Original barrel dimensions and muzzle wear/throat erosion

[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.

[Clark Howard]

Your barrel is nearly new. Both of your measurements are within new specs. Regards, Clark

[Merc]

Your barrel is nearly new. Both of your measurements are within new specs. Regards, Clark

Thank you. That's good to hear.

What do you think of a 1943 Savage No. 4 Mk 1* with a jump gap of .378"? A friend of mine is looking for a No. 4 Mk1* shooter. I may have found one for him, however, after I performed the measurement, I wasn't sure that a No. 4 with a jump gap distance of that magnitude would still be within acceptable tolerances.

[p246]

Thank you. That's good to hear.

What do you think of a 1943 Savage No. 4 Mk 1* with a jump gap of .378"? A friend of mine is looking for a No. 4 Mk1* shooter. I may have found one for him, however, after I performed the measurement, I wasn't sure that a No. 4 with a jump gap distance of that magnitude would still be within acceptable tolerances.

I have one that measures close to that, its a 1942 B.S.A. The muzzle end is still in good shape and it shoot decent groups. The velocity is not as good as my L.E.s with better bores using the same load. My nephew used it to take his first deer two years ago.

From my experience long throats effect muzzle velocity and muzzle condition/concentricity seem to have more effect on accuracy (But there is never a hard fast rule on this subject). This is on L.E. rifles with tight draws, and stocked up correctly (None are center bedded, they are in stock military condition). Seems like when I buy a rifle, even though it looks good, I always have a little buyers remorse until I put it on paper. With L.E.s I have screwed the pooch per say a few times thinking I bought a shooter but the paper says different. Good luck your mileage may vary.

[Merc]

Thanks for sharing your experiences. Muzzles can obviously stand some concentric wear and still shoot accurately. The muzzle on my No. 4 isn't worn and shoots accurately. However, the muzzle on my M1917 Winchester .30-06 does show some moderate wear. It should accept only the .3000" ring on my muzzle gauge if it was in like new condition, but it accepts the .3015" ring. It still shoots accurately so the .0015" wear must be concentric. It has a minimal (nearly un-measureable) jump gap so the velocity is probably very high since very little pressure is escaping around bullet as it moves through the gap. It would be nice to be able to predict how accurately any given rifle will shoot by simply measuring the muzzle diameter. Is there a way to tell if non-concentric muzzle wear is present without actually shooting the rifle?

[p246]

The problem is so many variables especially with Lee Enfields. Just the stocking up issues could fill pages. For instance I just found a good 42 Lithgow locally. The barrel was replaced in 43 and it didn't appear to get much use after that. Bore looked good. He let me loosen King screw and draws were nice and tight. I then looked at a 1943 Lithgow he also had, rebuilt and rebarreled in 46. Bore looked decent, loosened king screw and found a lot of movement indicating the draws were worn out or some type of draw damage. Looking at both rifles they appeared to be equals, but IF the 43 would have shot decent, which I doubt pretty soon you'd be dealing with a cracked stock. I brought the 42 home but he wouldn't move on the 43 price. It's all calculated risk. As far as I know a good eye, gauges, and if possible a bore scope are your best bet. Followed by how well the gun is stocked up. A good source of flat base new manufacture .311 and .312 FMJ bullets in some of these worn bores would help to.

Good luck the hunt can be fun or an ass kicker....

[JB White]

Merc, this is a battle rifle intended for minute of man, not minute of angle. Mass produced using mass produced ammo. All from various makers and subcontractors. Specifications are merely within acceptable parameters to maintain reliability in combat.
Sandbagged specifications for target accuracy don't exist. Either it shoots very well or simply well enough.
If you by chance happen across a good one or a great one, consider yourself lucky.

You could always opt to build up a new one using a Criterion barrel ordered to your specs.... if they offer that option.

[p246]

Merc, this is a battle rifle intended for minute of man, not minute of angle. Mass produced using mass produced ammo. All from various makers and subcontractors. Specifications are merely within acceptable parameters to maintain reliability in combat.
Sandbagged specifications for target accuracy don't exist. Either it shoots very well or simply well enough.
If you by chance happen across a good one or a great one, consider yourself lucky.

You could always opt to build up a new one using a Criterion barrel ordered to your specs.... if they offer that option.

Yep you can stil get No 4 barrels in original 303 or you can order them with 308 sized bores so one has better bullet options. It's pricey though, I think one would be better off finding a nice No 4 Mark II. When I looked into it looked like 5 bills by the time the smith was paid.

May not be a TAAc drivers but the mad minute is a lot of fun...especially with creme puff loads

[Merc]

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.

[PhillipM]

Yep you can stil get No 4 barrels in original 303 or you can order them with 308 sized bores so one has better bullet options. It's pricey though, I think one would be better off finding a nice No 4 Mark II. When I looked into it looked like 5 bills by the time the smith was paid.

May not be a TAAc drivers but the mad minute is a lot of fun...especially with creme puff loads

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?