Original barrel dimensions and muzzle wear/throat erosion

[p246]

A 30/303? What a great idea!

I don't mess with foreign rifles much, but was chewing the fat with a buddy that does the other day and he remarked the US was the only country to develop 308 bore ammo. How come?

That topic comes up from time to time with a friend whose strictly a collector but much older than I. His theory is the young nation moving up wanted to be a little different. When .311 was so popular why .308. There's got to be an ordnance study or a US 30 cal expert who knows the given reason by the government.

[p246]

P246 & JB,

Great advice as usual.

I'm not really looking for anything specific right now for myself, but you never know - something could develop at the next gun show, etc. I'm satisfied with the rifles I own and consider myself lucky that they're all great shooters considering their age and origins. I'm just trying to understand how wear affects accuracy and what the limits of wear are before rifles become inaccurate or unsafe to shoot.

Someone from out-of-state asked me to be on the look-out for a safe shooting No. 4 Mk 1* that likely saw WW2 service. I have several possible sources who might be able to produce such a rifle but I won't point him towards anything without at least checking for possible problems. I say this knowing from my own experiences that you have to be lucky to find a rifle that passes all the measurements and tests and can still shoot accurately and consistently. I obviously won't be able to take any of them them to the range to test fire, which is the ultimate test, so eyeballing is all I can do. Unfortunately, it's like buying an old used car without ever starting the engine.

Good analogy at the end. I know where a 45 LongBranch is that might be coming up for sale. I believe it was rebuilt by our northern neighbors in 1950. The bore looked good and the stock was tight. The guy would let me shoot it if I asked. If that flavor is on your friends table let me know. It does have the 300\600 L shaped flip sight which some people don't prefer. I could at least shoot a group of Privi and a group of MarkVii pulled bullets over 39 grains of Varget. If it will shoot both those it should be good. Let me know as any excuse to shoot is actually a reason. FYI I'd be interested but already have a nice 45 Longbranch example.

[Merc]

Good analogy at the end. I know where a 45 LongBranch is that might be coming up for sale. I believe it was rebuilt by our northern neighbors in 1950. The bore looked good and the stock was tight. The guy would let me shoot it if I asked. If that flavor is on your friends table let me know. It does have the 300\600 L shaped flip sight which some people don't prefer. I could at least shoot a group of Privi and a group of MarkVii pulled bullets over 39 grains of Varget. If it will shoot both those it should be good. Let me know as any excuse to shoot is actually a reason. FYI I'd be interested but already have a nice 45 Longbranch example.

I just emailed him and he will let you know.

My 1944 No. 4 Mk 1* has some stampings on the metal wrist band that has me wondering. The serial number is there and right above it is "51" and "K." Below the serial number is the letter "B" which also appears on the rear sight and adjustment knob. Since many of the No. 4s were rebuilt after the war, is the "51" the 1951 rebuild date and the "K" the inspector? Is the "B" also an inspector's mark? The broad arrow and crown proof symbols are also present on a few parts.

[Merc]

Good analogy at the end. I know where a 45 LongBranch is that might be coming up for sale. I believe it was rebuilt by our northern neighbors in 1950. The bore looked good and the stock was tight. The guy would let me shoot it if I asked. If that flavor is on your friends table let me know. It does have the 300\600 L shaped flip sight which some people don't prefer. I could at least shoot a group of Privi and a group of MarkVii pulled bullets over 39 grains of Varget. If it will shoot both those it should be good. Let me know as any excuse to shoot is actually a reason. FYI I'd be interested but already have a nice 45 Longbranch example.

He's looking for a British-made No. 4 that was made during WW2. His goal is to acquire a WW2 military rifle from each of the major participants. I will start attending the numerous western PA gun shows next month and hopefully will find one for him.

I always look at the gun show WW2 No. 4s that are for sale just to compare condition and price. I would say that most have been the Savage-made No. 4 Mk 1* rifles which surprises me since so many of the Long Branch and British versions were also made.

[JB White]

Not too surprising given that Savage made much more No4 rifles than any other maker

[p246]

He's looking for a British-made No. 4 that was made during WW2. His goal is to acquire a WW2 military rifle from each of the major participants. I will start attending the numerous western PA gun shows next month and hopefully will find one for him.

I always look at the gun show WW2 No. 4s that are for sale just to compare condition and price. I would say that most have been the Savage-made No. 4 Mk 1* rifles which surprises me since so many of the Long Branch and British versions were also made.

Savage and Long Branch did not have to endure the early to mid war bombings that England had to. Reason British " dispersal rifles" were built. BSA Shirley factory was bombed. Only Brit factory still making No. 1s. Dispersed salvaged equipment to other smaller factories to continue production. If memory served the wood furniture equipment was destroyed and they imported Lithgow furniture. I'd have to thumb through Skinnertons book to make sure but that's what memory seems to recall.

[Merc]

But still, you'd think a few British WW2 versions would show up at gun shows now and then. I can only remember seeing one Long Branch and zero British No. 4s over the past year or so. Of course, all that could change at the next show.

[p246]

Mainly here (Midwest) it's Savage and Longbrach followed by Lithgows and Isshys. Brits are out there in No 4s but not as common. It took me a while to find a good early BSA. Found a lot of worn rifles along the way. Jump back to WW1 I find mostly Brits and occasionally a Lithgow.

[Merc]

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.

Notes from a gun show I attended in Monroeville (near Pittsburgh) last Sunday:

A vendor had a nicely dressed up No. 4 Mk 1* Savage for sale with a bayonet and scabbard. It looked as if the stock, hand guards and external hardware had been replaced. In addition to my bore light, I always bring my headspace, muzzle erosion and jump gap gauges with me to these shows, just in case. Always being curious, I inserted my muzzle erosion gauge into the muzzle. To my utter amazement, it disappeared down into the bore completely and I had a heck of a time retrieving it. The vendor obviously never checked the condition of the barrel before putting all that time, effort and money into making the rifle look new-ish. It pays to bring your light and gauges to these shows if you're thinking about buying a rifle.

[Johnny P]

In the 1903 Springfield barrel the nominal bore diameter was .300 and .308 groove diameter. Manufacturing tolerances allowed a bore diameter of .2995 to .3015, and a groove diameter of .3075 to .3095. Going from one end of the tolerance to the other is going to skew the results with a breech bore gage even though both barrels are new.

I have an original August of 1940 M1 Rifle with the original barrel that reads 1.5 on the breech bore gage, while a new never installed Springfield Armory 1-52 barrel reads 2.5 on the same gage.