber until you know it's full. You don't want it to be pushed too far into the rifling leade.

I would suggest you coat the chamber with some wax or oil first, but Play Dough is pretty slippery stuff and designed not to stick to the sides of molds.

It's quite cold outside right now so after you fill the chamber to just past the leade, set the rifle out in the cold for a few hours, if possible, or put it in the freezer if you have one.

This will give you a very nice "chamber cast" that will be easily compared to your cartridges.

I was given a couple of "Lithgow" rifles that had been sporterized in Australia. The fellow owned a farm there and, in the area, where he lived, rifles that chambered the 303 Brit were banned.

Both rifles had been chambered by the same smith and were fitted with after-market barrels. I shot both of them for many years. They both had identical chambers and .308 bores. The case looked like the smith had a standard 303 Brit reamer reground to shorten the OAL appx 3mm, with a 40-degree shoulder, etc. The case dimensions to the shoulder were identical.

The Play Dough will need to be tapped out with a bit of wooden dowel or a cleaning rod. It will pop out easily unless you've pushed too much into the bore.

The frozen dough plug will give you a duplicate in reverse of what your chamber looks like and it will show any obstructions if there are any.

The last can of dough I purchased cost a toonie.
Click to expand...


I got 3 kids under 6
The toonie will stay in my pocket:)
 
303 left rcvr.jpg
303 right rcvr 2.jpg
303 right rcvr.jpg
303 full.jpg

Isn't she a beauty lol.
I'm not very well versed in Enfield markings but I believe it's a British made No1 Mk3. Casting measures very like a .308 Win, definitely not a 7.62x54R although that came to my mind immediately as well. I can try casting the bore at the muzzle but it looks like 0.308 when I try inserting a projectile.
 

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When you cast or "slug" the bore - if it is a 308 Win, should be .300" from top of one rifling to top of opposite rifling - very hard to get accurate measurement if it is a British "odd" numbered groove, like 3 or 5. The groove diameter should be .308" - that is the spec - actual production might have varied from that. For 303 British, should have been 0.303" from top of rifling to top of rifling, and in theory should be 0.311" groove to groove, although I have read of some groove sizing as much as 0.317" - war time standards back then were not like modern CNC standards.

Be aware that over the years, was VERY possible that an entirely different than original barrel was made and fitted to that receiver - it might "look" old, but might have been done 50 years after the rifle was made. To convert to 308 Win, (invented circa 1950's) probably requires a new barrel, a 303 British barrel probably too large chamber, too large bore. Was a thing at one time to make a "hybrid" - so a 308 Win chamber, but using 303 British bullets - so you could "set back" an original barrel - re-do the chamber, and continue to use that original sized bore - was often referred to as 30-303 or 308-303 or similar. I think the extractor in the bolt head might have had to be replaced to be able to grab the 308 Win rim - but maybe military 303 extractor worked for that?

Looking at your pictures - I do not think that barrel has a "knox form" - a flat area on top of the chamber area of the barrel - I am not sure that any SMLE barrels were done like that - goes to someone's work - NOT a military replacement or an "original" barrel.
 
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