Actual barrel dimension of bullet size for the Lee Enfield?

[Canuck Bob]

Please note the actual size of your barrel from molds or slgs. Due to the difficulty with measuring the odd groove barrels the best size for bullet accuracy would be great as well. If you have many rifles I guess pick the largest or best average. This is my first poll so I expect to really blow it.

Edit: I enabled multiple choices so choose away!

[Bloodman14]

My No. 4 Mk I* is .303x.316; my No. 4 Mk II has a 5-groove that measures a perfect .303x.308, according to this image posted by 303tom on the Reloaders Guide.
I'm still working on best boolit size.

[Multigunner]

The Small Arms Identification Drawings for british .303 rifles give an acceptable range of .303 Minor with groove depths of from .005 to .008.
Actual measurements of slugged bores show an even greater range of bore sizes.
A worn bore can have a minor of up to .307,and some rifles have had major diameters of up to .321 without signs of wear.

The SMLE Mk1 had a reverse taper lapped bore, the last 14 inches or so lapped progressively to several thousands of an inch larger than the first ten inches.
The intent was to relieve bullet friction so the MkVI bullet would have the same velocity from the Short rifle barrel as from the much longer LE barrel.
So long as the bore diameter was not increased more than a couple of thousandths, with minor diameter remaining the same, accuracy was still good.
The original Cordite Mark 1 propellent charge having delivered it maximum acceleration in the first ten inches of bullet travel.
The later Marks of the SMLE used the more coventional bore, and conventional replacement barrels were for the SMLE MkI were authorised in 1917, though not all got the new barrels.

So you can't really go by the stated optimum bore dimensions, the acceptable tolerances were just too great, and the barrels were kept in service till they failed rather broad gauging standards or began to keyhole at the range.

A proper bullet diameter should be taylored to the individual barrel.

According to Reynolds the best accuracy came with minimum bore diameter Iaccording to SAID .313) and maximum acceptable bullet size ( .312) this being FMJ of course.

So far I've only fired a few cast boolits in .311 and .314 diameters, not enough to give any recommendations.

[longbow]

I have two No. 5's and two No. 4's.

I have slugged the two No. 5's and they both have 0.315" throats and as best as I can measure 0.314" grooves. One has 0.305" bore and one has 0.303" bore.

One No. 4 has almost identical chamber and throat as it will chamber and shoot the same rounds neck sized only from the No. 5's with slight resistance closing the bolt. It has not been slugged though.

The "new" No. 4 has yet to be checked or shot. Got to get that remedied!

I cast 0.316"/0.317" then size to 0.315" and that just fits the throats of the two No. 5's and the "old" No. 4. they all shoot well with that (NOE 316299 and NOE 0.314" x 129 gr. lapped to 0.316"+).

Longbow

[Jack Stanley]

For this poll you could add ; all of the above and more

I like the Enfields and the cartridge it uses though I do wish they were a bit more uniform . I don't think I've ever had one that is as small as .311" , I do have one that takes .318" just fine though ........... Frank Marshall would be proud of this one .

The range I see tends to favor .316" to 318" , I found a number four mark two with a .312" groove and thought I was in hog heaven

Jack

[curator]

Probably should have specified 5-groove or 2-groove barrels. Most of my 5-groovers are right around .314 groove diameter. All of my 2-groovers are more than that. Some much more. Unlike the '03 -A3 Springfield 2 groove barrels that are 5/8 land and 3/8 groove, Lee Enfield 2-groove barrels are more like 5/6 land and 1/6 groove. Engineers and designers at the time made the grooves deeper to provide a place for all the displaced bullet metal to go when the .311 diameter bullet got swaged down as it entered the bore.

[Multigunner]

The Enfield bore was designed to compensate for excessive thermal erosion from Cordite Mk1.
It was carried on when the somewhat less erosive Cordite MD was developed.

When the M1917 was manufactured using the same Enfield pattern rifling only with major and minor suited to the .30 bullets of .3085 they found that the resistence to erosion of the British rifing gave the M1917 a greatly increased useful bore life over the more conventional four goove rifling of the 1903 and similar rifles in the same .30-06 chambering.

I know little about automatic weapons but I have read that the M1919 at one time used Enfield pattern rifling for extended bore life.
When this rifling was used for FN FAL barrels they reported a useful bore life of from 30,000 to 50,000 rounds.

The rifling used for the modern remington made Sniper and Long Range rifles appears to be a slightly improved version of the Enfield pattern.

[Canuck Bob]

Thanks,

This pertains specifically to my No.5 BSA June 1945 5 groove but is also to get educated on Lee Enfields generally so 2 groove is of educational interest..

As close as I can figure my groove dimension is .313 or .314. The throat had a taper and was at least .315 or .316 near the chambers end. I'm awaiting proper slugs from LBT and then he will confirm my dimensions properly. I got the groove by measuring the point on a slug just where the rifling starts, close but not precise. I recently reread Steve's article on his excellent 303 site so I asked to find others opinion;

http://www.303british.com/id71.html

[dnepr]

I don't know the exact dimensions of my Parker Hale sporter but a boolit sized to .303 is engraved by the rifling ever so slightly and a cerro safe cast of the chamber and a couple inches of barrel won't slide through my .314 lee sizer ,

[Multigunner]

A member of another board just ran across a BSA No.1 MkIII with a .309 major dia bore. He's experianced with the Enfields so I figure he slugged and miked properly for the five groove bore.
Thats the smallest bore of any Lee Enfield .303 I've heard of so far.
Should work fine with .308 J-words if that were all that was available.

With the type of gauges used by the British I'm not suprised when a bore is over sized, but it is suprising when one is found to be that much under sized.

My 1915 has a true .311 Major diameter, the nominal bore size for a commercial sporter but it should not have passed gauging in 1915 unless they loosened their tolerances due to war time production.

I've read that otherwise usable parts that were just a hair out of specification might have been held as a war time emergency store. The parts to be used it better parts were not available.
I've heard of a few BSA dispersal rifles found with major dia bores of .320 or over, at least near the muzzle but with no sign of wear.
The SMLE Mk1 bore was reverse taper lapped to reduce bullet friction so it gave the same muzzle velocity when MkVI ammo was used as the longer LE barrel. These have occasionaly been found with major diameter at the muzzle of .320. Those were bores that had been over lapped, as the intent was to only remove a couple of thou from the bottoms of the grooves from a point about fourteen inches from the muzzle.
They authorized a replacement barrel for these in 1917, to make them more compliant with the MkVII ammo.
Could be some SMLE MkI barrels ended up on BSA dispersal rifles by mistake.

[mwjones]

I have a '42 longbranch #4mk1* that measures .302/.3105.

I shoot a Lee 312-155-2r boolit (meant for 7.62x39) that drops about .313 and sized to .312. Using pure ww alloy with a gator gas check and yellow dragon lube from dragon bullet lubes.

I was getting about 4" groups at 100 yards with the micrometre sight shooting 40 grains of BL-C(2) at what i figure was around 2350fps.

After installing an ATI no gunsmith mount and an old Bell 3-9x32 scope, i was getting 1"-1.5" groups at 100 using Winchester super x factory ammo. Haven't got out to shoot cast with the scope yet!!

[yovinny]

I'd vote, but you wanted the largest size and your numbers dont go high enough for my pair of #4 Savage 2 grooves, which go .318 and change.

Only boolit I've tried is Lee 312-165 sized 314 to seat the check, which tumble very nicely in either rifle at anything over a pop-gun gallery load.

[3006guns]

I have several Enfields, but only one that I use for boolits so it's been slugged at .314. I see there's a number of members whose guns also measured .314 and that makes me feel better. I thought I had an "oversize" barrel!

[pipehand]

Believe it or not, my 1955 vintage Fazakerly No.4 Mk2 is close to the US standard .300/.308 bore and groove dimensions. The throat, will admit boolits of a much larger size, however.

[Canuck Bob]

I'd vote, but you wanted the largest size and your numbers dont go high enough for my pair of #4 Savage 2 grooves, which go .318 and change.

Only boolit I've tried is Lee 312-165 sized 314 to seat the check, which tumble very nicely in either rifle at anything over a pop-gun gallery load.

Sorry, I built the poll and didn't realize the amazing range of major bore sizes until later. There are rifles that can use the early Mauser bullets just fine!

I am finding that even with the large range the 312-314 range is better represented than I expected.

The drawing above suggests the acceptable range as 313 to a few tenths under 321 as within spec if all tolerances stack large. If a guy assumes under wartime production pressure they started with maximum sized tooling for repeated sharpening it is no wonder my choices were too limiting. It might be fun some day to check bore size against manufacture dates.

[gwpercle]

I have a 1942 dated No. 4 MK I , with a 5 groove barrel. It measures , as best as I can determine , .303 bore, .004 deep grooves which add up to a .311 dia. barrel. After reading about how bad war time manufacture was, and some of the oversize barrels a lot of people have, I was pleasantly surprised that mine seems to be in the satisfactory range.

Now I just need to find a Lyman 314299 and have some fun...........gary

[303Guy]

I have two two-groove No4's. The one I use has rust 'texturing' but still measures .304 and .318. It had been sporterized so nothing to lose - I cut off the tip of the barrel and fire-lapped it a bit to de-edge the rust pits. This thing is scary accurate with j-words but hopeless with cast.

I have one reverse tapered bore SMLE barrel on a LE action with a huge bore. It takes something like .320 boolits.

[enfield]

Well being a fellow Canuk I have a plethera (sp) of LE's ( 12 or so ? ) I usually just put the biggest boolit I got in. I still have a few pounds of a .316 multigroove boolit ( I think it was a mould from a group buy ). I only have one 2 groove #4 and it shoots the 314299 pretty good.

[Multigunner]

Main thing to watch out for when using over sized bullets is to be sure theres enough neck clearance.
Depending on bullet hardness and initial thrust of the propellent charge the bullet can bump up significantly before ever leaving the case neck, and iif clearance is insufficient this can cause a higher than normal chamber pressure.
I first heard of this from a warning against using salvaged .268 Carcano bullets when reloading for the Remington 6.5 Magnum. Apparently someone managed to blow up a Remington when using those bullets due to insufficient clearance.
From the information in that article it appeared that a lot of pull down bullets from degraded Carcano milspec ammo was on the market back back then.

[303british.com]

...I am finding that even with the large range the 312-314 range is better represented than I expected.

The drawing above suggests the acceptable range as 313 to a few tenths under 321 as within spec if all tolerances stack large. If a guy assumes under wartime production pressure they started with maximum sized tooling for repeated sharpening it is no wonder my choices were too limiting. It might be fun some day to check bore size against manufacture dates.

A few observations. Because of the different manufacturing plants, machining techniques, resharpened tooling and rifle conditions, you'll have a noticeable difference in diameters. Add improper 'post service' measuring techniques to the mix and you will find things get crazy quickly.

It might be fun to guesstimate, but anyone looking for a an average diameter so they can buy the correct diameter bullet will be disappointed. Whether it's cast or jacketed you're using, it would be in your best interests to slug the bore.

One thing is for sure, diameters of 0.313 and larger will be the majority for the poll, but does it apply to your rifle? Cast bullet shooters that do their homework have always had the accuracy advantage over the jacketed bullet crowd. The only time that gets dicey is when you're shooting long range.

Like most older rifles, there is no such thing as a correct bore diameter. Approximate, or close, like horseshoes and hand grenades, is the best you can hope for.

An entertaining poll for sure!