Thread: Gap between barrel and receiver
Retrieved: 06/19/2014

Was looking at an attractive 1926 Ishapore FTR with a '45-dated barrel (all serial numbers match.) Noticed that there was a bit of a gap between the barrel and the receiver. Is this normal? unusual? safe? cause for concern? I don't recall seeing a gap like that on any of my other Enfields.

SavageShooter
Sep 22, 2012

My opinion would be that it is cause for concern, and its unlikely that the rifle left an armorers workshop or factory FTR in that condition.

Sounds like a take off barrel fitted to replace a shot out or rusty barrel.

If the breech butts up tight to the bulkhead then one might take the barrel off and refit it properly using a breeching up washer. Brownells may have the proper sized washer, they use these on small ring mausers as well.

PS
There are some scandinavian rifles with barrels that were deliberately fitted to torque against an internal shoulder and a gap was left at the face of the receiver ring. I forget the details of those rifles, probably some sort of target rifle, but thats the only time I've heard of such a gap being proper for any rifle.

Demo
Sep 22, 2012

How big a gap is it theodore? I'm not at all familiar with Ishapores but the SMLE was not designed to tighten up on the shoulder. No breaching up washer was ever required on the shoulder but very fine shims were used on the inner face to correct an over clocked barrel. This correction is one cause of gap your talking about. Some one else will expand on this.

SavageShooter
Sep 22, 2012

The breeching up washer was introduced during wartime No.4 production. Never heard of any internal shims used to correct overclocking on the SMLE, can you explain that more fully?

Only SMLE takeoff barrels I've looked at had the same undercut shoulder with signs of crush fitting as found on No.4 take off barrels, indicating that they did in fact torque against the face of the receiver ring.

Ideally the barrel breech and shoulder should both come into full contact when the barrel is torqued down and clocked in. When the receiver ring face has been crushed by previous torquing down of a barrel there can be a visible gap. When receiver ring face is intact but a takeoff barrel with the shoulder previously crushed is used that will also leave a gap.

Theodore
Sep 22, 2012

It's a very small gap - maybe 1mm or less? It's still at the gun shop as far as I know, and I didn't have anything to measure it with.

With the serial number on the barrel matching that on the action (and nosecap and bolt) I wouldn't think it's been rebarreled in this country, but one never knows.

Son
Sep 22, 2012

I would consider a 1mm gap there huge!

Measure it with feeler gauges, I'll bet it is much smaller, but not saying don't be concerned.

The No.1 barrel locked up on the rear face of the barrel as Demo said. The shoulder should still be much closer than described, though.

A new barrel in a new receiver should have "clocked" to the correct position without shims. When you are fitting old barrels to old receivers, then you may find the barrel over turns a couple of degrees before it reached tension. There were shims used (.002" and .005") to correct this. In the many barrels I have changed, I have found that once you get to any more than a .005" shim, it becomes difficult to find a bolthead long enough to headspace correctly.

One possible explanation is the barrel may have had a bit machined off the back surface to allow it to screw in another turn to correct an "over rotation" problem, then re cut the chamber. Naturally to do this, the shoulder needs to be turned back the same amount, if overdone, leaving a bigger gap. It also may have been converted to the wildcat cartridge popular here years ago which basically was one thread shorter than standard... MkVII ammunition will not chamber in these, or even machined back and re cut to 7.62 x 39.

With the barrel matching the receiver, I would be checking it out a lot further... doesn't seem right if the gap is so big... Can you provide a couple of pics?

Demo
Sep 22, 2012

What is a takeoff barrel?

Son
Sep 22, 2012

Easy one!

They are all marked "6, 5, 4, 3, 2, 1" as seen in the pic...

Ok, have a look at all these barrels, picked randomly from the "No.1 barrels box" as a sample handful...

...find me one that doesn't look like it was locked up on the rear surface... case closed.

And just for information and example... here is a standard barrel along side of a wildcat converted standard barrel. The whole thing has been shortened by one thread to give the calibre 7.7 X 54 (it was also in the last pic)

Please note the shortened Knox... the rear surface was shortened as was the shoulder. If using this method to fix an over rotation problem, the chamber reamer would now be used to re-cut the chamber to size for .303 British. This one was done to change the calibre, and required no work to the chamber other than the extractor groove re-cut.

SavageShooter
Sep 23, 2012

A Take Off Barrel is a barrel that has been removed from one rifle to be used to repair another, barrels still fitted to sawn in half action bodies were (and may still be) were available and importers sometimes used these to rebarrel otherwise good rifles that had bad bores, not always with good results.

The Breeching up washer used to speed No.4 production required that .10 be turned off the shoulder of the barrel, then a washer nominally .10 with a variation of a few thousands or more was fitted. the washers were miked, sorted, and exact thickness noted.

This is explained on page 185 of Reynolds "the Lee Enfield Rifle."

If you have an SMLE barrel that clocks in and butts up to the internal shoulder but the barrel shoulder does not crush fit to the receiver ring face, then the only way you'll get that barrel to fit properly is to use the breeching up washer method. Unless you want to set the barrel back just short of one thread and freshen the chamber, which would also require turning off some of the shoulder.

The breeching washer is the most economical method, and keeps the barrel length and bedding at original condition.

If you prefer to shorten your barrel by one turn then be my guest, just get a good finishing reamer first, they can cost as much as a good barrel, even renting one is expensive. If you can borrow a reamer so much the better.

If one has never seen an Enfield that has a visible gap between barrel breech and the opening of the internal shoulder then they haven't seen all there is to see.

When the barrels don't reach the recommended angle when hand tight and excess force is used to clock in the barrel it can actually stretch the shank slightly to reach the internal shoulder, which caused the internal stresses that resulted in swollen and/or elongated chambers, if the shoulder or face of the receiver ring doesn't give first. The shoulder of the barrel is slightly under cut so that it will crush fit.

To give you an idea of the forces at play, the threaded rod of a screw jack is about 1/3 the diameter of a barrel shank yet you can raise half the weight of a truck by turning the crank with one hand.

If an internal shoulder washer is used to establish the proper clocking in of the barrel it would be to compensate for the receiver ring recess being too deep, otherwise installing such a washer would make it practically impossible to achieve acceptable headspace. The distance between the breech end of the barrel and the bolthead being what determines headspace.

If the depth of the receiver ring recess is proper then however thick the washer may be would be added to the distance the bolt body and bolt head would have to reach between locking lug surfaces and breech face. It would be far better to simply sort through the barrels and find one that clocked in properly with full contact.

When you are dealing with a action body that has been fitted previously with a barrel you are very very likely to be dealing with worn or deformed threads in the reciver ring. Add to that a barrel that has been previously fitted to a different action body and the threads of the shank are even more likely to be worn or deformed. The threads of either are no longer as they came from the machinery that made them, and this would be much the same situation as the "toleranced threads" of the No.4 barrels that required the extra efforts to fit properly without over stressing the shank or shoulders.

I've never heard of anyone claiming that a visible gap between receiver ring and barrel shoulder was no cause for concern, except in the case of that target rifle I mentioned (possibly a European Krag, and that a cadet rifle).

Model 98 Mauser barrels also butt against an internal shoulder as well as the receiver ring face, they seem to have had no such problems in fitting their barrels without gaps and without use of washers.

PS
Breeching Up

5Batt
Sep 24, 2012

My 1923 EFD MkV with original matching '24 dated barrel.

5Batt
Sep 24, 2012

Another, this one my 1918 SSA MkIII* again with its original barrel.

I have found at least 5 rifles in my photo files that appear to have a gap, all have their original barrels bar 1 but need to give them a clean and retake some pics.

BTW not all are war time production rifles and all pics have appeared on various forums.

SavageShooter
Sep 24, 2012

There's enough dust/lint and oil there that I don't see any gap, certainly not a noticable gap, no daylight showing, and not making full contact all the way to the edges would not be a gap.

If you cleaned all the oil and lint out of the corners and could see daylight between barrel shoulder an ring face right up to the shank then it would definitely be a gap.

Still not a honking huge 1mm gap.

I'm not the least perturbed that my SMLE barrel fits right up against the shoulder with no sign of a gap, cleaned and in a bright light and using a magnifying glass. It means my barrel is definitely fitted as well as such a barrel can be fitted and the shank perfectly matched to the receiver/"barrel socket."

When theres an internal shoulder as well as a receiver ring face you have a primary and a secondary torque shoulder. For the SMLE the primary may be the internal shoulder, but as with the 98 Mauser the barrel is meant to torque down solidly against both surfaces.

A friend used to "blueprint" mauser actions. He used the best micrometers money can buy. When he dressed the shank of a barrel it was fitted to within 1/10,000th of an inch to the internal and external shoulders. When torqued down there was no possiblity of a gap, and pressure on each mating surface was as equalized as possible. no shims or collars necessary, and there should never be any needed if the shank is properly proportioned to the barrel socket.

I can see that this level of precision would not be well suited to wartime mass production, and I can also see why they chose to shift the primary torque surface of the No.4 barrels to the receiver ring face.

My SMLE and every one I've cleaned up had no gap of any kind at the barrel shoulder. When I clean a rifle up I clean it up, no sense preserving layers of old grease and dust, so if there had been any gap at all I'd have seen it.

PS
The internal shoulder of the Mauser deflects .015" under torque. The internal shoulder of the Enfields looks a hair more substantial. When 125 pounds of torque are applied the barrel will draw tight if its at all properly fitted.

5Batt
Sep 25, 2012