#1 MK3 with 5 grove rifling. How in Blazes do you measure the bore slug ????

Skylark 4

Skylark 4

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:confused: Ok guys, I just picked up a 1916 #1 MK 3*. Slugged the bore as per normal. But with 5 rifling, how do I measure the bore? At any point on the slug I am on a Land and a Groove( 180 degrees to each other).

That and there in very little for Proof Marks on this thing. Right side of collar has GR(under Kings Crown)Enfield,1916, S(ht)MLE, III*. On the top left of action and barrel is a double broad arrow(pointing at each other(>< ). Other than the serial#(matches everywhere but bolt)are 3 or so tiny armorer's stamps. The 18 1/2 ton Proof mark was noticed missing right away.

The Regimental disk(original ?) has A. P.
* 16
2 84

Is this thing an Ishapor model ? It doesn't look to be a shooter but warmer weather will tell.

Ken
 
It is a British made rifle, made at Enfield Locke, 1916.

As for measuring the slug, if you carefully line it up you can get on the corner of two grooves. It may take a few tries.
 
To measure, use the same method commonly used by millwrights in similar situations. Rotate the slug as you close the mike and close it just until you feel resistance. You are not feeling for consistent resistance. You will feel it catch at certain points as you rotate. Those are the points where you are measuring between the leading and trailing edges of roughly adjacent grooves (lands on the slug).
 
B_noser said:
To measure, use the same method commonly used by millwrights in similar situations. Rotate the slug as you close the mike and close it just until you feel resistance. You are not feeling for consistent resistance. You will feel it catch at certain points as you rotate. Those are the points where you are measuring between the leading and trailing edges of roughly adjacent grooves (lands on the slug).
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Perfect! A common sense approach. Might not be the way a machinist would do it, but should be good enough for our purposes.
 
OK: I read and disagree with all of the methods above as none are going to give accurate measurements and if you can't get accurate measurements you might as well not do it at all.

Two ways to do this and the second is what you'll have to do if you don't have the Vee block in #1.

#1 use a 72 degree Vee block this will allow you to have contact with one land with your mike and two lands with the vee block. You measure over the land and to the bottom of the block then subtract the thickness of the block. You get the thickness of the block by measuring a .500 gage pin in the block to the bottom of the vee block. This will tell you the thickness of the block that is to be subtracted. This is the most accurate way depending on who made the Vee Block.

#2 Use a gage pin to measure the bore of the rifle. Then use calipers to measure the boolit over a land to a groove, directly across the diameter of the boolit.

If you have a .303 bore and you get .308 from the land to the groove then your rifling is .005 deep. Therefore your Groove dia. will be .313.

If you have a good muzzle and you know how to use the ID side of your calipers you can just measure the ID of the barrel, and you don't even need a slug.

Randy
Owner
Buchanan Precision Machine,,, Ex Millwright.
 
Ok, thanks guys. A little more involved then I have a my disposal. Tried using my calipers on opposing groves on the slug and came out with .315. Not good! So just for Giggle's I pulled the Expander rod from my Lee Full size die. It mic's at .311 exactly. Inserted it into the muzzle and ya its a bit of a loose fit, but for how far it ? It dropped in 7 1/8th inch before the .311 part of the button made contact with the bore walls. YUCK. So how is the Breach end ?? Same test and it went in 2 1/4 inch. YUCK AGAIN !! Oh well, for a 1916 rifle I wasn't expecting Match grade. If it will stay within a 10 inch group at 100 meter's I will be happy.

Still no idea where it was made ? Thanks CDN303, but if it was made in England, should it not be stamped as such or at least the factory and have the 18 1/2 ton per [] inch proof mark ? Still a mystery for sure.

Ken
 
Skylark 4 said:
should it not be stamped as such or at least the factory and have the 18 1/2 ton per [] inch proof mark ?.
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No mystery at all.

It IS stamped with the maker - Enfield, as in Royal Small Arms Factory Enfield, not Lee Enfield.

The .303 / 2.222" / 18.5 ton proof marks were only applied when the rifle was sold out of service and into the commercial market in Britain. The military proof marks will be on the chamber area of barrel, the crown / GR / crossed flags / P stamp. The other one that'll be a crown over E over a number is the factory inspector's mark.

The opposing broad arrows indicate it was released from service, the second opposing arrow cancels the original one.
 
If you are slugging the bore to shoot cast bullets - there is an alternative. With the 303 British I use a cast bullet diameter of 0.314" and size it to 0.314" to lock the gas check on, then I shoot it. The barrel will swage the bullet down to bore size.
This method has given me very good accuracy (usually under a inch at 50 yards).

Measure the bore at the muzzle too. Some of these guns have swamped bores from cleaning rods. I have a couple of 303s that needed to be cut back 0.2" to 0.5" to get to good rifling at the muzzle. This is radical and should not be done on a gun with collector value. But it will stop keholing bullets some of the time.
 
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