Point taken Amit, but maybe someone can ask the other forum the pertinent questions. But do iso in what Officer language would be termed 'demi-official' or 'diplomatically barbed'. That way, you put your point across but you leave a nice taste afterwards
'out-of-round chambers'................
That had been tried a while back. The tribal elders met and came out raising a chant "burn the witch"
If you like out of round chambers, I have proof they were made that way....
Any time you see a stretch mark or the case fails and parts in two just in front of the rim, its caused by excessive play. 8 of of 10 ten times it is excessive head spacing. The other causes are a too long chamber where the case is " blown out" to fill the shoulder area, or the chamber is out of round, drilled off center. Beleave it or not, this is not uncommon with these rifles. You gather up 10 Enfields and you will see fired cases from a couple of these rifles that show and off center / out of round chamber.
Why? You need to understand that these rifles were made in the time leading up to, or during a time of war. The British Army needed many,many rifles and needed then quickly added to the armories. Quality suffered as a result.
See, it was the war that did it. Drilling chambers too fast made them out of round!
H&K and CETME created fluted chambers to assist in case extraction for the auto rifles. The barrels were formed using rotary hammers, where a fluted and rifled mandrel is placed in a bored tube and the rotary hammers cold forge the barrel to fit the mandrel. So I guess you can get an out of rounc chamber if you really need one.
For what it is worth, I did attend a tool tryout in Conneticult in the 1980s were they were "drilling" a square hole in steel. Starting with a round hole, a special bit with pivoting cutter and a housing that controlled the travel/location of the cutter resulted in square sides of the hole and the corners were slightly rounded as the cutter could not get all the way in. Noisy and nasty if it came apart. I never followed up on it and suspect the concept was more interesting than the practicle application.
Actually, the technique in drilling square holes can be found in an old AMERICAN MACHINISTS HANDBOOK. I collect the books (also) and remember reading the account of how to do it. As Paul states, it does require special tooling but is quite possible.
The chambering reamer for the out of round chambers is probably just an improvement on the square hole tooling..... :-)##
The three fluted cutter naturally tends to make a square hole anyway, adding the controlled motion should result in quite a nice finshed product.
Two flute drills tend to make triangular holes- run a longish bit through a piece of sheet metal if you want visible proof. Just add one to the number of flutes to figure out what the natural wobble of a drill will be.
What I want are the specs on the "banana shaped chamber" cutting tools.
Actually, the technique in drilling square holes can be found in an old AMERICAN MACHINISTS HANDBOOK. I collect the books (also) and remember reading the account of how to do it. As Paul states, it does require special tooling but is quite possible.
The chambering reamer for the out of round chambers is probably just an improvement on the square hole tooling..... :-)##
Not quite drilling but the method of obtaining squre holes that I,m used to is a machine using spark erosion, which we have used many times on broken studs on ships main engines, when sheared at the entabliture ( but can be used on any stud sheared flush ) the machine would produce a square hole, to enable a square drive to remove the broken stud. sizes from around 1/2" up to 2" are common, one that springs to my mind was 3/4" drive and t bar that I used many times on a paticular engine, the T bar was specialy made and about 6 feet long.
"After doing extensive testing on the Enfield Rifles chambers, Just what are you trying to do? If the chamber is out of round, or the chamber is long due to the Indian Army mods, there is not much you can do."
"It sounds as if you have the common problem of the bolt body being milled back. 6/10 rifles sent to India will have this problem. Plus, bolt heads were also ground down. You need to measure your bolt head to see if it really is at spects."
Army needed many,many rifles and needed then quickly added to the armories. Quality suffered as a result.
Originally Posted by 
PM
