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Criterion Barrel Throat

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105GunGrunt View Drop Down
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    Posted: April 02 2020 at 2:41pm
I have thought about replacing the barrel on my 1942 No 4, Mk 1 with a Criterion barrel IF I could find one (all the sources I have tried say they are out of stock, or currently unavailable.)  I have seen a lot of comments on this forum regarding the bore, but none about the dimensions of the throat. 

As is typical of many military rifles, the Enfield throat is quite generous.  Original specs say the COAL for .303 British ammunition is 3.075", a length determined more by the limits of the magazine than by what might be an optimal length for accuracy.  When I tried to determine the correct cartridge length for an "on-the-lands" COAL I was able to push the bullet out of the seated case before it reached the lands and grooves.  Does anyone know if Criterions have the same extended throat?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 303 Hunter Quote  Post ReplyReply Direct Link To This Post Posted: April 02 2020 at 10:12pm
Mine doesn’t. Over all cartridge length with Woodleigh 174 pp sp is 3.071 inches.
The Lee Enfield is to the Canadian north what the Winchester repeater was to the American west.   Cal Bablitz
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 3:39am
 The throat is reamed with the chamber finish reamer.  Unless you happen to have a military reamer, it will be a SAAMI spec to the dimensions below.  

Did you try ordering direct from Criterion?  I got my barrel about a month ago. 



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 4:16am
If you are wanting to replace the barrel with a Criterion one just to improve accuracy by attempting to get the bullet to touch the lands. I would say forget it. 3.075" is going to be your best bet on the C.O.L. The No4Mk1 is a battle implement, designed to shoot a human target . No more no less. Yes, they have been used as target rifles,and yes,they can be tweaked enough through barrel bedding procedures to improve the aimed shot. Yes,you can tweak your handloads to improve on top of that to gain an edge for more accuracy.  The Enfield rifle No4Mk1 is not a tack driving behemoth.  The Enfield does need that bullet jump to the rifling however to keep the pressure down to avoid premature throat erosion. Criterion barrels apparently need to be finished reamed according to some. I personally would stick with the original barrel myself.  Criterion barrels are pretty expensive and need alot of fit and finish work to achieve the proper indexing. I have a 1943 No4MkI* Savage and a 1942 No4MkI* Long Branch. Both have N.O.S. replacement barrels and both have been tweaked enough to get MOA groups. All my handloads have a C.O.L. of 3.075" or less. One batch of FMJBT is seated to 2.985". Another batch that uses the 200 grn D166 7.62×54R .3105" bullet is seated to 3.055" and my fun one that pisses alot of people off when they actually see the results is my handload of 40.0grns of Norma 202 powder,magnum primed, and seated with a 168grn BTHP. 308 to a C.O.L. of 3.080" shot through a two groove Long Branch barrel.  Sub MOA groups. Whatever the loading manual suggests as a COL is about as good as it's going to be in my opinion for someone starting into reloading...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 6:48am
The throat in my BSA barreled Long Branch is very long, similar to the OP.  Using a Hornady bullet seating gage, a 174 gr SMK won’t touch the lands until the base of the bullet has cleared the case neck.  Yet, this rifle still holds about 2 MOA with the original service sight.  If your rifle shoots MOA, consider yourself very fortunate and don’t mess with it!

The other .303 barrels I have vary quite a bit in throat length.  I suspect variability of finishing reamers used and/or throat wear.

The criterion barrel comes short chambered, like most barrels do.  You have the option of getting one with breeching washers (.001 increments) to get the barrel to index, or a version with the shoulder set back which may require machining to index.  I’m about to install mine once I get the reamer T handle turned down to fit into the receiver. 

It’s getting hard to find .303 NOS barrels for the No. 4, I would buy a few if I could find them. 

Looking at the SAAMI chamber drawing, I expect the throat will be considerably shorter than what my current .303 barrels have.  


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Post Options Post Options   Thanks (1) Thanks(1)   Quote WilliamS Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 8:58am
I haven't installed a Criterion on an Enfield yet, but I have used their barrels on several other firearms.  They are short-chambered to ensure that there isn't excessive headspace once the barrel is timed in.  If the SAAMI spec reamer produces a shorter throat than wanted, you can always follow up with a throating reamer.  We often do that for people loading bullets that are very heavy for the cartridge, to ensure the bullet doesn't compress the load on chambering.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote 105GunGrunt Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 1:14pm
THANK YOU all for your great responses.  I think that I am over obsessed with trying to get a level of accuracy out of a rifle that was designed to win battles, not marksmanship matches.  I am going to take the advice of Goosic and simply enjoy my piece of history as is.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 1:26pm
britrifles has alot of wisdom on bedding techniques to achieve better accuracy from the No4 and would no doubt assist you should you need it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 1:29pm
I had stated in another post that if you are hitting a target at a distance of 100 yards,be it standing,prone, or sitting at a bench,and can cover those shots with just the palm of your hand, that the rifle is doing exactly as it should.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Honkytonk Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 1:56pm
Goosics above advise was instumental in me just enjoying shooting these rifles and realizing that any grouping I can cover with the palm of my hand is a good day at the range. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 2:03pm
Your comment, "Marksmanship Matches"  should start a whole "nuther" thread. Alot of Bisely matches were and still won with the venerable Lee Enfield rifle. The civilian marksmanship program, CMP has an as issued service rifle competition and the Lee Enfield plays a prominent role in that.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: April 03 2020 at 3:50pm
For a battle rifle, and thats what it is, the No. 4 is above average in accuracy.  With careful assembly, proper forend bedding, a good barrel, reloads with a quality match bullet, the rifle will hold close to MOA For 10 shot groups.  The shooter will open this group up, how much depends on many factors.  Gossic has beaten this standard with his skill at building rifles and shooting ability, but we should not expect to meet this standard with a “as issued” rifle.  

2 to 4 MOA can be expected of a good condition rifle when fired in the prone position with the issue aperture sights.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Armourer Quote  Post ReplyReply Direct Link To This Post Posted: April 04 2020 at 7:33am

Lee Enfield 'shoots 1 MoM' (Minute Of Man)


The official acceptable accuracy requirements.


SMLE (No1 Mk3) TESTING

For the SMLE All rifles were tested for accuracy by the Small Arms Inspection Department at 100ft, and 10% were also tested at 600 yds. All rifles were fired from a special mechanical rest, known as an Enfield Rest, and a special Telescope layer was used for laying an aim. The Enfield Rest was designed to simulate the conditions under which a rifle would be held when fired from the shoulder, and was provided with hand wheel adjustments for laying an aim. Trial shots were first fired and, if necessary the foresight was adjusted laterally, or replaced by one of a different height, until the shots on the target were within the required limits. Five rounds were then fired, and four of the five shots had to be contained in a rectangle 1 inch broad by 1½ in high. Rifle which failed this test were rejected. At 600 yds 10 shots were fired, nine of which had to fall within a 2 foot circle.

No 4 RIFLE TESTING

For the No 4 Rifle, the accuracy test was the same at 100ft ten per cent of all rifles were then fired at 200 yds when six of seven shots had to fall in a rectangle 6in x 6in , the point of mean impact having to be within 3 inches of the point of aim in any direction. Ten per cent of rifles fired at 200 yds were again fired at 600 yds when 6 out of seven shots had to be in a rectangle 18 inches x 18 inches the permissible deviation of point of mean impact being 9 inches up or down, or left or right. Two per cent of rifles were fired from the shoulder, ten rounds being fed into the magazine by charger and fired rapid to test “feeding up” and ejection. After these tests the barrel was inspected to ensure that there was no expansion in the bore or chamber and that it shaded correctly from end to end. (Was not bent)

No 5 TESTING

The firing test to which the No 5 rifle was subjected was the same as that for the No 4 at 100ft. It was not tested at 200 yds but 10 per cent were tested at 600 yards when the acceptance was ten out of ten shots contained in a rectangle 36 inches x 36 inches. Two per cent of the No 5 rifles were also submitted to the same functioning test as the No4 rifle.



Throughout World War 2 much of the accuracy testing was done by women shooters who quickly became proficient at the job. To speed up the procedure, the telescope layer was dispensed with, and aim was taken in the normal way through the back sight. The .1 inch aperture in the back sight was too large for easily laying a correct aim at 100ft, and a small spring steel adaptor was used.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: April 04 2020 at 8:15am
The No. 4 accuracy standard at time of production is essentially 3 MOA.  That was the minimum standard using Mk 7 ball ammunition.  It’s not too difficult to better this standard with handloads using a match bullet.  Correcting any issues with forend fit/bedding, lightening the trigger, smaller aperture, etc. will get this below 2 MOA.  With a scope and other non-match legal mods, accuracy for 10 shots can approach MOA.  Goosic has gotten 1/2 MOA...


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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Armourer Quote  Post ReplyReply Direct Link To This Post Posted: April 04 2020 at 8:28am
Originally posted by britrifles britrifles wrote:

The No. 4 accuracy standard at time of production is essentially 3 MOA.  That was the minimum standard using Mk 7 ball ammunition.  It’s not too difficult to better this standard with handloads using a match bullet.  Correcting any issues with forend fit/bedding, lightening the trigger, smaller aperture, etc. will get this below 2 MOA.  With a scope and other non-match legal mods, accuracy for 10 shots can approach MOA.  Goosic has gotten 1/2 MOA...




My Savage No4 is sub 1 MoA with 'factory' PPU ammunition and original 'iron sights'
Properly (military) bedded and no 'gimmicks.

Distance 82yards (75 metres) Lying prone, only elbow support, wind 10-12mph right to left, 2 warming rounds at 10 O'clock, then 5 rounds.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: April 04 2020 at 9:43am
Bear in mind those are the minimum requirements, not even the average.
Many can & have done much better.
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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