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A Full Race .303 Rifle

© 2014 – Ed Harris

ED w303

Notes on the .303 Enfield (link)

(takes you to the bottom of this article)


Notes on No.4 Bolt head size / headspace (link)


In my NRA days LTC John George, author of "Shots Fired In Anger" was on the NRA Board. He lived in DC and was a regular around HQ. A real rifle nut in every sense.  John spent his postwar years in East Africa until the late 1960's and had numerous contacts among the Safari Club International and Brits he had served with in the China Burma India Theater of World War II (CBI). I met some of those old soldiers and one of the gents was a retired British Army cartographer, an avid big game hunter who had once been an adviser to Wingate's Chindits.  He was a veteran of many African postwar "expeditions" conducted under auspices of the British Museum, although knowing now what was happening at the time, Mi6 may have encouraged some of his travels. The old boy had a "bush rifle" put together by Holland & Holland, which was essentially a scoped, heavy barreled jungle carbine in 7.62mm NATO. That particular rifle appeared in the British magazine Shooting Times and Country. I carried a dog-eared copy of the article around for years in search of a gunsmith to build my "fantasy No.4."  In those days (late 1970’s) I was thinking hard towards 7.62 NATO, but I would later be convinced otherwise and went .303 for my “race gun.” 


.303 Mk. VII Ball Ammo in Charger…

I left NRA and went to Ruger in 1984.  The company had a project making their Model M77 sniper 7.62 rifles for the RCMP to replace converted 7.62 No.4s they were having troubles with, as to durability. They regretted ever getting rid of their .303s they had, but the .303 surplus ammo was gone and they really needed a 7.62 rifle because they drew ammo from Canadian Force stores. I spoke with RCMP gunsmiths at great length.

To a man they said that there were always "issues" of one sort or another trying to make a reliable 7.62 rifle based upon the No.4.  While Long Branch and Savage receivers had better steel than UK production and ample strength, feeding was never 100%.   This was of no matter to British NRA and DCRA shooters because all their matches were fired single-loading, prone, no sustained or rapid fire.  When 7.62 converted No. 4s were shot "a lot" headspace loosened and they often had to refit the next larger size bolt head "before the barrel was shot out." I was advised in the strongest possible terms to forget about 7.62, but to keep the rifle in its original .303 caliber, I would be much happier.  I was also told it was completely OK to go ahead and use match quality .308 groove diameter barrels, of 10-inch twist, to enable use of common bullets and adequately stabilize everything. And that you could shoot ordinary .303 ammo down the .30 caliber barrel and this was just fine! 

I was skeptical of that claim, but Ruger had a special order for No.3 single shots chambered in .303 British to be exported for commercial sale in Canada. This provided justification to build pressure barrels with both .303 Brit and US cal. .30 rifling dimensions, because William B. Ruger Sr. [WBR] sure as hell wasn’t going to tool up to make .303 barrels just for a relatively small 1000-gun order. Ruger’s Engineering Department ordered .303 radial copper pressure test barrels cut to both sets of dimensions from CIL's contractor. We shot everything, Canadian and UK military, US and Canadian commercial and hand loads with Sierra and Hornady bullets of both diameters.

Bottom line, OK, yes, pressure is higher, but no, it is not dangerous, and resulting levels are within design limits of a sound Long Branch, essentially +3500 psi or 48,000 max vs. 44,500 max. - still much less than 7.62 NATO at 52,000+ which gave problems with bolts compressing, receivers stretching and spotty feeding. 

I was offered a DCRA style No. 4 match rifle which had been built in the 1970’s, with shot out barrel.  This was then re-barreled and re-bedded for me and  got imported OK.  I had scope mounts made in the experimental shops at Ruger. I removed the fragile A.J. Parker target sight and zeroed a standard WW2 style 2-leaf flip battle sight to zero at 200 and 400 yards with 180-gr. factory ammo. I could can use iron sights or scope at will and stripper clip load from the top. The scope comes off or goes back on easily without loss of zero. The barrel is hammer forged by Heym, a 7.62 blank of 4-groove government form, chamber cut with the SAAMI pressure-velocity test barrel reamer. The minimum SAAMI chamber does not blow the shoulder forward like the military “trench” chambers do. It shoots any factory .303 Brit ammo fine, or hand loads with common .308 diameter bullets. Brass life is good. A solid 2 moa rifle with good lots of ball ammo, and 1.5 moa or better with hand loaded Sierras. 








Short-stroke bolt and 10-shot magazine give it good rate of fire. I have shot just for laughs at Cherry Ridge Infantry Trophy. Starting with full magazine I can bang those off, reload with two strippers and usually get the second ten off in 50 secs. at the 300 yard scaled to simulate 500 and 600 with enough hits on the "E" silhouettes to get bonus points. I score about the same with it as I do my M1 Garand, though I may get off a few more shots with the M1, number of hits per string is the same until you get up to 300, where the Garand has the advantage in sitting rapid fire by not having to work the bolt.

100-yd. accuracy tests of Gibbs Rifle Co. (Martinsburg, WV) No. 4 Long Branch Jungle Carbine, "Historical Recreation"- CENTER BEDDED

Ammunition-------------------------Avg of Five Consecutive 5-shot groups at 100 yards with issue iron sights, fired from sandbags





Greek HXP Ball, 1975





Remington 180 Grain SPCL





World War 2 GB43 Mk. VII (Cordite)





This is the best which can be hoped for using an issue barrel and stock with original chamber, properly bedded, without glass. This Gibbs historical recreation is no longer available, but was a more accurate rifle than original No. 5 carbines, and equal to the best standard No.4 rifles because it is simply a cut-down standard No.4 Mk2* fitted into a new jungle carbine stock. The cut down No. 4 barrel is stiffer and more rigid than original carbine barrels. Fitting the No.5 carbine flash hider on the muzzle add some dampening. Also, the No. 4 receiver does not have the lightening cuts which WW2 carbines did. When assembling these rifles new barrels and wood were fitted, and these rifles were assembled by former Parker-Hale gunsmiths who had been trained in UK. They were good rifles out of the box and the test sample did not suffer from the "wandering zero" common of No.5s.

100-yd. accuracy tests of Don Hamilton "Bush Rifle" No. 4 Long Branch, Heym 7.62 NATO form chambered .303 British - CENTER BEDDED

Ammunition --------------------------Average of five consecutive 5-shot groups at 100 yards with Weaver K4 Classic scope, from sandbags





Greek HXP Ball, 1975





Remington 180 Grain SPCL





World War 2 GB43 Mk. VII (Cordite)





Handload, LC87 M118 pulls, 42 RL-15





Handload, Sierra 175MK, 40 grains of IMR 4064





This represents the reasonable expectation for a hunting weight rifle, properly set up with .30 cal. barrel and .303 chamber.


Notes on the .303 Enfield

While no longer a first-line battle rifle, .303 Enfield rifles and ammo are still fairly plentiful and less expensive than a modern "black rifle." If you learn to properly handle a bolt rifle, its short bolt stroke and 10-round box magazine give good rapidity of fire. In their day these rifles were "soldier-proof" and they are still a viable alternative for the budget-minded or if living somewhere that prohibit civilians from owning a semi-automatic military rifle.

The Lee-Enfield's rear-locking action is blamed for poor case life by hand loaders who experience difficulty. The Lee-Enfield action is adequately strong for its normal working pressures which should not to exceed 45,000 c.u.p. The poor case life actually results from excessive cold-working of fired brass which expands greatly by firing in military chambers having generous clearances, so that they will continue to function under "trench warfare conditions." Neck resizing only helps case life, and keeping pressures below 40,000 c.u.p., approximating .30-40 Krag velocities does too.

UK Military .303 chambers have a clearance of about 1/16" at the shoulder of the rifle chamber, to ensure rifles function with dirty ammunition under combat conditions of mud, sand, or dust. Because the .303 British headspaces on the rim, this shoulder clearance is inconsequential to headspace. But this shoulder clearance results in the case shoulder being blown forward upon firing, so if fired cases are then full-length resized so that the sizing die contacts the shell holder, the repeated cold working and re-fire-forming of the brass elongates the case body forward of the web, causing a case head separation on about the second reload.

Best case life when reloading for the .303 requires that brass neck-sized only, or that a full-length resizing die to be backed off, to pinch a dime between the press ram at the top of its stroke and the sizing die, to avoid setting back the shoulder.

Nominal .303 barrel dimensions are .302" bore and .312" groove diameter with +0.0015 allowed on either dimension. But post Dunkirk era WWII rifles vary widely, I slugged a No.4 Fazakerly that was .3185." The flat-based 174-gr. MkVII service bullet has a soft gilding metal jacket and lead core that readily upsets to provide reasonable accuracy, even in worn bores. The stiffer jacketed MkVIIIz boat tail bullet upsets less easily and gives poor accuracy in rifles with barrel throats eroded from excessive use of cordite ammunition.

Surplus rifles should be examined by a competent gunsmith prior to firing and barrels inspected for evidence of stress corrosion cracking, severe bore erosion or excessive headspace, common in mixed “parts” guns. Arsenal reworks with bright bores are satisfactory. If the throat appears worn, the bore should be well cleaned and the area forward of the chamber carefully examined with an optical bore scope. Barrels showing significant heat cracking or crazing under close optical inspection should be scrapped. Suspect barrels should be examined by magnetic particle inspection using the wet method with full circular continuous magnetization, if possible.

Jacketed bullets in sporting .303 ammunition are generally .311". Component bullets designed for the 7.62x39 give good results in new barrels if a .310 expander plug is used to provide adequate neck tension. The 123-grain spitzer soft point 7.62x39 bullets obtain about 2700 f.p.s. with full loads in the .303, have mild recoil and a flat trajectory.

Common issue-grade No. 4 or SMLE rifles, using milsurp ammunition are "at very best" only 4-minute groupers. You can only improve on this only by using the best quality sporting ammunition or hand loads with good quality bullets. Sako, Norma and Privi-Partisan ammo seems uniformly good. Winchester, Remington and Federal sporting ammunition is more accurate than mil-surp, but the brass does not last as long when reloaded. Sierra, Hornady and Speer .303 bullets are all good. Sierra 175 MK and 180 Speer Hot-Cor soft points are most accurate in my experience. In a well bedded rifle with properly tuned load 4-5 inch ten-shot groups at 200 yards are possible. This is the best which can be expected with rifles other than specially built competition or sniper rifles.

Commonwealth competitors using the Enfield at long range were always careful to dry the rifles' chambers with mineral spirits or acetone after cleaning. Otherwise the cartridge case would not grip the chamber walls upon firing. Additional thrust against the bolt face caused by a lubed chamber springs the action with respect to the vertical back-plate, causing vertical stringing on target. The first group fired after cleaning, may string vertically, but the second string will usually settle into a round group. Grouping improves about 30% when the hand guards and fore stock of the No. 1 MkIII* is relieved so the only barrel contact with wood is under the chamber and at the spring-tensioned V-block behind the nose cap.

Post World War II, British Commonwealth competitors became adept at bedding the No.4 for target shooting. Best results come when the barrel solidly bedded under the chamber, with the rest of the barrel free of contact except for upward pressure at its midpoint near the lower band. An alternate method is completely free floating from the lower band to the muzzle, or trying 4-6 lbs. up-pressure at the nose cap. It takes only about 10 minutes with a scraper to relieve the hand guards and cut sheet metal shims and cementing them in place with Acraglas gel.

Accuracy Results for Typical .303 rifles with service ammo


Average of five consecutive 10-shot groups at 100 yds. bench rest with issue sights.


Lithgow (Australia), No. 1 MkIII*, (1940)

U-notch tangent ramp sight

Bore .3023" x .3127" (inches)

Smallest   Largest     Average

Ammo Type               (inches)    (inches)    (inches)

Greek HXP-69            3.94           4.97           4.54

UK GB-7-48                4.50           6.0             5.36


ROF Fazakerley (UK) No. 4 MkI .303 (1943)

Issue receiver peep sight

Bore .3038" x .3166"

Smallest   Largest     Average

Ammo Type               (inches)    (inches)    (inches)

Greek HXP-69            4.50           6.0             5.26

UK GB-7-48                3.79           4.55           4.12


Long Branch Arsenal (Canada) No. 4 MkI* (1942)

Issue receiver peep sight

Bore .3023" x .3133"

Smallest   Largest     Average

Ammo Type               (inches)    (inches)    (inches)

Greek HXP-69            3.99           4.80           4.33

UK GB-7-48                3.80           4.45           4.23


Notes on No.4 Bolt head size / headspace and reloading:

.303 headspace measurements (0.064" / 0.074") British military specifications

A new No. 4 LE normally will have 0 (Zero) size bolt head fitted, but due to manufacturing tolerances it may have be a size 1, and that’s OK.

After a rifle is used in service, continued firing compresses the locking lugs, bolt, and the bolt head, shortening the assembly and headspace increases, armourers then fit the next size "up" bolt head and you away you go again for thousands more rounds, until it happens again, then fit the next size "up" bolt head and away you go again.

No. 4 Bolt heads were made in 4 sizes (0, 1, 2, & 3) with only a very, very small number of size 4 made. When a number 3 does not correct headspace a new bolt is tried with bolt head 0, 1, 2, or 3. If the headspace still could not be corrected it meant the lugs were buggered, and the rifle was scrapped.

To confuse the issue further bolt head size 'numbers' are almost meaningless, due to tolerance overlap. Measurement of 100 No.4 bolt heads gave the following results.

Size 0 went from 0.620" to 0.631"

Size 1 went from 0.622" to 0.635"

Size 2 went from 0.630" to 0.638"

Size 3 went from 0.632" to 0.640"

So you must still use a headspace gage and try several bolt heads, because it is possible to replace a size 2 head with a size 3 and worsen headspace (a smaller bolt head) If you need to tighten up your headspace specify a DIMENSION not a bolt head SIZE.

Get a replacement bolt head which produces a headspace between .064 &.074 and its going to be correct - It doesn’t matter if it’s a size 0 or a size 3. The amount of rounds we'll put down an Lee Enfield are unlikely to mean we'll need to replace the bolt head in our lifetime.

US brass (Remington, Federal, Winchester) tends to be 'thin' so you won't get as many reloads

Worst is S&B. Enfields have 'loose' chambers and S&B brass is not seem to be able to cope with them, 2 or 3 reloads and you'll have case separations.

Best .303 brass is Norma, Sako, milsurp Greek (HXP) and Serbian - Privi Partisan.

Neck sizing and using charges 5% below maximums in Speer No. 13 or 14 can get you 10 reloads.

The best US powders to approximate the ballistics of service ammunition are IMR4064, RL-15 and Varget. If you have a chronograph, adjust powder charges to obtain 2440 +/- 30 f.p.s with a 174-180 grain bullet. If you do NOT have a chronograph, stay 5% below the published maximum loads, using a charge approximately at the mid-range between the "starting" and "maximum" loads.


73 de KE4SKY

From the Home of Ed's Red

In Home Mix We Trust



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