IOF 30.06 receiver

[winnie_the_pooh]

You can take inspiration from this

https://bordenrifles.com/tube-gun-rifles/

[Kittu]

You can take inspiration from this

https://bordenrifles.com/tube-gun-rifles/

winnie thanks a lot.its wonderful.

[shooter50]

Dear kittu,
Forgive me if I am pedantic, but as I wrote in the "Modifying the IOF 3006" post. The problem is not so much the IOF but untrained and ignorant Gunsmiths in India. I shall suggest a sequence of action that may help you salvage the rifle.
The barrel is a tight fit on the receiver, removal by hammering it from side to side as I have seen a few Indian Gunsmiths do it is a sure way to damage it. The barrel studs are steel and the barrel is also a steel alloy. (Not Tungsten Carbide as you mentioned) . Tungsten carbide is an extremely hard material from which tooling broaches, drills, reamers etc are made to cut the riflings, chamber and other parts. Over tightening the studs, as again most gunsmiths do is a recipe for disaster. I am certain the cause for the receiver crack lies within these two errors.
* Ignorant welders are nobody to tell you what to do. Rifle receivers can easily be welded. Mauser 98 military steel receivers were cut, shortened and welded to make Mauser 98 short action. Most were made from cheap steel and case hardened. You have already made the grooves for butt welding the crack - good. You need a TIG welding process. Someone who fabricates industrial aluminium items should have it. If you are not able to access that then, go to the stainless steel welders. They use TIG. HOWEVER you can't let them do what they know. They have to be guided. Use an aluminium filler rod. These stainless steel welders tend to economise on Argon gas by not keeping the weld in the Inert zone and by switching on the gas after the initiation of the spark. A Big NO for our job. Make them do a practice run on aluminium blocks before trying on the rifle receiver.
* A very good video on TIG welding Aluminium is here. Go through it and make the Welder follow the steps.
https://www.youtube.com/watch?v=9WvrJPn713Y
* If the receiver is already badly screwed up by a botched welding effort and is beyond repair, then, send me a picture. I shall tell you where to cut it up from top to bottom. You will have to cut it and then mill it to perpendicularity. An easy job which any machinist can perform. The front part of the receiver which provides the recess for the barrel can easily be machined from a solid aluminium block. Make the front part, put the barrel in, line them up in a vise, insert the bolt, make sure the bolt operates smoothly and then TIG weld the joint.
* I doubt that anyone around you shall be able to machine a new receiver from steel or aluminium (Forgive me again). As a last resort contact IOF. You may need a letter from the licensing authority specifying the damage. Pulling strings at IOF will help or else it could be a dead end.
* Straight feed and staggered feed magazines have also been discussed in the above post with excellent inputs from Timmy, El, Vikram and others.
* If nothing works, send me a message.
All the best

[Kittu]

no,no i am sorry. i didnt meant to say barrel is made of tungsten i was referring to tugsten rod which have opposite rifling and chamber cut onto it.they puts this rod in a steel barrel and hammered forming rifling and chamber. i am not sure if lugs in barrel are also made this way or cut later.sorry i could not find correct word for that tungsten rod hence confusing.iof imported that hammer forging machine from styer it takes 2,3 minutes to make a barrel
i have not used hammer on any weapon in my life nor do i let any gunsmith do.to remove barrel i use a screw driver to loosen up receiver and barrel falls out of its on and same way i inserts it back.Thanks for offering help i will surely send you msg.if these things interests you then i have lots of things which you will love mainly related to gun finishing and stock finishing.i also have some good quality walnut lying around.

regards

[timmy]

I've studied this IOF 30-06, and there seems to be no definitive description of its operation or even an in-depth parts breakdown. The only description I could find was this:

The IOF 30-06 sporting rifle is a bolt-action rifle made by the Ishapore Rifle Factory. The rifle shares many design features with the Sauer 202 rifle, manufactured by Sauer & Sohn in Germany.

Which tells me very little, except that the IOF is "almost exactly the same but completely different" than the Sauer 202. (The sarcasm here is completely intended!)

So, looking at the available information about the Sauer 202, I find that it's not made any longer, but has been replaced in Sauer's product lineup by other rifles. This leads me to believe that IOF was able to negotiate the rights to use the Sauer 202, since as an older model, it wouldn't compete with Sauer's currently offered models.

The Sauer 202 was available as a "regular" rifle and as a takedown model. The takedown model used a cone and ball mechanism in the fore end with a quick release, which allowed removal of the barrel. The barrel was held in a close tolerance fit in the receiver.

The regular model had the barrel tenon held in the receiver in a similar manner as the old Colt Sauer bolt action, where the receiver ring was slotted and clamping allen bolts pinched the slot to tighten around the barrel tenon.


Colt Sauer rifle

Threading the barrel tenon to the receiver and making the receiver strong enough to hold this was avoided in this design, as the locking lugs at teh head of the bolt engage matching recesses in the barrel tenon. The receiver thus functions to hold and guide the bolt, attach a trigger firing group in relation to the bolt, and support the butt stock and fore end.

American Hunter, a publication of the American National Rifle Association (NRA) reviewed this Sauer system and said this:

The three bolt lugs lock into the barrel, so when the bolt is closed, barrel and bolt become a solid unit.

Frankly, this statement is rubbish. The system is strong, but there have to be clearances between the bolt and the locking surfaces in the barrel tenon, or one couldn't operate the bolt. Furthermore, as anyone familiar with two-piece billiard cue sticks or multi-piece fly fishing rods knows, these items simply don't and can't work and feel like a one piece cue stick or rod. Vibrations simply don't work that way in multi-piece structures!

Still, it is a good system and it works well in a number of firearms made in the past and present. The AR 15/M16/M4 is a rifle that uses this system, but the one that quickly comes to mind for me is the Sportco/Omark 44, an Australian target rifle that I'd very much like to own:



My point here is that the system of locking the bolt directly into the barrel is sound, and regarding the "pinch" system of holding the barrel tenon into the receiver with a direct bolt-barrel lock, this has also proven to be a sound system.

I found this picture of the Sauer 202 parts diagram, obviously a Sauer diagram:



The Sauer 202 was available with a steel receiver, and a light weight rifle was available with an aluminum receiver.

Kittu, regarding your experience of trying to repair the crack and the seemingly low melting point of the receiver, and also your reference to it being made of aluminum and zinc, I wonder whether IOF used zamak to make the receiver.

https://en.wikipedia.org/wiki/Zamak

The Henry Rifle Company of the USA uses zamak in the manufacture of some of its guns. Hi-Point, maker of low cost pistols, also makes extensive use of zamak to make its products. The (in)famous Raven/Jennings/Jimenez/Lorcin/Phoenix/etc ad nauseam 25 Auto pistol also was made largely of zamak. Recently, Ruger has come out with a cheap version of its Single Six 22 LR revolver that uses zamak for the grip frame. The Heritage 22 LR revolver is largely made of zamak.

As you look through the Wiki on zamak, you'll note that the melting points of the various zamak alloys are less than 400* C -- close to that of lead. This allows easy and quick casting methods.

Zamak can be a suitable material, especially for low cost guns, but it does not retain all of its strength over extended periods of time. In low-stress situations, this may not be an issue.

I can't say for sure whether the receiver of your IOF 30-06 is made of zamak, but from the description of your attempted repair, it does sound like it may be so. If I'm right, you will probably not be able to repair it.

As for making a steel receiver to replace it, consider the Sauer 202 parts diagram above: the receiver isn't a simple piece, like some bolt action receivers are. You would have a challenge in making that on a CNC machine, I think.

Single versus double column magazines: Some bolt action rifles, like the Colt Sauer and the Sauer 202, use a single column magazine. This allows for thicker stock walls around the action and reduces the openings needed in the bottom of the receiver, which can increase the receiver strength and the ability to bed the action firmly in the stock. Bedding may not be an issue in the Sauer 202's two piece stock.

Double column magazines, where the cartridges are held in two staggered columns, can increase magazine capacity, but at the cost of additional width. Another issue here is that it is easier to get cartridges to feed more reliably from a single column magazine that a double column, because the cartridges are only fed through the action at one angle in a single column design, rather than from two angles. This isn't to say that double column magazines aren't as good or can't be made to work reliably, because they are good and have been successfully made to work well for well over 100 years.

[winnie_the_pooh]

Timmy, the IOF 30-06 is a Sauer 202 rip off not an official copy. The receiver uses aluminum alloy and not zamak. Besides the 3 screws numbered 203 in the exploded drawing of the Sauer 202 posted by you, the part numbered 206 plays a crucial role in preventing the barrel from rotating. This keys into a groove in the barrel. The long bolt that holds the forend tight against the receiver screws into this part. The screws only need to be tightened so that the barrel is a snug fit. There is no need for these screws to be gorilla tight. The OP seems to have been in the habit of removing the barrel from time to time. Why he was doing it only he can tell. It is certainly not required for normal operation of the rifle.However the constant removal and overtightening of the screws might have eventually lead to stress fracture of the receiver.

[timmy]

Winnie, like I said, I'm seeing Sauer selling IOF the rights to make the 202 after they've moved on to newer models. While IOF may have made some changes to the design, I don't know, but doing so either for improvements (possible) or ease of manufacture (probable) is likely, given IOF's wording: it "shares many features." My reading of this is that they took enough of Sauer's intellectual properties to require paying Sauer for what they did, but that some/many/all 202 parts aren't interchangeable, either due to design or to dimensional changes.

I did see the barrel indexing part, but figured that it was just more information than the cracked receiver issue required.

That the clamping force doesn't need to be excessive is shown by the Sauer 202 Takedown: the quick release under the fore end only holds the barrel in and back against the receiver: it doesn't actually hold the barrel tenon. The minimal clearance between the receiver and tenon does that. This, to my intuition, doesn't seem sufficient to bed the barrel to the receiver and dampen vibration in such a way that the whole assembly vibrates the same way with each shot (which would be essential for accuracy), but apparently they make it work, and there's not much argument with what works.

So, your point about the pinch bolts not needing "torpedoman's torque"* is well-taken and proved, I think, by the takedown rifle's example.

Most of the things of this world are beyond my knowledge, but I will say that all of the allen headed bolts (hexagonal recess in the head) I've handled are very hard, not soft. Kittu says the bolts are purposely soft to prevent cracking (which is what actually happened) and I'm not here to dispute that -- I haven't worked with his rifle or the bolts in it.

True enough, as you say, regarding repeatedly taking the barrel on and off of the receiver. Aluminum (unless the wear surfaces are anodized or otherwise hardened) aren't going to resist constant disassembly and reassembly very well. Nor will the aluminum resist the fatigue that results from constant tightening and loosening very well. Again, here, I wasn't in on what was done, how it was done, and how many times it was done, so I can't discuss that very much. All I can say is that there are a host of ways bad things could happen in this practice, and leave it at that.

The heat used to melt the aluminum, while not beyond a torch, must have been quite hot. Welding aluminum with gas is possible, but what kind of quality the weld is is one question, and the kind of aluminum alloy is another, but I'm no welder and don't have valid input on the subject, certainly not beyond what shooter50 offered.

Just to be clear about my own personal preferences, I don't do zamak guns. I have electric toy trains that have die cast zinc bodies, and zinc is appropriate there -- but not guns for me.

*"torpedoman's torque": When I was young, I worked with guys who had been in the Navy. The fuze on a torpedo is the large nut on the nose:



They told me that the fuze was installed with a very large hand wrench. Torpedoman's torque was the sarcastically named process by which one overtightened a bolt, screw, or nut. The details of this process were to tighten the bolt until one feels it give, and then back off 1/4 turn. Of course, this ruins the bolt and'/or what it is threaded into.

[shooter50]

7 Newton Meter (5.2 ft pounds) is the recommended torque for tightening the barrel retaining/tightening Allen screws.