Enfield No.1 MK III

[wallenba]

I picked up this rifle at Gander Mountain recently and am attempting to determine it's bore by slugging. It's a five groove and proving problematic. Using a standard 1" mic it checks .312 across from a land to a groove. I was unable to measure the land height in the slug with my caliper end. I then used a jewelers loupe and good lighting to look while I held it in place in the mic trying to visualize the arc of the land to estimate it. If I am anywhere close doing this it would have a .314-.315 bore. If I size bigger than this does the Enfield have a chamber neck big enough to let it go? I don't have any live ammo for it yet and every where I looked there was none in stock.

[docone31]

Yeah, it is tough. I found my bore by accident. I had written on paper patching for the Enfield, and it was suggested .314. That is the number that worked for me. I actually had to send my dies back to have them modified.
You could probaby size to .316, and it might work.
I would try .314 though.

[Dan Cash]

You can come close enough to an accurate measure for your purposes by doing the following:

With a strip of tablet paper wrapped around the bullet and the ends pinched between your fingers holding bullet and paper tightly (only one layer of paper around the bullet);

Measure the diameter of the wrapped bullet with your micrometer and record the measurement;

With your micrometer, measure the thickness of the paper;

Subtract twice the thickness of the paper from the recorded diameter of the wrapped bullet and you have a reasonably accurate measurement of the groove diameter of the bullet with an odd number of grooves.

Dan

[wallenba]

You can come close enough to an accurate measure for your purposes by doing the following:

With a strip of tablet paper wrapped around the bullet and the ends pinched between your fingers holding bullet and paper tightly (only one layer of paper around the bullet);

Measure the diameter of the wrapped bullet with your micrometer and record the measurement;

With your micrometer, measure the thickness of the paper;

Subtract twice the thickness of the paper from the recorded diameter of the wrapped bullet and you have a reasonably accurate measurement of the groove diameter of the bullet with an odd number of grooves.

Dan
I'm not quite seeing the logic in that Dan, I see if the paper spans the gap over the groove made by the lands it could, but I can't 'feel' when the mic closes on it.
I'll think on it some though.

[Multigunner]

Enfields and some other milsurp rifles often have a heavy build up of carbon fouling mixed with atomized lead from open base FMJ bullets in the chamber neck.
A Chamber can look clean and shiny, but the age hardened baked on fouling can constrict the case neck on firing.
I found the best way to get this stuff out was by making a scraper from copper or brass tubing with a slot cut down one side and teeth filed in the open end.

Soften the fouling by soaking with solvent, then turn the tube scraper in. After each pass soak the surface again and spread the teeth enough to be sure they bite.

The agregate of lead, flash supressant, and carbon is usually too tough to get out with a chamber brush once it has set up over the years, and solvents barely penetrate the surface.

Once I cleaned my chamber necks pressure signs (flattened primers and swollen primer pockets) I'd had in my No.4 with factory loads and milsurp no longer appeared. Cases had seldom been reloadable, but after clearing away that deposit , and tightening headspace with a #3 bolthead, I get very good case life and excellent accuracy.

[Dan Cash]

I'm not quite seeing the logic in that Dan, I see if the paper spans the gap over the groove made by the lands it could, but I can't 'feel' when the mic closes on it.
I'll think on it some though.

If closing on paper bothers you, use some shim stock in the same manner.

[Boz330]

Take a calipers and measure the land and then the groove at the muzzle subtract the difference and add that number to the measurement of the slug.
I just roll the slug in the caliper jaws and that usually gets me close enough.
It would be wise to slug your barrel at the chamber end. Many of the #1s were shot with cordite ammo and have some pretty severe throat erosion. You will need to match that dimension as opposed to the barrel groove number.
My #1 turned most cast boolits sideways until I got a .316 mold. The last loads that I shot were getting close to 2 MOA which is about as good as it is capable of. Your first fired case should tell you whether you can get a .316 or larger boolit in it. Mine chambers just fine with them. Good luck.

Bob

[WILCO]

Have a machine shop measure it with a V-micrometer.
Good to have a pair handy:
http://www.grainger.com/Grainger/MITUTOYO-VAnvil-Micrometer-4CGE1

[mwjones]

If closing on paper bothers you, use some shim stock in the same manner.

x2. Just slugged my "new" enfield last week in this manner. Knocked an oversized fishing sinker through using 5" pieces of 1/4 inch hardwood dowel, wrapped with a piece of .0075 brass shim stock, mic'd, and subtracted .015. Mine came out to .312, so I guess my barrel was done with a new reamer/rifling buttons and wasn't shot much!

[1Shirt]

Know everybody and their pet goat seems to slug their bbls, except me! Have never slugged a bbl. Have normally gone with about 2 thousands over so called bore size, larger if those didn't shoot well. To me half the fun of reloading is testing the loads. Been at it for to maniy years to change now. If it works for me, I don't try to fix it!
1Shirt!:coffee:

[Catch]

I cut a v notch in a piece of oak. The notch or "v" must be 108 degrees. Place the slug in the notch and measure from the top of the slug to the straight bottom of the v block. Then measure from the bottom of the "v" to the bottom of the block and subtract. I got .314.
I read this on this forum I think......................

[303Guy]

Strickly speaking, only the throat dinensions matter - that's where the boolit is going to be aligned for final swaging down the bore.

Just for fun - the two-groove No.4 has a tapered throat which includes the leade angle and a bore of around .034 with a somewhat large groove diameter but the groove is only 80% of the bore so the bullet gets swaged down to bore diameter! Good for j-words.