Original barrel dimensions and muzzle wear/throat erosion

[Sunray]

There's no such thing as a "jump gap " measurement. There is a throat erosion though. However, a .30 calibre throat erosion gauge will tell you nothing about a .303 Brit chamber.
Dunno if you'll be able to get to this, but it's a BILINGUAL CF manual.
http://photos.imageevent.com/badgerd...%20Summary.pdf
The .303 British headspaces on the rim. Military spec Max OAL is 3.040". Accuracy depends on the diameter of the bullet vs the groove diameter. Most commercial ammo and bullet makers use .311" or .312"(Montana Bullet makes some larger diameter cast bullets). Accuracy will be poor if you use the wrong diameter bullet(like a .308" bullet) in an oversize barrel.
Any No. 4 Mk 1* still around is highly unlikely to have seen any W.W. 2 service. No. 4 was in use up here with Army Cadet Corps until the mid 90's, as I recall. Still used as DP rifles with colour parties.
All remaining Savage made rifles, parts and machinery got sent to Long Branch when the contract expired. Had one on my MIU long ago.
Lithgow Lee-Enfields are NOT No. 4's. They're No. 1 Mk III's. Aussies didn't use No. 4's. Ishapore didn't make 'em either.
"...original 303..." That was the bore diameter. Groove diameters were .311" to .315", even at Long Branch.
You used to be able to order a Criterion No. 4 Rifle barrel chambered in .308Win. It is not a .308" barrel chambered as a .303 Brit. No longer available.

[JB White]

There's no such thing as a "jump gap " measurement. There is a throat erosion though. However, a .30 calibre throat erosion gauge will tell you nothing about a .303 Brit chamber.
Dunno if you'll be able to get to this, but it's a BILINGUAL CF manual.
http://photos.imageevent.com/badgerd...%20Summary.pdf
The .303 British headspaces on the rim. Military spec Max OAL is 3.040". Accuracy depends on the diameter of the bullet vs the groove diameter. Most commercial ammo and bullet makers use .311" or .312"(Montana Bullet makes some larger diameter cast bullets). Accuracy will be poor if you use the wrong diameter bullet(like a .308" bullet) in an oversize barrel.
Any No. 4 Mk 1* still around is highly unlikely to have seen any W.W. 2 service. No. 4 was in use up here with Army Cadet Corps until the mid 90's, as I recall. Still used as DP rifles with colour parties.
All remaining Savage made rifles, parts and machinery got sent to Long Branch when the contract expired. Had one on my MIU long ago.
Lithgow Lee-Enfields are NOT No. 4's. They're No. 1 Mk III's. Aussies didn't use No. 4's. Ishapore didn't make 'em either.
"...original 303..." That was the bore diameter. Groove diameters were .311" to .315", even at Long Branch.
You used to be able to order a Criterion No. 4 Rifle barrel chambered in .308Win. It is not a .308" barrel chambered as a .303 Brit. No longer available.

Have you been mixing your meds with hooch again?
Nobody made any claim about Lithgows, Ishys, BSA dispersals being No4's. Only what was available on certain regional markets.
The "jump gap" being referred to is the Leade/Small cone. He used revolver slang...so, what?
Criterion did/does offer replacement No4 barrels. (I haven't looked in the past few months)

Any No. 4 Mk 1* still around is highly unlikely to have seen any W.W. 2 service.

What planet are you shopping on???

[bigedp51]

Questions of the day:

Where could one find the original barrel dimensions for a 1944 No. 4 Mk 1*?

How much concentric muzzle wear and jump gap distance can the No. 4 barrel sustain before it becomes inaccurate?

My No. 4 is still an accurate shooter even though it currently has a measured jump gap of .250". From what's been discussed on this forum and elsewhere, the No. 4's barrel and action were originally built to spacious specs. If true, what level of throat erosion does a .250" jump gap represent? What was the jump gap distance when it left the Savage factory? Zero?

The muzzle has a diameter of .3025". I was expecting to see a diameter of .303" which would match the caliber, not one that's actually .0005" smaller.

Weatherby Rifles are known for having long throats, a AR15 rifle has a throat twice as long as most .223 rifles. My Savage .223 with a 1 in 9 twist has a longer throat than my AR15 rifles.

A used Enfield rifle will have Cordite throat erosion and as long as the rifle met accuracy standards it was kept in service.

If the rifle looks in good shape and the muzzle is OK then buy the rifle and shoot flat base bullets.

Below is a 10 shot group fired at 50 yards from a well worn 1943 No.4 Enfield after making bedding adjustments to the rifles fore end. After this the sights were adjusted for 100 yards, and with a PH-5C target sight I could keep 5 rounds in the X ring at 50 yards.



And below is the best group fired at 50 yards with the same Enfield out of five targets before doing anything to the loose fore end. Some of these targets only had two bullet holes in the target because of bedding problems and not having the required 2 to 7 pounds of up pressure at the fore end tip.



Bottom line, the two best groups I have ever fired with a peep sight were with old worn military rifles and now rival what my older eyes can now do with a scoped rifle.

[Merc]

Weatherby Rifles are known for having long throats, a AR15 rifle has a throat twice as long as most .223 rifles. My Savage .223 with a 1 in 9 twist has a longer throat than my AR15 rifles.

A used Enfield rifle will have Cordite throat erosion and as long as the rifle met accuracy standards it was kept in service.

If the rifle looks in good shape and the muzzle is OK then buy the rifle and shoot flat base bullets.

Below is a 10 shot group fired at 50 yards from a well worn 1943 No.4 Enfield after making bedding adjustments to the rifles fore end. After this the sights were adjusted for 100 yards, and with a PH-5C target sight I could keep 5 rounds in the X ring at 50 yards.



And below is the best group fired at 50 yards with the same Enfield out of five targets before doing anything to the loose fore end. Some of these targets only had two bullet holes in the target because of bedding problems and not having the required 2 to 7 pounds of up pressure at the fore end tip.



Bottom line, the two best groups I have ever fired with a peep sight were with old worn military rifles and now rival what my older eyes can now do with a scoped rifle.

The original sights on my 1944 No. 4 Mk 1* are surprisingly accurate. I mounted a Bushnell scope on it for a while and found that I could shoot just as well at 100 yards with the ladder sight at its lowest setting. This was after I figured out the front blade needed some minor adjustments. With the ladder sight folded down and aiming through the peep sight, the groups are about 6 inches high at 100 yards.