No.4 Mk1 Barrel and receiver machinist drawings

[tbonesmith]

I had a batch made to .311 major bore diameter. It’s no drama for me to export to Canada either.
These were done by Lothar Walther and shoot fantastic.

[tbonesmith]

... no1 “H” profile and no4...

[Brian Dick]

I never slugged the CBI barrel. I just installed and tested it using loose parts I had lying around the shop. The rifle wasn't too pretty but shot like a house on fire. I've since spiffed it up a bit with Parkerizing and a little TLC on the woodwork. Now it shoots AND looks good.

[bigduke6]

Have you slugged a new Criterion? If so what dimensions did you measure out for grooves? Was it larger than the dimensions I quoted by at least a couple thou? The one I measured plus other people I have talked with confirmed my measurements.

There is a reason I am trying to make the barrels I am. I don’t want a milspec barrel.

I am trying to see how accurate I can make a .303 while still retaining the stock appearance.

Who knows. Maybe I will get no where with this project, maybe I will. All I can do is try.

If your not after a Milspec barrel, then I'd look at a .308/7.62mm barrel, lots of options there plus you can make it a .30/.303 and use the .303 case, think Bruce has covered this one before, As I was looking at doing one myself.

bayonet lugs etc can be added later use an old barrel and make a sleeve to fit over your new barrel. (I've yet to see anyone fix bayonets when I was on a firing point)

[Parker-Hale Mike]

I have 7.62 enfields and they are fun, unfortunately I sold my Parker-Hale T4 in a moment of weakness which I still kick myself for.

I want to replicate the .303 barrels that our army teams used to use for the competition rifles. That is my goal. They shot better than anybody else’s. I want to experiment with one.

---------- Post added at 09:58 AM ---------- Previous post was at 09:58 AM ----------

I had a batch made to .311 major bore diameter. It’s no drama for me to export to Canada either.
These were done by Lothar Walther and shoot fantastic.

How much are you asking?

[Bruce_in_Oz]

There is another catch, (or two)

The rifles were built around the ammo. All those odd little collars and spring plungers, and nose-cap muzzle-holes with an odd "window, ate there to optimize performance with a specific loading in a specific cartridge case.

Just as the boffins had to fool around a bit with the bedding regime at the changeover from Mk6 to Mk 7 ammo, every time you play with your reloads that use utterly different propellants, primers and bullets from Mk7 ball, you will be chasing your tail to squeeze consistent grouping and MPI at all ranges out to 900yds AND doing so with some vague reference to the numbers on the rear-sight leaf.

Number 4s using the EXACT same Mk7 ammo have a completely different bedding regime; and then there is the L42A1.

Making a new, "modern" barrel (.303" / .312") is the easy bit. Do you stick to the chunky "Enfield" 5-groove rifling to go with 5R / six-groove, or try one of the very interesting semi-ratchet, three-groove designs?

Original barrels can easily run out to .321" nominal groove diameter and still be within "spec" AND shoot up a storm. WITH MK7. The open-based bullet WILL "bump up" at the back end to seal in a good, concentric barrel with that sort of groove diameter.

Shoving closed-base, boat-tailed Sierras or Bergers through the same barrel may give disappointing results AND result in accelerated throat wear, especially if you shoot a lot and do a lot of rapid practices. Pre-loved "issue" .303 barrels that have digested a steady and protracted diet of Mk7 WILL have throats that are "flame-cut" to greater length and diameter dimensions than "factory new".

Original barrels have left-hand twist and the sights have "compensation" for the resultant "spin-drift" built into them. The front-sight base AND the "ears" of a SMLE nose-cap are offset fifteen thou' for this reason. Interestingly, the Canadians didn't seem to get too worried when they fitted 6-groove RH twist barrels to a bunch of No4s in WW2.

Plan "B" is to build a .30-.303, a chambering /barrel combo that has been around for several decades. .300 / .308 1:10" twist, just like a .30-06 barrel, BUT with a .303 chamber, cut using a reamer with a .299" pilot for the smaller bore. This actually works with the more abundant (and cheaper) .308" bullets out there. With a little creative carpentry, you can stuff a very chubby barrel under the woodwork of a No4 or even a No1. Naturally, the usual fun and games finding the "magic" load will ensue. Unless the reamer is custom-ground for a tight neck and throat (leade) this will NOT be a "bench-rest" chambering job, but it WILL function safely with .303 ball in a pinch. If you plan to ONLY EVER shoot .308" bullets no longer than the 168 SMK, you will probably get away with the even more common 1:12" twist barrel in your choice of Moly or stainless. If you are not doing virtually all this work yourself, carefully check the hourly rates at your local gun-plumber.

[Parker-Hale Mike]

My intent was a tight bore 5r 1-10 right hand twist.

Give the old girl a modern twist to an old idea.

[tbonesmith]

Plan "B" is to build a .30-.303, a chambering /barrel combo that has been around for several decades. .300 / .308 1:10" twist, just like a .30-06 barrel, BUT with a .303 chamber, cut using a reamer with a .299" pilot for the smaller bore. This actually works with the more abundant (and cheaper) .308" bullets out there. With a little creative carpentry, you can stuff a very chubby barrel under the woodwork of a No4 or even a No1. Naturally, the usual fun and games finding the "magic" load will ensue. Unless the reamer is custom-ground for a tight neck and throat (leade) this will NOT be a "bench-rest" chambering job, but it WILL function safely with .303 ball in a pinch. If you plan to ONLY EVER shoot .308" bullets no longer than the 168 SMK, you will probably get away with the even more common 1:12" twist barrel in your choice of Moly or stainless. If you are not doing virtually all this work yourself, carefully check the hourly rates at your local gun-plumber.

I got a reamer custom ground for this a few years ago and built a rifle up for a guy. I ran a new heavy sporter 1:12" twist barrel and set it up in L42 style wood. I tested it with 155gn sierra SMKs and it was just magic. With the vast array of 30 cal projectiles available and the reliability of the feeding and function of the .303 round in the action I'm surprised it's not done more.

[browningautorifle]

I'm surprised it's not done more.

I thought about using a 30-30 ream and doing one so I didn't have the effort of finding brass. I wouldn't be doing long range target though, just a hunter/shooter. Like, a #4 in 30-30...or a #1Mk3...

[Daan Kemp]

Check cartridge case dimensions to ensure reliable feeding through the magazine.